Written by Sig Silber
NOAA has issued their Seasonal Update on December 17. Unlike the last few updates, this one shows significant changes mostly with regards to the temperature outlook. The further-out part of the Outlook now more fully reflects a possible La Nina next winter. NOAA is not highly confident about their January forecast partly because of the difficultly of predicting the exact arrival and strength of the Madden-Julian Oscillation (MJO). Recent weather patterns and the current short-term outlook are more consistent with LA NINA conditions than El Nino conditions so one is wondering what is going on here? Something is very strange about this El Nino.
This is the Regular Edition 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.
NOAA has issued their Seasonal Outlook Update on December 17, 2015
Previous Jan – Feb – Mar Temperature Outlook
New Jan – Feb – Mar Temperature Outlook
Previous Jan – Feb – Mar Precipitation Outlook
New Jan – Feb – Mar Precipitation Outlook
Sometimes it is useful to compare the next month with the forecast for the next three months.
One can mentally subtract the January Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely February and March 2016. When I do that, I deduce that February and March will be:
Previous 14 month Temperature Outlook Maps: Jan 2016 – Feb 2017
New 14 Month Temperature Outlook: Feb 2016 – Mar 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:
Previous 14 Month Precipitation Outlook Maps: Jan 2016 – Feb 2017
New 14 Month Precipitation Outlook: Feb 2016 – Mar 2017
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 December 17, 2015
CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS
EQUATORIAL PACIFIC SST ANOMALIES REMAIN EXCEPTIONALLY HIGH, WITH NINO3.4 VALUES PEAKING AT 3.1 DEGREES C IN WEEKLY OI DATA DURING NOVEMBER. THE OFFICIAL MONTHLY NINO3.4 VALUE FROM ERSSTV4 FOR NOVEMBER IS 2.35 DEGREES C, RIGHT IN LINE WITH THE BENCHMARK 1997 EVENT. SUBSURFACE OCEAN TEMPERATURES FROM NEAR THE DATE LINE EASTWARD TO THE SOUTH AMERICAN COAST ARE AT LEAST 2.0 DEGREES C ABOVE AVERAGE TO DEPTHS OF 100 TO 150 METERS, EXCEEDING 6.0 DEGREES C ABOVE AVERAGE IN PARTS OF THE EASTERN BASIN. THIS SUBSURFACE VOLUME OF ANOMALOUSLY WARM WATER PROVIDES A RESERVOIR OF HEAT TO HELP SUSTAIN CURRENT POSITIVE SEA SURFACE TEMPERATURES. NEGATIVE ANOMALIES AT DEPTH (NEAR 150 METERS) HAVE CONTINUED TO SHIFT SLIGHTLY EASTWARD ACROSS THE WESTERN AND CENTRAL PACIFIC DURING THE PAST MONTH.
ENHANCED CONVECTION RETURNED TO THE EQUATORIAL CENTRAL PACIFIC DURING MID-NOVEMBER. NEGATIVE OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES INDICATING ENHANCED CONVECTION EXTEND FROM THE DATE LINE ACROSS THE EASTERN TROPICAL PACIFIC TOWARD CENTRAL AMERICA DURING THE PAST MONTH. POSITIVE OLR ANOMALIES WERE OBSERVED OVER THE MARITIME CONTINENT [Editor’s Note: Not really a continent but described here] . LOW-LEVEL (850-HPA) WESTERLY WIND ANOMALIES WERE OBSERVED FROM THE DATE LINE EASTWARD, WHILE UPPER-LEVEL (200-HPA) EASTERLY WIND ANOMALIES ARE PRESENT OVER THE CENTRAL EQUATORIAL PACIFIC. WELL DEFINED ANTI-CYCLONIC CIRCULATIONS BOTH NORTH AND SOUTH OF THE EQUATOR IN THE EAST-CENTRAL PACIFIC ARE ALSO EVIDENT.
IN JUST THE PAST SEVERAL DAYS, SUBSEASONAL TROPICAL CONVECTIVE VARIABILITY ASSOCIATED WITH THE MADDEN-JULIAN OSCILLATION (MJO) HAS BEGUN TO DESTRUCTIVELY INTERFERE WITH THE ENSO BASE STATE. SEE THE MONTHLY FORECAST DISCUSSION FOR MORE INFORMATION ON HOW THIS COULD IMPACT THE JANUARY OUTLOOK.
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. [Editor’s Note: Notice NOAA no longer advertises the level of the PDO index which I believe has declined.]
PROGNOSTIC DISCUSSION OF SST FORECASTS [Editor’s Note Forecasting a La Nina for next winter].
SINCE WE ARE NOW AT THE PEAK OF THE EL NINO EVENT IN TERMS OF SST ANOMALIES, THE RELEVANT QUESTIONS RELATE TO HOW QUICKLY THE EVENT DECAYS AND WHETHER WE SEE A TRANSITION TO LA NINA, WHICH FREQUENTLY FOLLOWS ON THE HEELS OF EL NINO EVENTS. THE CPC SST CONSOLIDATION FORECASTS A RETURN TO NEUTRAL CONDITIONS BY MJJ AND A 79% CHANCE OF LA NINA BY NEXT WINTER. [Editor’s Note: See my analysis at the end of this report where I assess the chances of a La Nina next winter. It seems more like 50% to me and most likely will not be a very powerful La Nina.] THERE IS A LARGE SPREAD AMONG THE NMME CONSTITUENT MEMBERS IN TERMS OF HOW QUICKLY A TRANSITION TO NEUTRAL CONDITIONS OCCURS. THE CFSV2 MAINTAINS ANOMALOUSLY WARM SSTS MUCH LONGER THAN THE OTHER GUIDANCE, WHILE THE GFDL AND CANADIAN MODELS ARE ON THE FASTER SIDE OF THE GUIDANCE.
THE CPC/IRI CONSENSUS FORECAST INDICATES THAT THE TRANSITION TO ENSO NEUTRAL IS MOST LIKELY BY EARLY SUMMER, AND ODDS OF LA NINA DEVELOPING BY JAS EXCEED 30%.
30-DAY OUTLOOK DISCUSSION FOR JANUARY 2016
REGRESSIONS INDICATE A SHIFT TOWARD ABOVE NORMAL TEMPERATURES OVER ALASKA, THE PACIFIC NORTHWEST, AND NEAR THE UPPER GREAT LAKES, WITH BELOW NORMAL TEMPERATURES FROM THE SOUTHERN PLAINS TO THE SOUTHEAST COAST. WHEN THOSE REGRESSIONS ARE APPLIED TO PRECIPITATION, THE STRONGEST SIGNALS ARE FOR ABOVE MEDIAN PRECIPITATION ALONG MUCH OF THE WEST COAST AND ACROSS THE SOUTHEAST, WITH LITTLE SIGNAL ELSEWHERE ACROSS NORTH AMERICA.
THE MADDEN-JULIAN OSCILLATION IS ALSO A POTENTIAL CONTRIBUTOR TO THE VARIABILITY OVER NORTH AMERICA DURING JANUARY. CURRENTLY, THE REAL-TIME MULTIVARIATE MJO INDEX (RMM) INDICATES ENHANCED CONVECTION OVER THE MARITIME CONTINENT. SOME MODELS INDICATE AN EASTWARD PROPAGATION OF A RELATIVELY STRONG SIGNAL TO THE WESTERN PACIFIC, WHICH WOULD DESTRUCTIVELY INTERFERE WITH THE ONGOING EL NINO AND POTENTIALLY DISRUPT THE DOWNSTREAM RESPONSE OVER NORTH AMERICA. THE UNCERTAINTY RELATED TO THE MJO LEADS TO SOMEWHAT REDUCED COVERAGE AND LOWER PROBABILITIES THAN IF THE FORECAST ONLY CONSIDERED EL NINO AND DYNAMICAL MODEL OUTPUTS. [Editor’s Note: Probably the correct approach but it is disappointing that the dynamic models are unable to deal with an important cycle like the MJO.]
MORE RECENT RUNS OF THE CFS INDICATE A WARMER PATTERN FROM THE NORTHERN AND CENTRAL GREAT PLAINS TO THE EAST COAST, INCREASING ODDS FOR BELOW NORMAL TEMPERATURES OVER THE INTERIOR WESTERN CONUS AND A WEAKENING COLD SIGNAL OVER WESTERN ALASKA. THE LATEST WEEK 3 AND 4 (THROUGH JAN 13) OUTPUT FROM THE CFS INDICATES A MUCH STRONGER COLD SIGNAL OVER ALASKA AND THE WESTERN CONUS, INDICATING THAT THE FORECAST FOR ‘THE LATTER HALF OF JANUARY IS WARMER FOR MUCH OF THE WEST AND ALASKA. [Editor’s Note: discussing the conflict between their full month January forecast which is probably prepared using statistical tools and their more recent first half of January forecast which is prepared using the models that extrapolate from current conditions]. THIS MAY BE REFLECTIVE OF A POTENTIAL PATTERN CHANGE ASSOCIATED WITH MJO ACTIVITY.
CORRELATIONS IMPLY ABOVE MEDIAN PRECIPITATION ACROSS THE SOUTHERN TIER OF THE CONUS, ALONG MUCH OF THE WEST COAST, AND SOUTHERN PORTIONS OF THE MID-ATLANTIC. WEEK 3 AND 4 OUTLOOKS INDICATE DRIER CONDITIONS OVER NORTHERN CALIFORNIA AND WETTER CONDITIONS OVER WESTERN ALASKA, COMPARED TO MONTHLY RUNS OF THE CFS, INDICATING HIGH UNCERTAINTY FOR THE JANUARY OUTLOOK AS A WHOLE IN THESE AREAS.
Three Month Outlook
Temperature
THE JANUARY-FEBRUARY-MARCH (JFM) 2016 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL TEMPERATURES ACROSS THE CONTINENTAL U.S., NORTH OF THE 40TH PARALLEL, ALONG WITH MUCH OF THE WESTERN U.S. ABOVE-NORMAL TEMPERATURES ARE ALSO FAVORED FOR MOST OF ALASKA. THE ODDS OF ABOVE-NORMAL TEMPERATURES ARE HIGHEST ACROSS THE PACIFIC NORTHWEST AND UPPER GREAT LAKES WHERE PROBABILITIES OF ABOVE-NORMAL TEMPERATURES EXCEED 60 PERCENT. INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES DURING JFM ARE FORECAST ACROSS PARTS OF THE SOUTH-CENTRAL AND SOUTHEASTERN U.S.
Precipitation
THE JFM 2016 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR CALIFORNIA, THE SOUTHWEST, THE CENTRAL AND SOUTHERN GREAT PLAINS, THE LOWER MISSISSIPPI VALLEY, AND FROM THE SOUTHEAST NORTH TO SOUTHERN NEW ENGLAND. THE PROBABILITIES ARE HIGHEST FOR ABOVE-MEDIAN PRECIPITATION ACROSS SOUTHERN CALIFORNIA, THE DESERT SOUTHWEST, WEST TEXAS, AND FLORIDA. BELOW-MEDIAN PRECIPITATION AMOUNTS ARE MOST LIKELY FOR PARTS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES, AND GREAT LAKES. A SLIGHT TILT IN THE ODDS FOR ABOVE (BELOW)-MEDIAN PRECIPITATION IS FORECAST ACROSS SOUTHERN COASTAL (WESTERN) ALASKA.
PROGNOSTIC DISCUSSION OF OUTLOOKS – JFM 2016 TO JFM 2017
BASED ON THE BEHAVIOR OF SST ANOMALIES AFTER MANY PAST EL NINO EVENTS AND THE CPC CONSOLIDATION NINO3.4 SST FORECAST, EFFECTS FROM POTENTIAL LA NINA CONDITIONS WERE CONSIDERED BEGINNING IN SON 2016 THROUGH JFM 2017.
TEMPERATURE
THERE ARE VERY FEW CHANGES TO THE EARLY LEAD TEMPERATURE OUTLOOKS, WHICH LARGELY HARVEST THE LOW-FREQUENCY ENSO RESPONSE [Editor’s Note: To me ENSO is a medium frequency oscillation unlike the PDO or AMO which are low frequency oscillations], EVIDENT AMONG ALL THE CURRENT DYNAMICAL AND STATISTICAL GUIDANCE. STATISTICAL GUIDANCE IS GENERALLY COLDER THAN THE DYNAMICAL GUIDANCE ACROSS THE SOUTHEAST, WHERE A VERY SLIGHT SHIFT TOWARD COLDER TEMPERATURES IS INDICATED NEAR THE GULF COAST. DYNAMICAL GUIDANCE INDICATES A SLIGHT COOLING TREND OVER THAT REGION COMPARED TO LAST MONTH. IN SPITE OF THE NEAR-RECORD WARM DECEMBER UNDERWAY ACROSS MUCH OF THE EASTERN TWO-THIRD OF THE CONUS, THE LOW-FREQUENCY CLIMATE SIGNALS STILL POINT TOWARD A COLDER SOLUTION FOR THE FAR SOUTHEASTERN CONUS. ALL TEMPERATURE TOOLS CONTINUE TO STRONGLY FAVOR ABOVE-NORMAL TEMPERATURES ACROSS THE NORTHERN HALF OF THE CONTINENTAL U.S. THROUGH THE EARLY SPRING WHICH IS CONSISTENT WITH A STRONG EL NINO. ALSO, ABOVE-NORMAL SSTS ALONG THE WEST COAST CONTRIBUTE TO THE ENHANCED ODDS FOR ABOVE-NORMAL TEMPERATURES IN EARLY LEADS. BELOW-NORMAL TEMPERATURES FAVORED FOR THE SOUTHERN HIGH PLAINS DURING THE 2016 SPRING ARE PARTLY RELATED TO THE EXPECTATION OF ABNORMALLY MOIST TOPSOIL AT THAT LEAD TIME.
A TRANSITION TO ENSO NEUTRAL CONDITIONS IS FAVORED DURING THE LATE SPRING AND SUMMER 2016 SO THE OUTLOOKS FROM MJJ THROUGH ASO 2016 FOLLOW A BLEND OF TREND, DYNAMICAL GUIDANCE WHERE AVAILABLE, AND OTHER STATISTICAL GUIDANCE. ENHANCED ODDS OF ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR THE ENTIRE CONUS AT TIMES DURING THIS PERIOD, BUT AT LOW PROBABILITIES. INCREASED ODDS FOR ABOVE-NORMAL TEMPERATURES OVER THE EASTERN CONUS COMPARED TO LAST MONTH ARE BASED ON THE LATEST MODEL GUIDANCE, LAGGED ENSO REGRESSIONS, AND THE SST CONSTRUCTED ANALOG. OVER TIME, ODDS OF ABOVE-NORMAL TEMPERATURES INCREASE OVER THE SOUTHWESTERN AND SOUTH-CENTRAL CONUS WHERE TRENDS ARE STRONG. PROBABILITIES THERE ARE SOMEWHAT RESTRAINED BY THE EXPECTATION OF ABOVE-NORMAL SOIL MOISTURE, ESPECIALLY EARLY IN THE WARM SEASON.
INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES FORECAST ACROSS THE SOUTHERN TIER OF THE CONUS FROM SON 2016 THROUGH JFM 2017 ARE BASED LARGELY ON THE ENHANCED PROBABILITIES OF LA NINA BY THAT TIME. A SLIGHT TILT IN THE ODDS FOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTH-CENTRAL CONUS BEGINNING IN NDJ 2016-17 IS RELATED TO THE POTENTIAL FOR LA NINA INFLUENCES AT THAT LEAD TIME. A VERY HIGH PROBABILITY OF ABOVE-NORMAL TEMPERATURES INDICATED FOR THE NORTH SLOPE OF ALASKA DURING THE AUTUMN IS DUE TO THE LIKELIHOOD OF ANOMALOUSLY OPEN SEA ICE DURING THAT TIME OF YEAR AND STRONG TRENDS.
PRECIPITATION
THE JFM 2016 PRECIPITATION OUTLOOK THROUGH THE EARLY SPRING CONTINUES TO FAVOR A PATTERN THAT IS TYPICALLY ASSOCIATED WITH EL NINO. ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS CALIFORNIA, THE SOUTHWEST, CENTRAL/SOUTHERN GREAT PLAINS, GULF COAST STATES, AND PARTS OF THE EAST COAST. THE HIGHEST PROBABILITIES (ABOVE 70 PERCENT) FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS THE FLORIDA PENINSULA FOR JFM 2016 WHICH TYPICALLY HAS THE STRONGEST WET SIGNAL DURING EL NINO. BELOW-MEDIAN PRECIPITATION IS FAVORED THROUGH THE EARLY SPRING ACROSS THE NORTHERN ROCKIES, PARTS OF THE NORTHERN GREAT PLAINS, GREAT LAKES, AND THE OHIO VALLEY. THE DRY SIGNAL ACROSS THE OHIO VALLEY PEAKS DURING THE JFM 2016 SEASON DURING EL NINO. THIS DRY SIGNAL SLOWLY WEAKENS WITH TIME THROUGH LATE SPRING AND EARLY SUMMER.
CONSISTENT WITH A SOUTHWARD AND EASTWARD SHIFTED STORM TRACK DURING EL NINO AND CONSISTENT WITH THE NMME DYNAMICAL MODEL GUIDANCE, BELOW MEDIAN PRECIPITATION IS FAVORED FOR WEST-CENTRAL MAINLAND ALASKA FROM JFM 2016 THROUGH MAM 2016. A SLIGHT TILT IN THE ODDS FOR ABOVE-MEDIAN PRECIPITATION ALONG SOUTHERN COASTAL ALASKA IS BASED ON EL NINO PRECIPITATION COMPOSITES AND ENSO REGRESSIONS.
LAGGED ENSO REGRESSIONS AND ENSO TRANSITION COMPOSITES SUGGEST ENHANCED ODDS OF BELOW-(ABOVE-) MEDIAN PRECIPITATION ACROSS PARTS OF THE NORTHEAST/MID-ATLANTIC (GULF COAST) FROM JJA THROUGH ASO. HOWEVER, THE PHYSICAL BASIS FOR THESE SIGNALS IS A LITTLE SUSPECT. THERE IS SUPPORT FROM THE SST CA ACROSS THE GULF COAST REGION, BUT NOT FARTHER NORTH. THIS IS AN ISSUE THAT WILL BE DISCUSSED FURTHER IN FUTURE OUTLOOKS, BUT AT THIS TIME NO CHANGES ARE MADE TO THE PREVIOUS OUTLOOK IN THIS REGARD. [Editor’s Note: and thus currently shows up as EC]
DURING THE FALL SEASON OF 2016 AND WINTER 2016-17, THE POTENTIAL FOR LA NINA CONDITIONS IS THE PRIMARY REASON FOR THE FAVORED AREAS OF BELOW- (ABOVE-) MEDIAN PRECIPITATION ACROSS THE SOUTHERN TIER OF THE CONUS AND SOUTHERN COAST OF ALASKA (PACIFIC NORTHWEST AND OHIO VALLEY/GREAT LAKES).
Let’s Now 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. This link 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. Right now a pretty impressive trough is shown. 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 thickness lines are not below 540 for many areas in CONUS. The 540 Level general signifies equal chances for snow at sea level locations. This suggests that snow is still not ready to be routine in CONUS other than in mountainous regions. The level of storm activity in the Western Pacific has declined recently but is picking up as the MJO transitions to its active phase. 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.
As I am looking at the below graphic Monday evening December 21, I still see a pattern which is much more active in the Northern part of CONUS than the Southern Tier except for the Southeast. But there is an effort for a trough to impact the Southwest. This graphic updates automatically so it most likely will look different by the time you look at it.
Below is an analysis of projected tropical hazards and benefits over an approximately two-week period. I am now only showing one view as NOAA seems to be updating only one of the two graphics but fortunately it is the one that shows both the Pacific and the Indian Ocean.
This graphic is scheduled to update on Tuesday and I am reading the Dec 15, 2015 Version and looking at the Week 2 of that forecast. Mostly I see for the period December 23 – December 29 moderately wet conditions for the Northern part of Australia with even a hint of possible cyclone activity combined with moderately dry conditions in Brazil.
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 bit. On some days, the forecast is showing a split low with each of the two lows weaker than a combined single Low and this is not characteristic of El Nino. Right now the forecasted Low has an hPa of 972 which is intense (the average in the winter is 1001hPa and 994 hPa for a non-split Low). It is a split low and the main part of the Aleutian Low is over by Kamchatka which is not at all ideal for El Nino. The rapidly shifting position of the Low makes a big difference. With this forecast, one can see how on Day 6 Pacific storms can not easily enter CONUS south of Canada or the Northwest. 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 one can certainly see the northern entry point for the Jet Stream which is not characteristic of El Nino. But the southern branch has been very active. Also the Jet Stream is now diving to the south creating the trough that is bringing storm systems to the south along the West Coast.
And the forecast out five days. Of course this is a forecast and changes daily or perhaps even more frequently.
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.
And when we look at Sea Surface anomalies below, we see a lot of them not just along the Equator related to El Nino.
The two graphics below show first the changes over the four weeks (ending November 4) as compared to the above graphic which shows the current SST anomalies and then the changes over the four weeks ending on December 16, 2015. Looking at both of these change in anomaly graphics is helpful in putting the current situation shown above into perspective.
First the four weeks ending on November 4, 2015
I am also showing the new version issued today which basically shows the changes over the last month in the Sea Surface Temperature anomalies.
These graphics are hard to interpret because they are four-week changes. But you have the daily values three graphics up. Here you see very little strengthening in the El Nino in the Nino 3.4 Measurement Area but some increase in the warm anomaly just off of Ecuador. More importantly you see cooling of the warm anomaly off of the West Coast of the U.S. (reducing the degree of PDO+) and also the pattern in the Indian Ocean eliminating the Positive IOD. The anomalies off the west coast of South America are also cooler signaling the setting of the stage for the decline phase of this El Nino So there are some changes taking place but not much change since last week. In fact there is an overall deamplification of the anomalies World-wide. The cooling of the waters in Beringia is also quite important re the impact on CONUS. One can clearly see the Indian Ocean heating up a bit but the Pacific not so much with a difference between the Eastern Pacific and the Western Pacific and north versus south of the Equator. The South Atlantic is interesting but I have not studied the South Atlantic very much. It tends to behave a bit opposite of the Atlantic north of the Equator as there is a mechanism that keeps the sum of the two in balance.
6 – 14 Day Outlooks
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 available in Part II of this report.
To put the forecasts which NOAA tends to call Outlooks into perspective, I am going to show the three-month DJF and the “early” single month of December forecasts and then discuss the 8 – 14 day Maps and the 6 – 14 Day NOAA Discussion within that framework. Some of these graphics are repeats of graphics that I presented earlier as part of the discussion of the NOAA Update.
First – Temperature
Here is the Three-Month Temperature Outlook issued on December 17, 2015:
Here is the “Early Released” January Temperature Outlook issued on December 17, 2015.
Below is the current 8 – 14 Day Temperature Outlook Map which will auto-update and thus be current when you view it. It covers the week following the current week. Today’s 6 – 14 Day Outlook is just nine days of the month and the map shown below of the 8 to 14 day Outlook only shows seven days. The 6 – 10 Day Map is available on Page II of this report. As I view this map on December 21 (it updates each day), it appears that the start of January may continue to have the east/west divide relative to temperature anomalies rather than the north/south divide more typical of an El Nino which is shown in the full month NOAA Outlook for January.
Now – Precipitation
Here is the three-month Precipitation Outlook issued on December 17, 2015:
And here is the month of January “Early Release” Precipitation Outlook which was issued on December 17, 2015.
Below is the current 8 – 14 Day Precipitation Outlook Map which will auto-update and thus be current when you view it. It covers the week following the current week. Today’s 6 – 14 Day Outlook is just nine days of the month and the map shown covers seven days of the nine. The 6 – 10 Day Map (the two maps overlap) is available on Page II of this report. As I view this map on December 21 (it updates each day) and also taking the 6 – 10 Day Outlook which you can find on Page II of this Report into account, it appears that the start of January may be a lot wetter on the East Coast and less wet in the Southwest than the full month outlook. But this forecast, unlike the temperature outlook, is much more volatile and changes a lot from day to day as NOAA tries to keep up with the vagaries of the Jet Stream.
Here are excerpts from the NOAA discussion released today December 21, 2015. It covers the full nine-day period not just the seven days shown in the 8-14 Day Map.
6-10 DAY OUTLOOK FOR DEC 27 – 31 2015
TODAY’S ENSEMBLE-MEAN DYNAMICAL-MODEL FORECASTS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA. TROUGHS ARE PREDICTED OVER THE SOUTHWEST PART OF THE CONUS AND THE BERING SEA, WHILE A RIDGE IS FORECAST BY ALL MODELS OVER EASTERN NORTH AMERICA, WITH ABOVE NORMAL 500-HPA HEIGHTS CENTERED OVER THE MID-ATLANTIC REGION. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN. TODAY’S 500-HPA BLEND CHART DEPICTS BELOW NORMAL HEIGHTS OVER THE SOUTHWESTERN PART OF THE CONUS AND ALASKA, AND NEAR TO ABOVE NORMAL HEIGHTS OVER THE REMAINDER OF THE CONUS. TODAY’S MANUAL 500-HPA HEIGHT BLEND IS COMPOSED PRIMARILY OF THE ENSEMBLE MEAN SOLUTIONS, BASED LARGELY ON CONSIDERATIONS OF RECENT SKILL AND ON ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE MODEL SOLUTIONS RESEMBLE CASES THAT HAVE OCCURRED IN THE PAST.
THE PREDICTION OF ABOVE NORMAL MID-LEVEL HEIGHTS AND ANOMALOUS SOUTHERLY FLOW LEAD TO INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR THE EASTERN CONUS. THE STRONG AGREEMENT BETWEEN AVAILABLE MODEL FORECASTS RESULTS IN PROBABILITIES FOR TEMPERATURES TO BE IN THE UPPER TERCILE OF HISTORICAL TEMPERATURES EXCEEDING 90 PERCENT OVER THE EASTERN U.S. THERE ARE INCREASED CHANCES OF BELOW-NORMAL TEMPERATURES FOR MUCH OF THE WESTERN CONUS CONSISTENT WITH GEFS AND ECMWF REFORECAST GUIDANCE. THE PREDICTION OF BELOW NORMAL MID-LEVEL HEIGHTS OVER ALASKA LEADS TO ENHANCED PROBABILITIES OF NEAR TO BELOW NORMAL TEMPERATURES OVER ALASKA.
THE TROUGH EXPECTED OVER THE SOUTHWESTERN CONUS FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE EASTERN HALF OF THE CONUS WHILE JET ENERGY MOVING ONSHORE OVER THE PACIFIC NORTHWEST TILTS THE ODDS TO ABOVE MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST. BELOW-MEDIAN PRECIPITATION PROBABILITIES ARE ENHANCED FOR THE NORTHERN PLAINS CONSISTENT WITH NAEFS AND GEFS REFORECAST GUIDANCE. THE TROUGH PREDICTED OVER THE BERING SEA ENHANCES PROBABILITIES FOR NEAR TO ABOVE MEDIAN PRECIPITATION FOR ALASKA.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL ENSEMBLE MEAN SOLUTIONS, AS WELL AS GOOD AGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR DEC 29, 2015 – JAN 04, 2016
TODAY’S ENSEMBLE-MEAN DYNAMICAL-MODEL FORECASTS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA INTO THE WEEK-2 PERIOD. THE PREDICTED CIRCULATION PATTERN IS SIMILAR TO THAT EXPECTED FOR THE 6-10 DAY PERIOD. TROUGH IS PREDICTED OVER SOUTHWESTERN NORTH AMERICA AT 8-14 DAYS LEAD TIME, WHILE RIDGES ARE PREDICTED OVER EASTERN NORTH AMERICA AND ALASKA. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE MAJORITY OF THE ANOMALOUS SOUTHERLY FLOW FORECAST DOMAIN.
ANOMALOUS SOUTHERLY FLOW LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR THE NORTHERN PLAINS AND THE EASTERN HALF OF THE CONUS. THERE ARE INCREASED CHANCES OF BELOW-NORMAL TEMPERATURES FOR MUCH OF THE WESTERN CONUS AND NEAR TO ABOVE-NORMAL TEMPERATURES FOR ALASKA CONSISTENT WITH NAEFS GUIDANCE AND BIAS CORRECTED TEMPERATURES FROM THE GFS AND ECMWF ENSEMBLES.
PROBABILITIES OF ABOVE MEDIAN PRECIPITATION ARE GREATEST OVER THE SOUTHERN PLAINS AND THE EASTERN U.S. AHEAD OF A PREDICTED TROUGH TO THE WEST. NEAR TO BELOW-MEDIAN PRECIPITATION PROBABILITIES ARE ENHANCED FOR THE WESTERN CONUS, AND THE NORTHERN PLAINS CONSISTENT WITH NAEFS AND GEFS REFORECAST GUIDANCE.
ANOMALOUS SOUTHERLY FLOW LEADS TO ENHANCED PROBABILITIES FOR NEAR TO ABOVE MEDIAN PRECIPITATION FOR ALASKA.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL ENSEMBLE MEAN SOLUTIONS, AS WELL AS GOOD AGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION 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 this El Nino. Notice their headline
Active Storm Track Forecast But Displaced North
NOAA it seems does not wish to acknowledge that this El Nino is displaced to the north and so far is not having the expected impacts of an El Nino but is behaving more like a La Nina.
Analogs to Current Conditions
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 analyzing this second set of information. This first set applies to the 5 and 7 day observed pattern prior to today. The second set which I am not using relates to the forecast outlook 6 – 10 days out to similar patterns that have occurred in the past during the dates covered by the 6 – 10 Day Outlook. That may also be useful information but they put this set of analogs in the discussion with the other set available by a link so I am assuming that this set of analogs is the most meaningful.
Analog Centered Day | ENSO Phase | PDO | AMO | Other Comments |
Dec 24, 1974 | Neutral | – | + | |
Dec 20, 1988 | La Nina | – | – | Strong La Nina |
Dec 4, 1998 | La Nina | – | + | Strong La Nina after Super El Nino |
Dec 5, 1998 | La Nina | – | + | Strong La Nina after Super El Nino |
Dec 5, 2004 | El Nino | – | + | Modoki Type II |
Dec 6, 2004 | El Nino | – | + | Modoki Type II |
Dec 17, 2007 | La Nina | – | + | Strong La Nina |
Dec 26, 2007 | La Nina | – | + | Strong La Nina |
One thing that jumped out at me right away was the narrow spread among the analogs from December 4 to December 26 which is just three weeks which may suggest a sound basis for making a forecast but that is just a hunch on my part. There are this time just two El Nino (Modoki) Analogs and five strong La Nina Analogs and just one ENSO Neutral Analog so this does not suggest that El Nino is a major factor in our weather over the next 6 – 14 Days but rather that we are in a La Nina pattern. The phases of the ocean cycles are unusually clear (PDO-/ AMO+) and point to McCabe Condition D with is the Southwest Drought Pattern that we have been in since 1998. 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.
El Ninos | La Ninas | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Start | Finish | Max ONI | PDO | AMO | Start | Finish | Max ONI | PDO | AMO | |
DJF 1950 | J FM 1951 | -1.4 | – | N | ||||||
T | JJA 1951 | DJF 1952 | 0.9 | – | + | |||||
DJF 1953 | DJF 1954 | 0.8 | – | + | AMJ 1954 | AMJ 1956 | -1.6 | – | + | |
M | MAM 1957 | JJA 1958 | 1.7 | + | – | |||||
M | SON 1958 | JFM 1959 | 0.6 | + | – | |||||
M | JJA 1963 | JFM 1964 | 1.2 | – | – | AMJ 1964 | DJF 1965 | -0.8 | – | – |
M | MJJ 1965 | MAM 1966 | 1.8 | – | – | NDJ 1967 | MAM 1968 | -0.8 | – | – |
M | OND 1968 | MJJ 1969 | 1.0 | – | – | |||||
T | JAS 1969 | DJF 1970 | 0.8 | N | – | JJA 1970 | DJF 1972 | -1.3 | – | – |
T | AMJ 1972 | FMA 1973 | 2.0 | – | – | MJJ 1973 | JJA 1974 | -1.9 | – | – |
SON 1974 | FMA 1976 | -1.6 | – | – | ||||||
T | ASO 1976 | JFM 1977 | 0.8 | + | – | |||||
M | ASO 1977 | DJF 1978 | 0.8 | N | – | |||||
M | SON 1979 | JFM 1980 | 0.6 | + | – | |||||
T | MAM 1982 | MJJ 1983 | 2.1 | + | – | SON 1984 | MJJ 1985 | -1.1 | + | – |
M | ASO 1986 | JFM 1988 | 1.6 | + | – | AMJ 1988 | AMJ 1989 | -1.8 | – | – |
M | MJJ 1991 | JJA 1992 | 1.6 | + | – | |||||
M | SON 1994 | FMA 1995 | 1.0 | – | – | JAS 1995 | FMA 1996 | -1.0 | + | + |
T | AMJ 1997 | AMJ 1998 | 2.3 | + | + | JJA 1998 | FMA 2001 | -1.6 | – | + |
M | MJJ 2002 | JFM 2003 | 1.3 | + | N | |||||
M | JJA 2004 | MAM 2005 | 0.7 | + | + | |||||
T | ASO 2006 | DJF 2007 | 1.0 | – | + | JAS 2007 | MJJ 2008 | -1.4 | – | + |
M | JJA 2009 | MAM 2010 | 1.3 | N | + | JJA 2010 | MAM 2011 | -1.4 | + | + |
JAS 2011 | FMA 2012 | -0.9 | – | + | ||||||
T | MAM 2015 | NA | 1.0 | + | N |
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.
Date | Current Reading | 30-Day Average | 90 Day Average |
Dec 15 | -8.9 | -10.56 | -14.12 |
Dec 16 | -11.2 | -11.05 | -14.19 |
Dec 17 | -6.5 | -11.65 | -14.21 |
Dec 18 | 2.9 | -11.65 | -14.06 |
Dec 19 | 2.0 | -11.55 | .13.90 |
Dec 20 | 13.6 | -10.92 | -13.58 |
Dec 21 | -0.9 | -10.98 | -13.42 |
The Inactive Phase of the MJO is playing out and is possibly shifting to the Active Phase but we have stopped seeing negative readings and now are seeing some positive (less El Nino-ish) readings.
The 30-day average, which is the most widely used measure, on December 21 is reported at -10.98 which is essentially no change from last week and 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). The 90-day average has not changed much this week and remains in El Nino territory at -13.42. The SOI continues to be indicative of an El Nino Event in progress.
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 that likely will change as the MJO changes phase and becomes more active.
In the below graphic, you can see how the convection pattern (really cloud tops) no longer shows the pronounced pattern that has existed for a number of months. This is especially evident to the west of the Date Line. But east of the Date Line the wet anomaly is now more robust and drifting slightly to the East which could be a precursor to more impacts on CONUS.
Let us now take a look at the progress of Kelvin Waves which are the key to the situation. We now see a fourth Kelvin wave which will extend the life of this El Nino. The most extreme temperature anomaly colored gray in the graphic, is beginning to slowly cover a smaller part of the Equator but has shifted to the east and is now located at 115W to 105W which means the extreme anomaly is no longer in the ONI/Nino 3.4 Measurement Area which runs from 170W to 120W. But it is now impacting Nino 3.0 and Nino 1+2. Previously (looking just a bit above the bottom of this Hovmoeller diagram) we saw a slow steady retreat to the east of the western extreme of this pattern. But now we see warmer water further west suggesting that there may indeed be a Kelvin Wave #5 in this strange story. Due to the slow speed of eastern progression of Kelvin Waves, this is unlikely to impact weather this winter but could extend the life of this El Nino further into Spring and might impact the next stage of the ENSO Cycle as the retreat to the west of the warm pool that has built up in the Eastern Pacific may not be able to begin its journey westward on schedule.
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 so that may be starting but has not progressed to any large extent as yet but there are signs that it is beginning.
Current Sub-Surface Conditions
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 2C (anomaly) water is impacting the area in which the ONI is measured i.e. 170W to 120W. The 2C anomaly now extends to 180W which is very impressive.The 3C anomaly now extends to beyond 160W so I am viewing the 3C anomaly as encompassing essentially 100% of the Nino 3.4 Measurement Area for the ONI along the Equator but not the full area which extends five degrees latitude to the north and south of the Equator. It explains why NOAA is coming up with high ONI estimates. The 4C anomaly is now intersecting the surface at 125W to 110W.
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 no longer reaches 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.
TAO/TRITON GRAPHIC
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.
And then the current version of the TAO/TRITON Graphic.
———————————————– | A | B | C | D | E | —————- |
With the current graphic, there is a lot of resemblance to the situation on October 4 in terms of the location of the warm anomaly but it is now much more intense.
The 2C anomaly on Oct 4 was showing all the way over to 170W. Now it extends even further to the west.This graphic changes quite a bit from day to day so my commentary can be out of date as quickly as tomorrow. The 3C anomaly now extends to 160W. We again today see a 3.5C Isotherm but it is located much further to the west and is not consistent with some other graphics presented in this report. The Easterlies are diminished but now show as Easterlies almost everywhere (top graphic) which is different than on October 4, 2015 when the anomalies were so strong that west of 150W they showed as having been converted into Westerlies. That could be an indication that the conditions for maintaining this El Nino are slowly changing.
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 December 21 in the afternoon working from the December 20 TAO/TRITON report, this is what I calculated.
Anomaly Segment | Estimated Anomaly |
A. 170W to 160W | 2.5 |
B. 160W to 150W | 3.3 |
C. 150W to 140W | 3.2 |
D. 140W to 130W | 3.0 |
E. 130W to 120W | 3.0 |
Total | 15.0 |
Total divided by five subregions i.e. the ONI | (15.0)/5 = 3.0 |
My estimate of the Nino 3.4 ONI after rounding has increased to 3.0. NOAA has today reported the weekly ONI as being 2.9 insignificantly higher than last week. Nino 4.0 is again reported as being 1.7. Nino 3.0 is again being reported as 2.9. I believe it peaked at 3.7 during the El Nino of 1997/1998. This is one of many reasons for thinking that this El Nino is shifted to the west to some extent. This shift right now is very evident in the TAO/TRITON Graphic and in my calculation for subregion B.
The action which I think is most important to track right now is in Nino 1+2 which is now reported as being 2.4 which is a bit higher than last week. The issue remains the extent to which warm water off of Ecuador and Peru impacts CONUS weather. I think it has very little impact except from the tropical storms that move up the west coast of Central America and sometimes contribute moisture to the circulation over CONUS. These part of an El Nino seems to have come to an end. Most El Ninos decay from east to west so it will be observed most clearly first in Nino 1+2 and we should see that process staring very soon now.
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.
One wonders about these calculations as they appear to not be related to the “adjusted” version of the NOAA forecast model which was discussed recently. So it is not clear to me how this El Nino will be officially recorded. September-October-November has now been recorded as having an ONI of 2.0. In the NINO value historical graphics on the right, eyeballing it you might conclude that the three months were observed as being 2.3, 2.4, and 2.5. So the impact of adjusting these observed values to what is considered “adjusted” is not obvious to me. If 2.3, 2.4, and 2.5 when averaged and adjusted by NOAA come to 2.0 how should we interpret the unadjusted weekly value of 2.9? To me (and some other knowledgeable folks) it is meaningless but I dutifully report it. One expects that OND value will be higher than 2.0 and rival or exceed the 2.3 max value. The full history of the ONI readings can be found here.
Although I discussed the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures.
I do not see much change week to week as watching an El Nino evolve is like watching paint dry. The cool anomaly in the west under the warm anomaly is slowly creeping east undercutting the warm anomaly and now is now over to 130W but with only slightly cooler than normal water. This sequence of four Kelvin Waves has made for a complex pattern. We still see at 100W perhaps a trend for cooler water to rise closer to the surface.
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. 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 also the current “hot spots” that are showing up and leading to the very high ONI readings. But one can also see the western edge of the warm anomaly starting to shift to the East. 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.
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 of the 30 day period is shown in the graphic. It is a way of seeing how the impacts of this El Nino of unfolded.
There is essentially no change since last week other than some deamplification of this La Nina pattern. It is certainly not an El Nino pattern. .
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 expect El Nino Impacts in CONUS.
El Nino in the News
Nothing to report.
View from Australia
El Nino
I do not see much change from the graphic released two weeks ago. Here is the discussion just released:
El Niño remains strong, but some cooling now observed at depth
Issued on 22 December 2015
El Niño remains near its peak, with the tropical Pacific Ocean and overlying atmosphere consistent with a strong event. Models suggest the event will start to decline in 2016, but a return to ENSO-neutral is not likely until at least autumn.
Sea surface temperatures and cloud patterns near the Date Line remain well in excess of El Niño thresholds. The Southern Oscillation Index (SOI) has returned to El Niño levels following a brief period of neutral values. Below-surface ocean temperatures in the eastern tropical Pacific remain significantly warmer than average, but clearly some cooling has occurred in the past fortnight. Changes in the sub-surface are an important indicator, as the sub-surface plays a significant role in maintaining the strength and longevity of El Niño events.
El Niño’s influence on Australian rainfall is variable at this time of year, with both wetter and drier summers observed in past events depending on how quickly the event breaks down. Both daytime and overnight temperatures tend to be warmer than average during an El Niño summer. For more information, see the official rainfall and temperature outlook.
The Indian Ocean Dipole has little influence on Australian climate between December and April. However, Indian Ocean sea surface temperatures remain very much warmer than average across the majority of the basin. This basin-wide warmth may provide extra moisture for rain systems across Australia.
Next update expected on 5 January 2016
IOD (Indian Ocean Dipole)
The graphic comes with only a very short discussion and here is that discussion
The Indian Ocean Dipole (IOD) is neutral. The index value to 20 December was +0.15 °C.
Sea surface temperatures (SSTs) remain significantly warmer than average across most of the Indian Ocean basin.
The influence of the IOD on Australian climate is weak during the months December to May as the monsoon trough shifts south over the tropical Indian Ocean. However, widespread record-warm sea surface temperatures in the Indian Ocean are likely to influence Australian climate during the summer months. These warm waters act as a source of moisture, and may provide extra moisture for rainfall systems developing over Australia.
The interrelationship between the IOD and El Nino is complicated and not fully understood.
Putting it all Together.
The subsurface reservoir of warm water in the Eastern Pacific has reached its maximum and is now beginning to discharge. This would have occurred earlier if not for Kelvin Wave #4. This El Nino I believe has peaked in intensity and plateaued.
The impacts in the Indian Ocean seem to have peaked and are moderating. Same goes for the Western Pacific. Now the focus shifts to North and South America. NOAA and JAMSTEC have issued forecasts but there does not seem to be an obvious match to any prior El Nino in the modern era which to me means there is no model to use to predict impacts. But this is a very strong El Nino. The best bet is that it will behave more like the two strong El Ninos which occurred with PDO+ than the one that occurred with PDO- and that is confirmed in the analysis at the beginning of this report. This would suggest that both NOAA and JAMSTEC generally are correct although their forecasts differ slightly. The three areas I used to categorize regional impacts are all likely to be wetter than normal/climatology. But the Southeast is not likely to be as wet as was the case with the 1997/1998 El Nino. So far, the impacts to CONUS appear to be shifted further north than usual for an El Nino. That may change as the winter unfolds but that is by no means certain.
We are beginning to speculate on the winter of 2016/2017 which it now seems increasingly likely will be a La Nina. One thing that is fairly certain for the U.S.based on historical patterns is that compared to this winter the following winter is likely to be:
- warmer in the south and less warm in the north and
- more dry in the south and less dry in the north
The below is the recently updated CPC/IRI forecast which is not much different from the Early December forecast. You can see the rapid shift away from El Nino that is now predicted starting in AMJ and really showing up in MJJ 2016 i.e. late Spring early Summer 2016. We also now see the rise in the probabilities for La Nina heading into next Winter.
I have done my own analysis of the probabilities of an El Nino being followed immediately by a La Nina and this is my analysis.
It is not a perfect procedure but I took a look at the ONI values for the Oct – Nov – Dec three-month period starting in 1950. I used an ONI of 0.5 or higher as an indication that it was a warm event and possibly an El Nino although it takes more than one three-month period of an ONI of 0.5 or higher to define an El Nino. Similarly, I took -0.5 or more negative to indicate La Nina conditions during that three-month period. Then I tabulated the number of times that there was a +0.5 or greater in one year followed by a -0.5 or more negative in the following year.
Year | ONI | Year | ONI | Year | ONI | Year | ONI | Year | ONI | Year | ONI |
1950 | -0.7 | 1960 | 0 | 1970 | -0.9 | 1980 | 0.1 | 1990 | 0.4 | 2000 | -0.8 |
1951 | 0.7 | 1961 | -0.2 | 1971 | -0.9 | 1981 | -0.1 | 1991 | 1.2 | 2001 | -0.3 |
1952 | 0.2 | 1962 | -0.3 | 1972 | 2.0 | 1982 | 2.1 | 1992 | -0.1 | 2002 | 1.3 |
1952 | 0.8 | 1963 | 1.2 | 1973 | -1.9 | 1983 | -0.8 | 1993 | 0.1 | 2003 | 0.4 |
1954 | -0.5 | 1964 | -0.8 | 1974 | -0.7 | 1984 | -0.9 | 1994 | 0.9 | 2004 | 0.7 |
1955 | -1.6 | 1965 | 1.8 | 1975 | -1.5 | 1985 | -0.2 | 1995 | -1.0 | 2005 | -0.4 |
1956 | -0.5 | 1966 | -0.1 | 1976 | 0.8 | 1986 | 1.0 | 1996 | -0.4 | 2006 | 0.9 |
1957 | 1.3 | 1967 | -0.4 | 1977 | 0.8 | 1987 | 1.2 | 1997 | 2.3 | 2007 | -1.2 |
1958 | 0.6 | 1968 | 0.6 | 1978 | -0.1 | 1988 | -1.7 | 1998 | -1.3 | 2008 | -0.5 |
1959 | -0.1 | 1969 | 0.8 | 1979 | 0.5 | 1989 | -0.2 | 1999 | -1.4 | 2009 | 1.2 |
My tabulation was nine times “no” and ten times “yes”. On two occasions there were two years of 0.5 or more then followed by a year with -0.5 or less. Not shown is the value for 2010 which was -1.3 which is one of the ten times that there was this year to year dramatic change. So I concluded that there is a 50% chance of a La Nina in the winter of 2016/2017 on a statistical basis alone. However my general feeling is that the winter of 2016/2017 is most likely to be ENSO Neutral or a weak La Nina.
To examine this question more carefully, I prepared the below table where I show what I know about the ten years where the ONI changed dramatically from positive to negative. I show what I know about the warm event which in most cases was an El Nino of some sort and I show the PDO and AMO with the sign/phase in the year shown followed after a comma by the sign/phase in the following year. It is not conclusive but I do not see the current pattern of PDO+ and AMO+ or Neutral represented in this table except in 1997 and probably also in 1987. I do not expect the PDO to be negative next year so that kind of invalidates the 1997 case as being predictive. 1987 was a Modoki and this now is a pretty much traditional El Nino, so I do not believe the 1987 case is particularly predictive Thus I conclude that the winter of 2016/2017 being a La Nina is less than 50%. If you knew nothing you might assign a probability of 25% for a La Nina year. Given that this winter will be an El Nino, you might assign a probability of 33% to the following year being a La Nina. It is like a box of one red, one blue and two white balls. If you draw from that box, the probability of a red ball is 25%. If you remove the blue ball because you just had an El Nino winter, the Markovian probability of a red ball increases to 33%. I think this is how Australia looks at things. But ENSO is not a four-year cycle but more like a 5 to 7 year cycle. So we could try to be more fancy but the results may not be better because we would have to take into account that some El Ninos and many La Ninas last for two years.
The possibility of Kelvin Wave #5 is additional reason to think that we might not have a La Nina next year but things could be quite dramatic.
Year | Comments | PDO | AMO |
1953 | -,+ | +.- | |
1963 | Modoki Type I | -,- | -.- |
1969 | Modoki Type II which started in 1968 | +,- | -.- |
1972 | Traditional El Nino | +,- | -.- |
1982 | Traditional El Nino | +,+ | -.- |
1987 | Modoki Type I | +,- | N.- |
1994 | Modoki | -,+ | -.+ |
1997 | Traditional El Nino | +,- | +.+ |
2006 | Traditional El Nino | -,- | +.+ |
2009 | Modoki Type II | N,- | +.+ |
I have no data on the 1953/54 El Nino and I do not know why but it appears not to have been recognized by Japan. So I do not know if we are dealing with half the events being Modokis are more than half. The reason that might be important is that a Modoki is closer to being a La Nina than a traditional/canonical El Nino as the warm water is not as far east. So it might be easier for a Modoki to convert to a La Nina except some Modokis transform into traditional El Ninos which just happened. The 2014/2015 Warm Event was probably best described as a Near Modoki Type II that has now transformed itself into a traditional but late in the season El Nino. Obviously we have more to learn.
We may or may not have a Pacific Climate Shift as the PDO+ may be simply related to the Warm Event and quite frankly at this point appears to be and may be moving back to PDO Negative. But for now we do have PDO+ but less so than a couple of months ago. The AMO being an overturning may be more predictable so the Neutral status moving towards AMO- is probably fairly reliable but not necessarily proceeding in a straight line as indeed the storm track for hurricanes in the Atlantic is suddenly unusually warm.
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.
A. Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks (Usefully bookmarked as it provides automatically updated current weather conditions and forecasts at all times. It does not replace local forecasts but does provide U.S. national and regional forecasts and, with less detail, international forecasts)
B. Factors Impacting the Outlook
1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)
2. Medium Frequency Cycles such as ENSO and IOD
3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.
C. Computer Models and Methodologies
D. Reserved for a Future Topic (Possibly Predictable Economic Impacts)
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.
D2. Climate Impacts of Global Warming
D3. Economic Impacts of Global Warming
D4. Reports from Around the World on Impacts of Global Warming