September 26, 2016 Weather and Climate Report – Not Quite the Camino Real

Written by Sig Silber

At this point we have a storm that appears to be headed towards Baja California today (Monday) and back towards Salt Lake City on Thursday. It made me think of the Camino Real or Royal Road of which there were at least a half dozen in Mexico. At any rate, this very meridional trough for so early in the Fall may well dominate CONUS weather this week. Elsewhere, Typhoon Megi may pass North of the Philippines on the way to Taiwan and then possibly Hong Kong.  Next week we may have an interesting situation in the Gulf of Mexico. Lots to talk about.

This West Coast storm to some extent seems to be retracing the path of a couple of the Royal Roads or El Camino Real of Old Mexico.But instead of Religion and Military uses and perhaps things of value like Macaws, the item this week will be moisture. 

First there is the Coastal Road which the trough is following south. Some call it the Mission Royal Road

There there is the more important, I believe, interior road.Those in California think their Camino Real is the real deal but the one that goes to Santa Fe connects to Mexico City so that kind of indicates which one was the real deal. It is odd that the one in California which was mostly a foot path is now a designated street in many places and the real one in New Mexico is mostly unknown but it passes near my house.

More on La Nada  But it could turn out this becomes a weak La Nina. There has been recent strengthening. But the report from NOAA today shows a weakening. It is tricky.

A New Mexico Fall Outlook Analysis that really covers the entire CONUS

I really like this graphic from the above article. .

The above does a good job of showing how many things are interconnected.

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

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

I have changed things up a bit and the below is a Day 3 Forecast not the Day 6 Forecast I usually present. It highlights the forecasted surface Highs and the Lows re air pressure on Day 3 (the Day 6 forecast can be found here.

You can enlarge the below daily (days 3 – 7) weather maps for CONUS only by clicking on Three Day or  Four Day or Five Day or Six Day or Seven Day 

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

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. I am leaving this explanation in the report but it may not be very significant until next October or so which now is NOW. But we do not yet see 540 snow levels so snow is likely now only in the mountains.

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 southwest winds approaching Baja California are of some interest. You can clearly see Tropical Storm Roslyn heading NE even though it is supposed to go north and then west.

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 weather patterns, except for the Southwest Monsoon, are moving from west to east. It highlights the 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 tropical activity forecast for this week but next week could be very very different.  

Below is the current water vapor Imagery for North America. 

Looking at the current activity of the Jet Stream.

Below is the forecast out five days.

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.

Special Alert re a Possible Week-Two Event

Here is the latest and it will auto-update. It is not clear what the impacts if any will be other than some increase in precipitation. This could  dissipate, impact Gulf Coast weather, pass over Central American into the Pacific etc. etc.It is not predicted to be a strong storm in terms of wind. But there is a good chance it will impact our weather. There is a new theory that it will turn north and impact Florida and perhaps then the East Coast. I think some of the quantitative precipitation forecasts have built that scenario into their estimates. I guess the definitive forecast on this is no one know where this tropical depression will go or what it might do.

Map courtesy of Kmusser  and Wikipedia

Four- Week Outlook

I am going to show the three-month OND Outlook (for reference purposes), the Updated Outlook for the single month of October, the 6 – 10 Day and 8 – 14 Day Maps and the Week 3 –  4 Experimental Outlook. 

First – Temperature

Here is the Three-Month OND Temperature Outlook issued on September 15, 2015, 2016:

Here is the Early Temperature Outlook for October which was updated on September 15, 2016

 6 – 10 Day Temperature Outlook

8 – 14 Day Temperature Outlook   

Looking further out.

 Now – Precipitation 

Here is the three-month OND Precipitation Outlook issued on September 15, 2016 :

And here is the Early Outlook for October Precipitation Issued on September 15,  2016

6 – 10 Day Precipitation Outlook

8 – 14 Day Precipitation Outlook 

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Here is the NOAA discussion released today September 26, 2016.

6-10 DAY OUTLOOK FOR OCT 02 – 06 2016

TODAY’S MODEL SOLUTIONS ARE IN GOOD AGREEMENT. TROUGHING IS GENERALLY PREDICTED OVER THE BERING SEA. SPLIT FLOW, WITH RIDGING OVER ALASKA AND TROUGHING INTO THE WESTERN CONUS, FOLLOWED BY DOWNSTREAM RIDGING OVER THE EASTERN CONUS ARE ALSO FEATURES COMMON TO THE AVAILABLE MODEL OUTPUTS. THE AVAILABLE MODEL SOLUTIONS ALSO AGREE ON BELOW AVERAGE HEIGHTS OVER THE GULF OF MEXICO. THE MODELS DIFFER ON HOW FAR SOUTH THE TROUGH IS LIKELY TO DIG OVER THE SOUTHWEST, WITH THE EUROPEAN CENTER MODELS DEPICTING LOWER HEIGHTS FROM THE SOUTHWEST TO THE GULF OF MEXICO. MANY GEFS RUNS HAVE A STRIP OF NEAR TO ABOVE AVERAGE HEIGHTS OVER THE SOUTHERN PLAINS. 

THE PATTERN DESCRIBED ABOVE FAVORS ABOVE AVERAGE TEMPERATURES FOR ALASKA, WITH RIDGING AND ABOVE AVERAGE HEIGHTS OVER MUCH OF THE STATE. SOME LOW-LEVEL EASTERLY FLOW COULD BRING TEMPERATURES CLOSER TO NORMAL FOR EASTERN ALASKA. TROUGHING OVER THE WESTERN CONUS FAVORS BELOW NORMAL TEMPERATURES FROM THE WEST COAST TO THE HIGH PLAINS. RIDGING ALOFT AND AT LOWER LEVELS FAVORS ABOVE NORMAL TEMPERATURES FOR THE EASTERN HALF OF THE CONUS.

THE TROUGHING OVER THE BERING SEA SEEDS A POTENTIAL STORM TRACK INTO WESTERN ALASKA, FAVORING ABOVE MEDIAN PRECIPITATION THERE, WHILE THE RIDGING OVER MAINLAND ALASKA FAVORS BELOW MEDIAN PRECIPITATION. TROUGHING OVER THE WESTERN CONUS OVER TOP OF LOW-LEVEL SOUTHERLY FLOW FAVORS ABOVE MEDIAN PRECIPITATION FROM NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST TO THE UPPER MISSISSIPPI VALLEY AND CENTRAL GREAT PLAINS. THE RIDGING OVER THE EASTERN CONUS FAVORS BELOW MEDIAN PRECIPITATION. SOME MODELS ARE INDICATING THE POTENTIAL FOR A TROPICAL CYCLONE TO MOVE INTO THE GULF OF MEXICO LATER IN THE PERIOD, WHILE THE GEFS-BASED SOLUTIONS RECURVE THE DISTURBANCE OVER THE BAHAMAS WITH POTENTIAL WEAKER IMPACTS TO FLORIDA. CORRESPONDINGLY, ODDS FOR BELOW MEDIAN PRECIPITATION WERE REDUCED OVER THE GULF COAST WHILE ODDS FOR ABOVE MEDIAN PRECIPITATION OVER MUCH OF FLORIDA WERE RETAINED FROM YESTERDAY’S OUTLOOK.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG MODEL SOLUTIONS IN A MORE AMPLIFIED LONGWAVE PATTERN, BUT INCREASED UNCERTAINTY DUE TO POTENTIAL TROPICAL CYCLONE ACTIVITY.  

8-14 DAY OUTLOOK FOR OCT 04 – 10 2016 

MODEL AGREEMENT ON THE PREDICTED 500-HPA PATTERN DECREASES FROM THE PRIOR PERIOD, ALTHOUGH THE ENSEMBLE MEANS FROM THE GFS, EUROPEAN CENTER AND ENVIRONMENT CANADA DEPICT GENERALLY SIMILAR PATTERNS. PREDICTED ANOMALIES ARE WEAKER IN THE GFS-BASED AND CANADIAN MODELS. GEFS-BASED SOLUTIONS GENERALLY HAVE A MORE EASTWARD TRACK FOR THE PREDICTED TROPICAL CYCLONE OVER THE CARIBBEAN AND WESTERN ATLANTIC. UNCERTAINTY ABOUT TROPICAL CYCLONE TRACKS AT THESE LEAD TIMES IS VERY HIGH COMPARED TO SHORTER-TERM OUTLOOKS, SO ONLY SLIGHT SHIFTS IN THE OUTLOOK WERE INTRODUCED UNTIL A MORE CONSISTENT TRACK IS INDICATED IN THE MODELS.

TROUGHING OVER THE BERING SEA, RIDING OVER MOST OF ALASKA, AND ABOVE NORMAL SEA-SURFACE TEMPERATURES NEAR WESTERN ALASKA FAVOR ABOVE NORMAL TEMPERATURES FOR THE STATE. A PREDICTED TROUGH OVER THE WESTERN CONUS FAVORS A CONTINUATION OF BELOW NORMAL TEMPERATURES FROM THE WEST COAST TO THE NORTHERN PLAINS AND SOUTHERN HIGH PLAINS. ABOVE NORMAL TEMPERATURES ARE FAVORED FROM THE GREAT PLAINS TO THE EAST COAST UNDER RIDGING ALOFT. MODELS DO DISAGREE OVER THE MIDWEST ON THE CERTAINTY OF ABOVE NORMAL TEMPERATURES WITH THE GEFS DEPICTING COOLER, MORE PROGRESSIVE SOLUTIONS. BOTH GEFS AND EUROPEAN CENTER MODELS INDICATE ABOVE NORMAL TEMPERATURES OVER THE SOUTHEAST, THOUGH THE EUROPEAN CENTER MODEL HAS MUCH HIGHER ODDS.

THE TROUGH OVER THE BERING SEA FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH OF WESTERN ALASKA. TROUGHING OVER THE WESTERN CONUS, THOUGH PREDICTED TO BE WEAKER THAN DURING THE 6-10 DAY PERIOD, STILL FAVORS AN ACTIVE PATTERN FROM NORTHERN CALIFORNIA TO THE CENTRAL PLAINS, THOUGH SOME PROGRESSION TO THE PATTERN EXTENDS THE NORTHERN PORTIONS TO THE GREAT LAKES. BELOW MEDIAN PRECIPITATION IS FAVORED ALONG THE APPALACHIANS, FROM THE SOUTHEAST TO THE LOWER GREAT LAKES. WEAK TROUGHING OVER THE WESTERN ATLANTIC FAVORS ABOVE MEDIAN PRECIPITATION FOR FLORIDA AND PORTIONS OF THE EAST COAST.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO  GOOD AGREEMENT AMONG THE TEMPERATURE TOOLS OFFSET BY UNCERTAINTY ABOUT THE POTENTIAL DEVELOPMENT OF A TROPICAL CYCLONE ACROSS THE CARIBBEAN SEA AND ITS EFFECTS ON THE PRECIPITATION OUTLOOK. 

THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON  OCTOBER 20

Some might find this analysis interesting as the organization which prepares it 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.

(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 September 16 to October 6 which is one day less than three weeks which is a fairly small 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 September 26. These analogs are centered on 3 days and 4 days ago (September 22 or 23). So the analogs could be considered fairly in sync with the calendar meaning that we will be getting weather that normally would occur this time of the year or a few days later including that forecast trough which is typical this time of the year.

There are this time four El Nino Analogs (why are there any?), zero La Nina Analogs (why are there none?), and six ENSO Neutral Analogs. The phases of the ocean cycles in the analogs point towards McCabe Conditions “C” and” D”. They are opposites and the forecasts is more in line with McCabe Condition “D”. So again it is confusing. 

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 almost the end of September, I have now removed the June and June – April – May – June 90 Day Graphics. They are available in Part II of this Report – If you click to go there and take a look, hit your “Return Key” to return to this article. 

Let’s look at the temperature and precipitation anomalies for the 30 days ending July 30, 2016

And now we looking at August. Here are the 30 Days ending September 3.

And the 30 Days ending September 24, 2016

NOAA updated their Seasonal Outlook on September 15. We reported on that on Sunday Sept 18. You can read that report here. If  you opt to go read my Report on NOAA’s Seasonal Outlook Update, please return from there to read this report which you can do by following the instructions at the end of that report or simply hitting your return button.

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 map and the control panel for you to see, but if you visit it Click Here you will be able to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. 

I can not display the interactive control board but 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 three days out whenever you view them. If you want the forecast for a different day Click Here

Precipitation

Temperature

But I know how to display the precipitation only forecast from Queensland Australia and here it is.

JAMSTEC has issued their Precipitation Forecast

Just to be complete I will show their temperature forecast

Here is the discussion that does with it.

Recently Issued Forecast from Japan

Sep. 21, 2016

Prediction from 1st Sep., 2016

ENSO forecast:

The SINTEX-F model predicts a La Niña Modoki/weak La Niña state [Editor’s Note: A La Nina State or Condition is not the same as a La Nina event because it takes a sufficient duration for a period of La Nina conditions to be declared to be a La Nina Event] will reach the peak in the boreal fall. Then, the tropical Pacific will return to a normal state by boreal spring. The model prediction is so far consistent with the observed evolution of the sea surface temperature (SST) anomalies.

Indian Ocean forecast:

The model has successfully predicted the negative IOD as observed in recent SST anomalies. The 2016 negative IOD will reach the peak in the boreal fall. It will bring a wetter-than-normal (drier-than-normal) condition over the eastern (western) side of the Indian Ocean; there is high possibility of floods in the region near Sumatra and Java. On the other hand, we warn dry conditions in East African countries.

Regional forecast:

In boreal fall, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while some parts of northern Brazil will experience a colder-than-normal condition.

According to the seasonally averaged rainfall prediction, eastern China, Indo-China, East Africa, and parts of southern Africa might experience a drier condition during boreal fall, while most parts of Indonesia, northern South America (including Colombia, Ecuador, and northwestern Brazil), southern West Africa, and western Central Africa will experience a wetter-than-normal condition; this may be mostly due to the negative IOD and the weak La Niña. Because of those climate conditions, Australia will receive above normal rainfall during austral summer. Most part of Japan will experience above normal temperature and above normal precipitation in fall, particularly in the western part of Japan.

Our monthly predictions fluctuate much in mid- and high- latitudes. The forecast skills in those latitudes on regional scales are still limited; predictions in those regions should be used carefully.

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

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.

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

Look at the Western Pacific in Motion.`

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 September 20. 2016 Version and looking at Week 2 of that forecast.

C. Progress of the Cool ENSO Event

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.

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

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.

* There is a +0.5C anomaly near the Nino 3.4 Measurement Area between 130W and 120W both north and south of the Equator. It is not directly on the Equator. It could indicate the cool anomaly is at least temporarily splitting into two pieces.

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 September 26, in the afternoon working from the September 25 TAO/TRITON report, this is what I calculated.

My estimate of the daily Nino 3.4 SST anomaly has risen to +0.1 which for sure is no longer a  La Nina value.  NOAA has reported the weekly ONI to be -0.4 which is a bit warmer than they reported last week and no longer is a La Nina value but is ENSO Neutral. But there is a big difference between -0.4 and +0.1.

Nino 4.0 is reported as being the same as last week at -0.2.  Nino 3 is being reported a bit warmer at -0.1 a very  small change.   Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported a lot warmer at +0.8. El Nino is not measured in Nino 1 + 2 but +0.8 would be an El Nino value if found further west.  The NOAA report of  -0.4 breaks the string of  NOAA reports of weekly LA NINA values of Nino 3.4.  The Australian Bureau of Meteorology recently reported that their estimate of the value for NINO 3.4 for August was -0.4 and their month to date estimate for September is again -0.4. IT IS THE SAME OCEAN.  So it looks like people are getting on the same page but the NOAA estimates appear to be a tad lower i.e. more La Nina-ish than the others.  The differences are small re weather impacts but significant re how this event will be recorded.

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.  NINO 1+ 2 stubbornly remains positive and determines the weather of Ecuador and Peru.

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.

Let us look 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 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 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.

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.

And now Let us look at the Atmosphere.

Low-Level Wind Anomalies near the Equator

Here are the low-level wind anomalies.

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

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 a comparison between Air Pressure at Tahiti and Darwin Australia 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.

The 30-day average, which is the most widely used measure, as of September 26 is reported at +12.97 which is about the same as last week and is definitely a La Nina level. The 90-day average at +6.69 is up slightly from last week and is now at a La Nina level. These may be the high water marks for the SOI re this cycle but I said that last week and the week before. 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. Different agencies use a different range to classify the SOI as being El Nino or La Nina. To some extent it is the change in the SOI that is of most importance.

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. September so far has not been particularly favorable for La Nina development and neither will be October in terms of the MJO. 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 in has mostly a short-term impact. Right now the impact is fairly muted. It 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.

Forecasting the Evolution of ENSO

The below is first the CPC/IRI (Early Month) forecast issued on September 8, 2016  followed by the (Late Month) forecast issued on September 15, 2016.  It is important to remember that the first report in each month is based on a survey of meteorologists and the second report later in the month is based on the analysis of the forecast models. It is a minor difference but a difference.

First the Early September “Probabilistic Forecast which includes a large component of input from meteorologists as compared to the second forecast in the month which is more tied to model results without interpretation. It is not a big difference but it is a difference. 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).

And now we have the recently released mid-month model based report

We have suggested that it is possible that some of the models and in particular NOAA’s model will be wrong about how fast the Eastern Pacific Warm Pool moves back towards its La Nina location and it may well be that next winter will be more of a Neutral year or even have some characteristics of an El Nino Modoki and thus be wetter than a typical year as the Warm Pool may still be more in the Central Pacific than shifted all the way west to its La Nina position.

The full list of weekly values can be found here.

Forecasts from Other Meteorological Agencies.

Here is the report issued September 27 from the Australian BOM

And here is the discussion they released this evening.

While most models now indicate the tropical Pacific Ocean is unlikely to cool to typical La Niña thresholds, individual model runs (ensemble members) suggest that La Niña (or near-La Niña) in 2016 remains a possibility. In addition, some atmospheric indicators of La Niña have intensified in the last few weeks. Despite this, the negative phase of the Indian Ocean Dipole is likely to remain the dominant driver for the remainder of spring.

Impacts on Australian climate patterns can still be felt during marginal events, particularly when La Niña-like patterns of warm ocean temperatures around northern Australia are present, as is currently being observed.

A La Niña WATCH status means there is approximately a 50% chance of La Niña developing in 2016, which is about twice the normal likelihood.

We also have the most recent JAMSTEC September 1 ENSO forecast.

The model shows ENSO Neutral for the next two years. The swings are a bit more intensified than in the prior model run. Indian Ocean IOD. The discussion was shown earlier as it contains a weather forecast.

Indian Ocean IOD

Not directly related is the IOD Forecast which also came out this evening.

The graphic comes with discussion, Here is that discussion:

The latest weekly IOD index value to 25 September is −0.9 °C. The negative IOD has re-intensified following a brief weakening during August. While this negative IOD event is likely to be the strongest such event in the observational record, model outlooks surveyed by the Bureau of Meteorology indicate a return to neutral values by the end of spring – consistent with the typical IOD event lifecycle. During the spring months, a negative IOD typically enhances rainfall over eastern Australia. For more information on the establishment of the negative IOD in 2016,

Information on the impact of a negative IOD on Australia can be found here

D. Putting it all Together.

Last winter’s El Nino has officially ended in terms of currently satisfying the criteria. We are now speculating on the winter of 2016/2017 which now according to some of the models seems likely to be a La Nina or Neutral with a La Nina bias. 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 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.

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.

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 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.

ONI Recent History

The official reading for Jun/Jul/Aug is now reported as -0.3. As you can see this recent El Nino peaked in NDJ and has now ended and depending on what system you use it is either the 2nd or 3rd strongest El Nino since modern records were kept which is considered to be 1950. You could argue for it being #1 based on a week of readings but few are buying that argument. Still #2 or #3 means it is one of the strongest ever based on the way these events are measured. I will be writing more about that soon in a separate article. I believe the measurement system is inadequate re being useful in forecasting Worldwide weather impacts. The JJA is not a La Nina Value. So there would need for there to be five periods of -0.5 or colder starting with JAS. It is not even clear that JAS will record as -0.5 or less. So the chances of this event being an official La Nina are very low.

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