We have Typhoon Chaba threatening Japan and Hurricane Matthew threatening the Western Antilles and points north and the cool ENSO Event is showing some life. Fear of drought is likely to be replaced by fear of drowning. Global Warming is more often about wet not dry.
It is kind of like money where PQ = MV. With Warming, E - P over Oceans must other than change in atmospheric inventory equal P - E over Land. It is an identity. This information can be found in the IPCC Reports. Again, like economics, there is an ocean - land water-trade balance. It is driven not by currency exchange rates but by the rotation of the Planet. If the days start to get longer than 24 hours, we have big problems.
Matthew and Chaba
It may not necessarily be Global Warming but warm oceans make for lots of clouds.
NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on September 30 and we will discuss that first by comparing the Updated Outlook to the Early Outlook issued on September 15.
Prior Outlook Issued on September 15, 2016
Updated Temperature Outlook Issued on September 30, 2016
Again the EC area has moved and this time clockwise from the Western Gulf Coast Area to a group of states centered on Nevada. Also the probabilities for being warm in the eastern part of CONUS have increased especially for the Great Lakes Region.
Prior Early Outlook Issued on September 15, 2016
Updated Precipitation Outlook Issued on September 30, 2016
This is somewhat of a La Nina pattern with a wet Northern Tier from Minnesota to the Pacific. The former dry anomaly centered around the Tennessee Valley now includes all of the interior Southeast. The Central Plains wet anomaly is gone. . .
Below is the discussion issued with this update.
30-DAY OUTLOOK DISCUSSION FOR OCTOBER 2016
THE OCTOBER TEMPERATURE AND PRECIPITATION OUTLOOKS ARE UPDATED PRIMARILY BASED ON SHORT, MEDIUM AND EXTENDED RANGE MODEL GUIDANCE TO ADJUST THE PREVIOUS MID-SEPTEMBER OUTLOOK.
ON AVERAGE, FORECAST RIDGING WITH POSITIVE HEIGHT DEPARTURES AND MEAN ANOMALOUS SOUTHWESTERLY FLOW EARLY IN THE MONTH ACROSS EASTERN NORTH AMERICA CONTRIBUTES TO FAVORED ABOVE NORMAL MONTHLY MEAN TEMPERATURES FOR AREAS OF THE CENTRAL AND EASTERN CONUS. THE HIGHEST PROBABILITIES ARE LOCATED IN PROXIMITY TO THE GREAT LAKES WHERE SHORT-, MEDIUM- AND EXTENDED RANGE GUIDANCE ARE CONSISTENT WITH INDICATING ABOVE NORMAL TEMPERATURES. THE CFS MONTH LONG FORECASTS PERSIST THIS SIGNAL IN THIS AREA AS WELL FOR THE REMAINDER OF THE MONTH.
EARLY IN THE MONTH, A TROUGH IS ANTICIPATED TO IMPACT THE WESTERN CONUS AND BELOW NORMAL TEMPERATURES ARE FAVORED FOR VARIOUS PORTIONS OF THE INTERIOR WEST ADDING SOME UNCERTAINTY FOR THE FORECAST OF MEAN TEMPERATURES FOR THE MONTH AS A WHOLE. CONSEQUENTLY, THE AREA DEPICTED WITH EQUAL CHANCES FOR ABOVE, BELOW OR NEAR NORMAL MONTHLY MEAN TEMPERATURES ARE SHIFTED WESTWARD FROM THE PREVIOUS OUTLOOK. WEEK 3-4 MODEL GUIDANCE INDICATES ABOVE AVERAGE TEMPERATURES RETURNING FOR THE WEST COAST AND AREAS ALONG THE NORTHERN TIER OF THE WESTERN CONUS SO WEAK PROBABILITIES FOR THE ABOVE NORMAL CATEGORY REMAIN IN THESE AREAS. WEEK 3-4 MODEL GUIDANCE IS LESS CLEAR ACROSS THE SOUTHWEST AS HIGHLIGHTED BY THE MONTHLY CFS FORECAST. [Editor's note: This totally disagrees with the 3-4 Week Outlook issued the same day on September 30 so one wonders about this. Was NOAA working from the prior run of the 3 - 4 week Outlook?]
ANTICIPATED MEAN POSITIVE 500-HPA HEIGHT DEPARTURES, SOUTHERLY FLOW AND ABOVE NORMAL OCEAN TEMPERATURES IN NEARBY WATERS FAVOR ABOVE NORMAL TEMPERATURES FOR THE ENTIRE STATE OF ALASKA. EQUAL CHANCES (EC) FOR ABOVE, BELOW OR NEAR NORMAL MONTHLY MEAN TEMPERATURES ARE INDICATED IN THE WHITE REGIONS LABELED WITH EC.
THE ABOVE MEDIAN PRECIPITATION AREA ACROSS THE CENTRAL PLAINS IN THE ORIGINAL OUTLOOK HAS BEEN EXPANDED AND SHIFTED NORTH AND WEST IN THE UPDATED OUTLOOK AS THIS IS MORE CONSISTENT WITH ANTICIPATED MEAN TROUGHING AT VARIOUS TIMES DURING THE OUTLOOK PERIOD. EARLY IN THE MONTH, A TROUGH IS FAVORED TO IMPACT THE WESTERN CONUS AND SUPPORT PRECIPITATION IN THE HIGHLIGHTED REGION. MORE ACTIVE WEATHER IS NOW ANTICIPATED ACROSS THE PACIFIC NORTHWEST OVER THE FORECAST PERIOD AND SO ELEVATED ODDS FOR ABOVE MEDIAN PRECIPITATION ARE NOW INDICATED FOR SOME AREAS IN THE UPDATED OUTLOOK. THE CFS MONTHLY FORECAST INDICATES MODESTLY HIGH PROBABILITIES ACROSS THE HIGHLIGHTED AREA FOR THE MONTH OF OCTOBER AS A WHOLE AS WELL.
ANTICIPATED MEAN RIDGING AND ALL INDICATIONS FROM SHORT, MEDIUM AND EXTENDED RANGE GUIDANCE CONTINUE TO SUPPORT DRY CONDITIONS FOR AREAS OF THE INTERIOR SOUTHEAST DURING THE MONTH SO THIS AREA REMAINS AND IS SLIGHTLY EXPANDED IN THE FORECAST UPDATE. A SUBSTANTIAL WILDCARD IN THE OUTLOOK IS THE EVOLUTION OF HURRICANE MATTHEW AND ANY POTENTIAL IMPACT TO AREAS OF THE SOUTHEAST AND EASTERN SEABOARD. THERE IS HIGH UNCERTAINTY FOR THE TRACK OF MATTHEW DURING THE EARLY PORTIONS OF OCTOBER. LATEST FORECASTS KEEP THE SYSTEM OFF THE EASTERN SEABOARD BUT THERE IS CONSIDERABLE FORECAST SPREAD IN ENSEMBLE MODEL GUIDANCE.
ABOVE MEDIAN PRECIPITATION IS FAVORED FOR SOUTHWESTERN PORTIONS OF ALASKA PRIMARILY DURING THE FIRST 10 DAYS OF THE PERIOD. EQUAL CHANCES (EC) FOR ABOVE, BELOW OR NEAR MEDIAN MONTHLY PRECIPITATION AMOUNTS ARE INDICATED IN THE WHITE REGIONS LABELED WITH EC.
Sometimes it is useful to compare the present month outlook to the three-month outlook
October plus October - December Outlook
One can mentally subtract the October Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely November and December 2016. If one does that you might conclude that:
The precipitation situation for November and December is projected to be similar to October with the wet anomaly smaller and the dry anomaly larger. The temperature situation for November and December would require that the area shown as being EC in October have really high warm probabilities in November and December and the area shown as EC in the three-Month forecast have cool anomalies in November and December for the three-month map to work out. But see below as what it takes to make this work out seems very unlikely to occur. . .
One has to keep in mind that we are now subtracting an October Map issued on September 30 from a September 15 three-month map so it is less reliable than the exercise we went through two weeks ago. We are assuming that the three-month outlook issued on September 15 would not change if it was released today. The results in the box above might be an indication of how November and December will differ from the three-month outlook or it might alternatively indicate how the three-month outlook might be modified if issued today. So the discussion in the paragraph above this may be overruled by a conclusion that the three-month outlook is no longer correct and October is a better predictor of the three-month outlook than the three-month maps issued on September 15. I suspect that is the case.
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.
Notice that there is not a lot of moisture around CONUS but some in the Texas north corridor and incoming from the Pacific into California. There is a lot in the Caribbean.
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.
Right now the forecasted Aleutian Low (in the Gulf of Alaska) has an hPa of 1004 (the average in the winter is 1001 hPa and 994 hPa for a non-split Low). It is a split low with actually three focal points as I view it Monday evening. The Gulf of Alaska Low may be the controlling factor for CONUS weather. The major middle foci of the low is over by Kamchatka and is tightly wound with a central low pressure of 980 hPa which is very low. There is also low pressure forecast for Day 3 north of the Great Lakes. The graphic changes every six hours so I can't keep up with it re my discussion. Hurricane Matthew is shown offshore of Florida (on Day 3). This is one forecast...there are many others some of which locate Hurricane Matthew further west.
The High Pressure off of California, the familiar RRR, is here and quite large but weak at 1024 hPa. The RRR continues to do a good 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 projected major precipitation events on the East Coast and immediately offshore due to Matthew. More on that later.
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 we begin to see 540 levels. So snow is likely now only in the mountains.
Not sure one can rely on this graphic to locate the Four Corners High as it seems to have been on vacation this Summer and Early Autumn. If it showed up on this graphic, one could draw or imagine a one-inch or so in radius circle overlain on the Four Corners High with an arrow showing the wind pattern is clockwise (anticyclone). One can then imagine where moisture might be being drawn into the edge of the High Pressure System. There is a High shown off the coast of Texas but it is moving around a lot. Oops..it is now shown in Old Mexico. I will have an impact but minor compared to Matthew.
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 very clearly in the above is the progression of the Western and Great Lakes Troughs and the Ridge north of the CONUS Rocky 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.
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 "new" tropical activity forecast for this week. Matthew is an existing tropical event.
Below is the current water vapor Imagery for North America.
Tonight, Monday evening October 3, 2016 (and this is the current situation not an animation of recent history), as I am looking at the above graphic, there is not much activity other than in the (inland) Northwest and Florida and points to the north of Florida. Water vapor imagery is a bit different than the above two graphics as it focuses on the water vapor in clouds rather than the clouds themselves.
Looking at the current activity of the Jet Stream.
The sub-Jetstream level intensity winds shown by the vectors in this graphic are very important. You can see how storms from the Pacific just above Baja have the ability to enter CONUS. One also sees a lot of activity across the Northern Tier both in the West and the East.
Below is the forecast out five days.
Agreement in the model forecasts re the exact location and timing of the multiple meteorological systems in play are required to predict with great precision exactly how this will play out. Right now the thinking is minimal impacts on the Southwest from the Pacific Storm. Now let's look at the situation on Day 5 below.
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. 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.That is exactly what is forecast for the Pacific cutoff low which may be formed by this trough. Surprisingly some of the thinking is that beyond five days, the Western Gulf of Mexico may have more impact on Texas and New Mexico than the Pacific storms.
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.
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 Temperature Outlook for October which was updated on September 30, 2016
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
As I view these maps on October 3 (two of the five update each day and one (the Week 3 - 4 Outlook) updates every Friday), it appears that through October 28 the pattern during the first half of October will begin with a warm southern tier and expand to be mostly warm all over. That pattern is expected to change in the second half of October to a warm east that extends further west at higher latitudes. Alaska is warm throughout the period.
Now - Precipitation
Here is the three-month OND Precipitation Outlook issued on September 15, 2016 :
And here is the Updated Outlook for October Precipitation Issued on September 30, 2016
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
As I view these maps on October 3 (two of the five update each day and one (the Week 3 - 4 Outlook) updates every Friday), it looks like precipitation leading up to October 28 is tending for the first half of October to be mostly a mixed wet and dry pattern for the northern tier and a mostly dry southern tier. The pattern is projected to evolve in the second half of October to be one with a Northwest wet anomaly and a Great Plains dry anomaly. Everywhere else is EC.
Here is the NOAA discussion released today October 3, 2016.
6-10 DAY OUTLOOK FOR OCT 09 - 13 2016
TODAY'S MODEL SOLUTIONS ARE IN FAIR AGREEMENT ON THE OVERALL 500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. MODEL'S AGREE ON FORECASTING A CLOSED 500-HPA CLOSED LOW NEAR WESTERN ALASKA, THOUGH THE EXACT POSITION IS UNCERTAIN. THIS TRANSLATES TO WELL BELOW NORMAL 500-HPA HEIGHTS OVER THE ALEUTIANS. DOWNSTREAM OF THIS LOW A RIDGE IS PREDICTED OVER PARTS OF WESTERN NORTH AMERICA, RESULTING IN ABOVE NORMAL HEIGHTS OVER THOSE AREAS. A TROUGH IS PREDICTED OVER EASTERN CANADA AND THE NORTHEAST BY ALL MODELS, HOWEVER THE STRENGTH OF THIS TROUGH IS UNCERTAIN. TODAY'S 0Z ECMWF-BASED MODELS DIFFERS GREATLY FROM TODAY'S GFS- AND CANADIAN-BASED MODELS. THE 0Z ECMWF IS PREDICTING A WEAKER TROUGH IN THE EASTERN U.S. THAN THE OTHER MODELS, MINIMIZING BELOW NORMAL HEIGHTS OVER THE GREAT LAKES REGION AND NORTHEAST. THE WEAKER TROUGH FORECAST BY THE 0Z ECMWF ALSO LEADS TO HURRICANE MATTHEW BEING SLOWER TO PROGRESS THAN IN THE OTHER MODEL SOLUTIONS. TODAY'S GFS- AND CANADIAN-BASED SOLUTIONS PREDICT HURRICANE MATTHEW TO QUICKLY MOVE NORTHWARD OFFSHORE AND BECOME ENTRAINED IN A TROUGH, HELPING TO INTENSIFY THE TROUGH AND INCREASE NEGATIVE HEIGHT ANOMALIES. THE 0Z ECMWF FORECASTS HURRICANE MATTHEW TO LINGER OFF THE EAST COAST, AND NOT BECOME ENTRAINED IN THE SYNOPTIC FLOW, LEADING TO A MUCH WEAKER TROUGH IN THE NORTHEAST. TODAY'S 0Z ECMWF RUN REMAINS AN OUTLIER, HOWEVER, AND BECAUSE THERE IS LESS CONFIDENCE IN THIS SOLUTION TODAY, THE ECMWF-BASED RUNS WERE GIVEN MUCH LESS WEIGHT IN TODAY'S MANUAL 500-HPA BLEND, WHICH HEAVILY FAVORS TODAY'S GEFS-BASED SOLUTIONS. THE MANUAL 500-HPA BLEND DEPICTS NEGATIVE HEIGHT ANOMALIES IN THE GULF OF ALASKA, SLIGHTLY POSITIVE HEIGHT ANOMALIES OVER MOST OF THE CONUS, AND SLIGHTLY NEGATIVE HEIGHT ANOMALIES IN MUCH OF THE EASTERN U.S.
STRONGLY SOUTHERLY LOW-LEVEL FLOW OVER ALASKA AND THE PACIFIC NORTHWEST FAVORS ABOVE NORMAL TEMPERATURES IN THOSE AREAS. BROAD SOUTHERLY LOW-LEVEL FLOW AND POSITIVE HEIGHT ANOMALIES FAVOR ABOVE NORMAL TEMPERATURES FOR THE WESTERN HALF OF THE CONUS. SURFACE HIGH PRESSURE ENHANCES THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES FOR PARTS OF THE GULF COAST. NEAR AVERAGE 500-HPA HEIGHTS OVER MUCH OF THE EASTERN U.S. INCREASES THE CHANCES FOR NEAR NORMAL TEMPERATURES THERE. BELOW NORMAL HEIGHTS OVER THE NORTHEAST FAVOR BELOW NORMAL TEMPERATURES THERE.
STORM SYSTEM ACTIVITY IN THE GULF OF ALASKA FAVORS ABOVE MEDIAN PRECIPITATION FOR THE ALEUTIANS, THE SOUTHERN COAST OF ALASKA, AND THE ALASKA PANHANDLE. SEVERAL SHORTWAVE TROUGHS ARE FORECAST TO COME ONSHORE IN THE PACIFIC NORTHWEST, INCREASING THE LIKELIHOOD FOR ABOVE MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST. PREDICTED SURFACE HIGH PRESSURE FAVORS BELOW MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHWEST, GREAT BASIN, AND NORTHERN PLAINS. A COUPLE OF STORM SYSTEMS FORECAST TO DEVELOP AND TRACK FROM THE SOUTHERN ROCKIES INTO THE CENTRAL PLAINS AND PARTS OF THE GREAT LAKES REGION FAVOR ABOVE MEDIAN PRECIPITATION FOR THOSE AREAS. SURFACE HIGH PRESSURE IS FORECAST TO SUPPRESS STORM SYSTEM ACTIVITY OVER THE GULF COAST STATES AND THE SOUTHEAST, INCREASING CHANCES FOR BELOW MEDIAN PRECIPITATION THERE. THE POTENTIAL IMPACT OF HURRICANE MATTHEW ENHANCES THE LIKELIHOOD FOR ABOVE MEDIAN PRECIPITATION IN THE NORTHEAST.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO A LOT OF DISAGREEMENT AMONG THE MODELS AND TOOLS IN THE EASTERN U.S.
8-14 DAY OUTLOOK FOR OCT 11 - 17 2016
THE PATTERN FORECAST FOR THE WEEK-2 PERIOD IS VERY SIMILAR TO THE 6-10 DAY PERIOD. THE NEGATIVE HEIGHT ANOMALIES OVER THE GULF OF ALASKA EXTEND A LITTLE FARTHER INLAND OVER ALASKA AND THE PACIFIC NORTHWEST IN THE WEEK-2 PERIOD, AND NEGATIVE HEIGHT ANOMALIES COVER A BIT MORE OF THE EASTERN U.S. THAN IN THE 6-10 DAY PERIOD. THE TEMPERATURE PROBABILITY FORECAST IN THE WEEK-2 PERIOD IS SIMILAR TO THE 6-10 DAY PERIOD, WITH A FEW EXCEPTIONS. OVER ALASKA, UNCERTAINTY IN THE PATTERN IS MORE UNCERTAIN IN THE WEEK-2 PERIOD COMPARED TO THE 6-10 DAY PERIOD, LEADING TO LOWER PROBABILITIES OF ABOVE NORMAL TEMPERATURES. THE SURFACE PATTERN IS FORECAST TO SHIFT EASTWARD BY THE WEEK-2 PERIOD, INCREASING SOUTHERLY LOW-LEVEL FLOW OVER MUCH OF THE EASTERN CONUS, FAVORING ABOVE NORMAL TEMPERATURES FOR MOST OF THE COUNTRY.
STORM SYSTEM ACTIVITY IN THE GULF OF ALASKA IS FORECAST TO MOVE SOUTHEASTWARD TOWARD THE PACIFIC NORTHWEST, REDUCING CHANCES FOR ABOVE MEDIAN PRECIPITATION FOR COASTAL ALASKA, BUT INCREASING PROBABILITIES OF ABOVE MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST. WITH SURFACE HIGH PRESSURE FORECAST TO BE IN CONTROL OF MOST OF THE COUNTRY BY THE WEEK-2 PERIOD, CHANCES FOR BELOW MEDIAN PRECIPITATION ARE ENHANCED ACROSS MOST OF THE REST OF THE COUNTRY.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIRLY GOOD AGREEMENT AMONG FORECAST MODELS AND TOOLS
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.
Sept 14, 1954
Long, Strong La Nina
October 3, 1957
Strong El Nino
Oct 8, 1975
Long, Strong, La Nina
Sept 12, 1997
Sept 13, 1997
Oct 6, 1998
Oct 7, 1998
Oct 12, 1998
Sept 22, 2008
(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 12 to October 12 which is thirty days which is a fairly large 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 29. These analogs are centered on 3 days and 4 days ago (September 29 or 30). So the analogs could be considered in sync with the calendar meaning that we will be getting weather that normally would occur this time of the year including the forecasted Western trough which is typical this time of the year.
I think NOAA would appreciate it if I said that these analogs are not a substitute for their very sophisticated forecasting software and I am not suggesting that they are. I present them partially for curiosity purposes but also to see how current conditions correlate with medium and low frequency cycles. The medium frequency cycle I track is ENSO and the two low- frequency cycles I track are the PDO and AMO. When I see that forecasts are consistent with the current phases of these cycles (as represented by the analogs), that seems very suggestive to me that our weather is probably fairly easy to forecast. If the analogs are all over the place then I have to wonder if the forecasts are good or if our weather is just not related to these cycles. That certainly can be the case. So I am doing some research here and you are seeing how I look at things. I hope you find it interesting.
There are this time three El Nino Analogs (why are there any?), five La Nina Analogs, and just one ENSO Neutral Analog. The phases of the ocean cycles in the analogs point towards McCabe Conditions "C" and" D" which is the same as last week. They are opposites and the forecast is more in line with McCabe Condition "D" which is consistent with La Nina. But having both El Nino and La Nina analogs and two or even three combinations of Ocean Phases in these analogs raises many questions.
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 the beginning of October, I have now removed the July and August Graphics.
Here is the 30 Days ending September 24, 2016
You see a lot of moderation in the precipitation but the Eastern warm anomaly is actually stronger. The precipitation anomaly is strange as it shows NM as about even when our NWS reports the past month as having been unusually wet. What everyone agrees on is that California has been dry and looks to stay dry.
And the 30 Days ending October 1, 2016
This gives us a comparison with last week (remember only 7 of the 30 days are changed with a 30 day average that is updated weekly but it also gives us a complete picture for September. Compared to the prior 30 day average I do not see important changes (the reader's eyes may be better than mine) but the warm anomaly does seem to have spread west a bit. California remains in trouble other than the part of California that shares in the Monsoon or Monsoon related tropical events.
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 simply hitting your "backspace" button on your keyboard.
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
It is hard to see the land masses that are shaded underneath the forecast map but if I am reading this correctly, BOM is forecasting Hurricane Matthew to be further west in three days than the NOAA forecast. They are also forecasting a High not a Low north of Matthew so the whole forecasted steering mechanism is very different.
But I know how to display the precipitation forecast from Queensland Australia and here it is.
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 rising SOI triggers a lot of wet around the World. Look for low grain prices.
JAMSTEC issued their Precipitation Forecast last week but it was out of date when issued. With these meteorological agencies the reader is always in the catch-up mode.
Recognizing that we are now at October 3 and this forecast is based on September 1 Model Runs, it is still pretty interesting especially for Northern South America, Eastern Asia and Africa, the Maritime Continent and the Mediterranean.
Just to be complete I will show their temperature forecast
The UK will be cool, and maybe Venezuela, and Eastern Siberia will be good for snowshoeing. Then there is northern Argentina. and Uruguay. Other than that, Global Warming Deniers might have to seek higher elevations.
Here is the discussion that does with it.
Sep. 21, 2016 Prediction from 1st Sep., 2016
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.
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
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. The graphic issued Sunday differs greatly along the Equator in the Eastern Pacific from what I saw Saturday so I do not know if the Oceans Changed or NOAA changed.
Remember this discussion is all about anomalies not absolute temperatures...so it is deviation from seasonal norms.
The waters off of Japan remain warm. South of Kamchatka Siberia the color on the graphic is intense. The Indian Ocean is now basically all cool. The southern coast of Australia is cool but the Southeast Coast is warm. Water northwest of Australia is warm. The waters south of Africa are warm to the west but a bit cool to the east.
The overall Northern Pacific looks to be PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape there but not very prominent). The Pacific Decadal Oscillation (PDO) Index rose to 2.4 in March which with El Nino fading may be significant. It was up to 2.62 in April but eased to 2.35 in May and then to +0.78 in June and then down to +0.18 for July and then recorded a negative value of -.66 for August and the July value was adjusted to +0.11. That would make the PDO now NEGATIVE. But it may record positive for September. The question remains about the PDO. Is it acting independently of the El Nino or is this the change from PDO- to PDO+ (until August) which would signal a multi-decadal change in the Pacific. I anticipated that the PDO would turn negative as the La Nina gained control and it has. But is that just temporary. Here is the list of PDO values. The waters west of CONUS are now slightly cool. This is not a good sign for a wet winter. Further north, the Gulf of Alaska is quite warm. The Pacific being warm north of 40N remains the most impressive feature of the overall pattern. Notice the water off of Baja California is no longer warm and that is why cyclones moving up the west coast have dissipated rapidly.
The Black sea appears now to be only slightly warm. The Caspian sea is a bit warm. So is the Mediterranean in fact the Western Mediterranean is quite warm.
The water directly west of South America is not showing much of a strong La Nina pattern even though El Nino is history. There is a narrow cool anomaly in the Pacific right along the Equator in the La Nina Measurement Area. Starting Sunday it has appeared to be more robust still gradually stretching west where it has crossed the Dateline but it also is now better connected to Ecuador. It is perhaps a La Nina pattern but too weak yet to qualify as an official La Nina and probably will remain borderline La Nina through the winter. It may ultimately turn out to be a La Nina Modoki i.e. shifted to the west more than the typical La Nina. The water off the West Coast of Central America is warm.
The water off the East Coast of CONUS is warm covering a large area. Matthew will not dissipate as quickly as these storms usually as they move north if it hugs the coast. 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 further south again shows and seem to be enlarging. There is a warm anomaly off shore of Northwest Africa. Hurricane formation may not be substantial as September ends except further south. The waters north of Antarctica East of South America are uniformly colder than climatology and we again see the warm anomalies north of that pattern.
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. 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 a warming trend between the East Coast of Africa and Madagascar. Of course, the Equator in the Pacific is controlling to a large extent. The changes there are significant as the warming trend has pretty much ceased i.e. the La Nina has ceased being canceled out for the moment. The changes in the Northern Hemisphere Pacific above 30N are a stabilization of the warming in the Gulf of Alaska (no change) an in the Eastern Pacific at about 30N to 40N. There is cooling of the west coast of Africa south of the Equator. 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.Right now we another Typhoon headed for Asia.
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 27, 2016 Version and looking at Week 2 of that forecast.
Mostly for the period October 5, 2016 to October 11, 2016, I see in week two that it will be likely dry for the southern tip of India. Elsewhere there is mostly either varying probabilities of wetter than climatology or increased cyclone risk. The wet areas include part of Argentina, Florida, the Maritime Continent, Indochina with the cyclone risk impacting the Philippines.
This graphic updates on Tuesdays and when it did on September 25, the risk to the Caribbean and Gulf of Mexico was shown as Week 2 and now shows up as Week 1. I rarely comment here on week one as I publish late on a Monday and most read the report Tuesday afternoon more or less when this graphic updates so what I see as Week 1 is gone by then and what I discuss as Week 2 is updated and shown as the new Week 1. I could go back into my article late on Tuesday and update the above discussion but I think that readers can interpret this graphic on their own after it updates as the Legend is very easy to understand.
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 -1C 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
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
* 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.But right on the Equator there may be cooler water surfacing or not being impacted by surface winds.
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 is 0 degrees of water along the Equator in the ONI Measurement that is even -1C or less which would be cool enough to be a moderate La Nina when just looking at the Equator. But 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 warm area has shifted to being east of 130W. It is actually El Nino warm which is not saying we are having an El Nino just that the warm water is squeezing the cool event into Neutral.
If you look at the TAO/TRITON graphic and the table above, it appears that this cool event is shifting from east to west and becoming an Modoki,
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 October 3, in the afternoon working from the October 2 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
(+0.3)5 = +0.1
(-1.8)/5 = -0.4
My estimate of the daily Nino 3.4 SST anomaly has fallen to -0.4 which is an ENSO Neutral value. NOAA has reported the weekly ONI to be -0.8 which is quite a bit cooler than they reported last week and very much a La Nina value. There is a huge difference between -0.4 and -0.8. But some other graphics I am showing this evening support the -0.8 calculation and others do not. So are we dealing with artifact or ground truth? I do not know. It could be the Easterlies.
Nino 4.0 is reported as being the same as being much cooler than last week at -0.5. This is in line with the westward expansion of the surface cool water anomaly. Nino 3 is being reported a bit cooler at -0.2 a very small change. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported a bit cooler at +0.6. El Nino is not measured in Nino 1 + 2 but +0.6 would still be an El Nino value if found further west.
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.
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 snap shots 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 autoupdates 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 blue cool anomaly has again moved further west and the dark blue which was not showing last week (look up a tad) is now again showing at the bottom which means current reading. You can see that the yellow ENSO Neutral water is creeping to the west a bit but a portion of it is no longer showing (bottom of graphic). This graphic explains to some extent the week to week changes in the Nino 3.4 Index Reading. Remember the +5, -5 degree strip around the Equator that is being measured. So it is the surface but not just the Equator.
I thought it would be useful to show this view which is more focused on the Equator but looks down to 300 meters rather than just being the surface. Here you can clearly see the cool blob (darker blue) at 170W to 155W which is the focus of this cool event. Does 10 to 15 degrees of Latitude make a La Nina? This could all be an issue of seasonal adjustments or the every five year trend adjustment.
Let us further 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 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 170W to the Coast of Ecuador. The -1C water shows most strongly between 170W and 155W. There is a gap between 155W and 120W (the eastern end of the Nino 3.4 Measurement Area) although that gap does not show up fully on the TAO/TRITON Graphic. The gap, if valid, suggests the possibility that this will evolve into a cool Modoki pattern. The eastern part of the cool water pool is increasingly unimpressive with actually some showings of warm water. Notice that there is very little water with a cool anomaly in excess of -2C. 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 at about 180 i.e. The Dateline which is about the same as last week. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm remains at 170W so we do not have ideal conditions for significant convection along the Equator east of the Dateline which is a characteristic of a cool event. Notice the steepness of the 28C, 27C and 26C Isotherms. This is a real boundary between warmer water and cooler water. The 25C isotherm is again at 135W to 140W which is similar to last week. The 20C Isotherm has moved close to the surface but is not reaching the surface and has not changed in weeks. The amount of warm water just west of the Dateline is also not real impressive either but growing but 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 ONI. So it is still a battle going on with La Nina nudging ahead but not looking like it can sustain itself. .
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 from 170W to 160W which is actually less (in this graphic) than last week. There appears to be more cool water at depth which I gather is the result of seasonal adjustments.
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 more prominent.
And now the Outgoing Longwave Radiation Anomalies which tells us where convection has been taking place.
In the above graphic, there is now almost no convection along the Equator.
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.
90 Day Average
The 30-day average, which is the most widely used measure, as of October 3 is reported at +13.23 which is about the same as last week and is definitely a La Nina level. The 90-day average at +7.96 is up from last week and is again 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 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. It has been increasing but may now be stabilizing.
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 was not particularly favorable for La Nina development and most likely neither will be October 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 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 the Early September CPC/IRI "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).
Notice that with this release, the probabilities for La Nina have changed dramatically since the August 18 analysis with Neutral being the most likely Phase of ENSO and the next El Nino beginning to show up on the meteorologist's radar.
And then we have the recently released mid-month model-based report
This is a lot more bullish on La Nina happening. Kind of a big change in a week. It is still pretty much a coin flip with the projected strength of this cool event being marginal for ruling in or out as being a La Nina Event.
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 mean of the NOAA model was until recently forecasting a fairly strong La Nina for next winter. The model gradually shifted to a weak La Nina Forecast and now to a marginal La Nina Forecast. Is the Mean of the forecast ensemble for the key periods NDJ and DJF below -0.5? For a few weeks weeks it looked like it no longer seemed to be but now suddenly it does albeit barely but now almost to a moderate level. The mean of the model ensemble for the ONI in the NOAA model has turned higher (less La Nina-ish actually on the El Nino side of Neutral) for the Spring of the coming winter as you can see. I doubt that this cool event will be recorded as a La Nina since it most likely will not meet the criteria for being classified as a La Nina. But I am not so sure of that in recent weeks It is forecasted to be close enough that whether it officially is logged in as a La Nina or Neutral, probably has very little impact on the weather we will have. It is a cool event pattern but not at all extreme.
Here is the Nino 3.4 report issued September 27 from the Australian BOM
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 ton September 27 (earlier actually but without its discussion.
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.
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 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; maybe as many as five but perhaps as few as zero as in we may have seen the PDO change phase with this recent El Nino.
E. Relevant Recent Articles and Reports
Weather in the News
Hurricane Matthew is covered extensively within the report this week. .
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.
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 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.
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