NOAA on November 10, issued this Advisory: La Nina Conditions exist. This November 10 post on Climate.gov from the person who prematurely declared there to be an El Nino in the Winter of 2014/2015 is clearly the trigger for the issuance of this NOAA Advisory. The use of the term "La Nina Conditions" is kind of a sleight of hand.
"La Nina Conditions" is a combination of an assessment of current conditions with an expectation that such conditions will prevail for a while. It is not a declaration that a La Nina Event occurred as that can only happen after the fact. So it is a lot like reporting half-time football scores as final scores. Then there is the question of the value of such a declaration. It does not in any way impact weather forecasts. I doubt that it changes how public safety and related agencies operate. I suspect those with the most interest in that declaration were commodity traders and that is what bothers me about it.
I want to be clear. It is not that one could not reasonably conclude that La Nina Conditions prevail. For me it is the question of why change the status of this Cool Event now. The SOI is not confirming that we have a true La Nina. The Nino 3.4 readings are marginal for a La Nina, have been more indicative of a La Nina prior to now, and are forecast to slowly increase i.e. move towards ENSO Neutral. So it is almost as if the thinking was that "if we do not upgrade the La Nina Status right now, we will not be able to justify doing so two weeks from now." That bothers me a bit.
A specific problem with the analysis by Emily Becker relates to her flow chart.
I think the correct answer to that question in her decision tree is clearly "No". Her use of the word "several" is problematic as "several" generally means at least four and that certainly is not what she meant. The models suggest that Nino 3.4 will remain less than -0.5C through January. This is November so that is not even several months. So, to me, it was clearly a stretch.
Of great interest is the question of how one detects ENSO signals in a world where oceans are warming. NOAA is diligent about updating their baseline along the Equator every five years. But that may not be sufficient to be able to identify ENSO states since although the anomalies along the Equator are the metrics used to identify the two extremes phases of ENSO: El Nino and La Nina, ENSO is more that just what is going on along the Equator in the Pacific Ocean. So this makes me a bit more sympathetic to this issuance of an upgrade.
A. Focus on Alaska and CONUS (all U.S. except Hawaii) - Let's Focus on the Current (Right Now to 5 Days Out) Weather Situation.
First some housekeeping information. Working on a Glossary of Terms but right now it is empty. But, at some point, it will be possible to look up acronyms etc by going to the GEI Weather Page Glossary. Also for those who want the forecasts beyond three months, we previously reported on the October 20 NOAA 15 Month Forecast and compared their the first ten months of the NOAA Outlook with that of JAMSTEC in a special Update that you can get to by clicking here. We will publish a new 15 Month Update Report shortly after November 17, 2016.
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.
First, this graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.
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 poised to cross the Northern Tier of CONUS.
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.
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.
The Aleutian Low It is now shown as a large Split Low with the more significant part with central air pressure of 976 hPa over by Kamchatka Siberia. The other part is near the Gulf of Alaska with the central air pressure being 1000 hPa. That Low is kind of westerly displaced and just south of the Middle Aleutian Chain. It is more consistent with La Nina perhaps but certainly less able to impact North America. 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 there (1020 hPa). Thus, right now the RRR is doing only a fair job of protecting the West Coast from Pacific storms and also providing northerly winds for California. 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.
Here is the seven-day precipitation forecast. More information is available here.
What you are seeing here is mostly West Coast precipitation but much further north than last week.
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. This week we do not see the 540 line thinking about entering CONUS. Remember that 540 relates to sea level. Inland from the Northwest you re above sea level so snow is likely.
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 somewhat muted Rocky Mountain Ridge and a trough along the East Coast. Remember this is a forecast for Day 7.
The graphic below is the Eastern Pacific a 24 hr loop of recent readings. It does a good job of showing what is going on right now. The winds and moisture approaching the West are of most interest. Notice
The graphic below (which is a bit redundant with the above) updates automatically so it most likely will look different by the time you look at it as the tropical weather patterns unlike the patterns north of 30N are generally moving from east to west. This graphic highlights tropical activity. Unlike the above which shows recent history, the below graphic is a satellite image with the forecast of tropical events superimposed on the satellite image. There is no significant "new" tropical activity that would appear to impact CONUS forecast for the beginning of this week. Tina does not appear to be a threat to CONUS but there may be a more significant storm next week. There is an area of interest in the Caribbean just off of Costa Rica and it is not clear what if anything might develop from that situation.
Below is the current water vapor Imagery for North America.
Tonight, Monday evening November 14, 2016 (and this is the current situation not an animation of recent history), as I am looking at the above graphic, we see mostly Northern tier activity.
Looking at the current activity of the Jet Stream.
One sees a split flow.
Now let's look at the situation on Day 5 below. You can see what appears to be significant activity. Of course this graphic changes every six hours.
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 very important in understanding the impacts north and south of the Jet Stream which is shown as the higher speed part of the wind circulation. 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.
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.
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 NDJ Outlook (for reference purposes), the Updated Outlook for the single month of November, the 6 - 10 Day and 8 - 14 Day Maps and the Week 3 - 4 Experimental Outlook.
First - Temperature
Here is the Three-Month NDJ Temperature Outlook issued on October 20, 2016:
Here is the Updated Temperature Outlook for November which was issued on October 31, 2016
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
As I view these maps on November 14 (two of the five update each day and one (the Week 3 - 4 Outlook) updates every Friday, it appears that the pattern during November 20 to 28 will be warm almost everywhere including Alaska and morph as we move into the November 26 to December 9 period into a pattern where a small part of the Northeast will be EC and a larger part of the West from mid-Oregon through Arizona will be EC with the rest of CONUS and Alaska being warm. To be "warm" with respect to anomalies means warmer than usual for this time of year and "cool" with respect to anomalies means cooler than usual for this time of the year. The graphic shows the level of probability of being different from EC.
Now - Precipitation
Here is the three-month NDJ Precipitation Outlook issued on October 20, 2016 :
And here is the Updated Outlook for November Precipitation Issued on October 31, 2016
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
Looking further out.
As I view these maps on November 14 (two of the five update each day and one (the Week 3 - 4 Outlook) updates every Friday, it looks like precipitation for November 20 to 28 will be generally dry in the Southeast and East Coast with wet weather systems entering the West at different Latitudes from time to time during this period. This will morph as we enter the period November 26 to December 9 into a pattern where we will have a small wet anomaly in the Northwest and a large North Central dry anomaly. This is more of an ENSO Neutral Pattern than a La Nina Pattern. When discussing anomalies, "wet" means wetter than usual for this time of the year and "dry" means drier than usual for this time of the year. The graphic shows the level of probability of being different from EC.
Here is the NOAA discussion released today November 14, 2016
6-10 DAY OUTLOOK FOR NOV 20 - 24 2016
TODAY'S NUMERICAL MODEL SOLUTIONS ARE IN FAIR AGREEMENT ON THE 500-HPA FLOW PATTERN PREDICTED OVER THE FORECAST DOMAIN. THE OFFICIAL BLENDED HEIGHT PATTERN FEATURES TROUGHS OFF THE WEST COAST AND OVER THE NORTHEASTERN CONUS. A RIDGE IS FORECAST OVER THE WESTERN CONUS AND WESTERN CANADA. BELOW NORMAL HEIGHTS ARE FORECAST FOR THE WEST COAST, EASTERN THIRD OF THE CONUS AND SOUTHERN ALASKA, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE PREDICTED FOR THE REMAINDER OF THE CONUS AND NORTHERN ALASKA. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE SMALL TO MODERATE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN. THE GREATEST WEIGHT WAS GIVEN TO THE GFS SUPERENSEMBLE MEAN BASED ON CONSIDERATIONS OF RECENT SKILL AND ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE FORECAST PATTERN MATCHES CASES THAT HAVE OCCURRED IN THE PAST.
BELOW NORMAL HEIGHTS AND TROUGHING OVER THE NORTHEASTERN CONUS TILT THE ODDS FOR BELOW NORMAL TEMPERATURES FOR MOST OF THE EASTERN CONUS. POSITIVE 500-HPA HEIGHT ANOMALIES AND RIDGING ENHANCE PROBABILITIES FOR NEAR TO ABOVE NORMAL TEMPERATURES FOR THE CENTRAL AND WESTERN CONUS AS WELL AS MAINE. ABOVE NORMAL TEMPERATURES ARE MOST FAVORED FOR THE SOUTHWEST, WHERE TEMPERATURE TOOLS ARE IN THE BEST AGREEMENT. NEAR TO ABOVE NORMAL TEMPERATURES ARE FAVORED FOR ALASKA, WHICH IS CONSISTENT WITH CALIBRATED REFORECAST TEMPERATURE TOOLS FROM GFS ENSEMBLE FORECASTS.
ABOVE MEDIAN PRECIPITATION IS FAVORED FOR THE WESTERN CONUS AHEAD OF A TROUGH PREDICTED OVER THE EASTERN PACIFIC. THERE ARE ENHANCED PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION FOR THE NORTHEAST IN ASSOCIATION WITH THE TROUGH OVER THE NORTHEASTERN CONUS. POSITIVE 500-HPA HEIGHT ANOMALIES AND RIDGING ENHANCE PROBABILITIES FOR BELOW MEDIAN PRECIPITATION FOR THE CENTRAL CONUS. BELOW MEDIAN PRECIPITATION IS FAVORED FOR MOST OF THE EASTERN CONUS IN ASSOCIATION WITH PREDICTED SURFACE HIGH PRESSURE. PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLE MEMBERS FAVOR BELOW MEDIAN PRECIPITATION FOR MUCH OF ALASKA.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE MODELS AND TOOLS.
8-14 DAY OUTLOOK FOR NOV 22 - 28 2016
TODAY'S ENSEMBLE MEAN DYNAMICAL MODEL FORECASTS ARE IN FAIR AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA FOR THE WEEK-2 PERIOD. TROUGHS ARE FORECAST OFF THE WEST COAST AND NEAR THE NORTHEASTERN CONUS, WHILE RIDGING IS PREDICTED OVER THE NORTHERN ROCKIES AND WESTERN CANADA. TODAY'S 500-HPA BLEND CHART DEPICTS BELOW NORMAL HEIGHTS FOR THE WEST COAST, EASTERN THIRD OF THE EASTERN CONUS, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE FORECAST FOR THE REMAINDER OF THE CONUS. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE TO LARGE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN. THE GREATEST WEIGHT WAS GIVEN TO THE EUROPEAN ENSEMBLE MEAN BASED ON CONSIDERATIONS OF RECENT SKILL AND ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE FORECAST PATTERN MATCHES CASES THAT HAVE OCCURRED IN THE PAST.
BELOW NORMAL HEIGHTS AND TROUGHING NEAR THE NORTHEASTERN CONUS TILT THE ODDS FOR BELOW NORMAL TEMPERATURES FOR MUCH OF THE EASTERN CONUS. POSITIVE 500-HPA HEIGHT ANOMALIES AND RIDGING ENHANCE PROBABILITIES FOR NEAR TO ABOVE NORMAL TEMPERATURES FOR THE CENTRAL AND WESTERN CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR ALASKA, WHICH IS CONSISTENT WITH CALIBRATED REFORECAST TEMPERATURE TOOLS FROM GFS ENSEMBLE FORECASTS.
ABOVE MEDIAN PRECIPITATION IS FAVORED FOR THE WESTERN CONUS, PARTS OF THE CENTRAL PLAINS AND THE MIDDLE MISSISSIPPI VALLEY AHEAD OF A TROUGH PREDICTED OVER THE EASTERN PACIFIC. POSITIVE 500-HPA HEIGHT ANOMALIES AND RIDGING ENHANCE PROBABILITIES FOR BELOW MEDIAN PRECIPITATION FOR THE NORTHERN ROCKIES AND EASTERN ALASKA. PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLE MEMBERS FAVOR BELOW MEDIAN PRECIPITATION FOR THE EAST COAST AND GULF COAST STATES.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE MODELS AND TOOLS.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON NOVEMBER 17
Some might find this analysis 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.
Nov 15, 1954
Long strong La Nina
Oct 31, 1958
Nov 1, 1958
Minor El Nino Modoki Type II
Nov 7, 1981
Minor El Nino Modoki Type II
Nov 10, 1981
Oct 30, 1983
After the 82/83 very strong El Nino
Nov 10, 1987
Modoki Type I
Nov 15, 2001
Nov 18, 2001
(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 October 30 to November 18 which is only 19 days which is a fairly tight spread. 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 November 9. These analogs are centered on 3 days and 4 days ago (November 10 or 11). 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 the Fall/Winter.
There are three El Nino Analogs (why are there any?), just one La Nina Analog (truly strange but consistent with the Aleutian Low situation), and five ENSO Neutral Analogs. The phase of the ocean cycles in the analogs points strongly towards McCabe Condition A. This is somewhat consistent with the 6 - 14 Day Outlook. .
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.
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 in recent months. Because it is now November, I have removed the July, August, and September Graphics.
Here is the 30 Days ending November 5, 2016
The pattern is more distinct and La Nina-ish than least week re Precipitation. The Temperature departures are not much changed. Remember only seven recent days have been added and seven more distant days have been removed.
And the 30 Days ending November 12, 2016
Not much change.
B. Beyond Alaska and CONUS Let's Look at the World which of Course also includes Alaska and CONUS
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 hitting your "backspace" key which 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
Notice the strong low pressure system in the North Atlantic.
Looking Out a Few Months
This is the precipitation forecast from Queensland Australia.
It is kind of amazing that you can make a worldwide forecast based on just one parameter the SOI and changes in the SOI. Notice that the FALLING SOI triggers a different pattern of wet and dry than we showed last week. A couple of weeks 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.
JAMSTEC issued their Precipitation Forecast recently based on the October 1, 2016 ENSO analysis. Notice this forecast is for December 2016 through February 2017.
It is pretty interesting especially for Southern Europe, Southeast Asia, Southern Africa especially to the west, South America, and a standard but muted La Nina Pattern for CONUS extending into British Columbia.
Here I just focused on Europe and CONUS
Kind of Dry! For the most part. Remember this is December 2016 through February 2017
Here is the temperature forecast
Northern Europe will be cool as well as parts of Northern Australia and Brazil and Kamchatka which could be important. Other than that, Global Warming Deniers might have to seek higher elevations.
There is a discussion that goes with it:. .
Oct. 17, 2016
Prediction from 1st Oct., 2016
According to the SINTEX-F prediction, the current weak La Niña Modoki will start decaying and the tropical Pacific will return to a normal state by boreal spring. The model prediction appears to be consistent so far with the observed evolution of the sea surface temperature (SST) anomalies.
Indian Ocean forecast:
The negative Indian Ocean Dipole will start decaying and disappear in boreal winter. A positive Indian Ocean Dipole may evolve in early summer of 2017. However, it is still uncertain at the present stage.
In boreal winter, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while some parts of Brazil, northern Europe, and northern Australia will experience a colder-than-normal condition.
According to the seasonally averaged rainfall prediction, eastern China, Indo-China, East Africa, most parts of Europe, U.S. and the Far East (including Japan) might experience a drier condition during boreal fall, while most parts of Brazil, southern West Africa, western Central Africa, and South Africa will experience a wetter-than-normal condition. Australia will receive above normal rainfall during austral summer. Most parts of Japan will experience above normal temperature and below normal precipitation (less snowfall) in winter. Those may be associated with a warm Indian Ocean and a weak La Niña Modoki in the Pacific.
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.
Remember this discussion is all about anomalies not absolute temperatures...so it is deviation from seasonal norms.
The waters north and east of Japan are very cool as are the waters south and east of Kamchatka Siberia, The Central Indian Ocean is now basically IOD Neutral or perhaps even Positive. The waters off the Southern Coast of Australia are very cool but the Southeast Coast is slightly warm. Water north and east of Australia is warm but not as much as one might expand with La Nina. The waters south of Africa are mostly cool.
The overall Northern Pacific no longer looks to be PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape there) mostly because of the lack of warm water east of the cool water. But the cool anomaly is growing. 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 -0.87. The above would make the PDO now NEGATIVE. Here is the list of PDO values.
The waters west of CONUS are now slightly warm and very warm west of Mexico up to Baja. Further north, the Gulf of Alaska is quite warm with the Bering Straits even warmer.
The Black sea and the Caspian sea are now cool. The Mediterranean is warm.
The water directly west of South America is not showing much of a strong La Nina pattern. There is a narrow cool anomaly in the Pacific right along the Equator in the La Nina Measurement Area. Recently it has appeared to be a bit more robust. We are told that the MJO is not significant right now but for a while it appeared to have moved the cool pool to the east as would occur with the Active Phase of the MJO. The water off the West Coast of Central America is quite warm.
The U.S. Great Lakes are warm. The water off the East Coast of CONUS is a bit warm but less so than recently. The Western Gulf of Mexico is warm. Further north in the Atlantic east of Newfoundland the North Atlantic is warmer than normal. The cool anomaly south of Newfoundland again shows. There is a a very small and weak warm anomaly off shore of Northwest Africa. The waters north of Antarctica East of South America are now much less cooler which is a big change.
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.
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 has no time component. It is simply the 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.
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 this week a decline in the warming trend in the Western Indian Ocean. Perhaps we also see a decline in the cooling trend for the Maritime Continent. 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.
Look at the Western Pacific in Motion.`
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 in motion (last 24 hours) not a forecast. But it provides a pretty good idea of what is heading towards Southeast Asia and the Maritime Continent. It also shows what is headed back towards CONUS. Information on Western Pacific storms can be found here. This is an unofficial private source but one that is easy to read.
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 November 8, 2016 Version and looking at Week 2 of that forecast.
Mostly I see for week one, the period November 16, 2016 to November 22, 2016, it will be likely dry for the Maritime Continent and the southern tip of India but possibly stormy for the Philippines It is kind of an El Nino pattern for Asia. But the wet anomaly in Brazil and the Antilles and the possible cyclonic activity for Panama is more common with La Nina. Looks like Africa will participate in higher than normal precipitation in places.
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.
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.
Location Bar for Nino 3.4 Area Above and Below
I have not provided here the information needed to assess the shift in the cool pool to the east.
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
Degrees of Coverage
As of Today
May 23, 2016
As of Today
May 23 2016
As of Today
In Nino 3.4
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
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 50 degrees of water anomalies cool enough to be a La Nina. Subtracting 50 degrees from the 50 degrees you end up with 0 degrees of ENSO Neutral and 50 degrees of water cool enough to qualify as La Nina i.e. temperature anomalies more negative than -0.5C. There are today 30 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 zero 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 when a La Nina is trying to get started. The water from 3N to 5N and from 3S to 5S had until recently remained relatively warm especially west of 150W. But now the cool anomaly is fairly well distributed within the Nino 3.4 Measurement Area but the cooler water below is not reaching the surface rapidly and is slowly dissipating.
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 November 14, in the afternoon working from the November 13 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
A. 170W to 160W
B. 160W to 150W
C. 150W to 140W
D. 140W to 130W
E. 130W to 120W
Total divided by five subregions i.e. the ONI
(-4.4)5 = -0.9
(-3.3)/5 = -0.7
My estimate of the daily Nino 3.4 SST anomaly has become less negative at -0.7 which is a La Nina value. NOAA has reported the weekly ONI to be slightly less La Nina-ish this week at -0.7 which is still a La Nina value. Their estimate and mine agree this week..
Nino 4.0 is reported as being slightly less cool at -0.5. Nino 3 is being reported slightly less cool at -0.4. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is back to positive at +0.4.
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.
This is from a legacy "frozen" NOAA system meaning it 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. The recent readings are lower than any we have seen so far.
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.
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 (please include white with the blue as white is not La Nina but it is ENSO neutral) has again moved further west. 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.
The Cool Event is still developing and has not definitively peaked but appears to not be developing with much gusto. We may soon see a Kelvin Wave signaling the demise of this Cool Event.
In recent weeks I have stopped showing the below graphic which is more focused on the Equator but looks down to 300 meters rather than just being the surface. There has until this week been almost no change from the prior week but over the last month there has been sufficient change to warrant including this graphic this week..
I think you can see that the cool pool is ever so slowly declining at least the more intense part and has shifted to the east a bit. That is probably related to ocean currents. There is a bit more cooling at 95W. We are also perhaps starting to see some warm water way to the west. It is pretty clear that this cool event has peaked.
Let us look in more detail at the Subsurface Water Temperatures.
Equatorial Subsurface Analysis
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.
Current Sub-Surface Conditions. Notice by the date of the graphic (dated November 9, 2016) that the lag in getting this information posted so the current situation may be a bit different than shown. 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 above pair of graphics showing the current situation has an upper and lower graphic. 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) and how both measures are useful but for different purposes.
The top graphic shows surface temperature anomalies. The coolest water at the surface shows up only in small non-connected areas. Water of La Nina coolness but not very intense shows up along the Equator from Dateline to the Coast of Ecuador but with significant gaps of less cool water. The -1C water shows most strongly between 170W to 120W. Notice that the cool anomaly in excess of -2C is not close to the surface within the Nino 3.4 Measurement Area and appears to be rotating to towards the coast. How is this cool event to be sustained?
Notice the warm water at depth west of 165E.
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. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm has shifted west a bit to 175W 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. Notice the steepness of the 28C, 27C and 26C Isotherms but they are less steep than recently especially the 26C Isotherm. The 25C isotherm is again at 140W which is similar to last week. The 20C Isotherm has moved close to the surface but is not reaching the surface this week. The amount of warm water just west of the Dateline is also not real impressive either but growing and staying fairly far east. 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. This graphic helps understand the logic behind some of the forecasts of the Nino 3.4 Index. So it is still a battle going on with La Nina nudging ahead but not looking like it can sustain itself. It should peak soon.
It is why the models are having a hard time figuring out if this it a real deal La Nina or simply a cool event that comes close to being a La Nina..
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
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.
There is cool water from 170W to the coast of Ecuador. But the coolest water, however, is only reaching the surface in the Nino 3.4 Measurement Area from about 170W to 125W which is a slight increase over last week. The cooler anomaly is way below the surface. So there is not much chance of the Nino 3.4 readings rising dramatically any time 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 it in percentages. It is the same ocean. The reported readings are very close but the Asian readings are generally just 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.
The Easterlies (the blue) are suddenly again no longer there in the Eastern Pacific probably because of MJO action. I know there is no MJO right now but there are also diminished Easterlies as if there was an active phase of the MJO right now in the Eastern Pacific. There are Easterlies in the Central Pacific.
And now the Outgoing Longwave Radiation Anomalies which tells us where convection has been taking place.
In the above graphic, the area of convection at about 120E has become a bit less intense since last week.
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.
90 Day Average
The 30-day average, which is the most widely used measure, as of November 14 is reported at -2.38 which is less negative (i.e. less El Nino-ish) than last week. The 90-day average at +5.13 is essentially unchanged from last week. 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 but may now be stabilizing or going down. 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. October was not particularly favorable for La Nina development and most likely neither will be November 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.
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
The below is first the Late October CPC/IRI fully Model-Based Forecast issued on October 20, 2016 followed by the new forecast issued on November 10 which is based on a combination of model results and views of meteorologists. There should not be a big difference between the first and second forecasts in each month (presumably for the early forecast, the meteorologists consult their models in addition to reading tea leaves) but it is a difference and recently a huge one. I assume they do it this way as to avoid forcing meteorologists to have to run their computers twice a month (some sarcasm expressed there). I call the Early Forecast the "Reading of the Tea Leaves" Forecast as I do not have a lot of respect for it.
So first we have the previously released late-month Model-Based version.
And then the early-month reading of the tea leaves.which is based on a combination of model results and views of meteorologists. Recently the early month analysis has been more favorable for a la Nina than the later in the month model-based analysis.
This is a lot more bullish on La Nina happening than the prior late October report. There are two issues with this analysis. First most of the meteorological agencies in other nations do not see it this way and the second issue is duration. The above analysis only shows that La Nina conditions are favored through DJF. The center of DJF is January so basically the forecast is for La Nina conditions (considering only Nino 3.4) are to last through January. I also expect that the next edition of this analysis which will be issued probably by Tuesday November 22 will look very different. IMO opinion, NOAA took advantage of this fairly unscientific (survey based) Early Month CPC/IRI work product to help justify their issuance of a change in ENSO Status. In my opinion it is a sloppy way of doing business.
Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.
Notice the forecast is for the Nino 3.4 anomaly to become less cool i.e. less La Nina-ish very soon. If the forecasts turn out to be correct, we are at the peak of the Cool Event now and that adds to the perplexity of taking this week to upgrade the status of this Cool Event.
Here is the Nino 3.4 report from the Australian BOM (it updates every two weeks)
Some La Niña indicators strengthen; negative IOD nears end
The tropical Pacific Ocean remains El Niño–Southern Oscillation (ENSO) neutral, while the negative Indian Ocean Dipole (IOD) has continued to decay over the past fortnight, and is likely to be near its end.
In the tropical Pacific, some indicators such as cloudiness near the Date Line show La Niña-like characteristics, whereas sea surface temperatures (SSTs) in the central tropical Pacific Ocean and the Southern Oscillation Index (SOI) remain at neutral levels. Recent strengthening of the trade winds in the western tropical Pacific brings the potential for some further cooling of ocean waters. However, this strengthening is likely the result of a Madden–Julian Oscillation (MJO) pulse. Trade winds are likely to weaken in the coming weeks as the MJO passes. Hence it does not appear that the tropical Pacific atmosphere and ocean are currently reinforcing each other, as they would during the developing stages of a La Niña.
Most climate models predict the tropical Pacific Ocean will remain cooler than average, but ENSO-neutral, through until the end of the 2016–17 summer. Only one of eight models suggests the Pacific may briefly reach weak La Niña levels towards the end of 2016. A La Niña developing this late in the calendar year has only occurred once since 1980.
Warmer than average sea surface temperatures to Australia's north suggest that some La Niña-like impacts may occur, even if an event does not fully develop.
The negative IOD event, in place since late May, has weakened over the past fortnight. The monsoon trough has begun to move southward over the IOD region, which changes the wind patterns. This change means the negative IOD event is near its end, and this is supported by model outlooks. Both a negative IOD and La Niña typically contribute to increased rainfall in spring for eastern and central Australia.
We also now have the most recent JAMSTEC October 1 ENSO forecast.
The model continues to show ENSO Neutral for the next two years.
Indian Ocean IOD (It updates every two weeks)
Not directly related to ENSO is the IOD Forecast:
Indian Ocean Dipole outlooks
The negative Indian Ocean Dipole (IOD) event is drawing to a close. The weekly index value to 6 November was −0.30 °C. This marks the second week the index value has failed to exceed the threshold for a negative IOD event.
IOD events typically decay during spring, and the influence of the IOD on Australian climate is weak during the months December to May. This is because the monsoon trough shifts south over the tropical Indian Ocean changing wind patterns, which prevents the IOD pattern from being able to form.
However, the continued presence of much warmer than average water to the northwest of Australia may see continued influence on Australia, including enhanced rainfall.
Information on the impact of a negative IOD on Australia can be found here.
D. Putting it all Together.
According to some of the models, it seems likely to have La Nina conditions or even be declared to have been a full La Nina. But Australia and Japan do not see it that way and are not calling for a La Nina at this point in time. So NOAA is a bit the Odd Man Out but it is mostly a question of degree and in the end NOAA may turn out to have been correct. NOAA is calling for a borderline La Nina and the others are forecasting a La Nina-ish event that does not quite meet the criteria for being labeled a La Nina and does not last long enough to meet the criteria.
Nothing has changed in the past month so one wonders why NOAA felt compelled to issue a highly questionable change in the status of this Cool Event. It has zero impact on how weather forecasts are made. It equates to changing the wording from "possible but not sure" to "not sure but possible". It provides zero additional information to most users of weather forecasts other than commodity traders.
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. Predicting a particular year is far harder.
The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. It looks like it will require one more La Nina or ENSO Neutral event and this appears to be the way this might unfold. 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.
I posted it sometime back but I have still not had the time to fully digest and analyze this very important report. So I am carrying it forward.
An important issue is the validity of RCP 8.5 as a benchmark. Here is a good article on that. It has page after page of comments so here may be a shorter version with somewhat fewer comments.
I need to really thoroughly review this very important article and that will take some time. But here are some initial thoughts.
I did want to mention that under the McCabe et al analysis, one of the four combinations of ocean phases was a drought phase so that suggested that for approximately 25% of the time the chances of drought were very good. Thus one would have expected a significant drought once a century. So that is not new information.
McCabe et al also calculated a change in the situation due to Warming. That is not new information either.
So although this new analysis is more recent than the older analysis which was just after the PDO and AMO were figured out, to me it is not very different. The main difference is this paper has scenarios for the future. One probably could have developed them from the McCabe et al analysis. And they are talking about 35 year droughts which is not all that different from the droughts we have had once per century. My quick reading of the article did not come across the mention of El Nino. Are they in the analysis? I need to read more.
The authors make things simple with basically 2C, 4C, and 6C scenarios. How the 2C is defined is important. Apparently it is mean warming from 2051 to 2100 compared to 1951 to 2000. I like to use simple approaches so my mind I will think about it as 2075 compared to 1975. There are other papers that use a different way of measuring 2C (and 4C and 6C). Some
go back to 1750 or the beginning of the Industrial Revolution. Well if 1975 is the base even if the growth rate is steeper then linear there is still some room to get to 2C. We are about 40 years into the 100 year period used by the authors.
More when I have had a chance to really study this important paper.
The below is the key graphic:
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.
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.
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.
J FM 1951
ONI Recent History
The official reading for Jul/Aug/Sept has now been increased to -0.6.The JAS reading was the first La Nina Value. The Aug/Sept/Oct reading has now been issued and is currently listed as -0.7. So there would now need for there to be three more periods of -0.5 or colder for this to be eligible to be formally recorded as a La Nina. 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.
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