The prior El Nino has been declared by NOAA to be complete but the current incipient La Nina may be dying before it is born.
Summer weather is inherently boring with occasional interruptions by tropical events. This week though we do have the interesting case of an Atlantic Hurricane crossing over Mexico and reforming as a Tropical Storm in the Eastern Pacific and impacting CONUS in that manner via mainly the Gulf of California. There was a name change from Earl to Javier but no sex change.
Not sure of what the rules are on that but I think it is the luck of the draw that the odd/even system did not change the sex of the name of this storm. Thus the media value is less but the weather impacts are the same and flooding is a risk which is the price the Southwest pays for moisture during the summer.
Progress of the Southwest Monsoon
Earlier this year we had tropical moisture cross from the Pacific to the Gulf of Mexico and collide with what would have been a minor tropical event for the Southeast and result in major flooding in South Carolina. Now we have a full fledged Hurricane that impacted Belize and then crossed over Central America through Mexico and has reformed as Tropical Storm Javier in the Eastern Pacific. It was of little interest in the U.S. until now. It created havoc where it visited but it was not impacting the U.S. And of course now that it is in the Pacific it changes its name and I think by accident retained the same sex. At any rate in might impact the Southwest Monsoon.
From the Monday Phoenix NWS Technical Discussion
Tropical Storm Javier was centered just off the southern tip of baja Mexico early this afternoon (monday). The storm will dissipate over/near the Baja Peninsula before ever reaching AZ/CA. However, it will be instrumental in a major moisture resurgence beginning Tuesday by initiating a Gulf surge plus provide some of it's own moisture. We've had tropical storm remnants flow over the region many times in the past - oftentimes with only minor impact. However, this time looks to be different due to troughing in the westerlies which will bring dynamical forcing associated with a wave moving through the bottom of the trough. Prime time for that forcing (over our forecast area) appears to be late Tuesday night into Wednesday. Of note, the best forcing will be north of our area.
All in all, we are still looking at an initial phase of storm behavior Tuesday afternoon and evening that will be highly capable of producing very strong - even damaging - winds as we get a combination of cape and dcape. That will also mean blowing dust potential. Then we transition to storms/showers mainly producing very heavy rain later Tuesday night through Wednesday. Thus, there will be flash flooding potential beyond the "run-of-the-mill" monsoon situation. As a result, we have issued a Flash Flood Watch for most of our Arizona zones
I may have discussed this article before. It has to do with the criteria for when the Southwest Monsoon should be considered to have started and ended. This Table from there may be of interest.
Here is the interpretation
A. W. ELLIS, E. M. SAFFELL AND T. W. HAWKINS
3.3. Seasonal anomalies The identification of wet (n=7) and dry years (n=8) as anomalous regional precipitation seasons (±1 standard deviation from the mean) allowed for recalculation of seasonal statistics (e.g. Table III) to demonstrate the interrelationships of the characteristics of the monsoon season. As might be expected, wet seasons (Table IV) are marked by earlier start dates (10 days) and later end dates (18 days) than average (Table III). In contrast, dry seasons (Table V) are marked by later start dates (7 days) and earlier end dates (14 days) than average (Table III). On average, wet seasons are approximately 46 days longer than dry seasons (Tables IV and V) and produce roughly twice the number of monsoon days (66 versus 33). Only minor differences exist in the mean dew-point temperatures on monsoon and non-monsoon days during wet seasons and those during dry seasons (dry seasons slightly lower). The same is true for the percentage of regional stations reporting precipitation: little difference is evident between wet and dry seasons. This suggests an importance of season length in the interannual variability of the monsoon season, as days within the season are very similar between wet and dry years; quite simply, there are more monsoon days during wet seasons. This similarity of the individual days can be seen by considering the percentage of days within each type of season (wet/dry) that are monsoon days: 66% in the case of wet years and 63% in the case of dry years. With the days of each type of year being similar, and their relative frequency with in the season being similar, the controlling variable is the length of the season.
The lesson is clear. The productivity of the Southwest Monsoon is proportional to its duration.
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.
Not sure one can rely on this graphic to locate the Four Corners High as it is moving around a lot but this evening it is showing up - Oh My Gosh - in two places for Day 7. The "H" over in Northeast Texas may be a bit out of the way to really stimulate the Southwest Monsoon for much other than Southeast New Mexico. The "H" in western Colorado may be too far north. But in six hours this graphic while show those features somewhere else. 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. One also sees a West Coast Trough and a Great Lakes Trough.which can lead to wet conditions in or in advance of the trough but that is not showing up in the NOAA forecasts for the Northwest. The Ridge in between and to the right of the Great Lakes Trough could suggest warm conditions and that is showing up.
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 which I believe covers the area from the Dateline west to 100E and from the Equator north to 45N `normally shows the movement of tropical storms towards Asia in the lower latitudes and the return of storms towards CONUS in the mid-latitudes. But now we see a storm moving towards Japan but kind of dying out on the way there.
As I am looking at the above graphic Monday evening August 8, the Monsoonal Moisture Boundary (MMB) is not significantly crossing the Arizona and Western New Mexico border. One can see some clouds some of which are debris clouds and some of which are the result of recycled precipitation from the major recent storms. The strong "red" areas are south of the Border but moving north. As discussed in the preamble to this report, it looks like a Monsoonal Burst will occur this week but only for a small number of days. It looks like Tuesday and Wednesday for Arizona and possibly Western NM. Looking at this graphic I am not real impressed as it looks like there is not much left of Javier.
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 except for the Southwest Monsoon.
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 August 2, 2016 Version and looking at Week 2 of that forecast.
Mostly for the period August 10, 2016 to Aug 16, 2016, I see very little of anomalies impacting major land areas.
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 continues to be a single band of tropical moisture and it is down by Southern Mexico. In general the tropical storms are not curving around and coming aground but heading out to sea rapidly. There is subtropical moisture that creates the occasional thunderstorm. Things could improve quickly but for now it is a minimal Monsoon. I am skeptical about this Monsoon really starting to impact CONUS in a significant way on a consistent basis.
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. But there is a small Low in the Gulf of Alaska. But the RRR continues to do a good job of 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. For CONUS, we do not see a lot of strong Highs or Lows. You can look at the difference in the shown air pressure for the Highs and the Lows and it is not a larger differential.
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 again is further south than usual for this time of the year. Thus it is likely to be suppressing the Southwest Monsoon. The sub-Jetstream level intensity winds shown by the vectors in this graphic are very important re the possible impact of Tropical Storm Javier on Arizona. It looks possible.
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. Notice the vectors with easterly direction entering California. This will impact the Monsoonal Moisture Plume. But it is important to understand that 300 mb is about 30,000 feet so the Monsoon can operate under the features shown in this graphic.
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 details.So there can be very higher PWATs i.e. the amount of moisture in the water column at a particular location but still no precipitation if there is no convection. A PWAT of 1.2 inches of water is sort of a summer trigger point and such levels and much higher are in New Mexico and Arizona now. Levels much higher than 1.2 inches of water could lead to hail.
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.
Remember this discussion is all about anomalies not absolute temperatures...so it is deviation from seasonal norms.
The waters off of Japan remain warm. The Indian Ocean is now mixed: cool especially off of Africa and 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). We now see some warm water off of Madagascar. The waters off of New Zealand are warm to the north but not the south.
The overall Northern Pacific is perhaps PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape) but is not as obvious and may not record as PDO+ as the waters just of the West Coast are cool not warm. The cool anomaly now is a belt south of a large warm anomaly. 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 and now down to +0.18 for July. 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 west of South America is not showing much of a strong 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. It is gradually stretching west. But the connection to Ecuador is weak. The waters northeast of South America are warm but less so than last week. This could show up as tropical activity. The water off the West Coast of North America is warm but only off of Baja California and that anomaly seems to be drifting away from the coast. The remnants of El Nino have circled back and are mostly dissipated. Further north, the Gulf of Alaska is quite warm. That really is the most impressive feature of the overall pattern.
The water off the East Coast of CONUS is very warm covering a large area. The waters of the Gulf of Mexico are 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 becoming warmer than normal and the cool anomaly seems to be fading. There is now a cool anomaly off shore of Northwest Africa. The waters north of Antarctica East of South America are uniformly colder than climatology but we see some warm anomalies intruding in that pattern. 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.
Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.
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 a different pattern of cooling along the Equator in the Pacific. On a relative basis the Eastern Pacific along the Equator off of Equator is warming i.e. the cool anomalies are less cool. The Indian Ocean continues to cool but not east and southeast of the Arabian Peninsula. The warming in the North/Central Pacific is this week slightly more intense but the cooling area below the warm area has shifted to the west closer to Asia. 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 Updated Temperature Outlook for August Issued on July 31, 2016
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
As I view these maps on August 8 (two of the five update each day and one updates every Friday), it appears that the main features through September 2 will during the second half of August be a warm West Coast, East Coast and Southern Tier transforming as the month evolves to have the Northern Tier warm anomaly shift to the Southern Tier with a large EC area in the Northern Tier from the Rocky Mountains to the East Coast. The Week 3 - 4 forecast covers two weeks so it could start out like the 8 - 14 Day Outlook suggests and morph into what is shown in the above graphic but it takes some faith that this is what will happen. Alaska starts warm and remains warm.
Now - Precipitation
Here is the three-month ASO Precipitation Outlook issued on July 21, 2016:
And here is the Updated Outlook for August Precipitation Issued on July 31, 2016
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
As I view these maps on August 8 (two of the five update each day and one updates every Friday), it looks like precipitation leading up to September 2 is tending for the second half of August to be wet in the Eastern part of CONUS then transforming as the month evolves into a small wet anomaly in the very North Central Part of CONUS with a dry anomaly stretching from New Mexico to New Jersey with a small EC break in West Texas. You may recall that last week the forecast was for a series of dry-wet-dry anomalies extending diagonally from the Northwest to Southeast. We thought that the large wet anomaly might shrink with the next edition of the forecast and it seems that it has and shifted further north. The next time the 3-4 Week Forecast is run which will be this coming Friday, it may look very different as the 6 - 14 Day Outlooks do not appear to meld into the Week 3 - 4 forecast easily. It may be simply that the 3 - 4 Week Forecast covers a two-week period and the earlier part of that period may be wet rather than dry where the dry anomaly is shown. The graphic updates automatically so if you look at this report next Friday, you will see the current 3- 4 week forecast by NOAA and of course it will be for seven days later than this one. .
Here is the NOAA discussion released today August 8, 2016.
6-10 DAY OUTLOOK FOR AUG 14 - 18 2016
TODAY'S MODEL SOLUTIONS ARE ONLY IN FAIR AGREEMENT ON THE PREDICTED 500-HPA HEIGHT PATTERN ACROSS THE FORECAST DOMAIN. INSPECTION OF THE DYNAMICAL MODEL RUNS REVEALS NOTABLE VARIATIONS IN BOTH AMPLITUDE AND PHASE OF PREDICTED MEAN CIRCULATION FEATURES. IN GENERAL, MOST SOLUTIONS DEPICT A RIDGE OVER THE BERING SEA, A BROAD TROUGH FROM THE GULF OF ALASKA TO NEAR THE PACIFIC NORTHWEST COAST, A WEAK RIDGE OVER THE ROCKIES AND/OR GREAT PLAINS, AND A TROUGH OVER THE EAST. THE DETERMINISTIC 0Z AND 6Z GFS RUNS, AND THE DETERMINISTIC 0Z ECMWF RUN, PREDICT THE STRONGEST RIDGING ACROSS THE VICINITY OF THE BERING SEA. OVER THE EASTERN CONUS, THERE IS SIGNIFICANT UNCERTAINTY REGARDING THE ANTICIPATED POSITION OF A TROUGH, WITH SOME MODELS DEPICTING THE MEAN TROUGH AXIS OVER THE MIDWEST, AND OTHERS NEAR THE ATLANTIC SEABOARD. THIS WILL HAVE A LARGE INFLUENCE IN WHERE THE MAIN PRECIPITATION PATTERN SETS UP IN THIS PART OF THE COUNTRY. THE 5820 METER ENSEMBLE SPAGHETTI MAPS DEPICT SURPRISINGLY LOW SPREAD ACROSS THE NORTHERN CONUS, AND A LOW-AMPLITUDE PATTERN.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR SOUTHEAST ARIZONA, MOST OF NEW MEXICO, SOUTH-CENTRAL PORTIONS OF BOTH THE GREAT PLAINS AND MISSISSIPPI VALLEY, AND THE LOWER TENNESSEE VALLEY. THIS IS MOSTLY DUE TO THE EXPECTED PRESENCE OF PRECIPITATION IN THIS AREA, AND IS CONSISTENT WITH CALIBRATED REFORECAST TEMPERATURE TOOLS FROM GFS AND ECMWF ENSEMBLE FORECASTS. NEAR NORMAL TEMPERATURES ARE FAVORED IN A RELATIVELY THIN BAND SURROUNDING THE AREA OF PREDICTED BELOW-NORMAL TEMPERATURES, MUCH OF WASHINGTON, AND NORTHWEST OREGON. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR ALL OTHER AREAS, WHICH INCLUDES A SIZABLE PORTION OF THE WESTERN, NORTHERN, AND EASTERN CONUS, AND ALL OF ALASKA. FORECAST CONSIDERATIONS INCLUDE PREDICTED ABOVE NORMAL 500-HPA HEIGHTS, CALIBRATED REFORECAST TEMPERATURES FROM THE GFS AND ECMWF ENSEMBLES, AND BIAS-CORRECTED GEFS, ECMWF, AND CANADIAN DYNAMICAL MODEL TEMPERATURE FORECASTS. CURRENT SEA SURFACE TEMPERATURES WERE ALSO CONSIDERED NEAR COASTAL AREAS.
ABOVE MEDIAN PRECIPITATION IS FAVORED FROM THE SOUTHERN PLAINS EASTWARD AND NORTHEASTWARD ACROSS THE LOWER MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, PORTIONS OF THE OHIO VALLEY, THE APPALACHIANS, ALABAMA, AND THE ATLANTIC COAST STATES FROM MAINE TO THE FLORIDA PANHANDLE. THIS IS BASED ON CALIBRATED REFORECAST PRECIPITATION FROM GFS AND ECMWF ENSEMBLES, AND CONSIDERATION OF DYNAMICAL MODEL PRECIPITATION FORECASTS FROM THE CANADIAN, GEFS, AND ECMWF MODELS. ABOVE MEDIAN PRECIPITATION IS ALSO FAVORED ACROSS SOUTHERN ALASKA, ATTRIBUTED TO THE PREDICTED PRESENCE OF A 500-HPA TROUGH. BELOW MEDIAN PRECIPITATION IS FAVORED FOR AREAS WEST OF THE CONTINENTAL DIVIDE, AND FROM MOST OF THE NORTHERN AND CENTRAL PLAINS EASTWARD ACROSS NORTH-CENTRAL SECTIONS OF THE MISSISSIPPI VALLEY TO SOUTHWEST MICHIGAN. BELOW MEDIAN PRECIPITATION IS ALSO FAVORED ACROSS NORTHERN ALASKA. THESE AREAS OF PREDICTED BELOW MEDIAN PRECIPITATION ARE BASED ON CALIBRATED REFORECAST PRECIPITATION FROM GFS AND ECMWF ENSEMBLES, AND CONSIDERATION OF DYNAMICAL MODEL PRECIPITATION FORECASTS FROM THE CANADIAN, GEFS, AND ECMWF MODELS.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: NEAR AVERAGE, 3 OUT OF 5, DUE TO COMMON LONG-WAVE FEATURES ANTICIPATED BY THE VARIOUS DYNAMICAL MODELS, BUT OFFSET BY SUBSTANTIAL DIFFERENCES IN PREDICTED LONG-WAVE AMPLITUDE AND PHASE.
8-14 DAY OUTLOOK FOR AUG 16 - 22 2016
DURING THE 8-14 DAY PERIOD, MOST MODELS PREDICT A FAIRLY ROBUST 500-HPA RIDGE OVER THE WESTERN BERING SEA/KAMCHATKA PENINSULA, WITH THE DOWNSTREAM TROUGH EXPECTED TO SHIFT WESTWARD FROM ITS PREDICTED 6-10 DAY POSITION OVER THE GULF OF ALASKA TO THE ALASKA PENINSULA AND EASTERN ALEUTIANS. A LOW-AMPLITUDE FLOW PATTERN IS EXPECTED ACROSS THE CONUS, WITH THE WESTERLIES CONFINED TO THE NORTHERN TIER OF STATES. THE BROAD TROUGH PREDICTED TO BE CENTERED OVER THE OHIO VALLEY DURING THE 6-10 DAY PERIOD IS FORECAST BY MOST MODELS TO ADVANCE TO NEAR THE EAST COAST DURING WEEK 2. MODEL SPREAD (AT 5820M) IS CONSIDERED TO BE LOW TO MODERATE FOR THE WEEK 2 FORECAST PERIOD.
THE PREDICTED SURFACE TEMPERATURE AND PRECIPITATION PATTERNS ARE EXPECTED TO BE SIMILAR TO THEIR RESPECTIVE 6-10 DAY PATTERNS. A MODERATION IN TEMPERATURE IS PROJECTED FROM PARTS OF THE SOUTHWEST AND SOUTHERN ROCKIES INTO THE SOUTHERN HIGH PLAINS, RELATIVE TO THE 6-10 DAY PERIOD. THE NEAR NORMAL TEMPERATURES FAVORED IN THE NORTHWEST DURING DAYS 6-10 ARE FORECAST TO SHIFT EASTWARD INTO THE NORTHERN ROCKIES. THE AREA OF FAVORED ABOVE MEDIAN PRECIPITATION ACROSS THE NORTHEAST DURING THE 6-10 DAY PERIOD IS EXPECTED TO MOVE OFFSHORE DURING WEEK 2, WITH THE TILT OF THE PRECIPITATION AXIS BECOMING MORE EAST-WEST ORIENTED.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: NEAR AVERAGE, 3 OUT OF 5, DUE TO DECENT AGREEMENT AMONG THE VARIOUS ENSEMBLE MEAN FORECASTS OFFSET BY THE PREDICTION OF VERY MODEST 500-HPA HEIGHT ANOMALIES OVER THE CONUS.
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 ENSO events.
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 2, 1953
August 3, 1953
July 30, 1954
Powerful two-year La Nina
August 8, 1954
Powerful two-year La Nina
August 10, 1954
Powerful two-year La Nina
August 4, 1960
August 5, 1960
August 22, 1973
August 7, 1980
August 9, 1990
One thing that jumped out at me right away was the spread among the analogs from July 30 to August 22 which is two days 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 August 11. These analogs are centered on 3 days and 4 days ago (August 4 or 5). One might be tempted to conclude that current conditions (as represented in the historical analogs) are generally a full week further advanced relative to a normal summer pattern. But if you assume the August 22 anomaly is an outlier, the midpoint changes to August 5 and the span is reduced to 12 days and everything seems be on time and quite condensed re the spread of the dates of the analogs.
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 is this time zero El Nino Analogs, six La Nina Analogs, and four ENSO Neutral Analogs. Again we see a number of La Nina analogs. The phases of the ocean cycles in the analogs are inconclusive with respect to McCabe Conditions. But many of the analogs seem to be associated with AMO Positive or Neutral. Also it is interesting that there are a number of 1953 and 1954 analogs as the La Nina that lasted from the Spring of 1954 to the Spring of 1956 was very powerful and associated with major drought conditions in the Great Plains and Southwest.
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 August 8 is reported at +4.15 which is unchanged from last week and which still Neutral is also clearly tilted towards La Nina. The 90-day average at +2.74 which is actually more Neutral than last week. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. 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 more 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 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 off of Ecuador 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 other than west of the Dateline.
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: But they are essentially unchanged from last week but should update very soon.
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 only in small isolated areas. Water of La Nina coolness but not very intense shows up along the Equator from 170W to the Coast of Ecuador. But there are small pockets of water slightly warmer than -0.5C mixed in. The cold subsurface water appears to be somewhat slow to rise to the surface. The -3C anomaly appears to have again 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. Surprisingly, the 20C Isotherm remains down at about 25 meters and not moving closer to the surface very rapidly but the 24C, 23C, and 22C isotherms reach the surface but only the 24C Isotherm does that within the ONI Measurement Area and that only slightly. 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
As of Today
May 23, 2016
As of Today
As of Today
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*
* There is a small -1.5C anomaly at about 140W and 5N which is small and seems to be moving north out of the ONI Measurement Area.
If you just look on the Equator, there are 45 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 45 degrees from the 50 degrees you end up with 5 degrees of ENSO Neutral and 45 degrees of cool enough to qualify as La Nina (with zero -1.5C or less degrees of water cool enough to be a 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 from 3S to 5S is still relatively warm especially west of 150W so that probably is why the ONI is still Neutral.
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 August 8, in the afternoon working from the August 7 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
(-2.7/5 = -0.5
(-2.5)/5 = -0.5
My estimate of the daily Nino 3.4 ONI is again -0.5. NOAA has again reported the weekly ONI to be -0.5 which is the borderline between neutral and La Nina territory. Nino 4.0 is reported as being slightly less warm at at 0.1. Nino 3 is being reported as slightly cooler at -0.5. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported quite a bit warmer at 0.5. WE REMAIN IN ENSO Neutral BUT WE HAVE HAD OUR FOURTH LA NINA WEEKLY REPORT although this one is again equivocal being exactly a borderline reading. Four 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. NINO 1+ 2 stubbornly remains positive and determines the weather of Ecuador and Peru.
ONI Recent History
The official reading for May/Jun/Jul is now reported as +0.2. So this El Nino is now officially over. 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 has now ended 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 just west of 140W which is less than 10 degrees of longitude. 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. Further to the east outside of the ONI Measurement Area cool water is reaching the surface. Right now we have westerly anomalies off the coast of Ecuador. In September the MJO may move that water further west into the ONI Measurement Area and we may get colder ONI readings. On the right you see every second week of this graphic historically so you can follow the progression. Notice how the subsurface cool anomaly has shrunk over time. It does not really look smaller compared to two weeks ago but there are pockets of lighter blue interior to the cool anomaly. The coldest water is ever so slightly moving to the west where it will not impact the ENSO Measurement Area if it surfaces there.
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 ENSO event.
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.
I do not usually show this NOAA Hovmoeller. It is similar to the above but reports the anomalies down to 300 meters but only on the Equator. If is useful in terms of estimating the subsurface cooling or warming that is in reserve. That heat content does not impact current weather but will impact future weather as it impacts the surface.
When I have shown it, I usually use the version that auto-updates but this version is a lot clearer. I use it mostly to show the Kelvin Waves. But I am showing it this time because it shows the deterioration of the cool anomaly. So the Upwelling phase of the prior Kelvin Wave is waning. That makes the La Nina call by some of the models suspect. I am showing last week's version followed by this week's version. As you can see, NOAA's graphic artists have an impact on the impression one gets from looking at these graphics. Unless the data has been, revised the dark blues in last weeks graphic compared to this weeks graphic are the work of the graphic artists. I have no way of telling. But you can see the larger areas of lighter blue at the bottom which are the current readings and you can see that the cooler water is located further to the west. For the moment, this potential La Nina is dying. .
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 track July. Here is the temperature and precipitation anomalies for the 30 days ending July 30, 2016
We are now able to take a look at the three month history or at least a 90 day history.
Re precipitation, it is a similar pattern but not nearly as extreme. The Temperature departures a a bit different as in July the heat anomaly extended to the East Coast.
And now we start looking at August.
Not much change from the 30 days ending July 30 which is two graphics above as the 90 day history is right above this graphic.
Weather in the News
Nothing to report
Global Warming in the News
Nothing to report.
Putting it all Together.
This El Nino has ended in terms of currently satisfying the criteria. We are now speculating on the winter of 2016/2017 which now according to some of the models seems likely to be a La Nina or Neutral with a La Nina bias. But Australia and Japan do not see it that way and are not calling for a La Nina at this point in time. So NOAA is a bit the Odd Man Out but it is mostly a question of degree. NOAA is calling for a borderline La Nina and the others are forecasting a La Nina-ish event that does not quite meet the criteria for being labeled a La Nina and does not last long enough to meet the criteria.
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 in the Fall with a possible strengthening in the heart of winter. 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. It takes JAMSTEC a while each month to get their results posted. The mean of the model ensemble for the ONI in the NOAA model has recently turned higher (less La Nina-ish) for the Spring of the coming winter as you can see. So this is forecast to be a short La Nina if it indeed actually meets the criteria to be recorded as a La Nina which remains to be seen.
We now have the JAMSTEC forecast and their commentary
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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