econintersect.com
       
  

FREE NEWSLETTER: Econintersect sends a nightly newsletter highlighting news events of the day, and providing a summary of new articles posted on the website. Econintersect will not sell or pass your email address to others per our privacy policy. You can cancel this subscription at any time by selecting the unsubscribing link in the footer of each email.



posted on 20 May 2017

NOAA and JAMSTEC Issue Seasonal Updates - Major Differences in Fall and Winter

Written by

NOAA issued their Seasonal Outlook on May 18 and JAMSTEC issued theirs at least a week earlier than NOAA.  There are significant differences in the two forecasts for the U.S. I also present the forecasts for the Rest of the World but cannot compare them to a NOAA forecast due to lack of available data. I provide separate maps for Europe. It is very important to understand these forecasts and track the development of a possible El Nino as the differences are very significant for the U.S. Europe, Asia, Australia and may impact world events in the Middle East.

 weather.caption for Updates


Please share this article - Go to very top of page, right hand side for social media buttons.


In this Update, we compare the JAMSTEC temperature and precipitation forecast maps, which are for the World, with the NOAA temperature and precipitation forecast maps that cover only CONUS and Alaska. We do this primarily for educational purposes. Remember: these are forecasts not guarantees. But the differences between the NOAA and JAMSTEC forecasts are significant - especially in the further-out months - and are mostly related to the differing perspectives on the evolution of a possible ENSO into Summer and Fall. JAMSTEC in their further-out forecast (which is out to Dec 2017 - Feb 2018) is reflecting a much higher probability of strong El Nino conditions this coming Fall into Winter.

Both the NOAA and ENSO forecasts are attempting to properly factor in the chances of an El Nino this Summer and into next winter. The difficulty with predicting an El Nino in May is discussed [click here ] This  makes all forecasts right now beyond the next three months somewhat of a WAG. But I am surprised at the extent of the differences between the JAMSTEC probability of an El Nino and the NOAA estimates of the probability of an El Nino. Those probabilities have a big impact on the projected weather and the impact of that weather which we will discuss in this article. It is also important because we are watching for a possible Climate Shift in the Pacific to a period lasting two to three decades of PDO Positive. A strong El Nino this winter would be supportive of that Climate Shift taking place.

Some Housekeeping Issues

This report will be posted late Saturday May 20 and will be referred to in the Weekly Report for reference until the Saturday after the next NOAA Update on June 15, 2017 which we will report on June 17. The Regular Weekly Report will be published on May 22. If you are reading this Update Report and wish to transfer to the Current Weather and Climate Report, Click here for the list of Weather Posts. That link takes you to the archive of all weather articles written by Sig Silber so you can if the new Weekly Weather Report has been published go there or back to an earlier report but please keep in mind that the graphics in earlier reports in some cases auto-update and the text may no longer apply to the graphics shown. Remember, if you leave this page to visit links provided in this article, you can return by hitting your "Back Arrow", usually top left corner of your screen just to the left of the URL box.


Below is a quick summary of the temperature and precipitation forecasts for three time periods and from left to right the NOAA forecast for Alaska and CONUS (the contiguous mid-latitude U.S), then JAMSTEC for North America (which includes Canada and Northern Mexico, and then JAMSTEC for Europe and surrounding areas. Larger graphics are provided later in the report. It is kind of a tease to keep you reading but you can see the evolution of the weather pattern through Summer, Fall into Winter. For some readers, these two sets of summary graphics may be all the information they wish to look at and that is fine.

Temperature

  NOAA Alaska + CONUS JAMSTEC North America JAMSTEC Europe
JJA JJA US Temperature Issued on May 18, 2017, NOAA Forecast JJA Temperature Based on May 1, 2017 JAMSTEC Forecast JJA Europe Temperature JAMSTEC May 1, 2017 Forecast
SON SON US Temperature Issued by NOAA on May 18, 2017 SON NA Temperature based on JAMSTEC May 1, 2017 Forecast SON 2017 Europe Temperature based on JAMSTEC May 1, 2017 Forecast

DJF

2017/2018

DJF 2017-2018 Temperature Issued by NOAA on May 18, 2017 DJF NA Temperature based on May 1JAMSTEC Forecast DJF Europe Temperature Based on May 1, 2017 Jamstec Forecast

Precipitation

  NOAA Alaska + CONUS JAMSTEC North America JAMSTEC Europe
JJA JJA US Precipitation Issued on May 18, 2017 NOAA Forecast JJA NA Precipitation Based on May 1, 2017 JAMSTEC Forecast JJA Europe JAMSTEC Precipitation May 1, 2017 Forecast
SON SON US Precipitation Based on May 18, 2017 Forecast SON NA Precipitation based on JAMSTEC May 1, 2017 Forecast SON 2017 Europe Precipitation based on JAMSTEC May 1, 2017 Forecast

DJF

2017/2018

DJF 2017 Precipitation based on May 18, 2017 NOAA forecast DJF US Precipitation based on May 1 JAMSTEC Forecast DJF Europe Precipitation Based on May 1, 2017 Jamstec Forecast

NOAA Updated Seasonal Outlook

NOAA issued their updated Seasonal Outlook on the third Thursday of the month i.e. May 18, 2017 as is their normal schedule. Let's first take a look at the NOAA maps. Then we will compare the NOAA Maps to those issued by JAMSTEC. A note about terminology; the deviations from climatology/normal are color coded but also labeled "A" for more than normal and "B" for less than normal. The area designated EC means Equal Chances of being more or less than normal. JAMSTEC relies on their color coding. In my comments I have used EC to cover all the situations where a clear anomaly is not shown.

First we will take a look at the Early Outlook for June 2017. It is called the Early Outlook because it will be updated at the end of May. Only the June Outlook will be updated at that time.

Temperature

June 2017 Early Temperature Report Issued on May 18, 2017

Precipitation

June 2017 Early Precipitation Outlook Issued on May 18, 2017

We have nothing to compare these maps with as NOAA does not in their Update provide a forecast for two months out separate from their three-month forecast. Thus I do not have June maps from the April 20, NOAA Report to compare against. And May is not over so we can not really compare the June forecast against May actual. It is probably best to just try to understand what NOAA is trying to convey about June which can be summarized as warm around the perimeter and wet in the Rocky Mountains where it also is likely to be cool.

Now we consider the three-month Outlook.

Notice that the three-month periods are abbreviated e.g. June/July/August is shown as JJA. You will see such abbreviations often in this report.

Prior Temperature Outlook for JJA 2017

JJA 2017 Temperature Outlook Issued April 20, 2017

New Temperature Outlook for JJA 2017

JJA 2017 Temperature Outlook Issued on May18, 2017

There is not much change but the EC area is somewhat larger.

Prior Precipitation Outlook for JJA 2017

JJA 2017 Precipitation Outlook Issued on April 20, 2017

New Precipitation Outlook for JJA 2017

JJA 2017 Precipitation Outlook issued May 18, 2017

The significant change is a larger Alaskan wet anomaly, the Great Lakes cool anomaly is no longer showing, and two CONUS wet anomalies in the prior forecast are now consolidated and shifted a bit to the east.

Now let us focus on the long-term situation and compare the new set of maps with the maps issued on May 18, 2016.

Prior 14 Month Temperature Outlook: JJA 2017 - MJJ 2018

14 Month Temperature Issued April 20, 2017 by NOAA

New 14 Month Temperature Outlook: JAS 2017 - JJA 2018

14 Month Temperature Outlooks Issued May 18, 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 the two sets of maps 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 of the form warmer for longer. This shows up mainly starting with JFM 2018 where the warm anomaly extends to the East Coast and starting in MAM 2018, the North Central EC anomaly is smaller than in the prior forecast. .

Prior 14 Month Precipitation Outlook: JJA 2017 - MJJ 2018

14 Month Precipitation Issued by NOAA on April 20, 2017

New 14 Month Precipitation Outlook: JAS 2017 - JJA 2018

14 month Precipitation Outlooks Issued on May 18, 2017

For precipitation the minor changes are too numerous to itemize. One big change starts in SON 2017 with the precipitation pattern then stretching across the Southern Tier but not including California but in the East extending to the north to include Virginia. Also in the heart of winter there is a dry anomaly centered on Idaho.

If you want larger versions of each map (temperature and precipitation) you can find them here. And then each of those maps can be clicked on to further enlarge them.

Sometimes it is useful to compare the present month outlook to the three-month outlook           

June plus JJA 2017 Issued on May 18, 2017

One can mentally subtract the June Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely July and August 2017. To  do that you need to take into account that:

For temperature there is a reduction in the CONUS Central EC anomaly in the three-month map as compared to the June Map. For Alaska, the warm anomaly also expands in the three-month map. Thus if you assume these colors are assigned correctly, it is a simple algebra equation to solve June/July probability for a given location = (3XThree-Month Probability - June Probability)/2*. So you can derive the July/August forecast this way. You can do that calculation easily for where you live.
Re precipitation, there is a wet anomaly in Alaska in the three-month map and the CONUS wet anomaly extends into Texas and the Plains States in the three-month map. So if you assume these colors are assigned correctly, it is a simple algebra equation to solve July/August probability for a given location = (3XThree-Month Probability - June Probability)/2*. So you can derive the July/August forecast this way. You can do that calculation easily for where you live.

* The concept is that the probabilities of a deviation from climatology in the First Month and the combined Month Two and Three forecast that one derives must average out to the probabilities shown in the three-month maps.

Discussion

Below are excerpts (significantly reorganized and with some of the redundancy removed) from the Discussion released by NOAA on May 18, 2017.

Headings that are "Initial Cap" only rather than all caps were added by the Author of this Update Report for clarity. Also we have organized the sequence of the sections of NOAA Discussion to first present the Atmospheric and Oceanic Conditions and then the Current Month, the Three or Four-month period, and finally the remainder of the 15 Month Forecast. We think that sequence with the three- to four-month period broken out separately, makes the discussion more useful for more readers.

CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS

OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC AS A WHOLE INDICATE ENSO-NEUTRAL CONDITIONS ARE CONTINUING. THE LATEST WEEKLY SST ANOMALY MAP INDICATES THAT WEAKLY POSITIVE SST ANOMALIES EXIST ACROSS NEARLY THE ENTIRE EQUATORIAL PACIFIC BASIN, WITH HIGHER AMPLITUDE ANOMALIES LOCATED NEAR THE SOUTH AMERICAN COAST. THE HEAT CONTENT ANOMALY OF THE UPPER-OCEAN LAYERS, TO A DEPTH OF 300 METERS, SUMMED ACROSS THE BASIN FROM THE DATE LINE TO 100W HAS REBOUNDED FROM THE DECREASE OBSERVED LAST MONTH AND IS NOW POSITIVE.

IN THE ATMOSPHERE OVER THE PAST MONTH, LOWER TROPOSPHERIC ZONAL WIND ANOMALIES WERE WEAK. OVER THE SAME PERIOD, MEASUREMENTS OF TROPICAL CONVECTION INDICATED THE DEVELOPMENT OF ENHANCED CONVECTION JUST SOUTH OF THE EQUATOR WITH WEAKLY ENHANCED CONVECTION CONTINUING OVER THE MARITIME CONTINENT. THIS COMBINATION OF THE ATMOSPHERIC AND OCEANIC EVOLUTION SUGGESTS A SHIFT FURTHER AWAY FROM THE REMNANT LA NINA BASE STATE.

ENSO-NEUTRAL CONDITIONS PERSISTED DURING APRIL, WITH NEAR-AVERAGE SEA SURFACE TEMPERATURES (SSTS) OBSERVED ACROSS THE CENTRAL EQUATORIAL PACIFIC, AND ABOVE-AVERAGE SSTS IN THE FAR EASTERN PACIFIC. A RESERVOIR OF SUBSURFACE WARMTH CONTINUES TO BE OBSERVED NEAR THE DATE LINE, CENTERED AT A DEPTH OF ABOUT 150 METERS. MAXIMUM TEMPERATURE ANOMALIES RANGE FROM ABOUT 3-5 DEGREES C ABOVE-AVERAGE. LOW-LEVEL (850-HPA) WIND ANOMALIES AVERAGED CLOSE TO NORMAL DURING THE PAST 30-DAYS. FOR THE SAME TIME PERIOD, THE OUTGOING LONGWAVE RADIATION (OLR) PATTERN (WHICH SERVES AS A PROXY FOR CONVECTIVE ANOMALIES ACROSS THE TROPICAL PACIFIC) DEPICTED AN AREA OF ENHANCED CONVECTION SOUTH OF THE EQUATOR FROM ABOUT 160E TO 125W, OR FROM ABOUT THE SOLOMON ISLANDS EASTWARD ACROSS THE SOUTH PACIFIC TO THE PITCAIRN ISLANDS. SUPPRESSED CONVECTION WAS NOTED ROUGHLY WITHIN THE SAME LONGITUDE BAND, THOUGH NORTH OF THE EQUATOR. THIS OLR FIELD IS NOT REPRESENTATIVE OF EITHER AN EL NINO OR A LA NINA.

PROGNOSTIC DISCUSSION OF SST FORECASTS

THE CPC NINO 3.4 SST INDEX CONSOLIDATION FORECAST, WHICH INCLUDES CANONICAL CORRELATION ANALYSIS (CCA), CONSTRUCTED ANALOG (CA), AND MARKOV STATISTICAL FORECASTS, ALONG WITH THE CFS DYNAMICAL MODEL, PREDICTS A MEDIAN TEMPERATURE ANOMALY OF BETWEEN +0.4C AND +0.5C FOR THE COMING SEASONS FROM APPROXIMATELY JJA THROUGH NDJ 2017, WITH EL NINO AS MOST LIKELY FROM LATE SUMMER THROUGH AUTUMN. THE CFS HAS BACKED OFF ITS EL NINO FORECAST IN A FAIRLY DRAMATIC FASHION OVER THE PAST MONTH, WHILE THE CA STATISTICAL FORECAST HAS BECOME THE WARMEST CONSTITUENT MEMBER OF THE CONSOLIDATION FORECAST. THE LATEST FORECASTS FROM THE DYNAMICAL SUITE OF MODELS FROM THE NMME CONTINUE TO FAVOR EL NINO DEVELOPMENT, THOUGH NOT AS STRONGLY AS LAST MONTH. THE LATEST OFFICIAL ENSO OUTLOOK FROM CPC/IRI PLACES THE ODDS OF EL NINO AND ENSO NEUTRAL AT ROUGHLY 45% FROM JJA THROUGH DJF. THE CONSENSUS FORECAST INDICATES THE LIKELIHOOD OF A REPEAT LA NINA EVENT TO BE SMALL DURING THIS FORECAST PERIOD.

30-DAY OUTLOOK DISCUSSION FOR JUNE 2017  

THE MADDEN-JULIAN OSCILLATION (MJO) WAS ACTIVE SINCE LATE APRIL, WITH THE ENHANCED CONVECTIVE PHASE CURRENTLY OVER THE INDIAN OCEAN. DURING THE NEXT TWO WEEKS, THE MJO IS FORECAST TO EXHIBIT EASTWARD PROPAGATION ACROSS THE INDIAN OCEAN AND MARITIME CONTINENT, BUT WITH VERY LOW AMPLITUDE. THEREFORE, THE MJO IS NOT LIKELY TO PLAY A SIGNIFICANT ROLE IN THE MONTHLY VARIABILITY OVER NORTH AMERICA DURING JUNE. ANTECEDENT SOIL MOISTURE WAS ALSO CONSIDERED FOR THE JUNE TEMPERATURE AND PRECIPITATION OUTLOOKS. SOIL MOISTURE IS ANOMALOUSLY HIGH OVER PORTIONS OF THE MIDWEST, AND SOUTH-CENTRAL PARTS OF BOTH THE MISSISSIPPI VALLEY AND GREAT PLAIN REGIONS. AT THIS TIME OF YEAR, THERE IS A SIGNIFICANT NEGATIVE CORRELATION BETWEEN SURFACE TEMPERATURE AND PRECIPITATION IN THIS GENERAL AREA; THAT IS, RELATIVELY COOL AND WET CONDITIONS OFTEN GO HAND-IN-HAND.

Temperature

DYNAMICAL MODELS FROM THE NMME SUITE GENERALLY INDICATED ABOVE-NORMAL MEAN TEMPERATURES FOR PORTIONS OF THE WESTERN, SOUTHERN, AND EASTERN CONUS, AND FOR MUCH OF WESTERN ALASKA. PROBABILISTIC AND CALIBRATED VERSIONS OF THE NMME TOOL WERE CONSIDERED FIRST-GUESS FIELDS FOR THE JUNE OUTLOOK. THE UNCALIBRATED NMME TEMPERATURE FORECAST APPEARED TO BE TOO WARM ACROSS THE MIDWESTERN STATES, WHERE CALCULATED SOIL MOISTURE RANKING PERCENTILES WERE EASILY IN EXCESS OF 70-80 PERCENT. THE CFS, THE CANADIAN MODEL (CMC1 CANCM3), AND THE NASA MODEL PREDICTED BELOW-NORMAL TEMPERATURES OVER PORTIONS OF THE NORTHERN AND CENTRAL ROCKIES, AND CENTRAL AND SOUTHERN PLAINS. THE OFFICIAL TEMPERATURE OUTLOOK FOR JUNE INCLUDES AN AREA OF FAVORED BELOW-NORMAL TEMPERATURES OVER MUCH OF WYOMING AND COLORADO, ESPECIALLY IN LIGHT OF THE NEGATIVE TEMPERATURE-PRECIPITATION CORRELATIONS NOTED EARLIER, AND THE FACT THAT THE ONE PRECIPITATION SIGNAL THAT IS CONSIDERED RELIABLE IS THE AREA OF PREDICTED ABOVE-MEDIAN PRECIPITATION OVER THIS SAME GENERAL REGION. OTHER MODEL SOLUTIONS, SUCH AS THOSE FROM GFDL AND NCAR, APPEAR TO BE TOO BULLISH ON THEIR PREDICTION OF NEARLY COAST-TO-COAST WARMTH ACROSS THE CONUS. IN WESTERN ALASKA, MOST (BUT NOT ALL) OF THE NMME SUITE PREDICTS ABOVE-NORMAL TEMPERATURES. RELATIVELY WARM SSTS, AND THE UNUSUALLY LARGE EXPANSE OF OPEN (ICE-FREE) WATER WEST AND SOUTHWEST OF BARROW BY MID-MAY, FAVOR ABOVE-NORMAL TEMPERATURES FOR THE WESTERN PORTION OF THE NORTH SLOPE.

Precipitation

THE JUNE PRECIPITATION OUTLOOK ALSO USES THE PROBABILISTIC AND CALIBRATED VERSIONS OF THE NMME AS ITS STARTING POINT. THE ONLY SIGNAL WHICH APPEARED RELIABLE IS AN AREA OF EXPECTED ABOVE-MEDIAN PRECIPITATION OVER THE VICINITY OF THE ROCKIES, AND CENTRAL AND SOUTHERN PLAINS. THE CFS, IMME, CANADIAN MODEL (CMC2 CANCM4), AND TO A LESSER DEGREE THE NASA MODEL, LEND SUPPORT FOR THIS WET SIGNAL. IN CONTRAST, THE GFDL FLOR MODEL PREDICTS BELOW-MEDIAN PRECIPITATION ACROSS THIS PART OF THE CONUS, WHILE THE GFDL CM2.1 AND NCAR MODELS PREDICT SOMETHING IN-BETWEEN THE TWO EXTREMES. ELSEWHERE, WHICH INCLUDES A LARGE PORTION OF THE CONUS AND ALL OF ALASKA, PRECIPITATION SIGNALS ARE EITHER TOO WEAK OR TOO INCOHERENT TO BE OF MUCH USE.

Three to Four Month June, July, August and Possibly September

Temperature

THE LATEST JJA AND JAS 2017 TEMPERATURE OUTLOOKS INDICATE ABOVE-NORMAL TEMPERATURES ARE MOST LIKELY FOR MUCH OF THE FORECAST DOMAIN, WITH THE EXCEPTION OF PARTS ROCKIES AND PLAINS. THE CHANCES OF ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE SLIGHTLY ENHANCED FOR MUCH OF THE PACIFIC NORTHWEST, BUT THE PROBABILITY OF ABOVE-NORMAL TEMPERATURES IS MODERATED BY RECENT POSITIVE SNOW AND SOIL MOISTURE ANOMALIES. ABOVE-NORMAL TEMPERATURES ARE PARTICULARLY ENHANCED FOR A REGION STRETCHING FROM THE SOUTHWEST, EASTWARD ACROSS THE FAR SOUTHERN TIER OF THE CONUS INTO THE EASTERN U.S. THE GREATEST PROBABILITIES EXCEED 50% FOR PARTS OF THE SOUTHWEST AND ALONG THE GULF AND ATLANTIC COASTS, FOLLOWING THE CALIBRATED PROBABILISTIC GUIDANCE FROM THE NMME. NEGATIVE SOIL MOISTURE ANOMALIES IN THE SOUTHEAST REGION ALSO CONTRIBUTE TO THE LIKELIHOOD OF ANOMALOUS WARMTH. DECADAL CLIMATE TRENDS ALSO SUPPORT THE OUTLOOK AND ARE A COMPONENT OF THE DYNAMICAL MODEL GUIDANCE. THESE FORECAST TOOLS ALSO SUPPORT ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR ALASKA.

POSITIVE SOIL MOISTURE ANOMALIES, COMBINED WITH PROBABILITIES FAVORING ABOVE-MEDIAN PRECIPITATION, SUPPORT SOME EXPANSION OF THE RELATIVE TEMPERATURE WEAKNESS OVER PARTS OF THE ROCKIES AND PLAINS STATES FOR JJA AND JAS.  ADDITIONALLY, ANTECEDENT TROPICAL AND EXTRATROPICAL SST BOUNDARY CONDITIONS MAY INDICATE SOME COMPONENT OF INTERANNUAL VARIABILITY THAT COULD DESTRUCTIVELY INTERFERE WITH LONGER TERM WARMING TRENDS OVER PARTS OF THE CENTRAL AND EASTERN CONUS. WHILE THE FORECAST STILL BROADLY FAVORS ABOVE-NORMAL TEMPERATURES, THE PROBABILITIES ARE NOT EXCEPTIONAL, AND INDEED THE NMME FORECAST AND THE OFFICIAL FORECAST SUGGEST A SLIGHTLY COOLER FORECAST FOR THE CONUS AS A WHOLE THAN THAT ISSUED FOR LAST SUMMER FOR JJA AND JAS.

Precipitation

THE JJA 2017 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE ROCKIES AND HIGH PLAINS, CENTERED EAST OF THE CONTINENTAL DIVIDE, EXTENDING SOUTHWARD THROUGH THE SOUTHERN PLAINS. ABOVE-MEDIAN PRECIPITATION IS ALSO SLIGHTLY FAVORED FOR PARTS OF MAINLAND ALASKA.

Longer Term Sept 2017 Through June/July/Aug 2018

AS THE FORECAST PROGRESSES TOWARD THE COLD SEASON, A SLIGHT TILT TOWARD EL NINO (RELATIVE TO LA NINA) IS INDICATED BY THE LATEST OBJECTIVE GUIDANCE AND EXPERT ASSESSMENTS. THIS HAS A SMALL IMPACT ON THE TEMPERATURE AND PRECIPITATION FORECASTS FOR THE SEASONS SPANNING SON 2017 THROUGH FMA 2018.

PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS

THE PRIMARY TOOLS USED FOR THIS SET OF SEASONAL OUTLOOKS INCLUDED BOTH STATISTICAL AND DYNAMICAL MODEL FORECAST GUIDANCE, AND IN PARTICULAR AT LONGER LEADS, DECADAL TEMPERATURE AND PRECIPITATION TRENDS. THE CALIBRATED DYNAMICAL MODEL GUIDANCE FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND, TO LESSER EXTENT, ITS INDIVIDUAL MODELS, INCLUDING THE NCEP CFS, WERE IMPORTANT CONTRIBUTORS TO THE OUTLOOKS THROUGH OND 2017. ANTECEDENT SOIL MOISTURE AND SNOWPACK ANOMALIES IN CERTAIN REGIONS ALSO IMPACTED THE OUTLOOKS AT EARLY LEADS. WHILE THE ENSO FORECAST REMAINS HIGHLY UNCERTAIN, THE SLIGHT TILT TOWARD EL NINO WAS CONSIDERED IN THE TEMPERATURE AND PRECIPITATION FROM SON THROUGH FMA.

PROGNOSTIC DISCUSSION OF OUTLOOKS - JJA 2017 TO JJA 2018

TEMPERATURE  

SUBTLE CHANGES WERE MADE TO LATER LEADS, FROM ASO TO FMA, BASED ON THE LATEST MODEL GUIDANCE AND STATISTICAL FORECASTS THAT EMPHASIZE A SLIGHT TILT TOWARD EL NINO IMPACTS. GENERALLY THIS IS SEEN AS A SLIGHT INCREASE IN PROBABILITIES FAVORING ABOVE-NORMAL TEMPERATURE ACROSS THE NORTHERN TIER OF THE CONUS, AND A REDUCTION OF THE SAME ACROSS THE FAR SOUTHERN TIER.

HIGH PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR THE NORTH SLOPE OF ALASKA DURING SON AND OND 2017 DUE TO DECADAL TRENDS IN THE SEASONAL CYCLE OF SEA ICE.

PRECIPITATION

FROM ASO THROUGH OND 2017, INCREASING CHANCES FOR EL NINO CONDITIONS AND DYNAMICAL MODEL FORECASTS OF GREATER THAN AVERAGE SSTS IN THE EASTERN TROPICAL PACIFIC LEAD TO A SOUTHWARD SHIFT OF THIS REGION OF LIKELY ABOVE-MEDIAN PRECIPITATION INTO THE SOUTHWEST CONUS, EXTENDING ACROSS THE FAR SOUTHERN TIER OF THE CONUS WITH STILL MODEST PROBABILITIES.

FOR LATE AUTUMN AND WINTER, FROM NDJ 2017-2018 THROUGH JFM 2018, THE LOW PROBABILITY OF A LA NINA AND ELEVATED CHANCES FOR A POSSIBLE EL NINO NOW RESULT IN THE INTRODUCTION OF PROBABILITIES ASSOCIATED WITH A CANONICAL EL NINO, ALBEIT AT VERY LOW AMPLITUDE AND COVERAGE DUE TO THE HIGH UNCERTAINTY. FOLLOWING JFM 2018, WEAK SIGNALS DUE TO DECADAL TRENDS IN PRECIPITATION ARE INDICATED, INCLUDING BELOW-MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHWEST BEGINNING WITH THE MAM 2018 SEASON AND ABOVE-MEDIAN PRECIPITATION IN THE NORTHERN-CENTRAL CONTIGUOUS U.S. BEGINNING WITH MAM 2018.

OVER ALASKA, CALIBRATED DYNAMICAL GUIDANCE FAVORS A SHIFT TOWARD ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE MAINLAND DURING THE EARLY LEADS. DURING SON, MODEST PROBABILITIES FAVORING ABOVE-MEDIAN PRECIPITATION ARE INTRODUCED OVER SOUTHERN ALASKA TO ACCOUNT FOR THE TILT TOWARD EL NINO; THAT SIGNAL CONTINUES IN THE FORECASTS THROUGH JFM 2018.

Forecasting the Evolution of ENSO

Here is the latest NOAA forecast of Nino 3.4 temperature anomalies.  You can see the "blue" newer model runs and the "red" older model runs. The Oceanic Niño Index (ONI) which is the three-month rolling average of the Nino 3.4 values is NOAA's primary indicator for monitoring El Niño and La Niña. The secondary indicator is the Southern Oscillation Index (SOI) which is based on the extent that the air pressure anomaly in Tahiti exceeds the air pressure anomaly in Darwin Australia.  It is a complicated formula and is intended to assess the response of the atmosphere to the changes in the pattern of warm and cool sea surface temperatures.

The question now is will the Warm Event that is taking place meet El Nino Standards?

 CFS.V2 SST Forecast May 19, 2017

This is the primary NOAA forecast tool and it is not showing an El Nino for Fall and Winter. In fact the probabilities decline after this summer.

A look at the subsurface is very useful.

Subsurface Conditions date May 13, 2017

This chart could update at any time but in this article I have frozen it so that if someone looks back at the article six months from now the text and graphics will be in sync. One can see that there is some subsurface warm water. You can not  tell from this one graphic but compared to a few weeks ago the warm anomaly along the coast of South America has decreased but the Pacific Warm pool has moved east quite a bit. In fact one sees an area around 140W where the warm area is moving to the surface. One also can tell by comparing to prior versions that the cool area has shrunk and has moved to the east outside of the Nino 3.4 Measurement Area. Overall it is picture of slow warming but is there enough subsurface warm water to really trigger an El Nino? That is where the volatility of the forecasts springs from. A note on the comment moving to the surface. Generally speaking the water at depth is not warmer than the water at the surface and does not rise because of that. What we see here are anomalies and the subsurface water is warmer than usual. So it is not clear what temperature it will be if currents move that water to the surface.
It could well be that the every five years adjustment mechanism NOAA uses for the Tropical Pacific is not able to keep up with Ocean Warming which may slightly overstate warm anomalies.

SOI values as of May 19, 2017

Normally La Nina Conditions are confirmed by SOI 30 day values that are greater than or equal to +7.0. El Nino Conditions are confirmed by SOI 30 day values that are less than or equal to -7.0. So right now both the Nino 3.4 Index and the SOI remain in the ENSO Neutral phase of ENSO.

El Nino Probabilities used by NOAA in Their Forecast (The forecast for the value of the Nino 3.4 Index receives the most attention).

And now we have the IRI/CPC May 18, 2017 fully model-based report. This (click to read) is the discussion that was issued with the May 18 Report (the graphic is on the right) and also the less formal mostly based on a Meteorologist survey a week earlier shown on the left.

May 18, 2017 IRI/CPC ENSO Side by Side Forecasts.

As you can see, IRI and CPC are more bullish re the probabilities for an El Nino very soon and lasting quite long than they were just a week ago. Also I am pretty sure the NOAA Seasonal Outlook issued on May 18 did not reflect the IRI CPC May 18th report. If it had, their overall forecast might have factored in an El Nino a bit more significantly. This may well have led to forecast maps that agreed more closely with the JAMSTEC forecast maps.

Here is the most recent Nino 3.4 report from the Australian BOM.

Australia POAMA ENSO model run May 7, 2017

The Australian BOM employs a different threshold for considering a SSTA to be either La Nina or El Nino. Note their forecast is showing ENSO Neutral through their forecast period. This report will be updated in a few days but we can only work from what has been published and is available. If it changes dramatically on Monday Night I may update this graphic.

Here is the recently released JAMSTEC forecast of the Nino 3.4 values. Notice they are forecasting a fairly high level for the Nino 3.4 Index (higher than the other Meteorological Agencies) but a rapid decline starting just prior to January. That is very significant relative to their DJF 2017 - 2018 forecast since some believe that the trend in the Nino 3.4 Index is as important as the absolute value. JAMSTEC's forecast for the Nino 3.4 Index is of course subject to change next month.

JAMSTEC May 1, 2017 ENSO Forecast.

The ENSO forecasts are not the only factor that is considered when making these fairly long-term forecasts but it is a very major factor so that ENSO forecast strongly influences the Temperature and Precipitation forecasts.

Now the Comparison of the NOAA and JAMSTEC Forecasts. I am only discussing the differences for Alaska and CONUS since NOAA does not cover the World in this set of forecasts. But the JAMSTEC World forecast is here for you to see and I comment on the highlights of that forecast also. I should note that JAMSTEC believes their model is most accurate at low latitudes. This makes sense as they would reasonably focus on Japan which is at about the same latitude as CONUS (the contiguous part of the United States in North America).

JAMSTEC works in three-month intervals and does not change the selection of months each time they update. So we have  JJA, SON and DJF 2018, to work with from JAMSTEC and the same are available from NOAA. That means that this is the one out of every three months where the comparison can be made starting with the immediate three-month period.

JJA

Temperature

NOAA

JJA 2017 Temperature Issued by NOAA on May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

JJA JAMSTEC extracted from May 1, 2017 World Forecast

NOAA shows a North Central area that is EC. For JAMSTEC, everything is warm.

And Now the JAMSTEC WORLD FORECAST

JJA Temperature Forecast from JAMSTEC May1, 2017 forecast.

For the World, JAMSTEC sees very little that is cool other than Northern Australia and Eastern Siberia. Other cool areas are a small part of West Africa and North and East of Hudson Bay Canada.

Precipitation

NOAA

NOAA SON 2017 Precipitation Issued May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

CONUS JJA Precipitation Extracted from May 1, JAMSTEC Forecast

For CONUS, NOAA shows Alaska wet and JAMSTEC is showing Alaska dry. For CONUS, NOAA shows mostly EC with a Central Rockies wet anomaly extending into Texas. JAMSTEC show this also but also shows Arizona wet, part of the Southeast wet and the Northeast Quadrant mostly dry.

JAMSTEC WORLD FORECAST

JJA 2017 Jamstec Precipitation Forecast From May 1, 2017

Of interest is the dry Europe. Southeast Asia is wet but part of India is dry. Just north of the Equator, Africa is wet. Australia is dry and South America is dry.

SON 2017

Temperature

NOAA

SON Temperature NOAA Issued on May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

SON North American Temperature extracted from JAMSTEC May 1 Forecast

NOAA shows all of Alaska and CONUS warm. For JAMSTEC, The Northeast 1/3rd of CONUS is cool as is Arizona.

JAMSTEC WORLD FORECAST

SON 2017 JAMSTEC Temp from May 1, 2017

For JAMSTEC outside of the North America situation which we already discussed the other cool area is Europe with Somalia and the extreme southern tip of India also being cool.  One has to search for cool areas these days.

Precipitation

NOAA

NOAA SON 2017 Precipitation Issued on May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

SON JAMSTEC Precipitation for CONUS based on May 1 forecast

NOAA and JAMSTEC pretty much agree on which part of Alaska will be wet. NOAA is showing a Southern Tier wet pattern and JAMSTEC shows more of a wet 2/3rd of CONUS to the west and 1/3rd of CONUS dry to the east. JAMSTEC show the Southwest wet which is kind of like a late Southwest Monsoon NOAA sees the pattern shifted a bit more east to Texas. That is a very big difference signifying a different moisture source.

JAMSTEC WORLD FORECAST

SON 2017 JAMSTEC Precipitation Forecast from May 1, 2017

Northern Europe is dry. Australia and more intensely the island nations north of Australia are dry. Only a small part of India is dry. Eastern Asia is dry. Equatorial and much of southern Africa is wet. Most of Western South America is wet.

DJF 2017-2018

Temperature

NOAA

NOAA DJF 2017- 2018 Temperature Issued May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

DJF 2017-2018 North America Temperature Forcast Extracted from the May 1 JAMSTEC Forecast

NOAA has both Alaska and CONUS warm. For JAMSTEC, only the Western third of CONUS is warm. The rest extending into Canada is cool. It is kind of shocking to see the difference between NOAA and JAMSTEC re the temperature anomaly in CONUS. The economic impact of the difference in forecasts is large. An example would be energy usage.

JAMSTEC WORLD FORECAST

SON 2017 JAMSTEC Temperature from May 1, 2017

One major cool area is CONUS. Another is Europe excluding Scandinavia. But there are other cool areas such parts of Central Asia and Southwest China.

Precipitation

NOAA

DJF 2017 Precipitation Issued May 18, 2017

And here is the forecast for North America that I extracted from the JAMSTEC World Forecast

JAMSTEC DJF precipitation extracted from their May 1 2017 Forecast

Last Month CONUS was not ready to forecast precipitation this far out. Now they have and it is similar to their SON Forecast. The JAMSTEC forecast is also similar to their SON forecast. Thus the differences remain the same. But JAMSTEC is especially adamant about a wet California. You can see the wet anomaly extending into the Pacific.

JAMSTEC WORLD FORECAST

DJF 2017-2018 JAMSTEC Precipitation Forecas from May 1, 2017

South Africa is wet, Australia is no longer dry (a big change from the forecast last month). Much of South America is wet but not northern South America which is important due to the unrest in Venezuela. Much of southern Asia is wet. Southern Europe is wet.

Conclusion

Both forecasts are based on an El Nino or Near-El Nino arriving. JAMSTEC assumes a stronger El Nino than NOAA and their forecast reflects this. In general an El Nino is a drought pattern for most of the World but not the U.S. The JAMSTEC forecast is simply more committed to a strong El Nino than is NOAA.

Click here for a list of Sig Silber's Weather Posts

>>>>> Scroll down to view and make comments <<<<<<










Make a Comment

Econintersect wants your comments, data and opinion on the articles posted. You can also comment using Facebook directly using he comment block below.




Econintersect Weather








search_box
Print this page or create a PDF file of this page
Print Friendly and PDF


The growing use of ad blocking software is creating a shortfall in covering our fixed expenses. Please consider a donation to Econintersect to allow continuing output of quality and balanced financial and economic news and analysis.







Keep up with economic news using our dynamic economic newspapers with the largest international coverage on the internet
Asia / Pacific
Europe
Middle East / Africa
Americas
USA Government





























 navigate econintersect.com

Blogs

Analysis Blog
News Blog
Investing Blog
Opinion Blog
Precious Metals Blog
Markets Blog
Video of the Day
Weather

Newspapers

Asia / Pacific
Europe
Middle East / Africa
Americas
USA Government
     

RSS Feeds / Social Media

Combined Econintersect Feed
Google+
Facebook
Twitter
Digg

Free Newsletter

Marketplace - Books & More

Economic Forecast

Content Contribution

Contact

About

  Top Economics Site

Investing.com Contributor TalkMarkets Contributor Finance Blogs Free PageRank Checker Active Search Results Google+

This Web Page by Steven Hansen ---- Copyright 2010 - 2017 Econintersect LLC - all rights reserved