If you like it hot, the 15 Month Forecast will be to your liking. For CONUS, unlike most of the World, La Nina means dry. But the dry conditions will pretty much hold off until winter so this is not a forecast for a major agriculture problem this summer.
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.
Monsoon Update: From Sunday Phoenix NWS
Although moisture levels will be decent (around average for this time of year) through Tuesday, convective activity will likely be limited by rather warm air aloft (500mb temps in the -5c to -6c range), the fact that most available moisture will be at 600mb or higher, and very light winds through the entire column. The impact of the warm mid-level temps, lack of moisture below 600mb, and light winds aloft can be seen in the latest NCEP sref 3h-MUCAPE and 3h- MLCAPE plumes, with the mean values remaining mostly aob 500 j/kg across the Phoenix area through Thursday. Thus, it will be hard to trigger any convective activity across the lower deserts, unless significant lift can be provided by strong outflows from storms over the higher terrain, or from weak mid-level disturbances, which are hard to forecast/time. Thus, have currently gone with mostly slight- chance pops across the lower deserts through Tuesday, with even lower pops on Wednesday and Thursday, as somewhat drier air moves back into the region. On the other hand, chances for locally gusty winds/blowing dust appear to be better, as outflows from storms over the higher terrain of south-central Arizona and Southeast Arizona (which are much more likely to develop than over our lower deserts) move into the lower elevations each afternoon/evening. Along with the low-end pops, have kept highs above normal through Thursday, with many Lower Desert locations likely once again reaching/exceeding 110 degrees on Wed/Thu as drier air/warmer air aloft moves back into the region.
I am not sure it is a factor in this case but moisture coming into Mexico from the Gulf of Mexico has to clear a mountain range so it comes in at a higher altitude than moisture coming in from the Gulf of California especially with regards to Arizona. It may be less of a factor for New Mexico as right now the moisture seems to be coming up the west side of Mexico and may not even be impacted by the Sierra Madre Occidental let alone the Sierra Madre Oriental. .
I thought this was interesting from today:
Friday through Sunday... although we are still expecting a uptick in the monsoon activity during this period, as easterly winds aloft increase and moisture levels rise further, there now appears to be a drying trends showing up in the latest model suites, especially on Friday. This is likely due to the fact that the global models seem to be having a tendency so far this Summer to weaken the upper-level ridging that has persisted over our region too much, and also pushing the Main Ridge axis too far to our north. This results in the airmass ending up drier and more stable, resulting in less convective activity.
It is important to remember that forecasting models have biases. The local forecasters become familiar with the biases as they impact their local area and adjust their forecasts accordingly. The human element remains important in weather forecasting.
Updated Seasonal Outlook
NOAA issued their updated Seasonal Outlook on the third Thursday of the month i.e. July 21, 2016 as is their normal schedule. Let's take a look.
Prior Temperature Outlook for ASO 2016
New Temperature Outlook for ASO 2016
The change is a little difficult to describe. It is basically a reduction in the size of the areas which have the highest probability of temperatures which are warmer than climatology. This involves mostly California, Nevada and Oregon in the West and from the Northern Mississippi east towards but not quite reaching the East Coast.
Prior Precipitation Outlook for ASO 2016
New Precipitation Outlook for ASO 2016
There is not much change. There were four anomalies shown last month for the next three-month period. Now (and it is a month later) the four anomalies have moved around just a bit and a fifth anomaly now appears centered on Mississippi and Alabama and parts of surrounding states.
Now let us focus on the long-term situation.
Prior 14 Month Temperature Outlook: Aug 2016 - Sep 2017
New 14 Month Temperature Outlook: Sep 2016 - Oct 2017
To compare maps from one release to another one needs to remember that the new release drops one three-month period and adds a later one. So to make the comparisons one has to shift the new maps to the right one position and that makes the map on the right drop down to become the left-most map in the next level. I do not have a computer software tool for doing that for you so you have to do it mentally. When I do the comparison I print them out and put them side by side and number the same three-month maps 1, 2, 3,.....,11 in both sets of maps to make it easier for me to easily compare the same three-month period in the new with the previous forecast. One uses the same procedure to compare the precipitation maps. Based on this procedure, I conclude that:
The changes are not very significant and basically represent for the early periods a little more precision in the probabilities highlighting where the most extreme temperatures are likely to occur. Precision does not imply accuracy as that will be judged after the fact by the temperatures that were actually recorded. The only major change is at the end in Jul - Aug - Sep 2007 with the EC area which in the prior Outlook was shown extending from Kansas and Nebraska to the East Coast and now is shown as being in the Upper Mississippi Valley. It actually begins to show up in the Jun - Jul - Aug period. JAS 2017 is a long way out and that part of the forecast is likely to change over time.
Prior 14 Month Precipitation Outlook: Aug 2016 - Sep 2017
New 14 Month Precipitation Outlook: Sep 2016 - Oct 2017
If you want larger versions of each map (temperature and precipitation) you can find them here. And each of those maps can be clicked on to further enlarge them.
The precipitation changes are fairly minor. The first real change I see is Apr - May - Jun 2017 with the addition of a dry anomaly for the Western Great Lakes and Jun- Jul - Aug 2017 with the Northwest Dry anomaly added. In both these cases it is the moving ahead the time when the anomaly is expected to occur by one three-month period earlier than before which generally means it is forecast to show up one month earlier. So that is not much of a change.
Excerpts (significantly reorganized and with some of the redundancy removed) from the Discussion released by NOAA on July 21, 2016. Headings that are "Initial Cap" only rather than all caps were added by the Author of this Weekly Report for clarity. Also we have organized the NOAA Discussion to show the Atmospheric Conditions, Current Month, the Three or Four-month period, and then 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 [Editor's Note: and Prognosis for the Development of a La Nina]
PACIFIC SST ANOMALIES ARE SLIGHTLY NEGATIVE CLOSE TO THE EQUATOR FROM THE DATE LINE EASTWARD TO THE SOUTH AMERICA COAST, WITH ABOVE-NORMAL SSTS PERSISTING IN OTHER REGIONS ACROSS THE TROPICAL PACIFIC INCLUDING THE WESTERN TROPICAL PACIFIC. THOUGH THE MOST RECENT THREE-MONTH AVERAGE NINO 3.4 SST ANOMALY IS +0.7 DEGREES C FOR AMJ, WITH THE RECENT EL NINO EVENT NOW TRANSITIONED TO ENSO-NEUTRAL, THE LATEST WEEKLY NINO 3.4 ANOMALY HAS NOW DECREASED TO -0.6 DEGREE C. A LARGE RESERVOIR OF ANOMALOUSLY COLD SUBSURFACE WATERS EXTENDS TO MORE THAN 150 METERS BELOW THE SURFACE, WITH THE LARGEST NEGATIVE ANOMALIES GREATER THAN 2 DEGREES C TO A DEPTH GREATER THAN 100 METERS BELOW THE SURFACE FROM 130 TO 180 DEGREES W. POSITIVE OLR ANOMALIES (SUPPRESSED CONVECTION) WERE PRESENT OVER THE EQUATORIAL PACIFIC, WHILE NEGATIVE OLR ANOMALIES (ENHANCED CONVECTION) IS PRESENT OVER INDONESIA, DURING THE PAST 30 DAYS. LOW-LEVEL, EASTERLY TRADE WINDS AT THE 850-HPA LEVEL HAVE BEEN NEAR AVERAGE DURING THE PAST MONTH, WHILE THE UPPER-LEVEL, 200-HPA WINDS ARE ANOMALOUSLY EASTERLY OVER A SMALL REGION OF THE EASTERN EQUATORIAL PACIFIC. ANOMALOUS INTEGRATED EQUATORIAL PACIFIC OCEAN HEAT CONTENT FROM THE SURFACE TO 300 METERS DEPTH HAS BEEN PERSISTENTLY NEGATIVE FOR THE LAST SEVERAL MONTHS. NEGATIVE OCEAN HEAT CONTENT ANOMALIES INCREASE THE CHANCE OF DEVELOPMENT OF LA NINA CONDITIONS DURING THE REMAINDER OF 2016. THE EXTRATROPICAL PACIFIC OCEAN REMAINS CONSISTENT WITH THE POSITIVE PHASE OF THE PACIFIC DECADAL OSCILLATION WITH ABOVE AVERAGE SSTS IN THE NORTH PACIFIC, TO THE SOUTH OF ALASKA, AND ALONG THE WEST COAST OF NORTH AMERICA. POSITIVE SST ANOMALIES PERSIST IN THE WESTERN ATLANTIC NEAR THE U.S. EAST COAST. ABOVE-AVERAGE SSTS ARE PRESENT ACROSS THE TROPICAL ATLANTIC INCLUDING THE GULF OF MEXICO.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE CPC SST CONSOLIDATION PREDICTS A SLIGHTLY LOWER PROBABILITY, COMPARED TO LAST MONTH, OF AT LEAST WEAK LA NINA CONDITIONS BEGINNING IN ASO AND INDICATES A PEAK AMPLITUDE BELOW -0.5 DEGREES C IN DJF 2016-17. PREDICTIONS FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) MEMBERS INDICATE A RANGE OF NINO 3.4 ANOMALIES, WITH THE ENSEMBLE MEAN NEAR -0.5 C FROM AUGUST THROUGH DECEMBER. THE CPC/IRI CONSENSUS FORECAST INDICATES THAT THERE IS ABOUT A 50 PERCENT LIKELIHOOD OF DEVELOPMENT OF LA NINA BY ASO 2016, WITH THE CHANCES OF LA NINA ABOVE 60 PERCENT BY WINTER.
30-DAY OUTLOOK DISCUSSION FOR AUGUST 2016
DURING THE PAST WEEK, THE WHEELER-HENDON RMM INDEX INDICATED SOME STRENGTHENING OF THE MADDEN-JULIAN OSCILLATION (MJO) SIGNAL OVER AFRICA. DURING THE NEXT TWO WEEKS, THE GFS ENSEMBLE INDICATES EASTWARD PROPAGATION AND GRADUAL WEAKENING OF THE MJO SIGNAL OVER THE INDIAN OCEAN. NEITHER THE CURRENT NEUTRAL PHASE OF ENSO NOR THE MJO SIGNAL ARE EXPECTED TO PROVIDE MUCH GUIDANCE IN THE FORMULATION OF THE MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR AUGUST 2016. THEREFORE, THE OUTLOOKS RELY PRIMARILY UPON THE LATEST DYNAMICAL MODEL GUIDANCE FROM THE NCEP CLIMATE FORECAST SYSTEM (CFS), THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME), THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), AND MODEL GUIDANCE FOR WEEKS 3 AND 4 FROM THE CFS, JAPAN METEOROLOGICAL AGENCY (JMA), AND ECMWF, AS WELL AS CLIMATE RELATIONSHIPS TO CURRENT SOIL MOISTURE CONDITIONS.
DYNAMICAL MODELS INDICATE INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE CONTIGUOUS U.S. AND ALASKA, WITH THE EXCEPTION OF PARTS OF THE NORTHERN AND CENTRAL PLAINS, UPPER MISSISSIPPI VALLEY, MOST OF THE GREAT LAKES REGION, AND PORTIONS OF THE SOUTHERN PLAINS, WHERE A NUMBER OF MODELS PREDICT EITHER THE LOWER OR MIDDLE TERCILE FOR TEMPERATURE. CURRENT SOIL MOISTURE CONDITIONS IN THESE AREAS GENERALLY RANK ABOVE THE 80TH PERCENTILE, AND CPC'S EXPERIMENTAL WEEK 3 AND 4 FORECASTS FAVOR EQUAL CHANCES (EC) OF BELOW AND ABOVE-NORMAL TEMPERATURES FOR MUCH OF THIS REGION, AND REDUCED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE SOUTHERN PLAINS. BASED ON SOME OF THE DYNAMICAL MODELS, CURRENT SOIL MOISTURE CONDITIONS, AND THE EXPERIMENTAL WEEK 3 AND 4 FORECASTS, EC IS CONSIDERED THE MOST LIKELY OPTION. HOWEVER, AS NOTED EARLIER, MUCH OF THE CONTIGUOUS U.S. AND ALASKA ARE FORECAST TO EXPERIENCE ABOVE-NORMAL TEMPERATURES DURING AUGUST. THIS IS CONSISTENT WITH MOST DYNAMICAL MODEL PREDICTIONS AND STATISTICAL TOOLS, WHICH INCORPORATE THE DECADAL CLIMATE WARMING TRENDS, AS WELL AS THE POTENTIAL INFLUENCE OF SEA SURFACE TEMPERATURE (SST) PATTERNS. IN ALASKA, PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE GREATEST IN THE FAR SOUTH, DUE IN PART TO SSTS IN EXCESS OF 1.5-2.0 DEGREES C.
CALIBRATED PROBABILITIES FROM THE CONSENSUS OF THE NMME DYNAMICAL MODELS, AND THE CFS, GFDL, NASA, AND CMC (CANADIAN) MODELS INDICATE AN INCREASED CHANCE OF ABOVE-MEDIAN PRECIPITATION FOR PORTIONS OF THE NORTHERN AND CENTRAL PLAINS, AND THE UPPER AND MIDDLE MISSISSIPPI VALLEY. THESE SAME TOOLS, IN ADDITION TO CPC'S WEEK 3 AND 4 FORECASTS, LEND SUPPORT FOR ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR PORTIONS OF THE DESERT SOUTHWEST. A CONSENSUS OF DYNAMICAL MODEL FORECASTS INDICATES AN INCREASED CHANCE OF ABOVE-MEDIAN PRECIPITATION FOR SOUTHEASTERN ALASKA AND THE PANHANDLE REGION. BELOW-MEDIAN PRECIPITATION IS FAVORED ACROSS THE INTERIOR NORTHWEST, THE CENTRAL GULF COAST REGION, AND MUCH OF THE GREAT LAKES REGION, AND IS SUPPORTED PRIMARILY BY THE IMME AND THE LATEST RUNS OF THE CFS.
Three-Month Outlook (August - September - October and maybe even November)
PRIMARILY IN THE FIRST SEVERAL SEASONS, THERE ARE SMALL CHANGES TO THE TEMPERATURE OUTLOOKS THIS MONTH RELATIVE TO THOSE RELEASED THE PREVIOUS MONTH, IN PART RELATED TO A SMALL DECREASE IN THE LIKELIHOOD OF LA NINA DEVELOPING. ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS ALL OF THE FORECAST DOMAIN FOR THE ASO OUTLOOK, CONSISTENT WITH BOTH THE DYNAMICAL MODEL GUIDANCE FROM THE NMME AND THE STATISTICAL GUIDANCE BASED ON THE PREDICTED NINO 3.4 INDEX AND DECADAL TIMESCALE CLIMATE TRENDS. LOWER PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE GREAT PLAINS, IN PART DUE TO HIGH SOIL MOISTURE CONDITIONS, AND WEST OF THE ROCKY MOUNTAINS SOMEWHAT RELATED TO DIMINISHED ABOVE-NORMAL SSTS OFF OF THE WEST COAST. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES DURING ASO ARE GREATEST ACROSS THE ALEUTIAN ISLANDS, SOUTHERN ALASKA, AND THE ALASKA PANHANDLE WHERE SSTS ARE WELL ABOVE NORMAL.
THE ASO 2016 TEMPERATURE OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS THE ENTIRE FORECAST DOMAIN, ALTHOUGH PROBABILITIES ARE TEMPERED IN AREAS TO THE WEST OF THE ROCKY MOUNTAINS, ACROSS THE GREAT PLAINS, AND THROUGH THE OHIO VALLEY. THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS SOUTHERN ALASKA, THE ALEUTIAN ISLANDS, AND THE ALASKA PANHANDLE.
THE PRECIPITATION OUTLOOKS ARE BASED ON THE LATEST MODEL GUIDANCE FROM THE NMME THROUGH SON 2016. FOR ASO, THE PROBABILITIES FOR BELOW-MEDIAN PRECIPITATION ARE INCREASED FOR MUCH OF THE INTERIOR NORTHWEST AS INDICATED BY BOTH THE NMME DYNAMICAL MODEL GUIDANCE AND STATISTICAL TOOLS. INCREASED CHANCES FOR ABOVE-MEDIAN PRECIPITATION ARE INDICATED FOR THE NORTHERN PLAINS FOR ASO AND SON 2016, BASED ON CALIBRATED GUIDANCE FROM THE NMME. A POTENTIAL INFLUENCE OF THE DEVELOPING LA NINA AND STATISTICAL FORECAST GUIDANCE SUPPORT A SLIGHT INCREASE IN THE PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION AMOUNTS ALONG THE GULF COAST OF TEXAS AND ACROSS FLORIDA DURING JAS AND ASO 2016. THE CALIBRATED NMME PROBABILITIES AND STATISTICAL PRECIPITATION GUIDANCE ARE IN DISAGREEMENT ON THE MONSOON PRECIPITATION FORECAST ACROSS THE SOUTHWEST DURING ASO AND SON 2016. THEREFORE, EQUAL CHANCES OF BELOW, NEAR, OR ABOVE-MEDIAN PRECIPITATION IS INDICATED FOR THE SOUTHWEST DURING THIS TIME PERIOD. MOST DYNAMICAL MODEL GUIDANCE SUPPORTS ENHANCED PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION FOR SOUTHEASTERN ALASKA AND THE ALASKA PANHANDLE FOR ASO AND SON 2016.
THE ASO 2016 PRECIPITATION OUTLOOK INDICATES AN INCREASED CHANCE OF ABOVE-MEDIAN PRECIPITATION FOR SOUTHEASTERN REGIONS OF ALASKA, THE ALASKA PANHANDLE, THE NORTHERN PLAINS, AND SMALL AREAS OF SOUTHERN TEXAS AND THE SOUTHERN FLORIDA PENINSULA. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY IN THE INTERIOR NORTHWEST AND ALSO IN THE INTERIOR SOUTHEAST OF THE CONUS.
Fifteen Month DISCUSSION OF OUTLOOKS - ASO 2016 TO ASO 2017 [Editor's Note: Focusing on the latter part of the 15 month period]
Transition to La Nina.
DURING AUTUMN AND INTO WINTER 2016-17, THE TEMPERATURE AND PRECIPITATION OUTLOOKS INDICATE THE MOST LIKELY IMPACTS OF LA NINA. BY WINTER BELOW-NORMAL TEMPERATURES ARE SLIGHTLY FAVORED OVER THE NORTHERN PLAINS, EXPANDING TO INCLUDE PARTS OF THE PACIFIC NORTHWEST IN LATER SEASONS. ABOVE-NORMAL TEMPERATURES ARE LIKELY TO PERSIST ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS 48 STATES DURING THE AUTUMN AND WINTER, WITH INCREASED CHANCES FOR BELOW-MEDIAN PRECIPITATION EXPECTED TO EXPAND ACROSS THIS SAME REGION DURING THESE SEASONS.
THE PREDICTED TRANSITION TO LA NINA CONDITIONS AND THE MOST LIKELY IMPACTS ARE CONSIDERED FOR THE SEASONAL OUTLOOKS PRIMARILY BEGINNING IN OND 2016 THROUGH THE WINTER SEASONS INTO EARLY SPRING OF 2017. IN ADDITION TO DYNAMICAL MODEL GUIDANCE FROM THE NMME, INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS), A SST-BASED CONSTRUCTED ANALOGUE AND ADDITIONAL STATISTICAL TOOLS, INCLUDING REGRESSION-BASED IMPACTS OF ENSO AND DECADAL TIMESCALE TRENDS, ARE CONSIDERED IN THE OUTLOOKS.
BEGINNING IN OND, EQUAL CHANCES FOR BELOW, NEAR, OR ABOVE-NORMAL TEMPERATURES ARE PREDICTED FOR THE NORTH-CENTRAL CONUS, WITH THIS AREA EXPANDING IN AUTUMN AND WINTER AS A RESULT OF THE POTENTIAL IMPACTS OF LA NINA. ALTHOUGH REGRESSION FORECASTS BASED ON THE PREDICTED LA NINA FAVOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTH-CENTRAL CONUS BEGINNING IN NDJ, A CONSISTENT SIGNAL IN THE DYNAMICAL MODELS FOR ABOVE-NORMAL TEMPERATURES IN THIS REGION CONTINUES THROUGH DJF 2016-17, WITH THE SAME SIGNAL ACROSS MOST OF THE CONUS. DURING DJF 2016-17, A SLIGHT INCREASE IN THE PROBABILITIES FOR BELOW-NORMAL TEMPERATURES IS INDICATED FOR THE NORTHERN PLAINS. THIS AREA OF INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES EXPANDS TO INCLUDE THE PACIFIC NORTHWEST AND INCREASES IN PROBABILITY DURING JFM 2017, CONSISTENT WITH THE CPC SST CONSOLIDATION FORECAST OF LA NINA. ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHERN TIER OF THE CONUS THROUGH THE UPCOMING WINTER SEASON, PRIMARILY RELATED TO THE MOST PROBABLE LA NINA IMPACTS. FOR ALASKA, AN EXPECTED REDUCTION IN SEA ICE RELATIVE TO THE LONG TERM AVERAGE CONDITIONS ELEVATES CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS NORTHERN AND WESTERN ALASKA DURING AUTUMN. AT LONGER LEAD TIMES BEYOND MAM 2017, THE TEMPERATURE OUTLOOK ACROSS THE FORECAST DOMAIN IS BASED ON DECADAL CLIMATE TRENDS AND THE TEMPERATURE AND PRECIPITATION CONSOLIDATION FORECAST OF AVAILABLE STATISTICAL TOOLS.
BEGINNING IN AUTUMN AND THROUGH THE WINTER OF 2016-17, THE MOST LIKELY IMPACTS OF A PREDICTED LA NINA ARE THE PRIMARY REASON FOR AREAS OF INCREASED PROBABILITIES OF ABOVE OR BELOW-MEDIAN PRECIPITATION ACROSS THE FORECAST DOMAIN. THE FORECAST PROBABILITIES HAVE NOT CHANGED SIGNIFICANTLY FOR THESE SEASONS FROM THE FORECAST MADE LAST MONTH, SINCE LA NINA CONTINUES TO BE THE MOST LIKELY INFLUENCE ON SEASONAL TEMPERATURE AND PRECIPITATION PATTERNS.
AT LONGER LEADS, FROM AMJ THROUGH ASO 2017, AN INCREASE IN THE PROBABILITY OF ABOVE-MEDIAN PRECIPITATION FOR NORTHERN AREAS OF THE GREAT LAKES REGION AND PARTS OF THE NORTHEAST IS RELATED TO DECADAL CLIMATE TRENDS, AS INDICATED BY THE CONSOLIDATION OF STATISTICAL FORECAST TOOLS, AS IS THE INCREASED LIKELIHOOD OF BELOW-MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST FOR JJA AND JAS 2017.
It would be helpful if NOAA divided "Decadal Trends" in the impact of the AMO and PDO and the impact of the secular trend of Global Warming. As it is. the reader is left with trying to figure out what NOAA is saying when they discuss Decadal Trends.
Sometimes it is useful to compare the present month outlook to the three-month outlook
One can mentally subtract the August Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely September and October 2016. When I do that, I deduce that:
Texas and an expanded area from North Central states extending east through the Great Lakes Region will need to have higher probabilities of being a warm anomaly for the three-month average to work out. When we looked at this a month ago, the whole area from Wisconsin down to Texas needed to have higher probabilities of being a warm anomaly for the three-month average to work out. It seems that now the area between the two EC areas for August has filled in with a warm anomaly. Remember that when I refer to maps from the last Seasonal Update, we are one month later so the three-month period now is the 2nd and 3rd month from the prior Seasonal Update and one month which was not included before but would have been the 4th month. With respect to precipitation, the Southwest Monsoon is not shown in the Three-Month Outlook suggesting that Arizona may be drier than EC in September and October. This is addressed in the NOAA Discussion and NOAA is not highly confident re their Southwest Monsoon forecast. In August, there is a dry anomaly shown for the Upper Great Lakes which is not in the three-month average and there are wet anomalies shown for South Florida and extreme Southern Texas in the three-month forecast which are not shown in August. So those anomalies in the Three-month average may have to be a bit more probable in September and October to have the math work out and the anomaly shown in the August Outlook but not in the Three-Month may require the opposite anomaly in September and October to make the average work out.
Of all of these differences between August and the three-month average, the main difference is a suggestion that the Southwest Monsoon may not be intense in September.
Let's Now Focus on the Current (Right Now to 5 Days Out) Weather Situation.
A more complete version of this report with daily forecasts is available In Part II. This is a summary of that more extensive report. Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks will take you directly to that set of information but it may take a few seconds for your browser to go through the two-step process of getting to Page II and then moving to the Section within Page II that is specified by this link.
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.
B. On rare occasions, source sites for graphics go down and the graphic does not appear in the article and you probably see white space. If you experience such an event and that graphic is important to your understanding of the report, please return later to view my weather and climate column. Sometimes the "outage" is only for several minutes, but often the duration can be a number of hours or even one or more days. We feel that this inconvenience is preferable to looking at "frozen" weather map images that do not update since I write the article on Monday evenings and you probably do not read it until Tuesday and perhaps later in the week. So I want you to have the advantage of seeing the most up-to-date graphics. If the source is down, the white space is the price paid for most of the time being able to see the latest available graphics.
First, here is a national animation of weather fronts and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. Beyond 60 hours, additional maps are available at 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.
Here is a World Precipitation Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the map only so to see it you have to click where I said "here". You can adjust the settings to show Temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool!
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 now see the Four Corners High forecast on Day 7 to be in a different place each time I look at this map which is based on one interpretation of the models. If the Four Corners High remains this far east, that would enhance the Monsoon rather than block it. If it were further north, it would make it easier for easterly wave moisture to undercut the Ridge. There is also shown an East Coast Trough and a West Coast Trough. The troughs and the location of the Four Corners High (Subtropical Ridge) pretty much determine the Temperature and Precipitation Pattern for CONUS during the summer. One graphic says a lot. Some forecasts show the Four Corners High migrating north into the Great Basin and others show it heading east as it is shown right now. So there is not a lot of confidence in how this will play out. Earlier Sunday, the forecast showed the Four Corners High in NE Arizona. Last evening it was forecast to (in seven days) be in Southwest Colorado. Today at 4 pm it was forecast in seven days to be in Northwest New Mexico. Now at 9pm my time it is shown to be in seven days on the Oklahoma/Missouri Border. The forecasters did say it would wobble a bit. Thus one concludes that the impacts may vary throughout the week. That is partly why we have a "low-grade Monsoon" this summer. The opportunities for moist air from the Gulf of California, Gulf of Mexico and the Mexican Plateau to cross the border into CONUS are not consistently there. This is not unusual as the Monsoon operates with bursts but this summer the bursts are short and far between.
If one draws or imagines a one-inch in radius circle overlain on the Four Corners High with an arrow showing the wind pattern is clockwise (anticyclone), one can imagine where moisture might be being drawling into the edge of the High Pressure System.
The MJO has had significant impacts this winter but the impact on August is not likely to be very noticeable other than alternatively accelerating and decelerating the development of the La Nina. It is forecast to be more significant in September.
The above graphic shows the movement of tropical storms towards Asia in the lower latitudes and the return of storms towards CONUS in the mid-latitudes. It is a little bit Helter-Skelter right now.
As I am looking at the above graphic Monday evening July 25, the Monsoonal Moisture Boundary (MMB) is crossing the Arizona and Western New Mexico border. Tropical Storm Frank (now a hurricane) may have contributed some of the moisture that is temporarily boosting the Monsoon. I am not real impressed. But it is an improvement over recent weeks.
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 July 19, 2016 Version and looking at Week 2 of that forecast.
Mostly for the period July 27 to Aug 2, 2016, I see a moderate probability of dry conditions for India and Indochina and the Philippines but wet conditions of the southern tip of India. Equatorial Africa again looks to be a bit dry but wet just north of the Equator. Looks like the tropical activity west of Central America will be further off shore.
For CONUS, the above graphic is more specific and near term with interpretation and has 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. It is actually a convenient graphic for tracking the Southwest Monsoon. As you can see, there is now a single band of moisture and and it is down by but not longer reaching Panama. There is some minimal moisture also arriving via the Gulf of California and possibly partially related to the tropical storms that are clearly noted in this graphic. But the storms are not curving around and coming aground but heading out to sea rapidly. It had looked like Tropical Storm Frank might provide a lot of moisture in the Gulf of California but that seems less likely now as it has strengthened to a hurricane and is now moving to the Northwest which takes it out of the picture. I am skeptical about this Monsoon really starting to impact CONUS in a significant way any time soon. There is subtropical moisture that creates the occasional thunderstorm. Things could improve quickly but for now it is a minimal Monsoon.
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 is not the controlling factor during the summer.
The High Pressure off of California, the familiar RRR, is here and quite large and strong extended into the Bering Sea and protecting the West Coast from Pacific storms and also providing northerly winds for California. 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.
Looking at the current activity of the Jet Stream.
The path of the current weather pattern is fairly clear from this graphic and it is across the Northern Tier of CONUS and over Canada and is no longer further south than usual for this time of the year. Thus it is less likely to be suppressing the Southwest Monsoon..
And below is the forecast out five days with a continuation of the overall northern tendency in the pattern but a somewhat reduction in the tendency for the westerlies to partially suppress the Southwest Monsoon. Pay attention to the wind vector arrows in addition to the areas shaded as being part of the Jet Stream. Some days they are cooperating and some days they are not. Also the ideal situation is for the mid-level to be cooler than the Boundary Level. You need to have a steep decline in temperature at higher altitudes for the atmosphere to be unstable and create a significant number of healthy clouds and storms. The Devil is in the detail.
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 to the east are cool. The Indian Ocean is cool especially off of Africa and now also off the southern coast of Australia. But water northwest of Australia to Indonesia is warm and suggestive of a La Nina Warm Pool but perhaps less intense than recently (see the four week change analysis in the following graphic). The waters off of New Zealand are warm to the north and west but not the south.
The overall Northern Pacific is indeed PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape) but is not as obvious. The Pacific Decadal Oscillation (PDO) Index rose to 2.4 in March which with El Nino fading may be significant. It was up to 2.62 in April but eased to 2.35 in May and then to +0.78 in June. The question remains about the PDO. Is it acting independently of the El Nino or is this the change from PDO- to PDO+ that would signal a multi-decadal change in the Pacific. I anticipate that the PDO will turn negative as the La Nina gains control. Here is the list of PDO values.
The water directly off of South America is not showing much of a La Nina pattern even though El Nino is history. There is a narrow cool anomaly in the Pacific right along the Equator in the La Nina Measurement Area but it does not extend very far north or south of the Equator but may be beginning to do so.The water off the West Coast of North America is warm especially off of Baja California. The remnants of El Nino have circled back and may now contribute to the North American Monsoon but so far have not and are fading. They now appear to be too far north to play that role. Further north, the Gulf of Alaska is quite warm.
The water off the East Coast of CONUS is very warm covering a large area. The waters of the Gulf of Mexico are very warm. The list of Atlantic Multidecadal Oscillation (AMO) values can be found here. Further north in the Atlantic east of Newfoundland the North Atlantic is cooler than normal and that seems to be moving south and fading. But the waters north of the British Isles now show a widespread warm anomaly. The waters north of Antarctica East of South America are uniformly colder than climatology. I have some additional commentary on this static analysis of the anomalies below where I examine the four-week change in these anomalies.
Since these are "departures" or "anomalies", it is not a seasonal pattern that is being shown it is the changes from what we would expect on a seasonal basis. It is important to understand that and interpret my comments above in the context of anomalies not absolute temperatures.
Comparing a four-week graphic to a prior four-week graphic is always tricky since only 25% of the data has changed and I am not showing the former graphic (it is in last week's report). I add the new one to my draft report, compare and comment on the change and then delete the old one to keep this report to a manageable size. Also it is important to recognize that what you see in this graphic is the change in the anomaly. So blue means either cooler or less warm. Red means warmer or less cool. So you have to refer to the graphic above this one to really interpret this graphic as what we are seeing here is the change in the anomalies. What we see in this graphic is four weeks of change not the current absolute anomalies which are shown in the above graphic. It is not derivatives in the mathematical sense but deltas. They are somewhat similar. The graphic above this one has no time component. It is simply the deviation from climatology and this graphic below shows the four week change in the deviation from climatology. So it is a bit like the first (graphic above) and second (graphic below) derivatives but not exactly. I take it a step further by comparing this 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 cooling along the Equator in the Pacific. You can see the red areas. The Indian Ocean continues to cool in parts in the West. The warming in the North/Central Pacific is slightly less intense. Of interest is the continued warming off of Baja California seems to have reversed. The East Coast of North America continues to warm. The area of the Northwest Coast of Africa has ceased into cooling. The cool anomaly southeast of South America has resumed its warming (becoming less cool). Remember we are talking about changes in the anomalies something like a second derivative so you have to refer to the graphic above this one to know if blue is cool or less warm and if red is warm or less cool.
Four- Week Outlook
I am going to show the three-month ASO Outlook, the recently updated Outlook for the single month of August, the 6 - 10 Day and 8 - 14 Day Maps and the Week 3 - 4 Experimental Outlook
First - Temperature
Here is the Three-Month ASO Temperature Outlook issued on July 21 , 2016:
Here is the Early Temperature Outlook for August Issued on July 21, 2016
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
As I view these maps on July 25 (two of the five update each day and one updates every Friday), it appears that the main features through August 19 will during the beginning of August be a cool anomaly in the Northwest and a second one in Arizona with everything else warm and transforming later in the month to a large EC anomaly forming in the area of the Northern Rocky Mountains east to the East Coast with a cool anomaly in the center of the EC area. Northern Alaska starts cool and gradually becomes EC. The south shore of Alaska remains very warm and the warm anomaly gradually expands to the north.
Now - Precipitation
Here is the three-month ASO Precipitation Outlook issued on July 21, 2016:
And here is the Early Outlook for August Precipitation Issued on July 21, 2016
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
As I view these maps on July 25 (two of the five update each day and one updates every Friday), it looks like precipitation leading up to August 19 is tending for the fist part of August to be drier than climatology in the Northwest and Texas with much of the East Coast and Southeast other than Florida wet. Later in the month there will be a wet anomaly in the area centered on South Dakota (impacting a large number of neighboring states) with a dry anomaly to the Northwest and also to the Southeast. I am just guessing as I have not looked (and I am not sure I can access) the Highs and Lows which go with this forecast. But I I would not be surprised if the model was showing a High - Low - High pattern going diagonally southeast across CONUS. The Southwest Monsoon has been weak but is now forecast to be stronger in August. It will show up from time to time mostly focused on Arizona but also impacting parts of neighboring states. The 6 to 14 Day Outlook issued today shows the Monsoon to be active during that period of time. But the local forecasters may not be as convinced that the results will be wetter than climatology for this time of the year.
Here are excerpts from the NOAA discussion released today July 25, 2016.
6-10 DAY OUTLOOK FOR JUL 31 - AUG 04, 2016
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE FORECAST 500-HPA CIRCULATION PATTERN ACROSS MOST OF THE FORECAST DOMAIN. TROUGHS ARE ANTICIPATED NEAR OR JUST OFF THE U.S. EAST COAST, OVER THE INTERIOR PACIFIC NORTHWEST, AND ALASKA, WHILE A SUB-TROPICAL RIDGE IS FORECAST TO DOMINATE MOST OF THE SOUTHERN TIER OF THE CONUS. THE MAIN JET STREAM IS EXPECTED TO BE ALONG THE U.S.-CANADIAN BORDER. RECENT DETERMINISTIC SOLUTIONS FROM THE GFS AND ECMWF ARE A BIT MORE AMPLIFIED WITH THE OVERALL CIRCULATION PATTERN AND INDICATE TIMING DIFFERENCES FOR SHORT WAVES MOVING THROUGH THE JET STREAM OVER THE NORTHERN TIER OF THE CONUS. THE ENSEMBLE SPAGHETTI CHARTS GENERALLY INDICATE LOW SPREAD OVER THE WESTERN CONUS, AND LOW TO MODERATE SPREAD OVER THE EASTERN CONUS. TODAY'S 500-HPA BLEND CHART DEPICTS SMALL MAGNITUDE HEIGHT ANOMALIES ACROSS THE CONUS, WITH NEAR TO ABOVE NORMAL HEIGHTS EXPECTED EXCEPT OVER THE PACIFIC NORTHWEST AND PARTS OF THE INTERIOR SOUTHWEST WHERE NEAR TO BELOW NORMAL HEIGHTS ARE ANTICIPATED. THE LARGEST POSITIVE HEIGHT ANOMALIES ARE EXPECTED OVER THE GREAT LAKES. BELOW NORMAL HEIGHTS ARE FORECAST OVER ALASKA EXCEPT FOR THE ALASKA PANHANDLE, THE ALASKA PENINSULA, AND THE ALEUTIANS, WHERE ABOVE NORMAL HEIGHTS ARE ANTICIPATED.
ABOVE NORMAL HEIGHTS TILT THE ODDS TO ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONUS. THE EXCEPTIONS ARE OVER THE PACIFIC NORTHWEST WHERE BELOW NORMAL HEIGHTS FAVOR BELOW NORMAL TEMPERATURES, AND OVER PARTS OF THE SOUTHWEST WHERE NEAR TO BELOW NORMAL HEIGHTS AND MONSOONAL FLOW TILT THE ODDS TO BELOW NORMAL TEMPERATURES. BELOW NORMAL HEIGHTS FAVOR BELOW NORMAL TEMPERATURES FOR MOST OF ALASKA, WHILE NEAR TO ABOVE NORMAL HEIGHTS AND WARMER THAN NORMAL SEA SURFACE TEMPERATURES ENHANCE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE, SOUTH COASTAL ALASKA, AND THE ALEUTIANS.
ABOVE NORMAL HEIGHTS TILT THE ODDS TO BELOW MEDIAN PRECIPITATION FOR PARTS OF THE NORTHEAST AND SOUTHEAST CONUS. A STALLED FRONTAL SYSTEM EXTENDING FROM THE CENTRAL CONUS EASTWARD TO THE MID-ATLANTIC COAST WILL SERVE AS A FOCUSING MECHANISM FOR SHOWERS AND THUNDERSTORMS ENHANCING PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE EAST-CENTRAL CONUS AND PARTS OF THE NORTHERN PLAINS, UPPER MISSISSIPPI VALLEY, AND GREAT LAKES. ABOVE NORMAL HEIGHTS TILT THE ODDS TO BELOW NORMAL PRECIPITATION FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS. SHORT WAVES MOVING WESTWARD UNDERNEATH THE SUB-TROPICAL RIDGE ENHANCE PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHWESTERN CONUS. SUBSIDENCE TO THE REAR OF THE TROUGH OVER THE INTERIOR PACIFIC NORTHWEST FAVORS BELOW MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST. THE TROUGH OVER ALASKA TILTS THE ODDS TO ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE STATE, WHILE SUBSIDENCE TO THE REAR OF THE TROUGH ENHANCE PROBABILITIES FOR BELOW MEDIAN PRECIPITATION FOR THE ALEUTIANS AND ALASKA PENINSULA.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODELS AND THE TOOLS.
8-14 DAY OUTLOOK FOR AUG 02 - 08 2016
THE WEEK-2 500-HPA ENSEMBLE MEAN SOLUTIONS FEATURE A LONG WAVE PATTERN VERY SIMILAR TO THE 6-10 DAY PERIOD. SOME DEAMPLIFICATION IS EXPECTED DURING WEEK-2 AND HEIGHTS ARE FORECAST TO RISE OVER ALASKA. A RIDGE IS FORECAST TO REMAIN STRONG OVER THE INTERIOR SOUTHWESTERN CONUS. SPREAD REMAINS LOW OVER THE WESTERN CONUS AND LOW TO MODERATE OVER THE EASTERN CONUS. TODAY'S BLEND CHART INDICATES NEAT TO ABOVE NORMAL HEIGHTS ACROSS MOST OF THE CONUS EXCEPT FOR THE PACIFIC NORTHWEST AND PARTS OF THE SOUTHERN PLAINS WHERE NEAR TO BELOW NORMAL HEIGHTS ARE ANTICIPATED.
THE EXPECTED TEMPERATURE AND PRECIPITATION ANOMALY PATTERNS FOR WEEK-2 ARE NOT SUBSTANTIALLY DIFFERENT FROM THOSE FORECAST FOR THE 6-10 DAY PERIOD, ALTHOUGH AS THE FLOW PATTERN DEAMPLIFIES SLIGHTLY, A WARMER REGIME IS ANTICIPATED FOR PARTS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. IN ADDITION, A DRIER PATTERN IS FORECAST TO EXPAND EASTWARD FROM THE SOUTHERN PLAINS TO THE WESTERN LOWER MISSISSIPPI VALLEY AS A WETTER REGIME EXPANDS EASTWARD OVER THE SOUTHEAST CONUS.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODELS, OFFSET BY SMALL MAGNITUDE HEIGHT ANOMALIES. [Editor's Note: Of course the August Outlook will be updated on Sunday July 31]
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON AUGUST 18
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 5 day period centered on 3 days ago and the 7 day period centered on 4 days ago. "Analog" means that the weather pattern then resembles the recent weather pattern and was used in some way to predict the 6 - 14 day Outlook.
Here are today's analogs in chronological order although this information is also available with the analog dates listed by the level of correlation. I find the chronological order easier for me to work with. There is a second set of analogs associated with the Outlook but I have not been regularly analyzing this second set of information. The first set which is what I am using today applies to the 5 and 7 day observed pattern prior to today. The second set, which I am not using, relates to the correlation of the forecasted outlook 6 - 10 days out with similar patterns that have occurred in the past during the dates covered by the 6 - 10 Day Outlook. The second set of analogs may also be useful information but they put the first set of analogs in the discussion with the second set available by a link so I am assuming that the first set of analogs is the most meaningful and I find it so.
August 1, 1955
August 2, 1955
July 16, 1963
Modoki Type I
July 31, 1981
August 7, 1996
August 8, 1996
July 25, 1999
Following the 1997/98 MegaNino
July 19, 2005
One thing that jumped out at me right away was the spread among the analogs from July 16 to August 8 which is only two day over three weeks. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, is about July 27 and these analogs are centered on 3 days and 4 days ago (July 21 or 22). I am kind of concluding that current conditions (as represented in the historical analogs) are generally five or six days further advanced relative to a normal summer pattern. My wording last week might have conveyed the opposite impression inadvertently. I want to be clear that last week the analogs were lagging the calendar and this week they are indicating that we are further into summer than the calendar suggests.
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 one El Nino Analog (why are there any?), three La Nina Analogs, and five ENSO Neutral Analogs. This may simply be suggesting that we are now beyond the time of the year where the Phase of ENSO is very important or that the analogs are indicating that conditions are in flux. But if we are headed into a La Nina we should soon see a lot of La Nina analogs.
The phases of the ocean cycles in the analogs are inconclusive with respect to McCabe Conditions. Since half of the analogs are associated with PDO Negative and we currently have a positive PDO which for the last two months has recorded less high values, it makes me wonder if this Positive PDO is really associated with the recent El Nino rather than a true PDO phase change.
The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time. One of the major reasons that I write this weather and climate column is to encourage a more long-term and World view of weather.
You may have to squint but the drought probabilities are shown on the map and also indicated by the color coding with shades of red indicating higher than 25% of the years are drought years (25% or less of average precipitation for that area) and shades of blue indicating less than 25% of the years are drought years. Thus drought is defined as the condition that occurs 25% of the time and this ties in nicely with each of the four pairs of two phases of the AMO and PDO.
Historical Anomaly Analysis
When I see the same dates showing up often I find it interesting to consult this list.
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 Cool ENSO Event
Let us start with the SOI.
Below is the Southern Oscillation Index (SOI) reported by Queensland, Australia. The first column is the tentative daily reading, the second is the 30 day moving/running average and the third is the 90 day moving/running average.
90 Day Average
The 30-day average, which is the most widely used measure, as of July 25 is reported at +3.56 which is much more La Nina-ish than last week and which still clearly Neutral is also clearly tilted towards La Nina. The 90-day average at +2.09 is Neutral but now no longer on the El Nino side of Neutral. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. Different agencies use a different range to classify the SOI as being El Nino or La Nina. The strictest range is -5 for El Nino and +5 for La Nina. Some meteorological agencies sometimes uses -8 or +8. So the range +5 to -5 is clearly neutral and above +8 is clearly La Nina and below -8 is clearly El Nino and between -8 and -5 and +5 to + 8 is somewhat marginal but suggestive of El Nino if negative and La Nina if positive.
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. August will not be particularly favorable for La Nina development but it may happen anyway but September is likely to be very favorable for the development of La Nina in terms of the MJO. It is complicated in that some models predict a strong active MJO for September which normally means westerlies. But the reports I am reading suggest that the there will be westerlies west of the Dateline and Easterlies east of the Dateline which may work to create a La Nina Modoki. It should be interesting to see how this plays out.
Low-Level Wind Anomalies
Here are the low-level wind anomalies. We now see westerly anomalies which are to some extent retarding the development of the La Nina.
And now the Outgoing Longwave Anomalies which tells us where convection has been taking place.
In the above graphic, we see basically no convection along the Equator.
Equatorial Subsurface Analysis
We are now going to change the way we look at a three dimensional view of the Equator and move from the surface view 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 coolest water at the surface shows up mostly between 150W and 130W. Water of La Nina coolness but not very intense shows up along the Equator from 170W to the Coast of Ecuador. The cold subsurface water appears to be somewhat slow to rise to the surface. The -3C anomaly appears to have shrunk since last week which is hard to explain. It is hardly evident at all.
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 28C Isotherm is still located at 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 160W with the 25C isotherm at about 140W but it also touches at 150W. Surprisingly, the 20C Isotherm remains down at about 25 meters and not moving closer to the surface very rapidly but the 21C Isotherm now breaks the surface at about 100W. So we do not have significant convection along the Equator east of the Dateline. But the amount of warm water just west of the Dateline is not real impressive either but growing but staying fairly far east. It is clearly a transition state and all of this is important not just for tracking this cool event but thinking about when the next El Nino might be triggered. This graphic helps understand the logic behind the JAMSTEC forecast of the ONI Index.
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 have deleted 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. It is useful for comparing the current situation with the pattern that prevailed near the peak of the El Nino this past winter.
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 cool anomaly extends further into the Pacific but is not as intense near the coast of South America.or further to the west north of the Equator.
Location Bar for Nino 3.4 Area Above and Below
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. The two rows just below that break point contribute to ENSO Neutral and after another break the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016.
Comparing Now to May 23, 2016
Subareas of the Anomaly
Degrees of Coverage
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
If you just look on the Equator, there are 40 degrees of La Nina anomalies with zero degrees of very cold water. There are 50 degrees of Neutral to La Nina and that is the maximum possible since the ENSO Measurement Area only stretches for 50 degrees. Subtracting 40 degrees from the 50 degrees you end up with 10 degrees of ENSO Neutral and 40 degrees of cool enough to qualify as La Nina (with zero -1.5C or less degrees of water cool enough to be a very strong La Nina) when just looking at the Equator. But away from the Equator it is generally warmer when a La Nina is trying to get started. So this table suggests La Nina but the water from 3N to 5N and more dramatically from 3S to 5S is still relatively warm especially west of 140W south of the Equator and remnant warmish water from 140W to 120W north of the Equator. .
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 July 25, in the afternoon working from the July 24 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
(-2.0)/5 = -0.4
(-1.1)/5 = -0.3
My estimate of the daily Nino 3.4 ONI has increased (less negative) to -0.3. NOAA has again reported the weekly ONI to be -0.6 which is in La Nina territory. Their calculation appears to me to be a bit on the cool side especially since there is now no -1.5C or colder anomaly shown in the TAO/TRITON graphic. TAO/TRITON may not be perfectly accurate but there are other data sources which tend to make me question the -0.6 reading for the ONI. But others have also reported values lower than -0.5. Nino 4.0 is again being reported at 0.3. Nino 3.0 is being reported a bit less cool at -0.5. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported a bit more warm at 0.2. WE REMAIN IN ENSO Neutral BUT WE HAVE HAD OUR SECOND LA NINA WEEKLY REPORT. Two weeks are not definitive (the criteria for declaring an El Nino or La Nina includes five overlapping three- month periods with the appropriate conditions) but suggests the direction things are headed. 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 Apr/May/Jun is now reported as 0.7. 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. What we have is only the upwelling phase of the series of Kelvin waves last winter.
You can now see that the El Nino is totally gone however there is warm water west of the Dateline. The coolest water, however, is only reaching the surface from 135W to 155W. Either this La Nina is shy or it is a Modoki. Or it is just not happening as rapidly as one might have expected. I think it is not happening to the extent originally forecast.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.
You read this Hovmoeller from bottom to top and you can clearly see how the El Nino ended and we flirted with La Nina but that has been a bit reversed. The blue colored water is more visible between 120W and 170W so it contributes to the ONI calculation but further east there are some El Nino remnants. They do not show up in the ONI calculations but they are there.
Recent CONUS Weather
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 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 then we started to track June.
Here is the 30 day period through June 25.
It has sure been dry. I has also sure been warm.
Here is the 30 day period through July 3. It completes the month of June.
Adding the seven days and removing the first seven days changed the precipitation picture for Arizona and Nevada and Texas. It also did so for the Northeast. It still presents mostly a warm and dry assessment of June, 2016..
And now we start to track July. Here is the temperature and precipitation anomalies for the 30 days ending July 16, 2016
And now one week later
The addition of one week and deletion of the earlier seven days really shows how dry the Southwest is actually the southern tier extending south to eastern Mexico. You can see a wet belt between the southern and northern dry belts and another wet belt across the Northern Tier from the Great Lakes on wet. The dryness is a bit moderated from what we see in the graphic above i.e the 30 days ending on July 16. The temperature pattern is similar but moderated.
Not very pleasant for ISIS (I could be sarcastic and say their supporters some of whom are places and persons that might surprise you need to provide more support but this is not a political report) but the non-political aspect is a question. Is climate a contributor to the unrest in the Middle East? I think the answer is obvious.
Putting it all Together.
This El Nino has ended in terms of currently satisfying the criteria. It is possible that officially it may not be declared dead until the end of July because the Apr - May - Jun value of the ONI at -0.7 satisfies the 0.5 cutoff.
We are now speculating on the winter of 2016/2017 which now according to most (but not all) of the models seems likely to be a La Nina or Neutral with a La Nina bias.
The below is first the CPC/IRI (Early Month) forecast issued on July 14, 2016 followed by the (Late Month) forecast issue on July 21, 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 now the Model -Based Analysis.
Notice that with this release, the probabilities for La Nina remain similar to the July 14 analysis. The methodology of these two graphics are different but I think the results are consistent with other information that is available. The new forecast however extends further in time to MAM 2017 and shows the most likely ENSO condition at that point in time is Neutral..
We have suggested that it is possible that some of the models and in particular NOAA's model will be wrong about how fast the Eastern Pacific Warm Pool moves back towards its La Nina location and it may well be that next winter will be more of a Neutral year or even have some characteristics of an El Nino Modoki and thus be wetter than a typical year as the Warm Pool may still be more in the Central Pacific than shifted all the way west to its La Nina position.
The mean of the NOAA model was until recently forecasting a fairly strong La Nina for next winter. The model gradually shifted to a weak La Nina Forecast and now to a marginal La Nina Forecast. Notice the blue members of the ensemble forecast which are the more recent ones. This week they suggest a slightly weaker La Nina. Is the Mean of the forecast ensemble for the key periods OND and NDJ below -0.5? It seems to be right now (-0.6?) but not by much or for very long. You can see the same thing in the Australian POAMA model and the July 1 JAMSTEC model run. The mean of the model ensemble for the ONI has recently turned higher (less La Nina-ish) for the second half of the coming winter as you can see.
We now have the JAMSTEC forecast and their commentary
And now we have the commentary from JAMSTEC
July 19, 2016
Prediction from 1st July, 2016
The SINTEX-F model which was run using July 1 SST conditions predicts almost a normal state (or at most quite weak La Niña-like state) in coming seasons in the tropical Pacific. This is rather a big change from predictions in the previous months. Since the NCEP GODAS shows an anomalously cold subsurface condition almost all the way along the equator even in July, the SINTEX-F model prediction might be biased by the simple SST data assimilation scheme. We need to be careful about the present prediction.
Indian Ocean forecast:
As predicted earlier, the negative Indian Ocean Dipole (IOD) has emerged clearly in the SST anomalies observed in June-July. The NCEP GODAS also captures the negative IOD evolution. The model predicts that the negative IOD will continue evolving and reach its peak in boreal fall, which may bring a wetter-than-normal (drier-than-normal) condition over the eastern (western) side of the Indian Ocean. There is high possibility of floods in the region near Sumatra and Java, and drought in East Africa.
In boreal fall, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while central U.S., western Brazil, and Central Europe will experience a colder-than-normal condition.
According to the seasonally averaged rainfall prediction, Indo-China and East Africa will experience a drier condition during boreal fall, while most parts of Indonesia and northwestern South America (including Colombia, Ecuador, and western Brazil) will experience a wetter-than-normal condition; this may be mostly due to the negative IOD and the evolving weak La Niña. Also, because of those climate conditions in Indian and Pacific Oceans, Australia is expected to receive above normal rainfall during austral spring and summer. The active South Pacific Convergence Zone (SPCZ) may play a role in this, too.
Most part of Japan will experience above normal temperature from summer through winter. We expect above normal precipitation in the western (northern) part of Japan in August (October). However, the skill in predicting monthly condition in such regional scales is still limited.
It is not predicting a La Nina. Notice the forecast shows a decline in the ONI followed by a small recovery (that has indeed occurred probably due to MJO activity) and then additional cooling this winter but not meeting the criteria for a La Nina designation. Then it shows warming not meeting the criteria for El Nino designation. It is a fluid situation. Notice that JAMSTEC does not have a high level of confidence in their forecast for reasons explained in the discussion.
Forecasting Beyond Five Years.
So in terms of long-term forecasting, none of this is very difficult to figure out actually if you are looking at say a five-year or longer forecast. The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS. It includes decade by decade predictions through 2050. Predicting a particular year is far harder.
The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. It looks like it will require one more La Nina and this appears to be the way this will unfold. The AMO is pretty much neutral at this point so it may need to become a bit more negative for the McCabe A pattern to become established. That seems to be slow to happen so I am thinking we need at least a couple more years for that to happen..maybe as many as five.
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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