NOAA has updated their June Forecast as is usual at the end of the prior month. The overall impact was to reduce both the temperature and precipitation anomalies for June. In recent days, the movement of weather systems from west to east has come to an almost complete halt for CONUS as is appropriate for this time of the year. Australia would not agree but overall, weather around the world is pretty much normal with minimal ENSO impacts with some possible Global Warming Impacts which of course are difficult to prove.
This is the RegularEdition of my weekly Weather and Climate Update Report. Additional information can be found here on Page II of the Global Economic Intersection Weather and Climate Report.
NOAA Update of their June Outlook
NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on May 31 and we will discuss that first by comparing the Updated Outlook to the Early Outlook issued on May 19.
Prior Outlook Issued on May 19
Updated Temperature Outlook Issued on May 31
Perhaps some higher probabilities for the warm anomaly in the Northwest, the downgrading of the warm East Coast anomaly north of North Carolina to EC, and the extension of the cool anomaly along the lee side of the Central Rockies down the lee side of the Rockies all the way to the Mexico Border (and probably beyond but not shown).
Prior Outlook Issued on May 19
Updated Outlook Issued on May 31
We now see a wet anomaly in the extreme Northeast extending down and west to the part of the Great Lakes area which had formally been listed as being anomalously dry, a dry anomaly in the mid Mississippi /Ohio River/Tennessee Valley area, and more dramatically the shrinkage of a very extensive wet anomaly shown previously as extending from Idaho to Georgia now reduced to an area which is mostly just Eastern and Southern Texas. .
Below is the discussion issued with this update. In addition to the forecast it also explains how they have refined the way they have integrated the experimental weeks 3/4 forecast to produce an integrated assessment for the month.
30-DAY OUTLOOK DISCUSSION FOR JUNE 2016
THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JUNE 2016 ARE BASED PRIMARILY ON THE LATEST DYNAMICAL MODEL GUIDANCE, WPC TEMPERATURE AND PRECIPITATION FORECASTS DURING THE FIRST WEEK OF JUNE, THE CPC 6-10/8-14 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, AND CLIMATE LINKAGES TO CURRENT SOIL MOISTURE CONDITIONS. THE MJO RECENTLY WEAKENED, BUT DYNAMICAL MODELS INDICATE THAT A MORE ROBUST MJO SIGNAL DEVELOPING OVER THE WESTERN INDIAN OCEAN BY MID-JUNE. EXCEPT FOR MODULATING TROPICAL CYCLONE ACTIVITY, THE MJO TYPICALLY HAS LESS INFLUENCE ON THE EXTRATROPICS DURING THE WARM SEASON. THEREFORE, THE MJO AND WANING EL NINO DID NOT PLAY A MAJOR ROLE IN THE UPDATED JUNE TEMPERATURE OR PRECIPITATION OUTLOOK.
THE AREA FOR INCREASED CHANCES OF BELOW-NORMAL TEMPERATURES IS EXPANDED SOUTH ACROSS THE GREAT PLAINS TO THE RIO GRANDE RIVER IN THE UPDATED OUTLOOK DUE TO: BELOW-NORMAL TEMPERATURES LIKELY DURING THE FIRST WEEK OF JUNE, BELOW-NORMAL TEMPERATURES FAVORED BY THE CFS MONTHLY, AND SOIL MOISTURE CONSIDERATIONS. AS OF MAY 30, SOIL MOISTURE IS ABOVE THE 70TH PERCENTILE FROM SOUTH DAKOTA SOUTH TO TEXAS WITH PARTS OF THE LOWER MISSOURI RIVER VALLEY AND TEXAS ABOVE THE 99TH PERCENTILE. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INCREASED ACROSS THE PACIFIC NORTHWEST IN THE UPDATED OUTLOOK SINCE TEMPERATURES ARE FORECAST TO AVERAGE MORE THAN 15 DEGREES F ABOVE-NORMAL THROUGH AT LEAST THE FIRST WEEK OF JUNE. THE COVERAGE OF INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES IS REDUCED ACROSS THE GREAT LAKES AND NORTHEAST DUE TO THE AMPLIFYING TROUGH EARLY IN THE MONTH.
ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE MAINTAINED ACROSS PARTS OF OKLAHOMA, TEXAS, AND THE WESTERN GULF COAST WHERE HEAVY RAIN IS LIKELY AT THE BEGINNING OF JUNE AND THERE IS NO STRONG SIGNAL FOR BELOW-MEDIAN PRECIPITATION DURING THE REMAINDER OF THE MONTH. A SLIGHT TILT IN THE ODDS FOR ABOVE-MEDIAN PRECIPITATION ACROSS SOUTHEAST FLORIDA AND THE FLORIDA KEYS IS BASED ON A CONSISTENT WET SIGNAL EARLY IN JUNE. NEW ENGLAND ALONG WITH PARTS OF NEW YORK AND THE EASTERN GREAT LAKES ARE ALSO FORECAST TO HAVE A SLIGHT TILT IN THE ODDS FOR ABOVE-MEDIAN PRECIPITATION AS THIS REGION IS LIKELY TO BE INFLUENCED BY CYCLONIC FLOW EARLY IN THE MONTH WITH WEAK PRECIPITATION SIGNALS THEREAFTER. THE MOST LIKELY AREA FOR BELOW-MEDIAN PRECIPITATION INCLUDES THE MIDDLE MISSISSIPPI VALLEY, OHIO VALLEY, AND TENNESSEE VALLEY WHERE THE DYNAMICAL MODELS ARE IN GOOD AGREEMENT FOR BELOW-MEDIAN PRECIPITATION AMOUNTS THROUGH THE FIRST TWO WEEKS OF JUNE AND THE ECMWF MODEL CONTINUES THIS DRY SIGNAL DURING WEEKS 3 AND 4. ALSO, RECENT MONTHLY PRECIPITATION FORECASTS FROM THE CFS MODEL HAVE TRENDED DRIER ACROSS THESE AREAS. DUE TO CONFLICTING PRECIPITATION SIGNALS AT DIFFERENT TIME RANGES, EQUAL CHANCES FOR BELOW, NEAR, OR ABOVE-MEDIAN PRECIPITATION ARE NECESSARY FOR THE WESTERN AND NORTH-CENTRAL CONUS.
LITTLE TO NO CHANGE IS REQUIRED TO THE PREVIOUS TEMPERATURE AND PRECIPITATION OUTLOOKS ACROSS ALASKA. THE HIGHEST CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE ALEUTIANS WHERE SEA SURFACE TEMPERATURE ANOMALIES ARE AVERAGING NEAR 2.5 DEGREES C ABOVE-NORMAL. ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE EXPANDED TO INCLUDE THE ALASKA PANHANDLE DUE TO EXPECTED WETNESS DURING THE FIRST TWO WEEKS OF JUNE.
Sometimes it is useful to compare the present month outlook to the three-month outlook
June plus June - July - August Outlook
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 2016. When I do that, I deduce that July and August will have:
A lot of areas shown as being warmer than climatology for the three-month period but shown as EC or cool for June will need to do some catching to have the three-month probabilities work out. Re precipitation, Texas, the Middle Mississippi/Ohio/Tennessee Valley area, the Great Lakes, and the Central Rockies will need to have different anomalies for July and August than shown for June for the three-month probabilities to work out.
One has to keep in mind that we are now subtracting a June Map issued on May 3l from a May 19 three-month map so it is less reliable than the exercise we went through two weeks ago. We are assuming that the three-month outlook issued on May 19 would not change if it was released today. The results in the box above might be an indication of how July and August will differ from the three-month outlook or it might alternatively indicate how the three-month outlook might be modified if issued today.
Let's Now Focus on the Current (Right Now to 5 Days Out) Weather Situation.
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Characteristics of a Weekly Weather Column.
Many graphics in this report are auto-updated by the source of the graphic. It is always my choice as the writer to allow these graphics to auto-update or "freeze them" to what they looked like when I write the article. Generally speaking graphics in research themes which appear above this point do not auto-update as they come from published scientific papers. When I make the decision to allow certain graphics to auto-update, it creates two issues:
A. As the graphic updates, my commentary becomes out of sync with the new version of the graphic. This can be very extreme if for example you take a look at my report from months ago.
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First, here is a national animation of weather front and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. Beyond 60 hours, additional maps are available at the link provided above.
The explanation for the coding used in these maps, i.e. the full legend, can be found here although it includes some symbols that are no longer shown in the graphic because they are implemented by color coding.
The map below is the mid-atmosphere 7-Day chart rather than the surface highs and lows and weather features. In some cases it provides a clearer less confusing picture as it shows only the major pressure gradients.This graphic auto-updates so when you look at it you will see NOAA's latest thinking. The speed at which these troughs and ridges travel across the nation will determine the timing of weather impacts. This graphic auto-updates I think every six hours and it changes a lot. Because "Thickness Lines" are shown by those green lines on this graphic, it is a good place to define "Thickness" and its uses. The 540 Level general signifies equal chances for snow at sea level locations. I am leaving this explanation in the report but it may not be very significant until next October or so.
We are no longer interested in the 540 snow line but the 582 thickness line might be associated with close to record warm temperatures. We also now see a 588 thickness isopleth. We now see a Western trough and a Great Plains Ridge and an Eastern Trough with a Closed Low right above New England. There is a Closed Low that is driving the Western Trough. Remember this is a Day 7 Forecast and changes to the forecast occur regularly although the overall pattern tends to be fairly robust. The High in Mexico is important as it is the beginning phase of the North American Monsoon.
The MJO has had significant impacts this winter but the impact on June is not likely to be very noticeable The MJO is not likely to have much of an impact for the month of June due to the time of the year and the lack of indication of the MJO cycle being strong at this time. But over the next few months, it might slow the development of the La Nina.
Notice the Northern Pacific is again more like a giant anticyclone with clockwise motion so that which gets sent west at low latitudes is to some extent returned to North America but at higher latitudes. That pattern was interrupted last week probably due to the demise of the El Nino and the impact of the MJO. We still do not see the rapid movement of storms at lower latitudes from east to west. Most of CONUS storms are originating from Asia without nearly as much support from storms related to the Equator although we see some of that occurring. The entire circulation has slowed down as one would expect this time of the year.
As I am looking at the above graphic Monday evening June 6, I see a new tropical system impacting the East Coast. As we move into a Summer Pattern, the concept of a storm track west to east becomes less relevant and we focus more on south to north movements i.e. the Monsoon in the Southwest and Tropical Storms in the East and Gulf of Mexico. You can see a small amount of wet air moving into the Southwest from Mexico possibly from one of the storms in the Pacific off the coast of Mexico. This graphic updates automatically so it most likely will look different by the time you look at it as the weather patterns are moving from west to east.
Below is an analysis of projected tropical hazards and benefits over an approximately two-week period. This graphic is scheduled to update on Tuesday and I am reading the May 31, 2016 Version and looking at Week 2 of that forecast.
Mostly I see for the period June 8 - June 14, 2016 a mix of moderate confidence wet and dry areas from the Maritime Continent west to and including Africa with a moderate confidence of a warm anomaly in Northwest Australia.. But there is also a moderate likelihood event related to a warm anomaly for parts of Brazil but a cool anomaly further south in Argentina. There is also a moderate likelihood of a wet anomaly impacting Central American and earlier this year such events ended up impacting the Southeast U.S. so we need to monitor that.
For CONUS, this is more specific and near term.
And here is pretty much the same information with interpretation and a focus on tropical storms. It does not cover as wide an area e.g. it does not cover the Western Pacific or the Atlantic far east of the U.S. I have not been showing this graphic during the winter. It is curious that the storm off of Florida is not shown. I guess it is too run of the mill.
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.
The Aleutian Low seemed to have retired for the Summer. But now it looks like it has decided to again pay us a visit and impact North American weather. It is a split low with one part in the Gulf of Alaska and the other part off Kamchatka. It is not very strong.
The High Pressure off of California, the familiar RRR, is here, is not particularly strong and hardly shows up at all today and is not real close to shore. It is normal for this time of the year unlike during the winter. Recently, I provided this K - 12 write up that provides a simple explanation on the importance of semipermanent Highs and Lows and another link that discussed possible changes in the patterns of these highs and lows which could be related to a Climate Shift (cycle) in the Pacific or Global Warming.
There us a lot of moisture around, so the potential for precipitation is there. And the two semipermanent air pressure features in the Eastern Pacific are still very much determining where that moisture enters CONUS namely the Northwest. So we still have a "progressive" character to our weather but it is muted.
Looking at the current activity of the Jet Stream which continues to be quite far north.
The path of the current weather pattern is fairly clear from this graphic. But the Jet Stream now is fairly weak. This means that weather patterns are moving from west to east more slowly than usual and this also raises flooding issues as storms can stay over a given area for longer times than during mid-Winter.
And here is the forecast out five days.
Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems. In some cases however a Low Pressure System becomes separated or "cut off" from the Jet Stream. In that case it's movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream.
To see how the pattern is projected to evolve, please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.
This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.
Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on "earth" adjusting the parameters and then clicking again on "earth" to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns.
And when we look at Sea Surface anomalies below, we see a lot of them not just along the Equator related to ENSO.
The waters off of Japan remain warm but may be changing. The Indian Ocean is warm but much less so than recently. The waters off of New Zealand are warm and are generating storms which impact surf conditions all the way to North America. There has been some limited tropical activity off the East Coast of Australia but the waters north of Australia to Indonesia are where the major part of the warm anomaly is found. The overall Northern Pacific is indeed PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape). The PDO Index rose to 2.4 in March which with El Nino fading may be significant. It is now up to 2.62 for April. Here is the list of PDO values. But the value for May has not been posted. The water off the West Coast of North America is very warm but perhaps not as intense as recently. It is not hugging the coast. The water off the East Coast is warm...beware of shark attacks. The water off of South America is not showing much a La Nina pattern even though El Nino is history. There is a very narrow cool anomaly in the Pacific right along the Equator. It visually looks more like ENSO Neutral than all the way to La Nina and it may be what is called a La Nina Modoki. There are still some warm anomalies mixed in with the cooling process especially just north of the cool anomalies. It is not straightforward. Further north in the Atlantic south of Greenland and Iceland rather than directly off the Coast of North America, the North Atlantic is cooler than normal which is consistent with AMO+ and has implications for the NAO i.e. parts of Europe. And that anomaly has moved to the east and now extends all the way to the British Isles. The Gulf of Mexico and the waters south of Florida are no longer dramatically warmer than climatology. The warm water off of West Africa is no longer there reducing the probabilities of an active hurricane season this summer at least for the time being. The waters north of Antarctica are uniformly colder than climatology but other than southeast of South America, it is less intense than recently. I have additional commentary on much of this static analysis of the anomalies below where I examine the four-week change in these anomalies.
This is a good time to discuss the Atlantic Decadal Oscillation or AMO. It has a big impact on CONUS summer weather especially precipitation and we will be disussing this more in the weeks ahead. This graphic is from the paper Variations in North American Summer Precipitation Driven by the Atlantic Multidecadal Oscillation QI HU,SONG FENG, AND ROBERT J. OGLESBY. Here is the link. We will be discussing this and related papers a lot more in the coming weeks.
You can see that the patterns are kind of the opposite of each other. One expects the AMO to be moving towards neutral but it has not just yet. The Index itself is measured from 0–60N, 7.5–75W. Here is the AMO Index.
Since these are "departures" or "anomalies", it is not a seasonal pattern that is being shown. Comparing a four-week graphic to a prior four-week graphic is always tricky since only 25% of the data has changed and I am not showing the former graphic (it is in last week's report). I add the new one, compare and comment on the change and then delete the old one to keep this report to a manageable size. Also it is important to recognize that what you see in this graphic is the change in the anomaly. So blue means either cooler or less warm. Red means warmer or less cool. So you have to refer to the graphic above this one to really interpret this graphic as what we are seeing here is the change in the anomalies. What we see in this graphic is four weeks of change not the current absolute anomalies which are today two graphics further up. It is not derivatives in the mathematical sense but deltas. They are somewhat similar. The graphic above this one (and above the AMO discussion) has no time component. It is simply the deviation from climatology and this graphic shows the four week change in the deviation from climatology. So it is a bit like the first and second derivatives but not exactly. I take it a step further by comparing this weeks version of the graphic to the prior week and report on the differences below.
What I see as I look at both last week's version of this graphic and the current one (before deleting the prior version) is less intensification of the warming pattern off of Japan. Also there is also the completion of the warming off of the west coast of Africa. The cooling off the East Coast of Africa now covers a larger area and has basically erased the long standing warm anomalies. There is some warming north of Australia. These are subtle changes but enough to influence weather especially the changes involving Japan and Australia and areas to the north of Australia. In many other areas. it is the cancelation out of anomalies of the opposite sign.
6 - 14 Day Outlook Plus the Week 3-4 Experimental Forecasts
Now let us focus on the 6 - 14 Day Forecast for which I generally only show the 8 - 14 Day Maps. The 6 - 10 Day maps are always available in Part II of this report but in the Winter and Spring I often show both maps as the forecasted weather patterns change during that nine day period.
To put the forecasts which NOAA tends to call Outlooks into perspective, I am going to show the three-month MJJ Outlook and the recently updated Outlook for the single month of June and then discuss the 6 - 10 Day and 8 - 14 Day Maps and the 6 - 14 Day NOAA Discussion ithin that framework.
First - Temperature
Here is the Three-Month MJJ Temperature Outlook issued on May 19, 2016:
Here is the Updated Outlook for June Temperatures issued on May 31, 2016.
Below are the current 6 - 10 Day and 8 - 14 Day Temperature Outlook Maps which will auto-update daily and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that as long as the patterns are moving from west to east fairly rapidly. I have also included the experimental Week 3 and 4 Outlook. The Week 3-4 Experimental Outlook updates weekly on Friday. Notice the Week 3-4 Experimental Outlook has fewer levels of probability starting with 50%.
As I view these maps on June 6, it appears that the main feature for the second third of June will be a very slow progression of the warm anomaly from west to east.
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
It is not easy to see how the 8 - 14 Day Outlook might morph into the Week 3 - 4 Experimental Outlook. But the Week 3 -4 forecast is consistent with the monthly forecast issued last Tuesday and since this was issued on Friday three days later, one has to assume that there are good reasons for thinking it will develop this way even if it is a big change from the forecast through June 20. It suggests a big change during the remainder of the month beyond June 20.
Now - Precipitation
Here is the three-month MJJ Precipitation Outlook issued on May 19, 2016:
Here is the Updated Outlook for June Precipitation Issued on May 31, 2016
Below are the current 6 - 10 Day and 8 - 14 Day Precipitation Outlook Maps which will auto-update and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that as long as the patterns are moving from west to east fairly rapidly. I have also included the experimental Week 3 and 4 Outlook. The Week 3-4 Experimental Outlook updates weekly on Fridays. Notice the Week 3-4 Experimental Outlook has fewer levels of probability starting with 50%.
As I view these maps on June 6 (they update each day), it looks like precipitation for the second third of June will be much less widespread with a big change during the period re the Great Lakes Area. .
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
Last week we said. "As of yesterday, it was easy to see how the 8 - 14 Day Outlook might morph into the Week 3 - 4 Experimental Outlook. But it seemed that it might take longer than suggested but on the other hand the above covers 14 days so it does not need to materialize as shown early in the period. But today's 8 -14 Day Outlook does not flow seamlessly into the 3-4 Week Forecast issued last Friday. One or the other or both will likely not work out."
This week, the progression from the 6 - 10 Day and 8 - 14 Day to the Week 3-4 forecast also is hard to understand how it can work out.
Here are excerpts from the NOAA discussion released today June 6, 2016.
6-10 DAY OUTLOOK FOR JUN 12 - 16 2016
THE VARIOUS ENSEMBLE MEANS ARE IN EXCELLENT AGREEMENT ON THE FORECAST CIRCULATION PATTERN FOR THE 6-10 DAY PERIOD. THE FORECAST PATTERN CONSISTS OF ANOMALOUS 500-HPA RIDGING SOUTH OF THE ALEUTIANS AND OVER CENTRAL NORTH AMERICA, WITH ANOMALOUS TROUGHS JUST OFF THE NORTHWEST AND NORTHEAST COASTS OF THE CONUS. RECENT DETERMINISTIC RUNS OF THE GFS AND ECMWF ALSO SUPPORT THIS PATTERN AND AS A RESULT, 30% OF THE OFFICIAL HEIGHT BLEND IS COMPRISED OF THOSE RUNS. THE PATTERN APPEARS FAIRLY STABLE, WITH A WAVE-5 HEMISPHERIC STRUCTURE EVIDENT IN THE 500-HPA HEIGHT FIELD. ADDITIONALLY, THE MANUAL BLEND HINTS AT WEAK BLOCKING STRUCTURES OVER BOTH NORTHWESTERN AND NORTHEASTERN NORTH AMERICA, POTENTIALLY CONTRIBUTING TO THE PERSISTENCE OF THE PATTERN. TELECONNECTIONS UPON FORECAST HEIGHT ANOMALY CENTERS OVER THE NORTH ATLANTIC AND NORTH PACIFIC YIELD REASONABLY COHERENT PATTERNS, THOUGH THEY DIVERGE WITH RESPECT TO THE SOLUTIONS OVER NORTH AMERICA. THIS IS EXPECTED, HOWEVER, GIVEN THE RELATIVE BREAKDOWN IN TELECONNECTIVITY IN BOREAL SUMMER.
THE SURFACE TEMPERATURE OUTLOOK IS DERIVED IN A STRAIGHTFORWARD MANNER RELATIVE TO THE OFFICIAL 500-HPA HEIGHT FORECAST. ABOVE-NORMAL TEMPERATURES ARE FORECAST NEAR THE UPPER-LEVEL RIDGE AXIS, WITH MAXIMUM PROBABILITIES JUST WEST OF THE RIDGE AXIS. ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM THAT REGION IN THE NORTH-CENTRAL PLAINS SOUTHEASTWARD. A SURFACE FRONTAL ZONE IS READILY INFERRED FROM THE AVERAGED MSLP CHARTS FROM THE VARIOUS MODELS, SUPPORTING THE RAPID TRANSITION FROM ABOVE-NORMAL TO BELOW-NORMAL TEMPERATURES HEADING SOUTH TO NORTH ALONG THE ATLANTIC SEABOARD. BELOW-NORMAL TEMPERATURES ARE FAVORED OVER THE PACIFIC NORTHWEST AND NORTHERN PARTS OF THE GREAT BASIN DUE TO BELOW-NORMAL 500-HPA HEIGHTS. WEAK RIDGING IS FAVORED OVER MUCH OF ALASKA, TILTING THE ODDS TOWARD ABOVE-NORMAL TEMPERATURES FOR THE 49TH STATE.
THE PRECIPITATION OUTLOOK IS MUCH LESS CONFIDENT THAN THE TEMPERATURE OUTLOOK, NOT UNUSUAL FOR AN EXTENDED RANGE OUTLOOK. ANOMALOUSLY LOW SURFACE PRESSURE OVER THE NORTHERN ROCKIES AND ASSOCIATED ANOMALOUS WESTERLIES TO THE SOUTH FAVOR BELOW-MEDIAN RAINFALL ACROSS PARTS OF THE HIGH PLAINS. ABOVE-MEDIAN RAINFALL IS FAVORED FOR PARTS OF THE SOUTHEAST EXTENDING THROUGH THE MISSISSIPPI AND OHIO VALLEYS TO THE WESTERN GREAT LAKES. THIS REGION IS LESS INTUITIVE BASED ON THE 500-HPA HEIGHT FORECAST, BUT IS CONSISTENT WITH EXPECTED WARM FRONTAL ACTIVITY AND ANOMALOUS WARM-SECTOR CONVECTION. ABOVE-MEDIAN RAINFALL IS FAVORED OVER THE PACIFIC NORTHWEST, EAST OF THE FORECAST TROUGH AXIS.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO EXCELLENT AGREEMENT AMONG VARIOUS FORECAST TOOLS, OFFSET BY UNCERTAINTY IN THE PRECIPITATION OUTLOOK OVER THE CENTRAL AND EASTERN CONUS.
8-14 DAY OUTLOOK FOR JUN 14 - 20 2016
THE FORECAST CIRCULATION FOR WEEK-2 REMAINS VERY SIMILAR TO THAT FOR THE 6-10 DAY PERIOD, WITH ONLY SOME VERY SLIGHT EASTWARD PROGRESSION OF FORECAST 500-HPA HEIGHT ANOMALIES OVER THE CONUS. AS ONE MIGHT EXPECT, THERE IS SOME DEAMPLIFICATION OF FORECAST HEIGHT ANOMALIES IN WEEK-2 COMPARED WITH THE EARLIER FORECAST PERIOD. THE REASONS BEHIND THE STABILITY OF THE PATTERN WERE DISCUSSED BRIEFLY IN THE 6-10 DAY DISCUSSION, AND SO THE VARIOUS MODEL SOLUTIONS FOR WEEK-2 SEEM REASONABLE.
THERE ARE VERY FEW CHANGES IN THE SURFACE TEMPERATURE OUTLOOK RELATIVE TO THE 6-10 DAY OUTLOOK PERIOD. SOME RELATIVE WARMING IS INDICATED OVER THE NORTHEAST, WHILE COVERAGE OF PROBABILITIES FAVORING BELOW-NORMAL TEMPERATURES IS EXPANDED OVER THE WESTERN CONUS. PROBABILITIES ARE GENERALLY OF LOWER AMPLITUDE THAN IN THE 6-10 DAY PERIOD.
THE PRECIPITATION OUTLOOK IS LIKEWISE SIMILAR TO THAT FOR THE 6-10 DAY PERIOD, ALTHOUGH THE CALIBRATED MODEL GUIDANCE, WHILE STILL SUGGESTING LIMITED SKILL DURING THIS SEASON, CONVERGES ON A DRIER SOLUTION OVER PARTS OF THE GREAT LAKES, NORTHEAST, AND MID-ATLANTIC. ABOVE-MEDIAN PRECIPITATION REMAINS MORE LIKELY OVER PARTS OF THE SOUTHEAST AND NORTHWEST, BASED ON SIMILAR ARGUMENTS AS THOSE PRESENTED IN THE 6-10 DAY FORECAST DISCUSSION.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL SOLUTIONS, OFFSET BY UNCERTAINTY IN THE PRECIPITATION OUTLOOK.
Some might find this analysis interesting as the organization which prepares it looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of this El Nino.
Analogs to the Outlook.
Now let us take a detailed look at the "Analogs" which NOAA provides related to the Outlook.
I prefer the set of analogs that relates 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. But the NOAA system for generating those pre-forecast analogs is not working. They publish a second set of analogs which relates the 6 - 10 Day Outlook to previous occurrences of that weather pattern and similarly for the 8 -14 Day Outlook. So that is what I am using today. It is explained here and here. I do not like my work being doubled so I decided to just use the second set of analogs which corresponds to Day 11 of the Outlook. In my mind that set of analogs tells you nothing (zilch) about the reliability of the forecasts but is helpful in predicting the outlook for the subsequent time periods. That is interesting also. I am also presenting them today in the order that they are provided which means the ones at the top have the highest level of correlation with the forecast and thus are more reliable for forecasting future time periods.
May 25, 1952
May 28, 1957
June 3, 1970
Start of strong La Nina
May 26, 1983
Tail end of strong El Nino
June 8, 1989
Tail end of strong La Nina
June 5, 1996
After a La Nina
May 23, 2001
After a strong La Nina
One thing that jumped out at me right away was the spread among the analogs from May 25 to June 8 which is just under two weeks. That can be a sign that current conditions (as represented in the historical analogs) are fairly consistent for this time of the year. I have not examined the centroid of this distribution carefully but it looks about right i.e. an unscientific analysis yields perhaps May 23 which is seven days before June 6 and these are analogs centered on 3 days and 4 days ago (June 1 or 2) so things seem to be in sync pretty well.
I think NOAA would appreciate it if I said that these analogs are not a substitute for their very sophisticated forecasting software and I am not suggesting that they are. I present them partially for curiosity purposes but also to see how current conditions correlate with medium and low frequency cycles. The medium frequency cycle I track is ENSO and the two low- frequency cycles I track are the PDO and AMO. When I see that forecasts are consistent with the current phases of these cycles (as represented by the analogs), that seems very suggestive to me that our weather is probably fairly easy to forecast. If the analogs are all over the place then I have to wonder if the forecasts are good or if our weather is just not related to these cycles. That certainly can be the case. So I am doing some research here and you are seeing how I look at things. I hope you find it interesting.
There are this time two El Nino Analogs, three ENSO Neutral Analogs and two La Nina Analogs suggesting indecision or that we are now beyond the time of the year where the Phase of ENSO is very important.
The phases of the ocean cycles in the analogs are indecisive with respect to the four McCabe conditions. It is hard for me to say that the overall set of analogs are consistent with the forecast. They do not trigger any useful thoughts to me other than that we are in transition. The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time.
You may have to squint but the drought probabilities are shown on the map and also indicated by the color coding with shades of red indicating higher than 25% of the years are drought years (25% or less of average precipitation for that area) and shades of blue indicating less than 25% of the years are drought years. Thus drought is defined as the condition that occurs 25% of the time and this ties in nicely with each of the four pairs of two phases of the AMO and PDO.
Historical Anomaly Analysis
When I see the same dates showing up often I find it interesting to consult this list.
With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.
J FM 1951
Progress of the Warm Event (Perhaps the title should change and it probably will next week)
Let us start with the SOI.
Below is the Southern Oscillation Index (SOI) reported by Queensland, Australia. The first column is the tentative daily reading, the second is the 30 day moving/running average and the third is the 90 day moving/running average.
90 Day Average
The 30-day average, which is the most widely used measure, as of June 6 is reported at +1.48 which is no longer associated with an El Nino (usually required to be more negative than -8.0 but some consider -6.0 or even -5.0 value good enough). It is now on the La Nina side of Neutral. The 90-day average barely remains in El Nino territory at -6.41. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. The SOI no longer continues to be indicative of an El Nino Event in progress.
The MJO or Madden Julian Oscillation is an important factor in regulating the SOI and Kelvin Waves and other tropical weather characteristics. More information on the MJO can be found here. Here is another good resource.
Low-Level Wind Anomalies
Here are the low-level wind anomalies. We now see light easterly anomalies which are probably an indication of both a lack of MJO activity and the death of the El Nino.
And now the Outgoing Longwave Anomalies which tells us where convection has been taking place.
In the above graphic, the convection zone east of the Dateline has vanished. The non-convection zone to the west of the Dateline has also vanished. A convection zone has started near the Maritime Continent.
I am discontinuing coverage of the Kelvin Waves until they become relevant again. 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.
Current Sub-Surface Conditions. Notice the lag in getting this information posted so the current situation may be a bit different than shown.
And now the pair of graphics that I regularly provide and which as I publish are currently able to be accessed from the NOAA website:
The above pair of graphics showing the current situation has an upper and lower graphic. The bottom graphic shows the absolute values, the upper graphic shows anomalies compared to what one might expect at this time of the year in the various areas both 130E to 90W Longitude and from the surface down to 450 meters.
The top graphic shows surface temperature anomalies. The 0.5 C anomaly now only shows up in very small pockets between 170E and 170W all of which is west of the ONI Measurement Area. Conversely we now see -1C cool anomalies extend out to 140W and -0.5C to 150W with gaps. But the coolest water at the surface does not extend very far north and south of the Equator which is why we are in ENSO Neutral not yet La Nina.
The bottom half of the graphic (Absolute Values which highlights the Thermocline) perhaps is now more useful as we shift our focus and begin tracking the progress of this new Cool Event.
It shows the thermocline between warm and cool water. The 25C Isotherm is now reaching the surface at 140W; 24C at 120W, and the 23C Isotherm at about 90W. The 28C Isotherm has moved west to about 170W. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm is now at about 155W. Clearly the area has moved west as one expects when an El Nino dies. But mostly the warm anomaly has simply vanished.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
We now have to change our focus from tracking the El Nino to tracking the transition to ENSO Neutral and most likely to ENSO La Nina. So I am deleting many of the TAO/TRITON graphics to show how the El Nino developed except one which was close to the maximum. It was not the maximum but it was the one that I froze which was the closest to the maximum that I saved.
And here is the current version of the TAO/TRITON Graphic.
We seem to be having a number of things going on at the same time. The warm anomaly is almost gone, the cool anomaly extends further into the Pacific but the cool anomaly near Ecuador is actually weaker. So the actual pattern may be more nuanced than is being measured by the models.
Location Bar for Nino 3.4 Area Above and Below
The 3.5C through 1.5C anomalies are no longer visible in the ONI Measurement Areas. So the maximum anomalies have declined by two and one half degrees Centigrade. This means that if one is attempting to mentally estimate the daily ONI, an approach would be to make an initial estimate of the midpoint of the 1C to 1.5C anomaly or 1.25C and subtract the reductions from there where the anomaly is less. What I have just described is not exactly the approach I use in my calculation below but it does provide a quick way to get a feel for the current strength of this El Nino. There is actually shading in the TAO/TRITON Graphic that might allow one to try to refine estimates a bit more than the contour lines but I rely on the contour lines. This El Nino is gone I believe. A little later in the article I will do my own calculation and report on the NOAA calculation.
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator I eliminated those rows but I may not have mentioned that a couple of weeks ago when I did that. The two rows just below that break point contribute to ENSO Neutral and after another break the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016 and may not have announced that in the week when I did that. May 23, 2016 is about when I began to focus on the cool phase of ENSO rather than the warm phase.
Comparing Now to May 23, 2016
Subareas of the Anomaly
Degrees of Coverage
May 23, 2016
In Nino 3.4
May 23, 2016
These Rows Show the Extent of ENSO Neutral Impacts on the Equator
0.5C or cooler* Anomaly
0C or cooler Anomaly
These Rows Show the Extent of the La Nina Impacts on the Equator
-0.5C or cooler Anomaly
-1C or cooler Anomaly
-1.5C or cooler Anomaly
* Actually the temperature inside of an isotherm could be warmer or cooler than the isotherm. But during an El Nino it is likely that the temperature will be warmer and during a negative phase of ENSO it is likely to be cooler. What I attempt to do is measure the extent of warm water along the Equator during the positive phase of ENSO and the extent of cool water along the Equator during the negative phase of El Nino. The Neutral Phase presents a challenge. That is why you see larger extents for the warmer isotherms as I am attempting to show the extent of different levels of cooler water. I could reverse the calculation approach and show the increasing extent of less-cool water but that would be meaningless. If one was looking at grade-point averages in education, one could report the number of failed students in different groups closer to passing or further from passing. How you chose to do this would depend on what you wanted to know. In this case, I am trying to show how much water along the Equator is contributing to moving into a La Nina Condition. Alternatively, I could be reporting how much water along the Equator has to cool down in order to achieve La Nina Conditions. It is somewhat like reporting the probability of having a La Nina versus the probability of not having a La Nina. Given that the ENSO Measurement Area is 50 degrees Longitude, for the column labeled "in Nino 3.4" one could subtract that number from 50 and obtain the alternative way of interpreting the data.
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 June 6, in the afternoon working from the June 5 TAO/TRITON report, this is what I calculated.
Calculation of ONI from TAO/TRITON Graphic
A. 170W to 160W
B. 160W to 150W
C. 150W to 140W
D. 140W to 130W
E. 130W to 120W
Total divided by five subregions i.e. the ONI
(+0.2)/5 = 0
(-0.7)/5 = -0.1
My estimate of the daily Nino 3.4 ONI has declined to -0.1. NOAA has reported the weekly ONI to be slightly lower than their report last week at -0.2 which is an ENSO Neutral value but slightly on the La Nina side of the scale. The surface isotherms in the cold part of the ONI Measurement Area are so close to each other that small changes in the ONI are essentially meaningless at this point in time. Nino 4.0 is being reported slightly lower at 0.5 still raising questions about if and how fast the Warm Pool is migrating to the West as it dissipates. Nino 3.0 is being reported the same at -0.3. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported as being +0.0. Notice that Nino 1+2 had gone fairly negative for a short period of time but then bounced back. This La Nina is not coming on like gangbusters. WELCOME TO ENSO NEUTRAL. I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in graphical form but going back a couple of more years can be found here.
ONI Recent History
The official reading for Mar/Apr/May is now reported as 1.1. I have discussed before the mystery of how the Nino 3.4 (ONI) CFSv2 values above get translated into the ERSST.v4 values shown below and if NOAA feels that working with two sets of books is a good way to operate, who am I argue. Many businesses do the same thing. As you can see this El Nino peaked in NDJ and is now declining and depending on what system you use it is either the 2nd or 3rd strongest El Nino since modern records were kept which is considered to be 1950. You could argue for it being #1 based on a week of readings but few are buying that argument. Still #2 or #3 means it is one of the strongest ever based on the way these events are measured. I will be writing more about that soon in a separate article. I believe the measurement system is inadequate re being useful in forecasting Worldwide weather impacts.
The full history of the ONI readings can be found here. The MEI index readings can be found here.
Although I did not discuss the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures which remains relevant.
You can now see that the El Nino is totally gone. The cool water is reaching the surface a bit more but only extends to just beyond 140W which is just a bit more than 40% of the ONI measurement area so it remains ENSO Neutral. There is a bit of a gap around the Galapagos Islands and in other places as well. On the right you see every second week of this graphic historically so you can follow the progression.
SST Surface Anomaly Hovmoeller
Here is another way of looking at it: Unlike the Upper Ocean Heat Anomaly Hovmoeller (I call it the Kelvin Wave Hovmoeller) which takes an average down to 300 meters, this just measures the surface temperature anomaly. It is the surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. A major advantage of the Hovmoeller method of displaying information is that it shows the history so I do not need to show a sequence of snap shots of the conditions at different points in time. Nevertheless this Hovmoeller provides a good way to visually see the evolution of this El Nino and later track its demise.
One can easily see the historical evolution of this El Nino. You can easily see how the intensity peaked in November 2015, declined in December and then declined substantially in late February and continued to decline. At the very bottom of this graphic, which shows the most recent readings, you can see the cool (shades of blue) anomaly developing off the coast of Ecuador. This graphic integrates from 5N to 5S so the cool area just along the Equator is average out with warmer water slightly away from the Equator.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
We have been showing snapshots of 30 Day temperature and precipitation departures over the life of this El Nino. The end date of the 30 day period is shown in the graphic. It is a way of seeing how the impacts of this El Nino have unfolded.
But now that El Nino is over, we are switching our focus and the number of graphics have been reduced to cover the final four months of the El Nino (January through April) and refocus our attention to the current situation which is ENSO Neutral and which most likely will evolve into a La Nina but the strength of that La Nina is still open for debate. Of course after it happens we will know.
Lets take a look at the combined results for the first three months of 2016: January, February and March.
Well that does not look like an El Nino pattern to me but more like a La Nina pattern for precipitation and just plain warm pretty much everywhere which is neither an El Nino nor a La Nina Pattern.
And here is the April (30 day) graphic.
We saw a gradual change in April to a more typical El Nino pattern. The Northwest is dry and the Southwest is a bit wetter than normal. One area along the Southern California western Arizona border had very good El Nino precipitation. The lee side of the Rockies for some reason were wet all the way to Canada and probably into Canada but not shown in this graphic. It certainly has remained dry in Mexico. The Temperature Pattern has been very close to a typical El Nino pattern in April.
And here is what May looked like:
The final days of this El Nino behaved like an El Nino. Quite interesting.
But looking at a longer time period in this 90 days or approximately three months.
Looking at the past three months (March - May), it certainly at least with respect to precipitation was more like a La Nina event than an El Nino event. Except for Texas. Northern California caught up and Northeast Mexico also. But Arizona, New Mexico and Southern California did not participate in this El Nino in 2016 although they did in the Fall of 2015. Variability is the norm
And now we start to track June and for that purpose I am repeating the prior 30 day period to make it easier to make comparisons.
And here is the new report which adds one week and removes the first week of the 30 Day Period.
The biggest change seems to be in temperature. A lot cooler. The precipitation pattern has not changed very much. The East Coast has been much dryer.
Re the above article the difference between GWP and GTP may be important. A good discussion can be found here
From that discussion:
GWP is defined as the increase in radiative forcing (RF) of the emission of one kilogram of the subject gas, relative to the increase in RF from release of one kilogram of carbon dioxide at the same time. Changes in radiative forcing drive climate change but the relationship is not simple, there are many environmental interactions (including feedbacks), and the calculation of global temperature change resulting from changes in radiative forcing requires complex mathematical models.
Because there are many processes that remove carbon dioxide from the atmosphere, some of which have environmental lifetimes in excess of 10,000 years, GWP is integrated over a specific time horizon and the Kyoto Protocol uses the 100 year values.
Compared to GWP, the Global Temperature change Potential (GTP) goes one step further down the cause -effect chain and is defined as the change in global mean surface temperature at a chosen point in time in response to an emission pulse — relative to that of carbon dioxide. While GWP is integrated in time, GTP is an end-point metric which is based on temperature change for a selected year. Thus GWP integrates the effects up to a chosen time horizon, giving equal weight to all times up to the horizon and zero weight thereafter, but GTP gives the temperature just for one chosen year with no weight on years before or after.
By accounting for the climate sensitivity and the exchange of heat between the atmosphere and the ocean, the GTP includes physical processes that the GWP does not. However, this makes it sensitive to atmospheric modeling assumptions about the climate sensitivity and heat-uptake by the ocean. There are significant uncertainties related to both GWP and GTP and the relative uncertainties are much larger for GTP; there are additional contributions from it being further down the driver-response-impact chain and from the inclusion of climate response
Here is part of the table from this analysis.
As you can see the big difference relates to methane because the GTP better takes into account the shorter half-life of Methane. On the other hand it shows that nitrous oxide is not reduced in importance by the half life because the half life for nitrous oxide is quite long as compared to methane. This suggests that there is going to be pressure to reduce the use of nitrogen based fertilizers.
One can find this information in many places including directly in the IPCC AR5 WGI, but this discussion from the European Fluorocarbons Technical Committee is easy to follow so I have used that for this discussion.
View from Australia
Below is the discussion just released. Notice the discussion re forecasting a La Nina for next winter.
Tropical Pacific Ocean continues its cooling trend
The tropical Pacific Ocean remains in a neutral El Niño–Southern Oscillation (ENSO) state—neither El Niño nor La Niña. Sea surface temperatures across the tropical Pacific have been at neutral levels for the past four weeks, with the central Pacific Ocean having recently cooled to levels close to the long-term average. Temperatures below the tropical Pacific Ocean surface are much cooler than average. In the atmosphere, indicators such as the trade winds, cloudiness near the Date Line, and the Southern Oscillation Index (SOI) are at neutral levels. The latest monthly SOI (+2.8 for May 2016) is the highest value since May 2014.
The Bureau's ENSO Outlook remains at La Niña WATCH. This suggests around a 50% likelihood of La Niña forming later in 2016. International climate models indicate the tropical Pacific Ocean will continue to cool, with six of eight models suggesting La Niña is likely to form during the austral winter (June–August). However, individual model outlooks show a large spread between neutral and La Niña scenarios. At least one model suggests La Niña conditions may be short lived, returning to neutral by October.
Typically during La Niña, winter-spring rainfall is above average over northern, central and eastern Australia.
Warm sea surface temperatures (SSTs) continue to cover much of the Indian Ocean. Recent values of the Indian Ocean Dipole (IOD) index have dipped below the negative IOD threshold of -0.4. However it will take several more weeks of similar temperatures before a negative IOD event is considered established. Model outlooks suggest a negative IOD event may form during the austral winter. A negative IOD typically brings increased winter-spring rainfall to southern Australia.
IOD (Indian Ocean Dipole)
The graphic comes with only a very short discussion and here is that discussion:
Indian Ocean Dipole outlooks
The Indian Ocean Dipole (IOD) is neutral. However, international models monitored by the Bureau indicate a negative IOD event may develop in the coming months. The weekly Dipole Mode Index value to 5 June is -0.65 °C, dipping to negative IOD levels for the second consecutive week. However, it would take several more weeks of similar IOD index values before a negative IOD would be considered established.
Negative IOD events are more likely to occur during La Niña. Hence, if La Nina does develop, this will increase the likelihood of a negative IOD event developing.
More broadly, sea surface temperatures (SSTs) are significantly warmer than average across much of the Indian Ocean. This warmth will likely provide more available moisture to weather systems as they cross the Australian continent.
Information on the impact of a negative IOD on Australia can be found here.
Putting it all Together.
This El Nino has ended in terms of current satisfying the criteria. It is possible that officially it may not be declared dead until the end of June because the Mar - Apr - May value of the ONI at 1.1 satisfies the 0.5 cutoff and it is possible that the Apr - May - Jun average ONI may still meet the criteria even though the daily and weekly values no longer meet the criteria.
We are now speculating on the winter of 2016/2017 which now according to most of the models seems likely to be a La Nina or Neutral with a La Nina bias.
The below is the CPC/IRI forecast issued on May 12, 2016. It is important to remember that the first report in each month is based on a survey of meteorologists and the second report later in the month is based on the analysis of the forecast models. It is a minor difference but a difference.
And one week later we have the second report recognizing that last week was based on a survey and this week is based on model means.
The new forecast shows increased confidence that next winter will be a La Nina winter. In fact the forecast is for El Nino to be over (switching to ENSO Neutral) by the May - Jun - Jul three-month period which means June. So one does not have much confidence that June will be much impacted by El Nino although El Nino impacts lag the demise of an El Nino.
We have suggested that it is possible that some of the models and in particular NOAA's model will be wrong about how fast the Eastern Pacific Warm Pool moves back towards its La Nina location and it may well be that next winter will be more of a Neutral year or even have some characteristics of an El Nino Modoki and thus be wetter than a typical year as the Warm Pool may still be more in the Central Pacific than shifted all the way west to its La Nina position.
We have reason to believe that the models may not be taking into account all factors such as the Equatorial ocean currents and that this El Nino may not transition to a La Nina quite as rapidly as some of the models, Such as the below NOAA model, are predicting.
The mean of the NOAA model was until recently forecasting a fairly strong La Nina for next winter. The model is gradually shifting to a weak La Nina Forecast. Notice the blue members of the ensemble forecast which are the more recent ones. You can see the same thing in the Australian POAMA model and this topic is discussed quite well in the NOAA Discussion that was released with their Seasonal Update and which was discussed here last week.
I now have the May 1 Run of the JAMSTEC Model.
It is forecasting a moderate La Nina for next winter and continuing as a La Nina or Neutral with a La Nina tendency for the subsequent winter. That could be the signal for the Pacific Climate Shift.
Here is a repeat of the Australian Model for comparison purposes.
It does not extrapolate as far into the future as the JAMSTEC model. It is somewhat similar to the NOAA model but seems to be less certain that we will have a La Nina rather then ENSO Neutral with a La Nina tendency.
I realize it is impolite but our way of identifying the phases of ENSO seems fairly primitive to me. The Warm Pool has been depleted so there is no reinforcing warm water to be sent east by Kelvin Waves. So it is not really possible to have another El Nino winter. Thus it is fairly certain that the Eastern Pacific SST's will be cooler than climatology. Does this in and of itself create a La Nina? If the only criteria is the ONI, it will record as a La Nina or close to it. One does not need fancy computer models to know that will be the case. But will we have the La Nina Walker Circulation. Without that, you do not have the impacts associated with a La Nina. So you would have a La Nina in name only.
Forecasting Beyond Five Years.
So in terms of long-term forecasting, none of this is very difficult to figure out actually if you are looking at say a five-year or longer forecast. The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS. It includes decade by decade predictions through 2050. Predicting a particular year is far harder.
The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. It may require one more La Nina. But it appears that "McCabe Condition A" is coming soon. Right now (in most weeks) we seem to have a blend of McCabe Conditions A and C which are opposites which may explain some of the forecasting difficult. The AMO is pretty much neutral at this point so it may need to become a bit more negative for the McCabe A pattern to become established. That seems to be slow to happen so I am thinking we need at least a couple more years for that to happen..maybe as many as five.
TABLE OF CONTENTS FOR PART II OF THIS REPORT The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page II where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
TABLE OF CONTENTS FOR PART III OF THIS REPORT - GLOBAL WARMING WHICH SOME CALL CLIMATE CHANGE. The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page III where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
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