Today we examine the question of theory versus practice. We know what the next few months should be like in theory and we have observed how the last three months deviated in practice from the theoretical forecast. So what is the best way to forecast April, May and June weather for CONUS?
This is the RegularEdition of my weekly Weather and Climate Update Report. Additional information can be found here on Page II of the Global Economic Intersection Weather and Climate Report.
A case can be made for this El Nino to be slow to return to its Western Pacific normal location and thus continue to impact CONUS weather into Spring. It is likely that the MJO will be active early in April. But the April Precipitation Outlook presented seems to me to be a bit like a gambler who bet wrong on January, February, and March Western U.S. precipitation patterns, increasing the amount wagered on April. NOAA stuck with their January and February forecast in March and that did not work out. The April forecast may work out. I have questions about May and June also so keep reading if you find this of interest.
NOAA issued their updated Seasonal Outlook on the third Thursday of the month i.e. March 17 as is their normal schedule. Let's take a look.
Prior Temperature Outlook for AMJ 2016
New Temperature Outlook for AMJ 2016
Not much change in the pattern. But an increase in coverage and substantially higher probabilities. Some of this is due to being one month closer. But it seems like more than that.
Prior Precipitation Outlook for AMJ 2016
New Precipitation Outlook for AMJ 2016
This is a big change. The small dry anomaly in the Northwest is new. The dry anomaly centered on the Western Great Lakes does not now extend as far south. The wet anomaly now extends from the Southwest all the way to the Atlantic Ocean. NOAA is betting that the Northern Branch of the Jet Stream will be drawn south by the MJO Active Phase and this could happen.
Now let us focus on the long-term situation.
Prior 14 Month Temperature Outlook: Apr 2016 - May 2017
New 14 Month Temperature Outlook: May 2016 - Jun 2017
To compare maps from one release to another one needs to remember that the new release drops one three-month period and adds a later one. So to make the comparisons one has to shift the new maps to the right one position and that makes the map on the right drop down to become the left-most map in the next level. I do not have a computer software tool for doing that for you so you have to do it mentally. When I do the comparison I print them out and put them side by side and number the same three-month maps 1, 2, 3,.....,11 in both sets of maps to make it easier for me to easily compare the same three-month period in the new with the previous forecast. One uses the same procedure to compare the precipitation maps. Based on this procedure, I conclude that:
The changes are subtle re area involved but with higher probabilities of warmer than climatology especially in the Southwest in the early part of the 15 Month Period followed by reduced probabilities of warmer than climatology as the forecast moves further out in time towards Oct -Nov - Dec, 2016. The Transition to La Nina begins immediately after that and is pronounced starting in Nov - Dec (2016) - Jan (2017) but that is not a change from the February 18, 2016 Release except that the cool anomaly in northern tier does not extend as far east as it did in the February 18 Seasonal Outlook. .
Prior 14 Month Precipitation Outlook: Apr 2016 - May 2017
New 14 Month Precipitation Outlook: May 2016 - Jun 2017
Almost no change in the 14 Month Period other than for May-Jun-Jul where a Northwest Dry Anomaly has been added, the Great Lakes Dry Anomaly does not extend as far south, the Southwest Wet Anomaly has expanded both to the west and to the east. That is a substantial change in that one three-month period. It is based on El Nino impacts lasting longer which makes some sense but is going way out on a limb. The switch to a La Nina Pattern remains in Sep - Oct - Nov 2016 which is again a month or two earlier than the transition with respect to temperature. .
If you want larger versions of each map (temperature and precipitation) you can find them here. And each of those maps can be clicked on to further enlarge them.
Excerpts (somewhat reorganized) from the Discussion Released by NOAA on March 17, 2016
CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS
WHILE EL NINO CONDITIONS PEAKED IN LATE 2015, EQUATORIAL PACIFIC SST REMAINS ANOMALOUSLY ABOVE CLIMATOLOGICAL MEANS. THE NINO 3.4 REGION, THREE-MONTH MEAN, SST ANOMALY PEAKED AT 2.3 DEGREES C, COMPARABLE TO THE 1997-98 EL NINO EVENT, BEFORE DECREASING SLIGHTLY TO 2.2 DEGREES C IN THE MOST RECENT THREE-MONTH AVERAGE ANOMALY. SUBSURFACE OCEAN TEMPERATURES FROM THE INTERNATIONAL DATE LINE TO ABOUT 90W LONGITUDE NEAR THE SOUTH AMERICAN COAST ARE AT LEAST 2.0 DEGREES C ABOVE AVERAGE TO A DEPTH OF ABOUT 50 METERS. NEGATIVE ANOMALIES AT DEPTH EXCEEDING -2.0 DEGREES C FROM 50 TO 200 METERS HAVE PROGRESSIVELY PUSHED EASTWARD TO NEAR 140W IN THE LAST TWO MONTHS. THIS EMERGENCE OF NEGATIVE HEAT ANOMALIES AT DEPTH IS AN INDICATOR OF THE POSSIBILITY OF TRANSITION TO LA NINA CONDITIONS DURING 2016.
STRONGLY ENHANCED CONVECTION OCCURRED OVER THE CENTRAL EQUATORIAL PACIFIC DURING FEBRUARY AND EARLY MARCH, STRETCHING FROM NEAR 160E TO 140W. [Editor's Note: That is only 60 degrees of Longitude and surprisingly little for such a powerful El Nino]. LOW-LEVEL WESTERLY WIND ANOMALIES WERE OBSERVED OVER THE CENTRAL EQUATORIAL PACIFIC IN LATE FEBRUARY AND EARLY MARCH, BUT HAVE RECENTLY WEAKENED.
THE MADDEN-JULIAN OSCILLATION (MJO) PLAYED A LARGE ROLE IN TROPICAL ATMOSPHERIC VARIABILITY DURING THIS EL NINO EVENT, THROUGH EARLY MARCH, AND CURRENT SUBSEASONAL FORECASTS INDICATE SOME CONTINUED MJO ACTIVITY. [Editor's Note: This seems to be the first time that NOAA has incorporated the MJO into their Seasonal Outlook.] SEE THE MONTHLY FORECAST DISCUSSION FOR FURTHER INFORMATION.
THE EXTRA-TROPICAL PACIFIC OCEAN REMAINS CONSISTENT WITH THE POSITIVE PHASE OF THE PACIFIC DECADAL OSCILLATION WITH ABOVE AVERAGE SSTS SOUTH OF ALASKA AND ALONG THE WEST COAST. STRONG POSITIVE SST ANOMALIES IN THE ATLANTIC NEAR THE EAST COAST HAVE PERSISTED FOR SEVERAL MONTHS AND POSSIBLY INFLUENCE THE CLIMATE AS WELL.
PROGNOSTIC DISCUSSION OF SST FORECASTS
WITH THIS EL NINO EVENT WEAKENING IN TERMS OF SST ANOMALIES, THE IMPORTANT QUESTIONS FOR THE SEASONAL FORECAST ARE HOW QUICKLY THE EVENT AND RELATED IMPACTS DISSIPATE AND WHAT IS THE LIKELIHOOD OF A TRANSITION TO A LA NINA EVENT, WHICH FREQUENTLY FOLLOWS EL NINO EVENTS. THE CPC SST CONSOLIDATION CONTINUES TO FORECAST A RETURN TO NEUTRAL CONDITIONS BY MJJ [Editor's Note: but the NOAA MJJ Forecast is an El Nino Forecast] AND MORE THAN 80% CHANCE OF LA NINA BY NEXT WINTER. THERE IS A LARGE SPREAD AMONG THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) MEMBERS IN TERMS OF THE TRAJECTORY OF TROPICAL SST ANOMALIES AND EXPECTED CONDITIONS BY WINTER OF 2016-17. THE CFS AND NCAR MODELS MAINTAIN ANOMALOUSLY WARM SSTS MUCH LONGER THAN OTHER MODELS,WHILE OTHER NMME CONSTITUENT MODELS PREDICT NEGATIVE SST ANOMALIES BY THE END OF SUMMER. IT IS OF NOTE THAT THE CFS AND NCAR MODELS USE A SIMILAR SET OF INITIAL CLIMATE CONDITIONS.
THE CPC/IRI CONSENSUS FORECAST INDICATES THAT THE TRANSITION TO ENSO NEUTRAL IS MOST LIKELY BY EARLY SUMMER, AND THE PROBABILITY OF LA NINA DEVELOPING FIRST EXCEEDS 50% IN SON.
30-DAY OUTLOOK DISCUSSION FOR APRIL 2016
THE APRIL TEMPERATURE AND PRECIPITATION OUTLOOKS WERE PREPARED WITH CONSIDERATIONS FROM ONGOING STRONG EL NINO CONDITIONS, CURRENT MJO ACTIVITY, MOST RECENT SOIL MOISTURE CONDITIONS AS WELL AS AVAILABLE DYNAMICAL MODEL GUIDANCE INTEGRATED OVER MULTIPLE TIME PERIODS.
STRONG EL NINO CONDITIONS REMAIN IN PLACE ACROSS THE EQUATORIAL PACIFIC OCEAN WHILE THE MJO CONTINUES TO BE ACTIVE WITH THE ENHANCED CONVECTIVE PHASE NOW CENTERED ACROSS THE EASTERN INDIAN OCEAN AND PROPAGATING EASTWARD WITH TIME. THE MJO IS FORECAST TO REMAIN ACTIVE OVER THE NEXT COUPLE OF WEEKS AND PROPAGATE ACROSS THE MARITIME CONTINENT TO THE WESTERN AND CENTRAL PACIFIC BY APRIL. THE MJO WILL FIRST DESTRUCTIVELY, THEN CONSTRUCTIVELY INTERFERE WITH THE EL NINO BASE STATE OVER THIS PERIOD AND THERE IS LIKELY TO BE CONSIDERABLE VARIABILITY IN THE PATTERN OF ANOMALOUS TROPICAL CONVECTION ACROSS THE MARITIME CONTINENT AND WESTERN PACIFIC DURING THIS PERIOD. BY APRIL, THERE MAY EMERGE A COUPLET OF EQUATORIAL SUPPRESSED/ENHANCED CONVECTION ACROSS THE MARITIME CONTINENT AND WESTERN PACIFIC THAT CAN BE CONSIDERED FOR POTENTIAL TELECONNECTION TO THE HIGHER LATITUDES DURING EARLY APRIL. ABOVE AVERAGE SOIL MOISTURE CONDITIONS ARE EVIDENT IN MID-MARCH FOR A REGION FROM THE SOUTH-CENTRAL CONUS NORTHEASTWARD TO PARTS OF THE MIDWEST AND OHIO VALLEY.
THE APRIL TEMPERATURE OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES FOR ALASKA, THE WESTERN CONUS AND PARTS OF THE EASTERN GREAT LAKES, MID-ATLANTIC AND NORTHEAST. AREAS IN ALASKA, THE PACIFIC NORTHWEST AND NORTHERN ROCKIES ARE CONSISTENT WITH EL NINO CONDITIONS AND STRONGLY SUPPORTED BY DYNAMICAL MODEL GUIDANCE AS WELL. ABOVE AVERAGE SEA SURFACE TEMPERATURES (SSTS) IN WATERS NEIGHBORING SOUTHERN ALASKA AND THE WEST COAST ALSO SUPPORT ABOVE NORMAL TEMPERATURES IN THESE AREAS. DYNAMICAL MODEL GUIDANCE SUPPORTS ABOVE NORMAL TEMPERATURES FOR THE CENTRAL AND SOUTHERN ROCKIES AND SOUTHWEST WHICH IS CONSISTENT WITH THE LACK OF EL NINO PRECIPITATION DURING THE WINTER MONTHS IN MANY OF THESE AREAS. LAGGED COMPOSITES WITH CURRENT MJO ACTIVITY SUPPORT POTENTIAL MEAN RIDGING AND ABOVE NORMAL TEMPERATURES ACROSS THE NORTHEAST CORNER OF THE CONUS IN EARLY APRIL AND THIS ALONG WITH SOME DYNAMICAL MODEL GUIDANCE SUPPORT FAVORS A TILT IN THE ODDS FOR ABOVE NORMAL TEMPERATURES IN THIS AREA. WET SURFACE CONDITIONS, POTENTIAL ABOVE MEDIAN PRECIPITATION ON AVERAGE OVER THE PERIOD AND MODEST DYNAMICAL MODEL SUPPORT FAVOR BELOW NORMAL TEMPERATURES FOR PARTS OF THE LOWER MISSISSIPPI VALLEY.
THE APRIL PRECIPITATION OUTLOOK FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE SOUTHERN HALF OF THE CONUS AND ALSO FOR PARTS OF WESTERN ALASKA. EL NINO CONDITIONS AND DYNAMICAL MODEL GUIDANCE SUPPORT AREAS ACROSS THE WEST, THE PLAINS AND GULF COAST STATES. MJO CONSIDERATIONS ALSO SUPPORT A SLIGHT TILT IN THE ODDS FOR ABOVE MEDIAN PRECIPITATION FOR AREAS IN THE OHIO VALLEY, TENNESSEE VALLEY AND SOUTHEAST EARLY IN THE MONTH. FOR ALASKA, BELOW AVERAGE SEA ICE COVERAGE AND CFS GUIDANCE SUPPORT ABOVE MEDIAN PRECIPITATION IN THE HIGHLIGHTED AREA. BELOW MEDIAN PRECIPITATION IS FAVORED FOR THE ALASKA PANHANDLE, PARTS OF THE PACIFIC NORTHWEST, NORTHERN PLAINS AND WESTERN GREAT LAKES AND IS CONSISTENT WITH EL NINO CONDITIONS AS WELL AS THE MAJORITY OF AVAILABLE DYNAMICAL MODEL GUIDANCE.
THE APRIL-MAY-JUNE (AMJ) 2016
WHILE EL NINO IS WEAKENING, THE SEASONAL OUTLOOK FOR AMJ 2016 IS STILL LARGELY INFLUENCED BY EL NINO. THE CURRENT EL NINO CONDITIONS ARE STRONG AND LIKELY WILL BE AT LEAST MODERATE AS APRIL BEGINS. SST ANOMALIES IN THE NINO 3.4 REGION ARE FORECAST TO REMAIN ABOVE +0.5 C FOR THE AMJ AVERAGE. DYNAMICAL MODELS OF THE NMME CONSISTENTLY PREDICT RELATIVELY GREATER HEIGHTS ACROSS CANADA AND LOWER HEIGHTS ACROSS THE SOUTHERN U.S. IN THEIR AMJ FORECASTS, CONSISTENT WITH AN EL NINO. HIGHER PROBABILITIES FOR ABOVE-NORMAL, ACROSS THE NORTHERN TIER, ARE IN PART DUE TO EL NINO. SSTS IN THE NORTH PACIFIC ARE EXPECTED TO ALSO INFLUENCE THE CIRCULATION PATTERN IN AMJ AND MJJ, THROUGH RIDGING OVER WESTERN NORTH AMERICA IN NMME FORECASTS.
THE APRIL-MAY-JUNE (AMJ) 2016 TEMPERATURE OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE CONTINENTAL U.S., HAWAII, AND ALL OF ALASKA. ABOVE-NORMAL TEMPERATURE ARE LIKELY FOR MOST OF THE WEST, FROM THE CENTRAL AND NORTHERN ROCKY MOUNTAINS ACROSS THE NORTHERN GREAT PLAINS INTO THE GREAT LAKES REGION, AS WELL AS MOST OF THE REGION TO THE EAST OF THE MISSISSIPPI RIVER VALLEY. THE CHANCES OF ABOVE-NORMAL TEMPERATURES ARE HIGHEST FOR THE PACIFIC NORTHWEST, THE NORTHEAST, AND THE MID-ATLANTIC COAST, EXCEEDING 50 PERCENT IN THESE REGIONS. BELOW-NORMAL TEMPERATURES ARE MORE LIKELY FOR A SMALL AREA OF CENTRAL TEXAS.
THE AMJ 2016 PRECIPITATION OUTLOOK INDICATES A SLIGHT INCREASE IN CHANCES OF ABOVE-MEDIAN PRECIPITATION ACROSS MUCH OF THE SOUTHERN CONTINENTAL U.S. AND SOME INCREASE IN CHANCES OF BELOW-MEDIAN PRECIPITATION FOR PARTS OF THE NORTHWEST AND THE WESTERN GREAT LAKES STATES. ABOVE-MEDIAN PRECIPITATION IS MOST LIKELY FROM CENTRAL AND NORTHERN CALIFORNIA ACROSS THE GREAT BASIN AND THE CENTRAL AND SOUTHERN ROCKIES INTO PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS STATES, AS WELL AS FOR THE GULF COAST AND SOUTHERN ATLANTIC COAST STATES. THE CHANCES OF ABOVE-MEDIAN PRECIPITATION ARE ONLY SLIGHTLY FAVORED OVER MOST OF THIS AREA, WITH GREATER PROBABILITIES IN PARTS OF THE SOUTHWEST AND COASTAL AREAS OF THE SOUTHEAST INCLUDING FLORIDA. ABOVE-MEDIAN PRECIPITATION IS ALSO FORECAST TO BE MOST LIKELY FOR MUCH OF ALASKA. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY FOR HAWAII.
15 Month Outlook - AMJ 2016 TO AMJ 2017 (notice the discussion covers 15 months but the set of maps only covers 14 months as the Apr - May - Jun Map is shown separately).
THE NMME, THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), AND THE INDIVIDUAL MODEL ENSEMBLE OF THE NCEP CLIMATE FORECAST SYSTEM (CFS) CONTRIBUTE TO THE SEASONAL OUTLOOKS THROUGH SUMMER 2016. OUTLOOKS FROM SON 2016 THROUGH AMJ 2017 RELY PRIMARILY ON CPC STATISTICAL MODELS, INCLUDING REGRESSIONS TO THE NINO 3.4 SST ANOMALY FOR THE IMPACT OF A LIKELY TRANSITION TO A LA NINA EVENT. WITH THE PREDICTION OF ENSO NEUTRAL CONDITIONS BY SUMMER 2016, ENSO REGRESSIONS WERE NOT CONSIDERED DURING THE WARM SEASONS OF 2016.
THE AMJ TEMPERATURE OUTLOOK IS SIMILAR TO THE OUTLOOK FROM A MONTH AGO, WITH SOME INCREASE IN PROBABILITIES, CONSISTENT WITH SHORTER LEAD TIMES AND DYNAMICAL MODEL FORECASTS. ALL TEMPERATURE TOOLS PREDICT INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS THE NORTHERN HALF OF THE CONTINENTAL U.S. THROUGH THE EARLY SPRING, CONSISTENT WITH AN EL NINO. EQUAL CHANCES OF BELOW-NORMAL AND ABOVE-NORMAL, OR INCREASED CHANCES OF BELOW-NORMAL ARE INDICATED IN PARTS OF THE SOUTH-CENTRAL CONTIGUOUS U.S. INCREASED CHANCES OF ABOVE-NORMAL TEMPERATURES CONTINUE ACROSS MUCH OF THE CONTIGUOUS U.S. AND ALASKA THROUGH THE SUMMER INTO AUTUMN, AS INDICATED BY MODEL FORECASTS, INFLUENCED BY THE COMBINED SIGNALS OF GLOBAL SEA SURFACE TEMPERATURE ANOMALIES AND A WARMING CLIMATE ON DECADAL TIMESCALES.
INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES FORECAST ACROSS PARTS OF THE SOUTHERN CONTIGUOUS U.S. AND A SLIGHT INCREASE IN THE PROBABILITY FOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTHERN U.S. FROM NDJ 2016 THROUGH AMJ 2017 ARE BASED LARGELY ON THE IMPACTS OF LIKELY LA NINA CONDITIONS. AN INCREASED PROBABILITY OF ABOVE-NORMAL TEMPERATURES FOR THE NORTH SLOPE OF ALASKA DURING THE AUTUMN IS DUE TO THE LIKELIHOOD OF ANOMALOUSLY OPEN SEA ICE AND THE FEEDBACK BETWEEN SEA ICE COVERAGE AND CHANGES IN THE CLIMATE STATE.
THE AMJ AND MJJ 2016 PRECIPITATION OUTLOOKS FOLLOW A PATTERN THAT IS ON AVERAGE ASSOCIATED WITH EL NINO. ENHANCED CHANCES FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST FOR AMJ AND MJJ 2016 FROM NORTHERN AND CENTRAL CALIFORNIA, ACROSS THE CENTRAL ROCKIES AND SOUTHWEST, INTO THE CENTRAL AND SOUTHERN GREAT PLAINS, AND FOR AMJ INTO THE GULF AND SOUTHERN ATLANTIC COASTS. EQUAL CHANCES IS INDICATED FOR SOUTHERN CALIFORNIA AND SOUTH-WESTERN ARIZONA, WHERE CLIMATOLOGICAL PRECIPITATION IS VERY LOW DURING THIS SEASON. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY THROUGH MJJ FOR NORTHERN REGIONS OF THE PACIFIC NORTHWEST AND THE WESTERN GREAT LAKES. A SLIGHTLY INCREASED CHANCE OF ABOVE-MEDIAN PRECIPITATION IS FORECAST FOR WESTERN AND NORTHERN ALASKA INTO SUMMER BY DYNAMICAL MODELS, RESULTING FROM ANOMALOUSLY OPEN SEA ICE AND WARM OPEN OCEAN TEMPERATURES.
DURING AUTUMN OF 2016 AND WINTER OF 2016-17, THE INCREASING LIKELIHOOD OF DEVELOPING LA NINA CONDITIONS IS THE PRIMARY FACTOR FOR INCREASED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. AND THE SOUTHERN COAST OF ALASKA, AND INCREASED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST AND OHIO VALLEY AND CENTRAL GREAT LAKES.
Sometimes it is useful to compare the present month outlook to the three-month outlook
One can mentally subtract the April Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely May and June 2016. When I do that, I deduce that:
With respect to temperature, the area that is EC in April will need higher probabilities in May and June than shown to reach the levels in the graphic. it is simply a question of how you calculate a three-month average. This applies to the warm anomaly for the East Coast down to Florida and the shift of the dry anomaly from the Lower Mississippi Valley over to West Central Texas. The Precipitation Outlook is perplexing as the pattern for May and June will be the same as in April but with lower probabilities in May and June. Given the weakening of the El Nino and the unpredictability of the MJO for May and June as compared to the first half of April, I would think that May and June would be more like EC and really average down the probabilities for the three-month average.
How Realistic is the NOAA Outlook?
We took a look at how the forecasts worked out for January and February and so far in March and considering the short-term forecast for the remainder of March which should be fairly reliable. This is what we found.
January Forecast [and this is the updated forecast issued on the last day of the prior month not the earlier forecast issued on the third Thursday of the prior month where you would expect more deviation between forecast and actual. In all cases we are talking about departures from climatology not absolute values. If course it is cooler in the north than in the south. These graphics show where it is either forecast to be wetter, drier, warmer, or cooler than normal for that time of year or where the actuals were wetter, drier, warmer or cooler than normal for that time of year]
And the forecasts in this case were made on the last day of the prior month and include 14 days of dynamic rather than statistical forecasts. And yet, the precipitation pattern of the forecast bears no resemblance to the actuals. The temperature forecast and actuals line up to some extent but not very well. As an example, Texas was slightly warmer rather than significantly cooler than climatology. That is important as cooler is expected with El Nino and warmer is expected with La Nina.
And again, the forecasts shown were issued on the last day of the prior month which is the least challenging forecast possible. Again the precipitation actual pattern bears no resemblance to the forecast. The temperature is better but not very good. There is more of a West/East pattern than the forecast North/South pattern.
March to date Actual.
And again the forecasts shown were issued on the last day of the prior month which is the least challenging forecast possible. And again the precipitation actual plus the recent forecast for the remainder of the month (shown later in this report) bears no resemblance to the full-month forecast. The temperature is a little better but not much. The forecast calls for the typical North/South divide and the actuals and short-term Outlook reflects a West/East divide.
The results for Jan - Feb - Mar have not been good even when the updated forecasts are used in the comparison. Now we are asked to put faith in a forecast for April issued on March 17 and forecasts for May and June also issued on March 17. As far as I can tell, the NOAA discussion just released briefly mentions that precipitation has not worked out as forecast but does not explain why the significant deviation from forecast to actual occurred in January, February and so far in March. It does not provide much to explain why one should expect the April, May and June forecasts to be more reliable other than an explanation that the MJO is now being given more consideration with respect to the April forecast which I find to add to the credibility of the April forecast to some extent especially the first half of April. I have no real criticism of the remainder of the NOAA Seasonal Outlook. It is not realistic to expect a forecast beyond June issued in March to be reliable due to the impact of the Monsoon which is difficult to predict and forecasts for next winter made in March are historical not very reliable. But a forecast made on the last day of a month for the next month should be more reliable than they were in January, February and it would appear for March. In a separate article, I will attempt to explain why the difficulty in forecasting has been the case. For now, all I want to say is that whatever has caused the deviation between theory and practice may end starting early in April or may not. We shall see.
Let's Focus on the Current (Right Now to 5 Days Out) Weather Situation.
A more complete version of this report with daily forecasts is available in Part II. This is a summary of that more extensive report. Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks will take you directly to that set of information but it may take a few seconds for your browser to go through the two-step process of getting to Page II and then moving to the Section within Page II that is specified by this link.
First, here is a national animation of weather front 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 the link provided above.
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.
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.
Right now it is showing for Day 7 a deep Trough passing over the Great Lakes and moving towards the East Coast. There is a West Coast Ridge and an East Coast Ridge which will be overrun by the trough. A new feature that just popped up this evening is a significant Low centered over Nevada and Idaho. It is unusual for that sort of feature to be shown on this graphic so I assume it is significant. The issue is how far south it will manage to go. This 500 MB forecast can be helpful for those planning travel as it is a good predictor of major surface weather features. This normally mean that one could decide what sort of weather one prefers and adjust their travel plans accordingly. 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. Other than at high elevations, it will be difficult to find much new snow south of Canada. Overall it has been a warm winter and it is already meteorological Spring. The groundhog may have gotten it correct.
The MJO shifted to its inactive phase for most of March. If the usual pattern applies, there will be another active phase late this month and for at least the first half of April. The MJO is thought by some to be relatively unimportant during the winter but perhaps a strong El Nino increases the relevance of the MJO.
Notice the Northern Pacific is like a giant anticyclone with clockwise motion so that which gets sent west due to El Nino is to some extent returned to North America but at higher latitudes. I am trying to see if I can discern a change in pattern towards lower latitudes for storms arriving from the Western Pacific but so far I do not see that in this animation.
As I am looking at the below graphic Monday evening March 21, I again see a somewhat northerly displaced weather pattern. This graphic updates automatically so it most likely will look different by the time you look at it as the weather patterns are moving from west to east especially in the north.
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 March 15, 2016 Version and looking at Week 2 of that forecast.
Mostly I see for the period March 23 - March 29, 2016 a moderate likelihood of below average precipitation for the Maritime Continent and a moderate likelihood of tropical cyclone formation in Northern Australia. We some some small areas of moderate likelihood of below average precipitation in parts of East Africa. There is also the persistent moderate likelihood of dry conditions in Eastern Brazil and Uruguay. You can see that the majority of the impacts continue to be west of the Date Line but even there they are much reduced as this El Nino dies.
Below is a graphic which highlights the forecasted surface Highs and the Lows re air pressure on Day 6 (the Day 3 forecast is available on Page II of this Report). This graphic also auto-updates.
In recent weeks, the projected location and strength of the Aleutian Low has varied a lot. On some days, the forecast is showing a split low with each of the two lows weaker than a combined single Low. Right now the forecasted Low has an hPa of 976 which is (the average in the winter is 1001hPa and 994 hPa for a non-split Low) much stronger than normal. It is now mostly a unified low with a small secondary low offshore of British Columbia. All through January and February we had a Supercharged El Nino Pattern that produced La Nina impacts. Then recently for the first time since December it looked like it would be a traditional El Nino Pattern for a while and California did get some precipitation. But the Aleutian Low has been weakening and was moving away from the Gulf of Alaska, which is the ideal El Nino location for the Aleutian Low, and at first seemed to be moving into the Central Pacific but now appears to be visiting Siberia and getting stronger. The rapidly shifting position of the Low makes a big difference in how storms are steered. A longer discussion of the climate of Beringia and the role of the Aleutian Low is in Part II of this Report: 2. Medium Frequency Cycles such as ENSO and IOD.
Looking at the current activity of the Jet Stream
The path of the current weather pattern is fairly clear from this graphic.
And here is the forecast out five days.
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 this case the Southern Branch of the storm track is going through Mexico and then impacting the U.S. East Coast. With the MJO switching to its active phase, we may have less of a split stream but the Jet Stream may be pulled further south. That will take whatever remains of the Southern Branch of the Jet Stream out of the picture for the first half of April but may bring the Northern Branch down and impact the Southwest for a week or two. NOAA seems to have another scenario in mind with the Southern Branch undercutting the RRR and impacting parts of the Southwest in that manner.
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.
Here is 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.
And when we look at Sea Surface anomalies below, we see a lot of them not just along the Equator related to El Nino.
There is a lot less warm water off of Peru and Chile. It is clearly not connected to the ENSO Warm Pool at the surface. So we essentially have a Modoki pattern at this point in terms of weather impacts. The overall Northern Pacific is indeed PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape). The water off the West Coast of North America is warm especially off of Central America. The water off the East Coast of the U.S. is also warm and the four-week analysis shows it may be slowly getting warmer. Further north but off the North American Coast and south of Greenland and Iceland, the North Atlantic is cooler than normal which is consistent with AMO+ and has implications for the NAO. But the four-week analysis does not show this water getting cooler. Waters around Australia are warm except immediately off the west coast but that might be cooling down.The waters off of Japan are now warm. The set up is for a typical PDO-/AMO+ weather pattern but we are not getting that just yet and NOAA is not noticing but making statistical forecasts when it is fairly obvious there is a missing variable in their equations. I believe that variable has been the location of the Aleutian Low which recently was starting to reposition itself more appropriately for an El Nino but the tail end of an El Nino and in recent days the Aleutian Low has decided to visit Siberia. A new theory is the pattern is so far north it may be undercut. This has been proposed twice before recently and perhaps the third time is the charm.
Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.
Since these are "departures" or "anomalies", it is not a seasonal pattern that is being shown. 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, compare and comment on the change and then delete the old one to keep this report to a manageable size. What I see as I look at both (before deleting the prior version) is an overall moderating of anomalies in the Pacific for both Hemispheres and also but to a lesser extent in the Indian Ocean It continues to warm around the Galapagos Islands.
6 - 10 Day Outlook
Now let us focus on the 6 - 14 Day Forecast for which I generally only show the 8 - 14 Day Maps. The 6 - 10 Day maps are always available in Part II of this report but in the winter I often show both maps as the forecasted weather patterns change during that nine day period.
To put the forecasts which NOAA tends to call Outlooks into perspective, I am going to show the three-month AMJ Outlook and the newly updated Outlook for the single month of April and then discuss the 8 - 14 day Maps and the 6 - 14 Day NOAA Discussion within that framework.
First - Temperature
Here is the Three-Month MAM Temperature Outlook issued on February 18, 2016 followed by the Three-Month AMJ Temperature Outlook Issue on March 17, 2016:
AMJ Temperature Outlook
As indicated earlier, Not much change in the pattern. But an increase in coverage and substantially higher probabilities. Some of this is due to being one month closer. But it seems like more than that.
Here is the updated Outlook for March Temperature followed by the Early Release for April Temperatures issued on March 17, 2016.
April Temperature Outlook
This is not a comparison with a prior forecast but considering the change from March to April. The area of and intensity of warm anomalies has been reduced. The cool anomaly in the southern tier has shifted from Arizona and New Mexico to the lower Mississippi Valley.
Below is the current 6 - 10 Day and 8 - 14 Day Temperature Outlook Maps which will auto-update and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that all winter as the patterns are moving from west to east fairly rapidly.
As I view these two maps on March 21 (it updates each day), it appears that Late-March and early April will yet again have an East/West divide of temperature anomalies not the North/South divide normally associated with an El Nino and which has been in the Seasonal Outlook in January, February and March. NOAA is very wedded to their statistical method of forecasting and seems to not have noticed that our weather is not conforming to that statistical analysis. The result is the 6 - 14 Day Outlooks (especially for precipitation) routinely bear little resemblance to the Monthly and three-month forecasts. That is a separate question from how well the 6 - 14 Day Outlooks work out. I will say the 6 - 10 Day and 8 - 14 Day Outlooks change a lot more on a day to day basis than one would expect from simply the addition of one day and the removal of one day.
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Now - Precipitation
Here is the three-month MAM Precipitation Outlook issued on February 18, 2016 followed by the three-month AMJ Precipitation Outlook issued on March 17, 2016:
AMJ Precipitation Outlook
As noted earlier, this is a big change. The small dry anomaly in the Northwest is new. The dry anomaly centered on the Great Lakes does not now extend as far south. The wet anomaly now extents from the Southwest all the way to the Atlantic Ocean
Here is the recently updated Outlook for March Precipitation.
April Precipitation Outlook
This is not a comparison with the prior forecast but a comparison of the change from March to April. Southern California is now EC and the wet anomaly extents into the Midwest.
Below are the current 6 - 10 Day and 8 - 14 Day Precipitation Outlook Maps which will auto-update and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that all winter as the patterns are moving from west to east fairly rapidly.
As I view these two maps on March 21 (they update each day), it looks like precipitation for Late-March and early April will begin with a West/East divide and shift to a pattern that looks a lot more like an El Nino. But it is a forecast based on a lot of things falling into place with regards to the Southwest.
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
Here are excerpts from the NOAA discussion released today March 21, 2016. It covers the full nine-day period and this week I have shown both the 6 -10 Day and the 8 - 14 Day Maps.
6-10 DAY OUTLOOK FOR MAR 27 - 31 2016
TODAY'S NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED 500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. A TROUGH IS PREDICTED OVER THE ALEUTIANS AND A STRONG RIDGE IS FORECAST FARTHER TO THE EAST OVER MOST OF THE REMAINDER OF ALASKA AS WELL AS THE NORTHWESTERN CONUS. DOWNSTREAM OF THIS RIDGE, SPLIT FLOW IS FORECAST OVER MUCH OF THE CONUS WITH A TROUGH IN THE NORTHERN STREAM FORECAST NEAR THE WESTERN GREAT LAKES AND A SOUTHERN STREAM TROUGH PREDICTED OVER THE SOUTHWESTERN CONUS. ENSEMBLE SPREAD IS GENERALLY LOW WITH THE EXCEPTION OF THE WEST COAST OF THE CONUS DUE TO MODEL UNCERTAINTY SURROUNDING THE POTENTIAL FOR SHORTWAVE ENERGY TO UNDERCUT THE RIDGE FORECAST OVER WESTERN NORTH AMERICA. TODAY'S OFFICIAL 500-HPA MANUAL HEIGHT BLEND CONSISTS PRIMARILY OF THE ENSEMBLE MEAN SOLUTIONS.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE CENTRAL CONUS BEHIND THE TROUGH PREDICTED OVER EAST-CENTRAL NORTH AMERICA. THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES AHEAD OF THE PREDICTED TROUGH AXIS FOR THE EASTERN SEABOARD. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR ALASKA AND THE WEST COAST OF THE CONUS IN ASSOCIATION WITH PREDICTED RIDGING OVER WESTERN NORTH AMERICA.
THERE ARE ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE EASTERN CONUS AHEAD OF A TROUGH PREDICTED OVER EAST-CENTRAL NORTH AMERICA. ABOVE MEDIAN PRECIPITATION IS ALSO FAVORED FOR THE CENTRAL ROCKIES DUE TO A TROUGH PREDICTED OVER THE SOUTHWESTERN CONUS AND THE POTENTIAL FOR ASSOCIATED UPSLOPE FLOW. MOIST FLOW AHEAD OF A TROUGH PREDICTED OVER THE ALEUTIANS LEADS TO ENHANCED PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION FOR MUCH OF ALASKA. CONVERSELY, FORECAST RIDGING FAVORS BELOW MEDIAN PRECIPITATION FOR PARTS OF THE ALASKA PANHANDLE AS WELL AS MOST OF THE WEST COAST OF THE CONUS.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO FAIRLY GOOD MODEL AGREEMENT.
8-14 DAY OUTLOOK FOR MAR 29 - APR 04, 2016
DURING THE WEEK TWO PERIOD, TODAY'S MODELS AGREE IN PREDICTING A STRONG RIDGE OVER ALASKA, WESTERN CANADA, AND THE NORTHWEST CONUS AND AN AMPLIFIED TROUGH DOWNSTREAM OVER EAST-CENTRAL CANADA EXTENDING SOUTHWARD TO THE GREAT LAKES REGION. SPLIT FLOW IS FORECAST OVER THE WESTERN CONUS WHILE GENERALLY ZONAL OR WEAKLY CYCLONIC FLOW IS FORECAST ACROSS THE SOUTHERN TIER OF THE CONUS. ENSEMBLE SPREAD IS THE HIGHEST NEAR THE WEST COAST OF THE CONUS DUE TO MODEL UNCERTAINTY IN RESOLVING INDIVIDUAL SHORTWAVE FEATURES WITHIN THE PREDICTED SPLIT FLOW PATTERN. THE WEEK TWO 500-HPA MANUAL HEIGHT BLEND IS BASED PRIMARILY ON THE ENSEMBLE MEAN SOLUTIONS. THE GREATEST WEIGHTS WERE GIVEN TO THE GFS AND ECWMF ENSEMBLE MEANS DUE PRIMARILY TO CONSIDERATIONS OF RECENT SKILL AND ON ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE FORECAST PATTERN MATCHES CASES THAT HAVE OCCURRED IN THE PAST.
THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR THE CENTRAL CONUS IN ASSOCIATION WITH THE AMPLIFIED TROUGH PREDICTED NEAR THE GREAT LAKES REGION. NEAR TO ABOVE NORMAL TEMPERATURES ARE FAVORED AHEAD OF THE PREDICTED TROUGH AXIS ALONG THE EAST COAST OF THE CONUS. THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR ALASKA AND THE WEST COAST OF THE CONUS DUE TO FORECAST RIDGING.
ABOVE MEDIAN PRECIPITATION IS FAVORED FOR THE EASTERN THIRD OF THE CONUS IN ASSOCIATION WITH THE TROUGH FORECAST OVER EAST-CENTRAL NORTH AMERICA. NEAR TO BELOW MEDIAN PRECIPITATION IS FAVORED BEHIND THE TROUGH AXIS FOR MUCH OF THE CENTRAL CONUS. THERE ARE ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR THE CENTRAL AND SOUTHERN ROCKIES AND PARTS OF THE SOUTHWEST CONSISTENT WITH GEFS REFORECAST GUIDANCE. CONVERSELY, BELOW MEDIAN PRECIPITATION IS FAVORED FOR THE NORTHWEST CONUS AND THE ALASKA PANHANDLE IN ASSOCIATION WITH PREDICTED RIDGING. THERE ARE ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR MOST OF THE REMAINDER OF ALASKA AHEAD OF A TROUGH FORECAST OVER THE ALEUTIANS.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE TO REASONABLY GOOD MODEL AGREEMENT.
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 this El Nino.
Analogs to Current Conditions
Now let us take a detailed look at the "Analogs" which NOAA provides. Two sets of analogs are usually provided. The analogs provided by NOAA are listed by the level of correlation. I find chronological order easier for me to work with so I reorganize them chronologically. Two sets of analogs are provided. One relates to the conditions 5 and 7 days prior to the forecast and I usually work with those. There is a second set of analogs associated with the forecast but I have not been analyzing this second set of information. However, for the last two days NOAA has had difficulty publishing the full set of the first category of analogs so I am today using the second set which correlates the forecast with prior conditions. I prefer the other set which looks at the conditions that applied to the prior 5 and 7 day periods but that information is only half available today I assume due to a technical problem with their Internet site. The state advantage by NOAA of this set is we get a correlation coefficient which today is quite high at 0.96 (rounded).
Feb 25, 1954
Apr 1, 1962
Mar 20, 1974
Apr 4, 1977
Mar 24, 1990
Apr 5, 1990
Apr 13, 1990
Mar 27, 1994
Apr 1, 1994
Apr 9, 1997
One thing that jumped out at me right away was the spread among the analogs from Feb 25 to April 13 which is about eight weeks. We can not compare this spread to the spread last week as it is a different kind of analog. It suggests that the current forecasts are highly correlated with weather patterns which in the past occurred over a wide range of dates as shown. This is new territory for me but I notice there are no analogs with dates more recent than 1997 and seven of the ten are during the Pacific Climate Shift from 1977 through the 1997 date. The Pacific Climate Shift was when the PDO shifted from PDO Negative to PDO Positive. There are this time two El Nino Analogs and seven ENSO Neutral Analogs and one La Nina Analog suggesting that El Nino is not in full control over our weather for the next 6 - 14 Days or perhaps more accurately the forecast best correlates with periods of time when ENSO was neutral.
I acknowledge that I do not full understand this category of analogs. To me they serve almost no useful purpose but perhaps that is because I do not understand them. It seems like one makes a forecast and then attempts to find similar patterns in the past. I have no idea what that proves other than the forecast is not so unusual that this pattern has never occurred before. I find the other set of analogs much more useful as they relate recent conditions to historical conditions the week prior to this forecast. To me that has predictive value. This set of analogs may also have predictive value going forward but I do not see them as confirming the forecast. But it is not clear to me how NOAA uses either set of analogs.
The phases of the ocean cycles in the analogs point towards McCabe Condition A or B which are somewhat opposites of each other raising questions about the level of confidence in the 6 - 14 Day Outlook. One way of looking at this is that the Atlantic is in control. Another way is that the current forecast relates to mostly ENSO Neutral periods of time. 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.
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.
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
Progress of the Warm Event
Let us start with the SOI.
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 inactive phase of the MJO is changing to the active phase and you see this in the La Nina-ish SOI readings that started the week then moderated throughout the middle of the week and then switched to the El Nino direction the end of the week. The 30-day average, which is the most widely used measure, as of March 21 is reported at -13.15 which is definitely a reading that is associated with an El Nino (usually required to be more negative than -8.0 but some consider -6.0 value good enough). There have been no such El Nino-ish daily readings this past week. The 30 day average which is most widely used was considerably less El Nino-ish by the end of the week. The 90-day average remains in El Nino territory at -14.56 little changed from last week. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. The SOI continues to be indicative of an El Nino Event in progress but it is pretty much passed the time of year where it is very meaningful re El Nino development. I believe we will continue to see a moderating trend in the SOI from here on with the possible exception of the Active Phase of the MJO which has begun and will last for perhaps three weeks or four.
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 and it shows that right now the MJO is inactive in the Pacific Ocean.
Low-Level Wind Anomalies
Here are the low-level wind anomalies. In October, the area from 180W to 160W was of interest and quite intense. There then was an area of interest at 160W which also was quite intense. Now, calm appears to prevail but there recently was a WWB (Westerly Wind Burst) in January near and east of the Date Line related to Tropical Storm Pali which has long since dissipated. But look at the intensity of the wind anomaly associated with that WWB: 14 That might be "all she wrote" for this El Nino as calm winds prevail. Well that is until two weeks ago when we had a MJO induced WWB at 180W to 160W. I suspect it is too late to generate Kelvin Wave #6. Some claim to have detected the presence of a Kelvin Wave #6 but I do not see it so if there was one, it was very weak. We now for the first time see Easterly anomalies, the blue area at the bottom of the Hovmoeller graphic.
In the above graphic, you can see how the convection pattern recently shifted a bit to the east probably due to the active phase of the MJO and now has returned to the position it has been in since August 2015. We predicted that to happen last week.
Let us now take a look at the progress of Kelvin Waves which are the key to the situation. From the earliest to the most recent they can be named #1 through #5. Kelvin Wave #1 will soon be pushed off the top of this graphic as more recent information is added at the bottom.
Kelvin Wave #5 which was fairly late in the El Nino development phase introduced a new episode of warming from 150W to 100W. But this Kelvin Wave was less intense than Kelvin Waves #3 and #4 and has now moved through the NINO 3.4 Measurement Area (170W to 120W) and no longer significantly impacts the ONI calculations. But Kelvin Wave # 5 did slow the retreat to the west of the Eastern Pacific Subsurface Warm Pool. That is why I believe the transition to ENSO Neutral will proceed more slowly than some have predicted. I see no sign of a Kelvin Wave #6 unless one views the slight retraction of the upwelling wave following Kelvin Wave #5 as being Kelvin Wave #6. If so it is so insignificant that it can be ignored. This El Nino is now dying. We now see the next Upwelling Phase of this Kelvin Wave which is the Coup de Grace for this El Nino.
One should keep in mind that for a new Kelvin Wave, the period of time from initiation to the termination of impacts is about six months. So when you have four or five in a row, the pattern of impacts on different indices and geographic areas becomes quite complex. It is further complicated as you can see above because the Kelvin Waves do not necessarily originate at the same location i.e. longitude. Looking at many factors I have come to a conclusion that his El Nino may have the greatest impact on CONUS during March and probably also April of 2016 rather than in Dec 2015 and January - February of 2016. The major impacts have started a bit later and most likely will last a bit longer. The pattern in January and February have not been for the West typical of an El Nino. March appears to be developing with the same pattern. Will April behave like a more typical El Nino?
We are now going to change the way we look at a three dimensional view of the Equator and move from the surface view to the view from the surface down. This El Nino appears to be fading slowly from west to east. The real decline will be from east to west.
Current Sub-Surface Conditions. Notice the lag in getting this information posted so the current situation may be a bit different than shown.
Top Graphic (Anomalies)
The above graphic 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.
The top graphic is still the most useful of the two and shows where the 2C (anomaly) water is impacting the area in which the ONI is measured i.e. 170W to 120W. The 2C anomaly again extends to 180W or a bit further to the west and this may well indicate that the Warm Pool has begun its journey to the Western Pacific. At the eastern end, the 2C anomaly is intersecting the surface at about 105W. But there is a gap between 150W and 130W with sub-2C anomalies. This is easier to see in the TAO/TRITON graphic presented later and which is more current. The 3C anomaly no longer intersects the surface and thus is a non-factor. It explains why NOAA is coming up with lower ONI estimates. The 4C anomaly is now very small and is east of the ONI Measurement Area. The 6C and 5C anomalies no longer exist. Water temperatures off the Coast of South America near the Equator have returned to normal. But there is warming near the Galapagos as Kelvin Wave #4 comes to the surface.
Bottom Graphic (Absolute Values which highlights the Thermocline)
The bottom half of the graphic may soon become more useful in terms of tracking the progress of this Warm Event as it converts to ENSO Neutral and then La Nina.
It shows the thermocline between warm and cool water which pretty much looks like this as shown here during a Warm Event. You can see that the cooler water is not yet fully making it to the surface to the east along the coast of Ecuador. In fact, the 25C Isotherm temporarily is not reaching the surface. We now will pay more attention to the 28C Isotherm as west of that temperature is where convection is more easy to occur. The 28C Isotherm has pretty much remained in the same place for months but appears now to be drifting to the west. However there is now a shallow (20m? and will soon mix out) 28C Isotherm east of 140W which I believe is the warm pool surfacing and moving to the west. That could impact the weather for Ecuador and Peru.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
This discussion is longer than necessary to describe current conditions but I am retaining the snap shots of the earlier TAO/TRITON graphics to allow the reader to understand how this El Nino evolved and how it is not decaying.
Let us compare the situation as reported on October 4 to the most recent graphic. Remember each graphic has two parts the top part is the average values, the bottom part is those values expressed as an anomaly compared to the expected values for that date. Generally I am mainly discussing the bottom of the pairs of graphics namely the anomalies
First the October 4 version which I am providing for purposes of comparison. I "flash froze" the daily value that day so that it would not auto-update.
And then the December 14 version which I also "flash froze" to stop it from updating.
And then the current version of the TAO/TRITON Graphic.
Location Bar for Nino 3.4 Area Above and Below
It is quite a bit less intense than on December 14. The 3.5C anomaly is no longer visible. Neither is the 3.0C anomaly and neither is the 2.5C anomaly. The 2C anomaly also no longer exists in the Nino 3.4 Measurement Area except for the small extension from the Eastern Pacific barely edging into the Nino 3.4 Measurement Areas. So basically the maximum anomalies (which did not appear everywhere) have declined by a full degree and one half Centigrade. This means that if one is attempting to mentally estimate the daily ONI, an approach would be to make an initial estimate of the midpoint of the 1.5C to 2.0C or 1.75C and subtract the reductions from there where the anomaly is less.What I have just described is not exactly the approach I use in my calculation below but it does provide a quick way to get a feel for the current strength of this El Nino. There is actually shading in the TAO/TRITON Graphic that might allow one to try to refine estimates a bit more than the contour lines but I rely on the contour lines.
And an earlier but recent reference point close to the peak of this El Nino re the bottom half of the TAO/TRITON Graphic. You can certainly see the difference that six weeks makes.
The below table tracks the changes. It only addresses the situation right on the Equator so visually the TAO/TRITON graphic contains more information. But the below table turns visual information into quantitative information so it may be useful. The degrees of coverage shown in the rightmost two columns shows that the extent of the warm water directly on the Equator has been reduced in the past few weeks. The way I constructed the table, the 1.0C anomaly as an example includes all water warmer than 1.0C so the 1.5C anomaly is included within it as well as the 2.0C anomaly which you can tell by the way I recorded the westward and eastward coordinates. I could have constructed this table in a different way. Note the 3C anomaly no longer exists. The 2.5C anomaly also no longer exists as of mid-week. As this El Nino decays I am including the less warm anomalies in the table below.
Comparing Now to January 19, 2016
Subareas of the Warm Anomaly
Degrees of Coverage
January 19, 2016
January 19, 2026
January 19, 2016
I calculate the ONI each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W ONI 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 March 21, in the afternoon working from the March 20 TAO/TRITON report, this is what I calculated.
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
(9.1)/5 = 1.8
(7/7)/5 = 1.5
My estimate of the daily Nino 3.4 ONI after rounding is down to 1.5. NOAA has reported the weekly ONI to have further declined slightly to 1.7. If I had taken into account the shading in the TAO/TRITON Graphic I might have ended up with a value of 1.6 ie. I might be one week early with my estimate. Nino 4.0 is being reported as slightly lower at 1.4. Nino 3.0 is being reported as slightly higher at 1.7. The action which I think is most important to track right now is in Nino 1+2 which is now reported as having backed down to 1.0. This is summarized in the following NOAA Table. I am only showing the currently issued version as the prior values are shown in the small graphics on the right with this graphic. Notice that all the primary El Nino related indices i.e. Nino 3.4 and Nino 3 are in decline. The key index Nino 3.4 is declining rapidly.
The official reading for Dec/Jan/Feb is now reported as 2.2. I have discussed before the mystery of how the values above get translated into the values below and if NOAA feels that working with two sets of books is a good way to operate, who am I argue. Many businesses do the same thing. As you can see this El Nino peaked in NDJ and is now declining 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 full history of the ONI readings can be found here. The MEI index readings can be found here.
Is this El Nino a Modoki?
It did not evolve as a Modoki unless you consider it to be a continuation of the Faux El Nino Modoki of 2014/2015 which is a possible interpretation. But the Walker Circulation appears to be much like that of a Modoki. These graphics help explain this.
Although I discussed the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures.
Watching an El Nino evolve is like watching paint dry. The undercutting cool anomaly which had withdrawn to the west quite a bit is again expanding to the east and again quite rapidly basically arriving close to 110W (the easternmost extension which was faint on the graphic last week is now darker indicating cooler water) which means it has now undercut all of the NINO 3.4 Measurement Area. All that remains is for "The Grand Switch" to occur with the cool anomaly reversing positions with the warm anomaly. So either this will be a slow process or some event will just flush the warm water to the west. It may be the next Inactive Phase of the MJO that does just that. So that may be about a month away. It may not be significant but you can see that the warm pool is almost splitting at around 140W. You can see this on some other graphics also. You can also see cooler water rising but still at depth (200m) in the Eastern Pacific. It will replace the warm water in a few months.
SST Surface Anomaly Hovmoeller
Here is another way of looking at it: Unlike the Upper Ocean Heat Anomaly Hovmoeller (I call it the Kelvin Wave Hovmoeller) which takes an average down to 300 meters, this just measures the surface temperature anomaly. It is the surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. 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. Nevertheless this Hovmoeller provides a good way to visually see the evolution of this El Nino and later track its demise.
One can easily see the historical evolution of this El Nino and the "hot spots" that existed in December and which resulted in the very high ONI readings. You can see at the very bottom of this graphic, which shows the most recent readings, the easing of the extreme temperature anomalies in the Nino 3.4 Measurement area (see the scale on the right: red is less warm than dark red) namely 170W to 120W. That explains the slight reduction in NOAA ONI estimate. That is likely to continue to be the trend. You can see the steady decay in the anomalies from the east between 80W and beyond 150W. You also can clearly see the separation of the Warm Anomaly from the coast of South America. You also see the drifting to the west which could be Kelvin Wave #6 but I believe more likely it is the beginning of the return voyage of the warm pool to the Western Pacific. That is what the ENSO CYCLE is all about. Back and Forth....Back and Forth.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
Below are snapshots of 30 Day temperature and precipitation departures over the life of this El Nino. The end date of the 30 day period is shown in the graphic. It is a way of seeing how the impacts of this El Nino have unfolded.
Remember this is a 30 day average and only seven days were added and seven days were removed. The La Nina pattern persists for the West with respect to both precipitation and temperature and has even spread to the Southeast. IT IS QUITE DRAMATIC! But you see that California has gotten some relief and parts of Mexico and Texas have also gotten some relief. For the Mississippi Valley that relief (two weeks ago) may not have been totally welcome. The East Coast has joined in the warmer anomalies. This is one strange El Nino and for the 2nd or 3rd strongest in modern history it is a mystery that has not been given adequate attention.
I realize this is a lot of graphics but one needs to look at the history of an event to assess it. As you can see, so far we are not having the expected El Nino Impacts in CONUS.
El Nino in the News
Noting to report this week.
Putting it all Together.
This El Nino has peaked in intensity and is now in rapid decline. We are beginning to speculate on the winter of 2016/2017 which now according to some of the models seems increasingly likely to be a La Nina.
The below is the CPC/IRI forecast issued on February 18, 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.
You can see the slower decline of the El Nino which has been obvious to us for a long time. The new Plume-Based model results show increased confidence that next winter will be a La Nina winter.
We have suggested that it is possible the models 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.
We have reason to believe that the models may not be taking into account all factors such as the Equatorial ocean currents and that this El Nino may not transition to a La Nina quite as rapidly as some of the models are predicting.
What is really strange is the NOAA's own model disagrees with their official IRI/CPC Model. What is that all about?
Notice the NOAA model is forecasting a mild El Nino for next winter. It is too soon to begin discussing the Spring Prediction Barrier this week but I would take all these forecasts with a grain of salt at this point in time. It is only March 21 and too early to forecast next winter.
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.
TABLE OF CONTENTS FOR PART II OF THIS REPORT 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.
TABLE OF CONTENTS FOR PART 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.
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