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posted on 27 December 2016

December 26, 2016 Weather and Climate Report - Pacific Climate Shift Explained

Written by Sig Silber

JAMSTEC has suggested that there may be a Climate Shift in the Pacific to PDO Positive. What does that mean for World weather the next twenty years? The key is to understand that 1947 to 1976 is considered a period where the PDO was generally in its Negative Phase. Similarly, the years 1977 to 1998 are considered to be a period of time when the Pacific was in the PDO Positive Phase. And the period 1999 to the present is considered to be a period of time when the PDO has been in its Negative Phase. JAMSTEC is suggesting that we may be returning to 1977 to 1998 conditions. Read on to find out more.


First some housekeeping information. For those who want the forecasts beyond three months, we reported previously on the December 15 NOAA 15-Month Forecast and compared the first nine months of the NOAA Outlook with that of JAMSTEC in a special Update that you can get to by clicking here. We will of course publish a new 15 Month Update Report shortly after January 19, 2017. Remember if you leave this page to visit links provided in this article, you can return by hitting your "Back Arrow", usually top left corner of your screen just to the left of the URL box.

From the recent JAMSTEC discussion which we commented on last week:

Interestingly, majority of the ensemble members indicate recurrence of a moderate El Niño event in the latter half of 2017. It will be interesting if an El Niño event really evolves in 2017, which may suggest a decadal turnabout in the tropical Pacific climate condition to El Niño-like state after a long spell of La Niña-like state, which led to the global warming hiatus.

We will now attempt to explain.

A. What is meant by a Pacific Climate Shift

B. Why it is reasonable to believe it might happen soon.

C. How the Pacific and Atlantic are linked.

This is a long discussion and one can jump over it if they are more interested in current weather than what we might be dealing with during the next twenty years. It is to a large extent material that I have covered in the past.

First. What is the PDO? Surprisingly it is simply the pattern of warm and cool water in the Pacific. It is not necessarily the warming or cooling of the average temperature of the water in the Pacific. One reason the pattern is important is that clouds form over the warmer parts of the Pacific so the pattern of warm and cool water and the temperature gradients determine where convection (warm moist air rising) occurs and this impacts the storm patterns which generally move from West to East.

But for CONUS, the PDO also determines if the waters off the West Coast are warm or cool. For example with PDO Negative, the coastal waters are cool which may be good for marine life but reduces coastal precipitation. There may be other important impacts. With PDO Positive some believe the ratio of El Nino's to La Nina's may be higher. Also the location of the Equatorial sea surface temperature (SST) anomalies associated with El Nino and La Nina may be different. In my articles I discuss Modokis and perhaps there are fewer of them with PDO Positive. So the range of impacts may be quite broad.

If one is not Northern Hemisphere Centric, one talks about the IPO the Interdecadal Pacific Oscillation rather than the PDO. Fortunately the Northern Pacific and Southern Pacific are highly correlated so we can pretend that only the Northern Hemisphere exists and not go too far wrong. But scientists sometimes address the IPO so wherever in this report you see IPO you are free in your thinking to think PDO.

At this point, it might be useful to discuss the PDO. The below shows the different pattern of where the surface water is warm and where it is cool in the Pacific during the two most discussed phases of the PDO. The graphic on the left is PDO+. The scale is surface water anomalies in degrees Centigrade. Notice the Southern Hemisphere is shown and the pattern is slightly different. Also notice the Gulf of Mexico is correlated with the PDO. Elsewhere perhaps I will discuss the reality that all of our oceans are correlated with each other due to both ocean currents and wind patterns.

PDO Positive (+) --------------------------------------------------------------- PDO Negative (-)


PDO Phase Graphics

PDO Positive has been described as a horseshoe pattern with a cool Central Pacific surrounded by warmer water to the north, east and south. Conversely the PDO Negative is pretty much the opposite pattern with the warm anomaly in the Central Pacific and the less warm water to the north, east and south. Now we will attempt to discuss what influences this pattern and changes the pattern.
Notice that in some ways, PDO+  resembles El Nino in that the Eastern Equator is warm. Also notice that in some ways PDO- resembles La Nina in that along the Equator the Eastern Pacific is neutral to cool and there is warm water to the west. So some look at PDO+ as really a very long El Nino and likewise La Nina is a very long PDO-. But this interpretation does not work very well as ENSO phases last for one winter or sometimes two and PDO phases last for from 20 to 35 years. But there does appear to be some connection. The most obvious one is that during PDO+  it is easier for an El Nino to form and be located properly and with PDO- it is easier for a La Nina to be formed and properly located. So that is important to keep in mind. I have to look up the ratios but it is something like twice as many El Ninos to La Ninas during PDO+ and twice as many La Ninas to El Ninos during PDO-. But I either have to find that statistic or recalculate it myself and I am not sure I remember it exactly right but for sure that ratio is different for PDO+ and PDO-. But some of the stronger events occur out of phase with the PDO. For example the 72/73 El Nino was strong and occurred with PDO-. The information to sort this out is at that end of every Weekly Report as it could be of interest to Water Planners.
Areas which are normally wet when the PDO is Positive are likely to be more wet in the future for a decade or more than they have been since 1999. Similarly areas which are normally dry when the PDO is Positive are likely to be more dry in the future for a decade or more than they have been since 1999. Same goes for warmer than usual and cooler than usual.

How does the  PDO impact weather?

One rule of thumb is that PDO+ causes impacts somewhat similar to a mild El Nino and we have discussed that many times; PDO - causes impacts similar to a mild La Nina. But let's examine it more closely.

It is important to remember that the PDO and IPO are oscillations not regular cycles and most likely represent three or more separate phenomena. The Aleutian Low may have its own cycle. The Kuroshio-Oyashio Extension (KOE) may exhibit cyclical behavior. ENSO is a well known cycle. Some of these cycles may be impacted by the AMO. There is a South Atlantic version of the AMO also. So the PDO and IPO may be a combination of cycles with different wavelengths. So a change in the Pacific may take many different forms and occur in an irregular manner. The below graphic shows the differences over a multi-year period. One could view the analysis by year and see how it is impacted by the ebb and flow of the situation in the Pacific but it would be difficult to interpret that amount of data so this approach is easier to interpret but we should recognize that the conditions in the Pacific are not binary but vary and not in a totally regular way. The same goes for the Atlantic.

Impact of Pacific Climate Change

The key to understanding these graphics is to understand that 1947 to 1976 is considered a period where the PDO was generally in its Negative Phase. That does not mean that the PDO Index registered as Negative all the time during that approximately twenty year period. Similarly the years 1977 to 1998 are considered to be a period of time when the Pacific was in the PDO Positive (sometimes abbreviated as PDO +) Phase. And the period 1999  to the present is considered to be a period of time when the PDO has been in its Negative Phase. 

This provides the basis for comparing weather in those three periods of time. And if the PDO indeed changes its Phase to PDO+ we might expect weather that is more like 1977 to 1998 than 1999 to present. The differences might include rates of precipitation, the land temperature, the types of ENSO events and their frequency and other factors. The below only deals with  precipitation which is of most interest to most people.

There are three graphics below and they are explained in the legend but to use larger type, Graphic "a" compares the PDO Positive Period of 1977 to 1998 with the PDO Negative Period of 1999 to 2010 (since this paper was written shortly after that point in time); the "b" graphic does the same but compares the PDO Positive period 1977 to 1998 with the PDO Negative Period 1947 to 1976 and Graphic (c) combines "a" and "b" but screens out the values which are not statistically significant. Thus two PDO Negative Periods are compared to a PDO Positive Period namely 1977 to 1998. The precipitation in the PDO Positive Period is subtracted from the precipitation in the two PDO Negative Periods thus providing an assessment of the difference between PDO Negative and PDO Positive.

Climate Shift LyonFigure 4

Thus we should expect THE OPPOSITE OF WHAT IS SHOWN HERE in Graphic "c" if the PDO shifts back to PDO Positive as JAMSTEC has suggested it might soon do. 

To assist in viewing the Graphic "C" I have blown it up.

PDO - Precipitation Anomalies

So if JAMSTEC is correct, where we see brown we will be seeing green and where we currently see green we will be seeing brown. Thus we might see a wetter CONUS  West and Middle East including Iran, Afghanistan and Pakistan and East Africa and Bolivia with a drier Amazon Basin and South Africa and Maritime Continent and Southern Tip of India.
It would be unusual if things worked out exactly as above but it is a guide to the impacts of a Climate Shift in the Pacific.

This set of maps has limitations since it covers the March - April - May period rather than the winter which is impacted the most but it is useful as it is directly related to Climate Shifts. I was not able to locate a comparable set of graphics for the winter but I am sure they exist but I do not have them so I am using this set. I suspect the Spring anomalies and the winter anomalies are fairly similar with the winter anomalies being more extreme but pretty much in the same places. That is conjecture on my part.

Here is the discussion from the paper where I obtained these graphics and remember the discussion relates to the impacts of PDO Negative so if we are going to be PDO Positive the opposite impacts are like to be the result. This information comes from this paper "Tropical Pacific Forcing of a 1998–1999 Climate Shift:  Observational Analysis and Climate Model Results for the Boreal Spring Season  Bradfield Lyon,  Anthony G. Barnston, David G. DeWitt".

The following is from the Summary and Conclusions Section of their paper:

"Observationally-based analyses and reanalysis products have been used to document a multidecadal shift in Pacific SSTs in 1998–1999 and associated atmospheric changes that are akin to the shift of 1976–1977. Emphasis is on the 3-month season of MAM, which has received only modest attention from previous investigators examining related multidecadal SST variations. The motivation for the study was to examine in greater detail the abrupt decline in MAM East African rainfall reported by LD  [Editors Note: From the  paper written by Bradfield Lyon and David G. DeWitt] that occurred in 1999 in order to view those results in a global domain and on multidecadal timescales. The associated PC time series shows a shift in 1999 indicative of, among other features, a change in the background state of Pacific SSTs towards cooler than average conditions in the east-central tropics. A composite difference of the full SST field in fact shows an average cooling of over 0.5 for the period 1999–2012 relative to 1977–1998 in that region. The PC time series of the residual SST EOF reveals earlier shifts in 1925, 1946 and 1976, which are all consistent with previously reported shifts in the PDO (e.g., Mantua et al. 1997)

As expected, the precipitation response to the 1999 shift in SST is large scale, with statistically significant changes in MAM season totals for the post-1998 period seen in multiple locations including drying over East Africa and central-southwest Asia, coastal regions of southeastern China, parts of northeastern Australia and the southwestern US. Drier conditions are also seen over the central Indian Ocean and the east-central Pacific Ocean. Wetter conditions include a zonally elongated band across the northern Indian Ocean extending from the eastern Arabian Sea eastward across southern India to the Philippines, the western tropical Pacific and northern South America.

 Southwestward displacement of the SPCZ is also identified.

Aside from the issue of the season studied, another deficiency in the above analysis is that it does not consider variations in the Phase of the Atlantic or Indian Ocean Low-Frequency Cycles. So it actually underestimates the impact of the Pacific Climate Shift. Weather cycles come with a variety of frequencies. The high-frequency cyclies have period lengths of days to a couple of years. ENSO is a medium-frequency cycle. The three main low-frequency cycles have a period of approximately 60 years. So looking at the impact of only the PDO does not factor in the impacts of the similar length cycles in the Atlantic and Indian Oceans: such cycles not generally being in sync with the PDO. 

I do not want to get into a long discussion tonight but here is a short discussion of the impact of the combinations of the Pacific and Atlantic Cycles on drought probabilities in CONUS.

The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. And here is a later version but I do not have a link that shows it in color but I believe the maps have not changed from the earlier version. 

The key maps are shown below:

-McCabe Drought AMO/PDO

Drought frequency (in percent of years with red being drought and blue not drought) for positive and negative regimes of the PDO and AMO. (A) Positive PDO, negative AMO. (B) Negative PDO, negative AMO. (C) Positive PDO, positive AMO. (D) Negative PDO, positive AMO.

So if the PDO becomes Positive, the four possibilities are reduced to two: "A" and "C". So we are still left with the task of forecasting the AMO. I will get to that in a bit.

There are other cycles also. Two important ones are the Arctic Oscillation and the North Atlantic Oscillation. These differ from the PDO and AMO as they are atmospheric cycles not ocean cycles. But of course they are related. Below is An Attempt to Extrapolate the Impact of Ocean Cycles Worldwide  - a First Attempt at Putting it all Together.

Geographical Area PDO+ PDO- AMO+ AMO- Comments *
Western US

Wet. High ratio of El Ninos to La Ninas

Dry. High ratio of La Ninas to El Ninos Amplifies PDO -

Amplifies PDO +

The Arctic Oscillation (AO) mediates the impact of the PDO on the Northern Tier and other parts of the U.S.
Eastern US Dry Wet

Cold Winter

Dry and Warm Summer

Warm Winter

Wet and Cold Summer

AMO Negative tends to correlate but lag by several years the North American Oscillation (NAO)  which means a colder Europe and cold air intrusions into the Center of the U.S. and the North East.

AMO Positive is the opposite but the correlation with the NAO is lower.

Europe NA NA

Cold Winter

Wet and Warm Summer

Warm Winter

Dry and Cold Summer

South America West Coast impacted more Often by El Nino East Coast impacted more often by La Nina Moisture further North Wet Summer Note when the North Atlantic is Warm the South Atlantic is Cool and the Intertropical Convergence Zone (ITCZ) shifts to the south.  
West Africa NA NA Wet Summer Dry Summer Wet West African summers tend to increase hurricane activity in the U.S.
Australia Dry Wet NA NA PDO Impacts the Indian Ocean Dipole IOD so that impacts both Australia and India but probably in the opposite way as India and Australia are in different hemispheres.
India Dry Wet NA NA
Comments Arctic Oscillation (AO) very important mediator of PDO impacts in the US especially the Northern Tier. North American Oscillation (NAO) very important mediator of AMO impacts especially for the Central and Norther Tier of the U.S. and Europe  

Cycles are not like light switches where they are either on or off. They become increasingly more positive or negative but often in an irregular way. So what is in this table are average impacts.

So let's now go back to why we believe that the JAMSTEC announcement is a reasonable forecast.

The paper I want to discuss can be found here.

Joint statistical-dynamical approach to decadal prediction
of East Asian surface air temperature
LUO FeiFei & LI ShuangLin

The following Graphic from the Luo and Li paper is very interesting. The dashed lines are the actual readings of the Index that measures the AMO, (IPO  which is a proxy for the PDO) and the somewhat similar but not very well know oscillation in the Indian Ocean. The higher-frequency version of the IOBD is well know but the low-frequency component which has a period similar to the PDO and AMO is not well known. The solid lines are the best fit with models of the index readings which were then used to forecast the index readings out to 2040. This allows me to estimate what the combination of AMO and PDO using the IPO as the surrogate for the PDO will be at the end of each decade.

ShaungLinLi Ocean Cycle Decadal Projections

Now I have modified the above to line up some key dates in the graphics namely the beginning of decades starting from the one we are in and looking forward. The decades are numbered across the top as "1", "2", "3", "4".

ShaungLinLi Ocean Cycle Projections 10 Year Increments with Numbers

So combining the work of McCabe et al with the work of Lou and Li , what can we say about these beginning years in the decade which started in 2014 and subsequent decades out into our future?

1. 2010

This was clearly AMO+/PDO-. This is McCabe Condition D and full explains the approximately twice a century severe drought in the Southwest and also in the Great Lakes area.  

2. 2020

This might be PDO+/AMO+ to AMO Neutral. This might be somewhere between McCabe A and McCabe C but closer to McCabe C. McCabe C is associated with extreme drought in the Northern Tier west of the Great Lakes. McCabe C also is associated with a high probability of drought in the South Atlantic Coast states extending into the Mid-West.

3. 2030

PDO-/AMO Neutral. This might be somewhere between McCabe B and McCabe D. Note the IPO (which I am using as a surrogate for the PDO) is forecast by Lou and Li to be less negative at its low point presumably due to the combination of subcycles with different amplitudes within the IPO. Also notice the significant difference between McCabe B and McCabe D. This illustrates the importance of the Atlantic SST's

4. 2040

PDO+/AMO Neutral. This might be somewhere between McCabe A and McCabe C.  McCabe C seems to flip drought in the West from south to north. So McCabe A and McCabe B both spare the Southwest but the condition of the Atlantic may have a big impact on the Northern Tier west of the Great Lakes.  McCabe C also is associated with a high probability of drought in the South Atlantic Coast states extending into the Mid-West.

5. And dare we project out to say 2050? This might be PDO?/AMO-. That might result in conditions intermediate to McCabe A and McCabe B. McCabe B would raise the risk for drought in the Southeast including moderate probability of drought in Florida and small areas of extreme drought in other places.  


  • There is no intention of suggesting that the drought probability for a particular year in a particular geographic area can be predicted accurately with this methodology. It is intended to provided a reasonable scenario of how these probabilities might vary over time. This can be very useful for water planning. 
  • The IPO is not the PDO but they are highly correlated.
  • The authors show significant confidence intervals around their projections. i.e. the timing of the peaks and valleys of these cycles could fall in the shaded area of the graphic rather than exactly as shown.
  • Other authors might project these cycles slightly differently
  • I believe the authors have taken Global Warming into account. But RCP 4.5 (which was used in this analysis) may be considered by some as being too conservative. 
  • The McCabe et all maps are maps of drought frequency. I am assuming they are highly inversely correlated with amounts of precipitation.

I have not tried to interpret the implications for each state in the Lower 48. The McCabe et al analysis is a mathematical analysis based on historical data. Underlying the data are climate patterns determined by mountains and interactions with Canada and Mexico. If I better understood all of these patterns I would feel more confident in making predictions state by state. I am hoping that my experiment with combining the emerging information on ocean cycles with the work of McCabe et al and similar will inspire others to undertake more work in this area. 

Is the Lou and Li analysis realistic? Is it an outlier or is it consistent with the work of other researchers in the field.

The Lou and Li methodology is described in their paper. I have studied at least three similar papers and what I have found is that all three authors believe the two (in the case of Lou and Li three) cycles are synchronized to each other. I have consolidate the information from the three papers and here is what I came up with. This table relates the AMO to the PDO. So "Lead" means the AMO reaches a peak or minimum and begins to trend in the other direction in advance of the PDO beginning to change its direction (if it is positive begin to become less positive and then become negative or vice versa)."Lag" means the AMO chances direction later than the PDO which could be expressed as the PDO leads the AMO. So yes this is a difficult concept to grasp when looking at a table of numbers. For me it is more understandable when I look at a graph of the time series of the amplitudes of the surface temperature anomalies of the AMO and PDO. 

AMO relationship to the PDO re Leads and Lags Lead Lag

Sum of Absolute Values of the Lead and Lag

Twice the number in the prior column
Orgeville and Peltier -13 +17 30 60
Wu, Liu, Zhang and Delworth* 12 to 14 12 to 13 26 52
Li and Luo -(16 to 18) 19 to 21 37 74

* This paper decomposes the PDO into a high-frequency 20 year cycle and a low-frequency presumably 60 year cycle. The above data is for the low-frequency Cycle and in this paper the authors also report a high correlation for the PDO lagging the AMO by 1 - 3 years which represents an additional scenario. Although I show a positive correlation for this paper in the above table in regards to the AMO leading the PDO it may well be that I have not read the paper carefully enough and that the correct sign of that correlation is also negative. So I would not conclude that this paper is inconsistent with the other two. 

Curiously the most common belief is that the AMO controls the PDO. This is counterintuitive since winds move from West to East but they do not in the lower latitudes where the Trade Winds blow from East to West. Also the Pacific and Atlantic are connected via the Arctic Ocean. What are called teleconnections are often quite complex. Also it is important to recognize that there really is no such thing as the PDO or AMO. They both and especially the PDO are a combination of many different cycles. We talk about the PDO and AMO because it is easier to talk about two cycles than six to ten cycles. And the goal is to be able to regress actual weather to these cycles and it is more difficult to do so with six to ten cycles then with two. So when one does what is called spectral analysis one finds many different cycle lengths (i.e. the spectral analysis is actually recognizing the subcycles within the PDO and AMO) and what I have reported above is the information on the lead and lags that have the highest correlation coefficient in the three studies. Highest correlation does not mean 100% correlated so what we are describing is tendencies not certainties.

And of course we do not know how Global Warming might change the length of these cycles or the lead and lag. It is also useful to recognize that information on the AMO and PDO has only been known in the last twenty years and the PDO was figured out before the AMO. This information is all less than twenty years old. It is so new that most meteorologists and climatologists are not conversant in it. Neither are most universities. People are more conversant with the PDO since it was figured out first. There is much more to be learned. But we now know enough to expect that our climate will be impacted somewhat along the lines of the time frame I have laid out above.


If JAMSTEC is correct (and remember their forecast is conditional on there being an El Nino next winter and is expressed by JAMSTEC as that sequence may suggest a decadal turnabout in the tropical Pacific climate condition), we should expect weather patterns that are more like 1977 to 1998 than the weather patterns we have been having in recent years.

So we are early in the  process. Probably many who have been studying this believe that a change to PDO Positive will happen soon. So really the question is how soon is soon?

Is it two years or perhaps it has occurred already.

Or do we need one more cycle of El Nino - La Nina - El Nino for this to occur.

JAMSTEC seems to be suggesting sooner rather than later.

A. Focus on Alaska and CONUS (all U.S. except Hawaii)

First Let us focus on the Current (Right Now to 5 Days Out) Weather Situation.

This graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.

 Center for Western Weather and Water Extremes, Scripps/UCSD.

Image credit:  Center for Western Weather and Water Extremes, Scripps/UCSD.  More explanation can be found at Atmospheric Rivers (Click to read full Weather Underground Dr. Bob Henson article)

To turn the above into a forecasting tool click here and you will have a dashboard for a short-term forecasting model.

Notice that right now the major moisture inflow is mostly from the Gulf of Mexico and impacts the Gulf Coast and points north mostly inland from the East Coast States. There is also moisture preparing to enter the Northwest from the Pacific and that entry point is controlled by the Aleutian Low and the northerly displaced RRR. (North Pacific High). There is also a cut-off low off of California that may impact CONUS later this week.

Here is a national animation of weather fronts and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. Beyond 60 hours, additional maps are available at links provided below.

current highs and lows

The explanation for the coding used in these maps, i.e. the full legend, can be found here although it includes some symbols that are no longer shown in the graphic because they are implemented by color coding.

U.S.  3 Day to  7 Day Forecasts

Below is a graphic which highlights the forecasted surface Highs and the Lows re air pressure on Day 3. The Day 6 forecast can be found here.

Day 3 Weather Forecast

The Aleutian Low is a non-split Low with central air pressure very low but it is so coiled up that I can not read it from this graphic right now but I am guessing it is in the 960 hPa range which is very low. It is centered over Kamchatka. The average sea level air pressure in the winter is 1001 hPa and 994 hPa for a non-split Low. This graphic changes every six hours.
The High Pressure off of California, the familiar RRR, is back with Central Pressure of 1040 hPa but this high is right now quite far north and out to sea but reported as being a Blocking High moving the jet stream further north than its usual position. Thus, right now the RRR (Ridiculously Resilient Ridge) is for the moment not doing its job of protecting the West Coast from Pacific storms. In fact you can see a small Low east of the RRR.
I provided this  K - 12 write up that provides a simple explanation on the importance of semipermanent Highs and Lows and another link that discussed possible changes in the patterns of these highs and lows which could be related to a Climate Shift (cycle) in the Pacific or Global Warming. Remember this is a forecast for Day 3. It is not the current situation but Day 3 is not very far out.

This is perhaps a good place to describe what a "Canonical" La Nina looks like. It is part of a very good write up covering many topics which can be found here.

La Nina Pattern

For almost all of this Fall and Winter the Aleutian Low has been where the blocking high should be with the Pacific High pushed to the South. That is why that although this is clearly a cool ENSO pattern, the actual impacts have been somewhat different than one would expect from a Canonical La Nina. Right now the pattern is more consistent with this graphic.

You can enlarge the below daily (days 3 - 7) weather maps for CONUS by clicking on Day 3 or Day 4 or Day 5 or Day 6 or Day 7. These maps auto-update so whenever you click on them they will be forecast maps for the number of days in the future shown.

Short term forecasts

Here is the seven-day precipitation forecast. More information is available here.

Seven Day WPC Quantitative precipitation forecast

There is some activity in the Northwest but the major activity is west of the Appalachian Mountains arriving from the Gulf of Mexico. It will however to a lesser extent impact the East Coast.

The map below is the mid-atmosphere 7-Day chart rather than the surface highs and lows and weather features. In some cases it provides a clearer less confusing picture as it shows only the major pressure gradients.This graphic auto-updates so when you look at it you will see NOAA's latest thinking. The speed at which these troughs and ridges travel across the nation will determine the timing of weather impacts. This graphic auto-updates I think every six hours and it changes a lot. Because "Thickness Lines" are shown by those green lines on this graphic, it is a good place to define "Thickness" and its uses. The 540 Level general signifies equal chances for snow at sea level locations. Remember that 540 relates to sea level.

7 Day 500 MB Geopotential Forecast

Thinking about clockwise movements around High Pressure Systems and counter- clockwise movements around Low Pressure Systems provides a lot of information.
What you can see in the above graphic is a Low over Hudson Bay which may impact the Great Lakes to some small extent and a fairly deep western trough
Remember this is a forecast for Day 7. Note the 540 Thickness Line re the above discussion of thickness and snow likelihood. The 540 line on Day 7 now intrudes into CONUS mostly in the Northwest but may also impact the northern Great Lakes area.

The graphic that I have been showing below was the Eastern Pacific a 24 hr loop of recent readings. When working, it does a good job of showing what is going on right now. When I published and for the past two weeks, that graphic was not being displayed but the NOAA website indicated that was a temporary outage. So for the time being I have substituted a static version of that image which works almost as well. However you can obtain somewhat similar imagery loop image by clicking here. It actually provides more functionality than the either the previously or currently displayed version but you have to click to get it as I have not figured out how to get it to display otherwise. It is really cool imagery and explains a lot. For now you have the static image without clicking but can click to view a more elaborate loop image. The loop image provides a better feel for the speed at which things are taking place.

Eastern Pacific Static not Loop

The winds and moisture approaching the West are of most interest. You can clearly see activity that is impacting the Northwest but also the cut-off Low off of Southern California which has become less visible.

I have stopped showing the Tropical events graphic. We are still having tropical events even though it is late December but we can track them with the other graphics that I am presenting including the graphic above and below.  They are both the same graphic which you can tell by looking at the date and time stamp but the above graphic covers a larger area and is centered on the Eastern Pacific and the graphic below is centered on North America. That provides more resolution that trying to work with a single graphic that covers a larger fraction of Planet Earth. 

Below is the current water vapor Imagery for North America.

 Water Vapor Imagery

Tonight, Monday evening December 26, 2016 (and this is the current situation not an animation of recent history), as I am looking at the above graphic, we see the activity in the Northwest and from Louisiana stretching at a 45 degree angle up to New York State and additional water vapor streaming in from the Pacific.

Looking at the current activity of the Jet Stream.

First the current situation. Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems. The sub-Jetstream level intensity winds shown by the vectors in this graphic are also very important in understanding the impacts north and south of the Jet Stream which is the higher-speed part of the wind circulation and is shown in gray on this map. In some cases however a Low-Pressure System becomes separated or "cut off" from the Jet Stream. In that case it's movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream. This usually is more significant for the lower half of CONUS i.e. further south than the Jet Stream.

Current Jet Stream

One sees the current jet stream above. It barely impacts the Northwest. You can see the cut-off Low and the Jet Stream to the north of it possibly bringing subtropical air into the Southwest.

Now looking at the 5 Day Forecast

Jet Stream Five Days Out .

You can see the recently consistent Zonal Flow kind of remaining zonal but with split flow. This is the forecast of one model 5 days out. So a lot can happen between now and then.

Putting the Jet Stream into Motion and Looking Forward a Few Days Also

To see how the pattern is projected to evolve,  please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.

This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.

When we discuss the jet stream and for other reasons, we often discuss different layers of the atmosphere. These are expressed in terms of the atmospheric pressure above that layer. It is kind of counter-intuitive to me. The below table may help the reader translate air pressure to the usual altitude and temperature one might expect at that level of air pressure. It is just an approximation but useful.

air pressure and altitude
Re the above, H8 is a frequently used abbreviation for the height of the 850 millibar level, H7 is the 700 mb level, H5 is the 500 mb level, H3 is the 300 mb level. So if you see those abbreviations in a weather forecast you will know what they are talking about.

Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on "earth" adjusting the parameters and then clicking again on "earth" to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns. This amazing graphic covers North and South America. It could be included in the Worldwide weather forecast section of this report but it is useful here re understanding the wind circulation patterns.

Four- Week Outlook

I am going to show the three-month JFM Outlook (for reference purposes although I do not have a lot of confidence in it), the Updated Outlook for the single month of January,  the 6 - 10 Day and 8 - 14 Day Maps and the Week 3 -  4 Experimental Outlook. I use "EC" in my discussions although NOAA sometimes uses "EC" (Equal Chances) and sometimes uses "N" (Normal) to pretty much indicate the same thing although "N" may be more definitive.  

First - Temperature

Here is the Three-Month JFM Temperature Outlook issued on December 15, 2016:

JFM 2017  Temperature Outlook Issued on December 15, 2016

Here is the "Early" Temperature Outlook for January Issued on December 15, 2016

January Early Temperature Outlook Issued on December 15, 2016

 6 - 10 Day Temperature Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on December 26 was 5 out of 5)

6 - 10 Day Temperature Outlook

8 - 14 Day Temperature Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on December 26 was 5 out of 5) 

8-14 Day Temperature Outlook

Looking further out.

Experimental Week 3-4 Temperature Outlook

Consolidation of 6 - 10, 8 - 14 and Experimental Week 3-4 Forecasts (interpreted on December 26, 2016

January 1 to January 9 January 7 to January 20
Alaska will be warm, Northwest cool and the Southeast and Southwest warm with the Northwest cool anomaly expanding and the warm anomaly gradually moving south and east. The transition to the patterns shown in the Week 3 - 4 Forecast seems to be a smooth transition. But the Northwest cool anomaly may overwhelm the Southeast cool anomaly.
Remember the Week 3-4 Experimental Outlook was issued last Friday and I am looking at the 6 - 10 and 8 - 14 day forecasts issued today i.e. Monday. So that explains the overlap of dates. Remember that the Week 3 - 4 Forecast covers two weeks so it can appear to not mesh perfectly but actually do so over that two-week period. At this point it meshes fairly well.


One concludes that the temperature is consistent with a La Nina Pattern.

Now - Precipitation

Here is the three-month JFM Precipitation Outlook issued on December 15, 2016 that I do not have much confidence in.

JFM 2017 Precipitation Outlook Issued on Decemberf 15, 2016

And here is the "Early" Precipitation Outlook for January issued on December 15, 2016

January Early Outlook Precipitation Outlook Issued on December 15, 2016

6 - 10 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on December 26 was 5 out of 5)

6 - 10 Day Precipitation OutlookUnlink

8 - 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on December 26 was 5 out of 5)

Current 8 - 14 Day Precipitation Outlook

Looking further out.

Weeks 3 and 4 Experimental Forecast..

Consolidation of 6 - 10, 8 - 14, and Week 3-4 Forecasts as of December 26, 2016
January 1  to January 9  January 7 to January 20, 2017
Alaska is mostly wet except for the south coast and the Panhandle. CONUS starts mostly wet with only minor dry anomalies with only small parts of the Northwest and Southern Texas to be forecast dry. There are three small dry anomalies shown: one for the Alaskan Panhandle, a second for South Texas and the other for Florida. There is a single Wet anomaly shown with two areas of highest probability one centered on Utah and the other on the Mid-Mississippi States. In between these wet and dry anomalies is EC.
Remember the Week 3 - 4 Experimental Outlook was issued last Friday and I am doing this analysis on Monday which explains the overlap in dates.


The Precipitation seems to be more consistent with ENSO Neutral than either La Nina or El Nino since it is neither far to the North or far to the South.

Here is the NOAA discussion released today December 26, 2016

6-10 DAY OUTLOOK FOR JAN 01 - 05 2017





8-14 DAY OUTLOOK FOR JAN 03 - 09 2017 





Some might find this analysis click to read interesting as the organization which prepares it focuses on the Pacific Ocean and looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of ENSO events.

Analogs to the Outlook.

Now let us take a detailed look at the "Analogs" which NOAA provides related to the 5 day period centered on 3 days ago and the 7 day period centered on 4 days ago. "Analog" means that the weather pattern then resembles the recent weather pattern and was used in some way to predict the 6 - 14 day Outlook.

Here are today's analogs in chronological order although this information is also available with the analog dates listed by the level of correlation. I find the chronological order easier for me to work with. There is a second set of analogs associated with the Outlook but I have not been regularly analyzing this second set of information. The first set which is what I am using today applies to the 5 and 7 day observed pattern prior to today. The second set, which I am not using, relates to the correlation of the forecasted outlook 6 - 10 days out with similar patterns that have occurred in the past during the dates covered by the 6 - 10 Day Outlook. The second set of analogs may also be useful information but they put the first set of analogs in the discussion with the second set available by a link so I am assuming that the first set of analogs is the most meaningful and I find it so.





Other Comments

Dec 20, 1988 La Nina - - Strong La Nina
Dec 23, 1988 La Nina - - Strong La Nina
Jan 1, 1989 La Nina - - Strong La Nina
Dec 12, 1994 El Nino - - Questionable re duration
Dec 13, 1994 El Nino - - Questionable re duration
Dec 6, 1998 La Nina - + Following 1997/1998 MegaNino
Dec 13, 2001 La Nina - +  
Jan 9, 2006 El Nino + +  

(t) = a month where the Ocean Cycle Index has just changed or does change the following month.

One thing that jumped out at me right away was the spread among the analogs from December 6 to January 9 which is 34 days which is a bit more than last week. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, is about December 23. These analogs are centered on 3 days and 4 days ago (December 21 or December 22). So the analogs could be considered in sync with the calendar meaning that we will be getting weather that normally would occur at about this time of year.

For more information on Analogs see discussion in the GEI Weather Page Glossary.

There are three El Nino Analogs (why are there any?, five La Nina Analogs and zero ENSO Neutral Analogs. Looks like the analogs are suggesting that both La Nina and El Nino Conditions prevail. The phase of the ocean cycles in the analogs points strongly towards McCabe Condition B which fits with the 6 - 14 Day Forecasts.

The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time. One of the major reasons that I write this weather and climate column is to encourage a more long-term and World view of weather.

McCabe Maps modified to include the subtitles

McCabe Condition Main Characteristics
A Very Little Drought. Southern Tier and Northern Tier from Dakotas East Wet
B More wet than dry but Great Plains Dry
C Northern Tier and Mid-Atlantic Drought
D Southwest Drought extending to the North and also the Great Lakes

You may have to squint but the drought probabilities are shown on the map and also indicated by the color coding with shades of red indicating higher than 25% of the years are drought years (25% or less of average precipitation for that area) and shades of blue indicating less than 25% of the years are drought years. Thus drought is defined as the condition that occurs 25% of the time and this ties in nicely with each of the four pairs of two phases of the AMO and PDO.

Historical Anomaly Analysis

When I see the same dates showing up often I find it interesting to consult this list.

Recent CONUS Weather

This is provided mainly to see the pattern in the weather that has occurred recently.

Here is the 30 Days ending December 17, 2016

December 17, 2016 30 Day temperature and precipitation departures.

Big change from last week. The temperature change is most obvious from warm departures to now balanced with the obvious cool anomaly in the Northwest Quadrant and close to normal for the Northeast Quadrant. Precipitation is also different and notice the wetness is mid-latitude for CONUS not an obvious La Nina pattern. Remember this is a 30 day average and only 7 days were added and 7 more distant days removed.

And the 30 Days ending December 24, 2016

December 26, 2016 30 Day Temperature and Precipitation Departures

Definitely wetter and shifted south rather than north as one would expect with a La Nina. With temperature the cool anomaly has expanded into the Plains States. Remember this graphic shows a 30 day average so 7 days are added and seven more distant days are removed. So it changes slowly.

B. Beyond Alaska and CONUS Let's Look at the World which of Course also includes Alaska and CONUS

Near Term

World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click Here you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the "Back Arrow" usually found top left corner of your screen to the left of the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool.

Although I can not display the interactive control panel in my article, I can display any of the graphics it provides so below are the current worldwide precipitation and temperature forecasts for three days out. They will auto-update and be current for Day 3 whenever you view them. If you want the forecast for a different day Click Here


BOM World Preciptation  Wednesday

Again the North Atlantic is interesting. One can really see the situation in the Pacific with this forecast with the location of the North Pacific Lows and the Middle Latitude Highs. Counting the number of major Lows from left to right I believe equates to the Wave Number of the Pattern which looks like about 4. You can read more about that here.                    


BOM Current Temperature Wedensday

Australia is forecast to be warm. The Middle East is forecast to be cold.

Looking Out a Few Months

The new precipitation forecast from Queensland Australia was based on a rapidly rising SOI. That did not seem to be correct October and November. Below are the numbers as of December 19. I am not  confident in the numbers released this week due to a very extreme value released for December 23 so I have not updated the data below since last week.

So I used the feature to create a forecast based on stable SOI and this is what was generated.

Stable near zero SOI  forecast for Jan - Mar 2017.

It is kind of amazing that you can make a worldwide forecast based on just one parameter the SOI and changes in the SOI. Recently, we ran a weather column with the Title El Nino or La Nina? The point of that article was simply that ENSO is not solid La Nina at this point. We are getting mixed signals. This project may be based on a mixed signal but it also is based on the lag between the SOI and weather impacts so it may be valid even if the SOI begins to increase now.

Here is the most recent JAMSTEC three-month Temperature Forecast. 

DJF 2016.2017 Temperature JAMSTEC

It is mostly warm but with notable cool areas in Northern Brazil, Australia, and Southern Canada and CONUS other than the Southwest. 

And here is the most recent three month JAMSTEC  Precipitation Forecast.

D 2016 JF Jamstec Precipitation Forecast

Of interest is the wet South America. South Africa and Australia and dry Maritime Continent and Japan. The Eastern Part of CONUS is wet.

And then to get more focus, I extracted and enlarged an image for CONUS on the left and Europe on the right.


For many purposes 55N latitude is the dividing line in Europe in regards to the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) Impacts. You see that here with Scandinavia wet and southern Europe dry. It is suggestive of AO+. The NAO is highly correlated with the AO so  it is also suggestive of NAO +. For CONUS it is a La Nina pattern but different than shown below for NOAA and it is not a North/South divide. 

There is a short but very important JAMSTEC discussion:

Dec. 19, 2016  Prediction from 1st Dec., 2016

ENSO forecast:

According to the SINTEX-F prediction, the current La Niña Modoki/La Niña state will continue until late winter. Interestingly, majority of the ensemble members indicate recurrence of a moderate El Niño event in the latter half of 2017. It will be interesting if an El Niño event really evolves in 2017, which may suggest a decadal turnabout in the tropical Pacific climate condition to El Niño-like state after a long spell of La Niña-like state, which led to the global warming hiatus.

Indian Ocean forecast:

The negative Indian Ocean Dipole has started decaying and will be terminated by the end of 2016. Then we expect a positive Indian Ocean Dipole in summer of 2017. We also expect the Ningaloo Niño off the west coast of Australia in late austral summer, which may persist until late austral fall. However, the prediction plumes are spreading and those expectations are still uncertain at the present stage.

Regional forecast:

On a seasonal scale, most part of the globe will experience a warmer-than-normal condition, while some parts of northern U.S., southern Canada, northern Brazil, and Australia will experience a colder-than-normal condition in the boreal winter.

According to the seasonally averaged rainfall prediction, most parts of southeastern China, Indonesia, eastern Africa, eastern half of Europe including Italy, and Caribbean countries including Florida will experience a drier condition during winter, whereas the Philippines, the eastern U.S., and the western part of Europe will experience a wetter-than-normal condition. Most parts of Brazil, Australia and South Africa will experience a wetter-than-normal condition during austral summer. Most parts of Japan will be warmer and quite drier than normal in winter. However, we note that highly fluctuating mid- and -high latitude climate in winter may not be captured well by the current model.

Additional forecasts from JAMSTEC including future time periods can be found at this link.

Sea Surface Temperature (SST) Departures from Normal for this Time of the Year i.e. Anomalies

My focus here is sea surface temperature anomalies as they are one of the two largest factors determining weather around the World.

And when we look at the current Sea Surface anomalies below, we see a lot of them not just along the Equator related to ENSO.

Daily SST Anomaly

What happened to the presumed La Nina? Did it go into Hibernation? It will take a while to fade totally but there is less of it now than two months ago. The readings along the Equator in the Pacific vary dramatically day to day which reduces confidence in the reliability of this graphic. The weekly version only updates once a week so it is not necessarily a good alternative.  Remember this discussion is all about anomalies not absolute it is deviation from seasonal norms. 
The Tropical Pacific is NEUTRAL in the Nino 3.4 Measurement area. The cool anomaly is slowly fading. The waters off the West Coast of South America have become quite warm.
The waters west and east of Japan have become warm but the waters southeast of Kamchatka Siberia remain cold, The Central Indian Ocean is now mostly cold but south of the cool anomaly is a warm anomaly. The waters off the Southern Coast of Australia are pretty much neutral but the Southeast Coast is warm. Water north of Australia is close to neutral. The waters south and southeast of Africa are mixed. To the west of Africa especially in the Gulf of Guinea, the water is warm.
The overall Northern Pacific cool anomaly is growing and extending to the east. Warm water has developed to the south of the cool anomaly but closer to the Dateline and less obvious than last Monday. The NOAA Pacific Decadal Oscillation (PDO) Index as reported by NOAA (Washington University also reports the PDO but using a different methodology which results in higher index numbers) has been 2016-January 0.79, 2016- February 1.23, 2016- March 1.55, 2016- April  1.59. 2016- May 1.40, 2016-June 0.76, 2016-July 0.12, 2016-August-0.90, 2016- September -1.09, 2016- October -0.88 and now November +0.53. 
The above would make the PDO now POSITIVE (JAMSTEC Noticed). Here is the list of PDO values.
The waters west of CONUS are now mostly neutral probably due to the northerly winds creating upwelling. But with the North Pacific High moving inland the surface water just offshore may be warming.
The Gulf of California is neutral. Further north, the Gulf of Alaska is warm but only where it is very close to land with the Bering Straits also warm but not overly impressive,
The Black Sea and the Caspian Sea are now cool. The Mediterranean is very slightly warm.
The U.S. Great Lakes are neutral. The North Atlantic is warm. North of Scandinavia and to the east is warm. The Northern Gulf of Mexico is warm.  The waters north of Antarctica East of South America are again cool but further out to sea.
I have some additional commentary on this static analysis of the anomalies below where I examine the four-week change in these anomalies. The list of Atlantic Multidecadal Oscillation (AMO) values can be found here.
Since these are "departures" or "anomalies", it is not a seasonal pattern that is being shown it is the changes from what we would expect on a seasonal basis. It is important to understand that and interpret my comments above in the context of anomalies not absolute temperatures.

Just for fun I thought I would try to draw in the NINO 3.4 area into today's graphic. It is frozen unlike the graphic above, it will not auto-update.

December 26, 2016 NINO 3.4 SST Anomaly

As you can see there is some cool water in the rectangle shown as the NINO 3.4 Measurement Area but it is mostly white as in Neutral. NOAA is barking up a wrong tree. Essentially all other Worldwide Meteorological Agencies see what you are seeing and draw the appropriate conclusions but for some reason NOAA is unable to part with their La Nina hypothesis.

Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.

Comparing a four-week graphic to a prior four-week graphic is always tricky since only 25% of the data has changed and I am not showing the former graphic (it is in last week's report). I add the new one to my draft report, compare and comment on the change and then delete the old one to keep this report to a manageable size. Also it is important to recognize that what you see in this graphic is the change in the anomaly over the last four weeks. So blue means either cooler or less warm. Red means warmer or less cool. So you have to refer to the graphic above this one to really interpret this graphic as what we are seeing here is the change in the anomalies. What we see in this graphic is four weeks of change not the current absolute anomalies which are shown in the above graphic. It is not derivatives in the mathematical sense but deltas. They are somewhat similar. The graphic above this one is simply the current deviation from climatology and this graphic below shows the four week change in the deviation from climatology. So it is a bit like the first (graphic above) and second (graphic below) derivatives but not exactly. I take it a step further by comparing this week's version of the graphic to the prior week and report on the differences below.  

December 26 four week change in SST Anomalies

What I see as I look at both last week's version of this graphic and the current one (before deleting the prior version) is warming along the Equator in the Pacific. It is a lot warmer over by South America. The Pacific cooling trend continues to be less impressive off the Coast of CONUS. Northeast of Australia the cooling trend is gone. The warming trend in the North Atlantic over by the British Isles is gone and off the extreme northern coast of North America the cooling trend has moderated and extends further out to sea. But further south there is a warming trend impacting the Southeast Coast of the U.S. Gulf of Mexico and the Antilles. West of Africa in the Gulf of Guinea the warming trend has stabilized in the Gulf of Guinea but remains further south and all the way around the Cape into the Indian Ocean. East of South America the cooling trend has moderated and close to shore the waters are warming. Remember we are talking about changes in the anomalies something like a second derivative so you have to refer to the graphic above this one to know if blue is cool or less warm and if red is warm or less cool.  

Below is an analysis of projected tropical hazards and benefits over an approximately two-week period. This graphic is scheduled to update on Tuesday and I am reading the December 20, 2016 Version and looking at Week 2 of that forecast.

Tropical Hazards

Mostly I see for Week Two (this graphic updates on Tuesdays and I post on Monday which is almost  a week later so Week Two applies unless I go back on Tuesday and update the discussion when the map updates), the period December 28, 2016 to January 3, 2017, it will likely be wet and stormy for Northeast Australia with some rainy conditions for parts of the Maritime Continent with wet conditions approaching Venezuela.

Look at the Western Pacific in Motion. NOAA is having problems with their web site so I have temporarily substituted a static image but you can find a somewhat similar loop version by clicking here.  It actually provides more functionality than the displayed version but you have to click to get it as I have not figured out how to get it to display otherwise.

Western Pacific Tropical Activity

The above graphic which I believe covers the area from the Dateline west to 100E and from the Equator north to 45N normally shows the movement of tropical storms towards Asia in the lower latitudes (Trade Winds) and the return of storms towards CONUS in the mid-latitudes (Prevailing Westerlies). This is recent data not a forecast. But, it ties in with the Week 1 forecast in the  graphic just above the graphic. Information on Western Pacific storms can be found here. This is an unofficial private source but one that is easy to read.

C. Progress of the Cool ENSO Event

A major driver of weather is Surface Ocean Temperatures. Evaporation only occurs from the Surface of Water. So we are very interested in the temperatures of water especially when these temperatures deviate from seasonal norms thus creating an anomaly. The geographical distribution of the anomalies is very important.
To a substantial extent, the temperature anomalies along the Equator have disproportionate impact on weather so we study them intensely and that is what the ENSO (El Nino - Southern Oscillation) cycle is all about.
Subsurface water can be thought of as the future surface temperatures. They may have only indirect impacts on current weather but they have major impacts on future weather by changing the temperature of the water surface.
Winds and Convection (evaporation forming clouds) is weather and is a result of the Phases of ENSO and also a feedback loop that perpetuates the current Phase of ENSO or changes it. That is why we monitor winds and convection along or near the Equator especially the Equator in the Eastern Pacific. 

Starting with Surface Conditions.

TAO/TRITON GRAPHIC (a good way of viewing data related to the part of the Equator and the waters close to the Equator in the Eastern Pacific  where we monitor to determining the current phase of ENSO. It is probably not necessary to follow the discussion below, but here is a link to TAO/TRITON terminology.

I have deleted many of the TAO/TRITON graphics we looked at when we were watching El Nino develop and decline. But I saved this one which was close to the maximum. It was not the maximum but it was the one that I froze which was the closest to the maximum that I saved. It is useful for comparing the current situation with the pattern that prevailed near the peak of the El Nino this past winter. Since most of my graphics auto-update,  in order to be able to view a prior version of a particular graphic, I "freeze it" by basically cut and paste to a graphics file and then embed that "frozen graphic" in my article.

January 19, 2016 Frozen TAU/TRITON Graphic

And here is the current version of the TAO/TRITON Graphic.

The above should be compared to the bottom part of the following graphic. Notice the pattern is remarkably similar. The difference is that in January, the anomaly was a warm anomaly stretching from 130W to 160W and now it is a cool anomaly. When it was a warm anomaly, it was a 3C anomaly in the center ring. Now the center ring is a -0.5C anomaly. So this is opposite to last winter but the intensity is a third or less of the situation last winter.

Current SST and wind anomalies

Location Bar for Nino 3.4 Area Above and Below
------------------------------------------------  A       B       C      D       E       -----------------


The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. The two rows just below that break point contribute to ENSO Neutral and after another break, the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016.

Comparing Now to May 23, 2016

Subareas of the Anomaly

Westward Extension Eastward Extension Degrees of Coverage

As of Today

May 23, 2016

As of Today

May 23 2016

As of Today

In Nino 3.4

Dec 12, 2016

May 23, 2016

These Rows Show the Extent of ENSO Neutral Impacts on the Equator
0.5C or cooler Anomaly









0C or cooler Anomaly









These Rows Show the Extent of the La Nina Impacts on the Equator
-0.5C or cooler











-1C or cooler Anomaly









-1.5C or cooler Anomaly










*There is a small cool anomaly of -1C+  north of the Equator.

It is useful to start comparing the rightmost column to the column to the left of it. One can now usefully compare the current longitudinal extent of the water temperature anomalies with the situation on May 23, 2016. As of today the cool event is less prevalent along the Equator than it was on May 23 and the more recently established reference point of December 12, 2016.
If you just look on the Equator, there are 50 degrees of Longitude of Neutral to La Nina anomalies which is the maximum possible as the ONI Measurement Area is 50 degrees of Longitude wide and that also is the maximum possible since the ENSO Measurement Area only stretches for 50 degrees. There are today again only 25 degrees of water anomalies cool enough to be a La Nina. Subtracting 25 degrees from the 50 degrees you end up with 25 degrees of ENSO Neutral and 25 degrees of water cool enough to qualify as La Nina i.e. temperature anomalies more negative than -0.5C. There are today 0 degrees of water along the Equator in the ONI Measurement that is -1C or less which would be cool enough to be a moderate La Nina when just looking at the Equator and there are 0 degrees of -1.5C water. The ONI Measurement Area extends 5 degrees of Latitude North and South of the Equator so the above table is just a guide and a way of tracking the changes. Away from the Equator it is generally warmer. The water from 3N to 5N and from 3S to 5S had until recently remained relatively warm. At 130W the warmer water is intruding from both the north and the south as the cool anomaly is being broken into two pieces as part of its transformation into ENSO Neutral.

I calculate the current value of the ONI index (really the value of NINO 3.4 as the ONI is not reported as a daily value) each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W Nino 3.4 measuring area into five subregions (which I have designated from west to east as A through E) with a location bar shown under the TAO/TRITON Graphic). I use a rough estimation approach to integrate what I see below and record that in the table I have constructed. Then I take the average of the anomalies I estimated for each of the five subregions.

So as of Monday December 26, in the afternoon working from the December 25 TAO/TRITON report, this is what I calculated. [Although the TAO/TRITON Graphic appears to update once a day, in reality it updates more frequently.]

Calculation of ONI from TAO/TRITON Graphic
Anomaly Segment Estimated Anomaly
  Last Week This Week
A. 170W to 160W -0.5 -0.4
B. 160W to 150W -0.5 -0.7
C. 150W to 140W -0.3 -0.2
D. 140W to 130W -0.2 -0.0
E. 130W to 120W -0.3 -0.3
Total -1.8 -1.6
Total divided by five subregions i.e. the ONI (-1.8)5 = -0.4 (-1.6)/5 = -0.3


My estimate of the daily Nino 3.4 SST anomaly is a bit warmer at -0.3 which remains an ENSO Neutral value. NOAA has also reported the weekly Nino 3.4 to be a La Nina Neutral value at -0.3. There had been prior to two weeks ago three weeks of NOAA reporting an ENSO neutral value for Nino 3.4. Then two weeks ago perhaps the Inactive Phase of the MJO gave NOAA a temporary reprieve or perhaps they just made the -0.6 up as I did not believe that their estimate that week was correct as a weekly estimate. Let's leave it at that. Then last week they reported a -0,4 and this week we again have an ENSO Neutral reading submitted by NOAA. So over the past five weeks, NOAA has reported one La Nina value and four ENSO Neutral values but they still maintain that we have La Nina Conditions. It is a travesty.
Nino 4.0 is reported as being at bit warmer than last week at -0.1. Nino 3 is being reported quite a bit warmer at -0.2.  Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is now again warmer at positive +0.6. What is left of this Cool Event is now focused in mostly one cool spot which we report on elsewhere in this report.
I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in table form but going back a couple of more years can be found here. 

December 26, 2016 Nino Readings

From Tropical

CDAS Legacy System

This is from a legacy "frozen" NOAA system meaning the software is maintained but not updated. It seems to show a cycle in the Nino 3.4 Index Values. I see that as I monitor the TAO/TRITON graphic. My best guess is that it is related to the MJO but it certainly is intriguing. If this was read like a stock chart one might conclude that there had been a triple bottom and an upside breakout. Below is a "frozen" version of this graphic that I first prepared three weeks ago and updated today with the trend lines for the highs and lows added. I think it is pretty clear that this method of analysis has value.  .

December 26, 2016 Tropical Tidbits CDAS Nino 3.4 with lines drawn in by Sig Silber

It had been kind of a declining wedge (bullish) with an upside breakout not able to move through the upside resistance at +0.4C.  As expected we then had a down phase of the cycle and as expected this did not pierce the bottom line drawn (shown last week but I have not carried forward that graphic. Look  above one  graphic to the live version we see 5 down days followed by just a couple of up days and now a plateau at just warmer than -0.5 i.e. just warmer than La Nina values. If you look at the three red lines I drew in you see the lows getting higher rather steeply, the highs gradually getting higher and the intermediate highs kind of stuck for the moment barely in ENSO Neutral territory. I predict that the next time I do this analysis in a week or two, -0,3C will seem to me the dominant value. There is not space to extend the trend lines by two months and I am not arguing that the pattern is linear but it does look like the lows are increasing by about +0.2C to +0.3C per month. This is a lot simpler model than NOAA uses but I have found that simplifications of complex models can provide a lot of insight.

Sea Surface Temperature and Anomalies

It is the ocean surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. So we are interested in the actual ocean surface temperatures and the departure from seasonal normal temperatures which is called "departures" or "anomalies". Since warm water facilitates evaporation which results in cloud convection, the pattern of SST anomalies suggests how the weather pattern east of the anomalies will be different than normal.

December 26, 2016 Equatorial Pacific SST Anomalies

A major advantage of the Hovmoeller method of displaying information is that it shows the history so I do not need to show a sequence of snapshots of the conditions at different points in time. This Hovmoeller provides a good way to visually see the evolution of this ENSO event. I have decided to use the prettied-up version that comes out on Mondays rather that the version that auto-updates daily because the SST Departures on the Equator do not change rapidly and the prettied-up version is so much easier to read. You can see that the cool anomaly (bottom of the Hovmoeller is vanishing right before our eyes with almost no blue, more white and now some yellow. This graphic explains to a large extent the small week to week changes in the Nino 3.4 Index Reading. Remember the +5, -5 degree strip around the Equator that is being reported in this graphic. So it is the surface but not just the Equator.
There has been a clear pattern of the Cool Anomaly vanishing everywhere in Nino 3.4 Measurement Area. You can really see the yellow area off to the left extending to the east. One also sees patches of yellow in many place. It is a slow process but relentless. The Cool Event is almost over.
The Cool Event sure looks like it has peaked and is in decline. There are now other reasons to believe it is not temporary but the decline phase of this quasi-La Nina Modoki. But really there has not been much of a change this week.

I had stopped showing the below graphic which is more focused on the Equator but looks down to 300 meters rather than just being the surface. But over the last month there has been sufficient change to warrant including this graphic.

December 26, 2016 Upper Ocean Heat Anoma

NOAA has dashed-in the upwelling phase of the multiple Kelvin Waves that has created this pseudo-La Nina and you can see that it is playing out just as NOAA upgrades the status of this Cool Event. However a small cool area has been clearly visible at 155W to 145W which has caused the Nino 3.4 reading hover around La Nina range. But now we see that cool anomaly is no longer there on this graphic.  On the other hand way to the west you can see the warm pool building for the next El Nino.
The life cycle of a La Nina is based on the reservoir of cool water that formed in the Eastern Pacific rising or mixing out or being warmed by sunshine or otherwise returning to a more normal temperature. Unlike an El Nino, there is no reinforcements from the west available to the Cool Event. So it is just a matter of time for the surface to return to ENSO Normal Limits. The currents in the subsurface are complex and there are winds impacting the surface so the exact process is difficult to forecast. So really the only issue here is will the process play out in December or in January. The white and yellow area is ENSO Neutral. So only that small blue area between 170W and 120W is in play right now but in this graphic we see no blue there. It is a very slim reed for those who conclude that we are in a La Nina.

Let us look in more detail at the Equatorial Water Temperatures.

We are now going to change the way we look at a three-dimensional view of the Equator and move from the surface view and an average of the subsurface heat content to a more detailed view from the surface down. Notice by the date of the graphic (dated December 19, 2016 but it has been updated but NOAA has not gotten around the correct the date) that the lag in getting this information posted so the current situation may be a bit different than shown although this graphic was updated today so it is more current than usual. The date shown is the midpoint of a five-day period with that date as the center of the five-day period.

And now the pair of graphics that I regularly provide. The bottom graphic shows the absolute values, the upper graphic shows anomalies compared to what one might expect at this time of the year in the various areas both 130E to 90W Longitude and from the surface down to 450 meters. At different times and today in particular, I have discussed the difference between the actual values and the deviation of the actual values from what is defined as current climatology (which adjusts every ten years except along the Equator where it is adjusted every five years) and how both measures are useful but for different purposes.

Subsurface Heat Anomalies

Re the top graphic, let us first look at surface temperature anomalies. The coolest water at the surface shows up only in very small non-connected areas except right off the coast of Ecuador.  Water of La Nina coolness but not very intense shows up along the Equator from 170W to the Coast of Ecuador but with significant gaps of less cool water. The -1C water shows most strongly east of the Nino 3.4 Measurement Area and only in a small area from 165W to 150W. Subsurface Temperature Anomalies: Notice that the cool anomaly in excess of -1C no longer exists within the Nino 3.4 Measurement Area and appears to be rotating towards the coast and diminishing in size. How is this cool event to be sustained? It looks like 140W to 110W has gone to totally Neutral.
Notice the warm water at depth all the way to 140W. It is not a Kelvin Wave but may be a sign of things to come. We may see a Kelvin Wave in January or February.

The bottom half of the graphic (Absolute Values which highlights the Thermocline) is now more useful as we track the progress of this new Cool Event.

It shows the thermocline between warm and cool water. The 28C Isotherm is again located close to the Dateline at about 175W. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm is at 170W so we do not have ideal conditions for significant convection along the Equator east of the Dateline which is a characteristic of a Cool Event but it is shifting to the East. The 25C isotherm is at 140W (and the 24C isotherm is over almost to 120W) indicating the decline of the Cool Event. The 20C Isotherm seems to be being depressed. But all in all it is not much different than the December 14 graphic other than the subsurface warm anomaly consolidating. It is clearly a transition state and all of this is important not just for tracking this cool event but thinking about when the next El Nino might be triggered.
The flattening of the Isotherm Pattern is an indication  of ENSO Neutral just as the steepening of the pattern indicates La Nina or El Nino depending on where the slope shows the warm or cool pool to be.

Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.

Equatorial Temperature Simulation

Isotherm Simulation

Although I did not fully discuss the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures which remains relevant. What we have is only the upwelling phase of the series of Kelvin waves last winter.

December 26,  2016 Subsurface Temperatures.

There is cool water from 160W to the coast of Ecuador. But the coolest water, however, is only reaching the surface in the Nino 3.4 Measurement Area in one small place 165W to 150W and other graphics suggest it not longer reaches the surface there. The cooler than -1C anomaly no longer exists near the surface in the Nino 3.4 Measurement Area. So there is not much chance of the Nino 3.4 readings rising dramatically any time soon. And there is warmer water under the cool anomaly extending continuously and strengthening all the way to 140W. The coolest water remains over to the east where La Nina is not measured by NOAA. It is closer to the surface suggesting it will be gone soon. This is probably not the best place to express the thought but this way of measuring an ENSO event leaves a lot to be desired. Only the surface interacts with the atmosphere and is able to influence weather. The subsurface tells us how long the surface will remain cool (or warm). Anomalies are deviations from "Normal". NOAA calculates and determines what is "Normal" which changes due to long ocean cycles and Global Warming. So to some extent, the system is "rigged". Hopefully it is rigged to assist in providing improved weather forecasts. But to assume that any numbers reported can be assumed to be accurate to a high level of precision is foolhardy. It is strange to me that the Asian forecasting services generally conclude that that this cool ENSO Phase is not a La Nina but a near La Nina and NOAA concludes it is a La Nina but they express their confidence in that declaration in percentages. It is the same ocean. The reported readings are very close but the Asian readings are generally slightly higher (less La Nina-ish) than the NOAA reading and their cut-off points for declaring a La Nina are a bit different and the parts of the Equator they look at are a bit different. It might be explained by what part of the ENSO pattern impacts their area of geography but it just seems to me that NOAA is a bit over eager. And I wonder why.

And now Let us look at the Atmosphere.

Low-Level Wind Anomalies near the Equator

Here are the low-level wind anomalies.

Low Level Wlind Anomalies

The Easterlies (the blue) are suddenly again no longer there in the Eastern Pacific probably because of MJO action. There are Easterlies west of the Dateline. It is fairly normal at this point. Some of the forecasts call for a weak Inactive Phase of the MJO followed by a weak Active Phase which should first enhance the Easterlies in the Eastern Pacific and then decrease the Easterlies in the Kelvin Wave Generation Area and create the conditions for a Westerly Wind Burst creating a Kelvin Wave. The system is not ready for that just yet.

And now the Outgoing Longwave Radiation Anomalies which tells us where convection has been taking place. 

OLR Anomalies Along the Equator

This is the graphic used by NOAA to justify the upgrade in status of the Cool Event based on lack of cloudiness near the Dateline and to the east. That is true but there is a lack of cloudiness over by 80E as well and not much convection at 120E and convection from 80W towards land. Hard to describe this as anything other than ENSO Neutral.

And Now the Air Pressure which Shows up Mostly in an Index called the SOI.

This index provides an easy way to assess the location of and the relative strength of the Convection (Low Pressure) and the Subsidence (High Pressure) near the Equator. Experience shows that the extent to which the Atmospheric Air Pressure at Tahiti exceeds the Atmospheric Pressure at Darwin Australia when normalized is substantially correlated with the Precipitation Pattern of the entire World.

Below is the Southern Oscillation Index (SOI) reported by Queensland, Australia. The first column is the tentative daily reading, the second is the 30 day moving/running average and the third is the 90 day moving/running average.

Date Current Reading 30-Day Average 90 Day Average
Dec 20 +23.66 +2.51 +0.43
Dec 21 +20.60 +3.12 +0.58
Dec 22   -0.36 +2.95 +0.49
Dec 23   *  (-670.93)?    
Dec 24   -7.84    
Dec 25   -6.12    
Dec 26   -0.36    

* The reported value  for December 23  is questionable so I will wait to see if there is a correction to that reported value. The 30-day average, which is the most widely used measure, as of December 22 (to avoid having to deal with the question of the reasonableness of the value reported on December 23) was reported at +2.96 which is up a bit from last week but remains an ENSO Neutral Value. The 90-day average at +0.49 is similar to last week and again solidly Neutral. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. The disparity between the two is one reason why we look at both. (Sustained values over +7 are usually associated with La Nina and less than -7 are usually associated with El Nino). To some extent it is the change in the SOI that is of most importance. It had been increasing in September but now in October and November and through most of December has stabilized in the Neutral Range. That could change but for now the SOI is not signaling a La Nina but ENSO Neutral.

The MJO or Madden Julian Oscillation is an important factor in regulating the SOI and Kelvin Waves and other tropical weather characteristics. More information on the MJO can be found here. Here is another good resource. November was not particularly favorable for La Nina development and most likely neither will be December in terms of the MJO.The forecasts of the MJO are all over the place and not suggesting a strong Active or Inactive Phase of the MJO any time soon.The MJO being Inactive is more favorable for La Nina than the MJO being Active. But the MJO goes back and forth from being Active, Inactive, strong and weak so it has mostly a short-term impact. It is possible that a weak Inactive Phase of the MJO might be giving this dying La Nina a little reprieve but the forecast is that this will soon change to a weak Active Phase so it is not very significant other than on a weekly basis.

Lately, the impact has been fairly muted. But the change in the SOI recently and some other changes suggest that we are having an Active Phase of the MJO even if such is not being reported and what we have is not the MJO but something else that is impacting the cool pool in a similar way as an Active MJO would. The forecast for the MJO is updated weekly and can be found here. If the MJO is not in its Active Phase then perhaps some other pattern is impacting the SOI and also shifting the cool pool to the east. We are also having a non-split fairly strong Jet Stream which is also consistent with an Active MJO. So I am calling it a Stealth MJO.

The MJO tends to be more important when the situation is ENSO Neutral and the MJO can start the process of an El Nino getting started. It is less significant re the initiation of a La Nina but is a factor. It is surprising how weak the MJO has been for months. But it may account for what seems like a cycling of the estimate of Nino 3.4 as the cool water is blown first to the west and then to the east. This impacts the upwelling also.

Forecasting the Evolution of ENSO

We have the December early-month report from CPC/IRI which I call the reading of the tea leaves in that it is based on a combination of model results and a survey of the views of meteorologists.

Figure 1 is based on a consensus of CPC and IRI forecasters, in association with the official CPC/IRI ENSO Diagnostic Discussion

December 8, 2016 IRI/CPC Consensus based ENSO forecast.

Now we have the December 15, 2016 fully model-based version .

December 15, 2016 Model Based ENSO Forecast

And here is the discussion that was released with the graphic.

What is the outlook for the ENSO status going forward? The most recent official diagnosis and outlook was issued one week ago in the NOAA/Climate Prediction Center ENSO Diagnostic Discussion, produced jointly by CPC and IRI; it carries a La Niña advisory and called for weak La Niña to last through winter 2016-17 (i.e., for December-February), and for a transition to neutral to occur by late winter. The latest set of model ENSO predictions, from mid-December, now available in the IRI/CPC ENSO prediction plume, is discussed below.  Those predictions suggest that the SST could remain in the weak La Niña category during the rest of 2016 and into the early part of 2017, or may return to neutral by the New Year.

As of mid-November, 17% of the dynamical or statistical models predicts La Niña conditions for the initial Dec-Feb 2016-17 season, while 83% predict neutral ENSO.  At lead times of 3 or more months into the future, statistical and dynamical models that incorporate information about the ocean’s observed subsurface thermal structure generally exhibit higher predictive skill than those that do not. For the Mar-May 2017 season, among models that do use subsurface temperature information, no model predicts La Niña conditions, 89% predicts ENSO-neutral conditions, and 11% predicts El Niño conditions. For all model types, the probabilities for La Niña are 9% for Jan-Mar 2016-17, and less than 5% for all subsequent seasons out to Aug-Oct 2017. The probability for neutral conditions is at least 70% for all seasons through the final season of Aug-Oct 2017, and rise to greater than 90% from Jan-Mar through Apr-Jun 2017. Probabilities for El Niño are near zero initially, rise to 5-10% by Mar-May 2017, and to 25-30% from Jun-Aug through the final season of Aug-Oct.

So even the IRI/CPC realizes the game is up re promoting a phantom La Nina. Even if one accepted the NOAA JAS reported value which I do not, this Cool Event does not qualify to be recorded as a La Nina due to insufficient duration. It may be accepted by NOAA as having been a La Nina but it will not be in Asia and this complicates statistical analysis and is not a good practice. One needs discipline to be a scientist and NOAA has been showing a disturbing lack of discipline. This is a Cool Event and close to meeting the criteria for being considered a La Nina but close only counts in horseshoes.

Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.

 CFS.V2 SST Forecast

The estimated current actually after the adjustments have been applied is cooler (more La Nina-ish)  than last week. It is now Borderline La Nina but rising into Neutral. And out to next summer you see some El Nino members of the forecast ensemble but it is before the Spring Prediction Barrier which means we need to wait a few months before getting  excited about that. But we clearly are forecast to be in ENSO Neutral for the rest of this Winter.

The full list of weekly values can be found here.

Forecasts from Other Meteorological Agencies.

Here is the Nino 3.4 report from the Australian BOM (it updates every two weeks)

Australia POAMA ENSO model run

Discussion (notice their threshold criteria are different from NOAA but also their actuals are higher than recorded by NOAA and yet Nino 3.4 is standard. So someone is incorrect OR WORSE.)

Here is the discussion.

ENSO outlooks

Outlooks from the eight international climate models surveyed by the Bureau indicate that neutral ENSO conditions are likely for the remainder of the southern hemisphere summer.

One model continues to indicate an increased likelihood of the central tropical Pacific Ocean briefly exceeding La Niña thresholds before warming. All models indicate warming of the central Pacific is likely over the coming months.

Most models maintain neutral outlooks through to May 2017; however one model suggests strong warming may be possible in autumn, reaching El Niño thresholds in May. It must be noted that this outlook straddles the autumn predictability barrier—typically the ENSO transition period—during which most models have their lowest forecast accuracy.

We also have the most recent JAMSTEC December 1,  2016 ENSO forecast.

JAMSTEC December 1, 2016 Two Year Enso Forecast

The model continues to show ENSO Neutral or what they call a weak La Nina Modoki gradually ending. The potential for an El Nino had been taken out of the forecast last month but is  back in the  forecast again.  The JAMSTEC Discussion is shown earlier in this report.

Indian Ocean IOD (It updates every two weeks)

The IOD Forecast is indirectly related to ENSO but in a complex way.



Indian Ocean Dipole outlooks

The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 18 December was −0.23 °C.

The influence of the IOD on Australian climate is weak during the months of December to April. This is because the monsoon trough shifts south over the tropical Indian Ocean changing wind patterns, which prevents an IOD pattern from being able to form.

However, the continued presence of much warmer than average water to the north and northwest of Australia may see continued influence on Australia, including enhanced rainfall

D. Putting it all Together.

Looks like this Cool Event is no longer even properly described as La Nina Conditions Apply.

Forecasting Beyond Five Years.

So in terms of long-term forecasting, none of this is very difficult to figure out actually if you are looking at say a five-year or longer forecast. The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.   It includes decade by decade predictions through 2050 which this week I have included in the discussion in the first part of this Weather and Climate Report. Predicting a particular year is far harder. Parts of that discussion are in the beginning  section of this week's Report.

The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. It looks like it may follow  this ENSO Cool Event this summer or perhaps the Cool Event will last for one more year.  JAMSTEC is suggesting that if there is an El Nino in the winter of 2017/2018 this could signify that the PDO has entered its Positive Phase. The AMO is pretty much neutral at this point (but more positive i.e. warm than I had expected) so it may need to become a bit more negative for the McCabe A pattern to become established. That seems to be slow to happen so I am thinking we need at least a couple more years for that to happen. JAMSTEC is suggesting it might occur very soon.

E. Relevant Recent Articles and Reports

Weather in the News

Nothing to report

Weather Research in the News

Nothing to report.

Global Warming in the News

Nothing to report

F. Table of Contents for Page II of this Report Which Provides a lot of Background Information on Weather and Climate Science  

The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page II where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.

1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)

2. Medium Frequency Cycles such as ENSO and IOD

3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.

4. Computer Models and Methodologies

5. Reserved for a Future Topic  (Possibly Predictable Economic Impacts)

G. Table of Contents of Contents for Page III of this Report  - Global Warming Which Some Call Climate Change.  

The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page III where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.

1. Introduction

2. Climate Impacts of Global Warming

3. Economic Impacts of Global Warming

4. Reports from Around the World on Impacts of Global Warming

Useful Background Information

With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.

  El Ninos La Ninas
  Start Finish Max ONI PDO AMO Start Finish Max ONI PDO AMO
            DJF 1950 J FM 1951 -1.4 - N
T   JJA 1951  DJF 1952 0.9 - +          
   DJF 1953  DJF 1954 0.8 - + AMJ 1954  AMJ 1956 -1.6 - +
M MAM 1957   JJA 1958 1.7 + -          
M SON 1958  JFM 1959 0.6 + -          
M   JJA 1963  JFM 1964 1.2 - - AMJ 1964  DJF 1965 -0.8 - -
M  MJJ 1965 MAM 1966 1.8 - - NDJ 1967 MAM 1968 -0.8 - -
M OND 1968   MJJ 1969 1.0 - -          
T  JAS 1969   DJF 1970 0.8 N -  JJA 1970  DJF 1972 -1.3 - -
T AMJ 1972  FMA 1973 2.0 - - MJJ 1973 JJA 1974 -1.9 - -
            SON 1974 FMA 1976 -1.6 - -
T ASO 1976  JFM 1977 0.8 + -          
M ASO 1977

 DJF  1978

0.8 N -          
M SON 1979  JFM 1980 0.6 + -          
T MAM 1982  MJJ  1983 2.1 + - SON 1984 MJJ 1985 -1.1 + -
M ASO 1986  JFM 1988 1.6 + - AMJ 1988 AMJ 1989 -1.8 - -
M MJJ 1991     JJA 1992 1.6 + -          
M SON 1994   FMA 1995 1.0 - - JAS 1995 FMA 1996 -1.0 + +
T AMJ 1997   AMJ 1998 2.3 + + JJA 1998 FMA 2001 -1.6 - +
M MJJ 2002   JFM 2003 1.3 + N          
M  JJA 2004 MAM 2005 0.7 + +          
T ASO 2006   DJF 2007 1.0 - + JAS 2007  MJJ 2008 -1.4 - +
M JJA 2009 MAM 2010 1.3 N + JJA 2010 MAM 2011 -1.4 + +
            JAS 2011 FMA 2012 -0.9 - +
T MAM 2015 NA 1.0 + N          


ONI Recent History

ONI History Updated on December 5, 2016

The Aug/Sept/Oct reading has been issued and is currently listed as -0.7. The Sep/Oct/Nov preliminary estimate is -0.8 so there would now need for there to be two more periods of -0.5 or colder for this to be eligible to be formally recorded as a La Nina. I suspect there will be one more but not two. NOAA seems to be determined to make that happen. THEIR FUNDING MAY DEPEND ON THAT.

The full history of the ONI readings can be found here. The MEI index readings can be found here.

Click here for a list of Sig Silber's Weather Posts

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