As relative humidity increases, the heat content of the lower atmosphere expresses itself as warmer nights and not quite as hot days. So 600dm may not be as big a threat to life but may be more uncomfortable. We most likely will approach and may reach 600dm this week. The dew point and the position of the Monsoonal Ridge has probably not yet reached the level to declare the Monsoon to have begun. But we are within a week or two of that happening and it may well happen this week for Arizona.
I am beginning to think it will be a wet Summer for the Southwest and perhaps dry for the Plains States but it is not yet clear that this is how it will develop because the prior El Nino was not well behaved and the La Nina that is developing also appears to be a bit westerly displaced. I continue to discuss the Southwest Monsoon siince it is very important to Summer Weather and a topic where science has not yet figured it out. It is very important to the future of many states.
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.
Other than Tropical Storms, the major feature impacting CONUS in the Summer is the Southwest Monsoon or North American Monsoon if you prefer.
Here is a very good paper that explain the U.S. Monsoon.
A METHOD FOR DEFINING MONSOON ONSET AND DEMISE IN THE SOUTHWESTERN USA ANDREW W. ELLIS, ERINANNE M. SAFFELL and TIMOTHY W. HAWKINS Office of Climatology, Department of Geography, Arizona State University, Tempe, AZ 85287-0104, USA
The method employed by the Phoenix NWSFO [Editors' Note. See below i.e. this method is no longer officially used] in determining the onset and demise of the annual monsoon season locally is the only full attempt at such a declaration. The NWSFO in Tucson only declares the onset, using a similar method to that used at Phoenix, whereas other NWSFOs make no such declarations regarding the monsoon season. The beginning of the monsoon season at Phoenix or at Tucson is defined as the first day of the first occurrence of three successive days during the summer months characterized by mean daily dew-point temperatures of 55°F (12.8°C) and 54°F (12.2°C) or greater respectively. Any subsequent day exhibiting a mean dew-point temperature equal to or greater than the threshold is classified as a ‘monsoon day’ up through to the ending date of the monsoon season. The end date at Phoenix is determined in retrospect by a forecaster upon the review of daily moisture conditions and atmospheric circulation patterns nearing the fall season. Using this method, the monsoon season at Phoenix traditionally begins on 7 July (Table I), but it has begun as early as 19 June and as late as 25 July. Similarly, the season typically begins at Tucson on 3 July (Table I), but it has begun as early 17 June and as late as 25 July. The season at Phoenix typically stretches across a 70 day period through to 14 September (earliest end date: 19 August; latest end date: 10 October), but it has been as short as 34 days and has persisted for as long as 104 days (Table I). Between the beginning and end of the monsoon, the mean number of monsoon days is 55, with a minimum of 27 days and a maximum of 99 days.
Notwithstanding the above, Phoenix and Tucson NWS have moved away from formally predicting the start of the monsoon by the meeting of particular criteria. Now the Monsoon in Arizona starts on June 15. I am not sure of the reason for this downgrade in precision but I assume it means less phone calls from the media. When dealing with the media, KISS. The Phoenix NWS in their daily technical discussion is quite detailed in discussing the onset of the NAM. So the level of analysis has not declined just the way things are described officially
An oddity about the recording of Monsoons is discussed in part in this paper. The follow are my comment on their analysis.
The purging of the June 5 Start in 1972 of the Monsoon in Phoenix is interesting. Prior to this year's El Nino. the 1972/73 El Nino was the third strongest ever and then ONLY STRONG EL NINO to occur with AMO-. I have presented the evidence before and will present it again in the near future and it is available on Page II of this report that AMO- is correlated with the annual migration of the Bermuda Low and is correlated with strong Monsoons. So it is not a surprise that 1972 produced a very early Monsoon.
Here is a good recent paper on the evolution of the NAM. Mechanisms for the Onset and Evolution of North American Monsoon Ehsan Erfani and David L. Mitchell Desert Research Institute, Reno, Nevada University of Nevada, Reno, Nevada
It focuses on Sea Surface Temperatures (SST's) and is not a surprise. The reason for the study is interesting. NOAA was having difficulties forecasting precipitation during a Monsoon. It does raise questions about the logic of concluding that Global Warming will reduce the strength of Monsoons. The paper concludes that 29C in the Northern Gulf of California is necessary to have this Monsoon. 27.5C is the general estimate of what causes Convection but apparently the Marine Boundary Level requires 29C for what is called CIN (temperature inversion) to be surmounted. But there are other factors. One has to be creative to figure out how more convection leads to a drier Planet.
The Monsoon Moisture Boundary has already been observed in Southern Arizona. But so far it has only penetrate the lower atmosphere and may not be consistent. Given there are not accepted criteria for defining when a Monsoon has arrived, I conclude that Arizona is still in the pre-Monsoon Phase.
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.
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 over in Texas almost to Louisiana. Or is this the second high further east of the Four Corners High that we observed last week. It does not matter. It is positioned to pull moist air into Arizona and New Mexico. The question is how much of that moisture is there. That High (and remember it is a forecast seven days out) is not well positioned to pull moist air in from the Gulf of California where the warm water is. So it is half of loaf of Monsoon. There is a major Trough headed past the Great Lakes and another one over the Northwest. It is a fairly typical summer pattern but the Pacific is just not right for summer to go into full swing. There needs to be more of a trough off the West Coast.
The MJO has had significant impacts this winter but the impact on June and soon July is not likely to be very noticeable
I was going to stop showing the above graphic for the summer but there is something about the pattern in the Eastern Pacific that looks strange to me. I can not quite figure out what is going on so perhaps it is significant.
As I am looking at the above graphic Monday evening June 27, there is some Pre-Monsoonal Activity in Arizona, New Mexico and Texas. The Monsoonal Moisture Boundary (MMB) right now reaches up to the Utah Colorado Border. Phoenix NWS has been inclined to declare it to be the real deal but I am not so sure.it will be sustained This a pretty moisture starved image for summer re the Northern Tier of CONUS. The situation is pretty dynamic and changes quickly. One issue is that moisture being driven in by high pressure to the east come in at relative high altitude because it has to cross a mountain range. Moisture from the Gulf of California does not face that hurdle. So the Water Vapor imagery by itself does not tell the full story.
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 June 21, 2016 Version and looking at Week 2 of that forecast.
Mostly I see for the period June 29 - July 5, 2016 a mixed situation with respect to precipitation in the Western Pacific and Indian Ocean. The most significant is the situation for Southern India which is wet. There is a moderate chance for cyclonic development off the Yucatan Peninsula in Mexico. No temperature anomalies are shown.
For CONUS, the above graphic is more specific and near term with interpretation and a focus on tropical storms. It does not cover as wide an area e.g. it does not cover the Western Pacific or the Atlantic far east of the U.S. It is actually a convenient graphic for tracking the Southwest Monsoon. As you can see there is not that much moisture intrusion into Arizona and New Mexico as the more intense moisture track, the remnants of the El Nino, are further south and feeding a potential tropical storm off the Yucatan Peninsula.
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 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 which continues to be quite far north.
The path of the current weather pattern is fairly clear from this graphic and it is across the Northern Tier of CONUS. This time of the year, weather patterns are moving from west to east more slowly than usual and this also raises flooding issues as storms can stay over a given area for longer times than during mid-Winter.
And here is the forecast out five days with a continuation of the overall northern tendency in the pattern.
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. The Indian Ocean is increasingly cool rather than warm. The waters off of New Zealand are warm to the north but not the south. The overall Northern Pacific is indeed PDO Positive (the horseshoe pattern with the cool anomaly inside the horseshoe shape). The PDO Index rose to 2.4 in March which with El Nino fading may be significant. It was up to 2.62 in April but eased to 2.35 in May. It looks to me like it may be declining further. 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. Here is the list of PDO values. The water off the West Coast of North America is very warm. The remnants of El Nino have circled back and may now contribute to the North American Monsoon. The water off the East Coast is warm. The water off of South America is not showing much of a La Nina pattern even though El Nino is history. There is a very 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. There is some cool water right off of Ecuador but then there is warm water from about 90W to 130W. The TAO/TRITON graphic is showing more of a La Nina. Further north in the Atlantic east of Newfoundland the North Atlantic is cooler than normal and that seems to be moving south. But the waters off the British Isles now show a warm anomaly. The warm water off of West Africa is becoming a bit more intense. 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.
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 general cooling of the ENSO measurement area along the Equator. La Nina had been fading but that probably was a MJO impact and that has ceased. Of special interest is the warming off of Baja California but cooling further south. For Africa the Bay of Guinea is warming again. The Central North Pacific is quite interesting and we may see a lowering of the PDO but I am not able to go from the visual to the index value just yet.
Four- Week Outlook
I am going to show the three-month JAS Outlook, the recently updated Outlook for the single month of July, the 6 - 10 Day and 8 - 14 Day Maps and the Week 3 - 4 Experimental Outlook
First - Temperature
Here is the Three-Month JAS Temperature Outlook issued on June 16, 2016:
Here is the Early July Temperature Outlook Issued on June 16 (I am not showing the earlier Full Month June Temperature Outlook since by the time you read this article, most of June will not even be represented in the 6 - 10 Day Outlook)
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Looking further out.
As I view these maps on June 27, it appears that the main features through July 22 will be intense heat in the West rotating across the Southern Tier to the East Coast with the Plains States having a tendency to be closer to EC especially as the progression unfolds. It is not clear that this sequence will be able to play out as drawn up.
Now - Precipitation
Here is the three-month JAS Precipitation Outlook issued on June 16, 2016:
And here is the Early Precipitation Outlook for July Issued on June 16, 2016 (Again, I am not showing the full month June Precipitation Outlook for the same reason I did not show the Temperature version of that Graphic - It is available in last week's Report).
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
As I view these maps on June 27 (they update each day), it looks like precipitation leading up to July 22 is tending towards a pattern of a dry northwest, a moderate Monsoon in the Southwest providing moisture for states to the East but ultimately narrowing to just Arizona and New Mexico with the the East Coast having a likelihood of less than climatology precipitation. Again, it is not clear that things can work out as drawn up. There is an indication that towards the end of this period the situation impacting the extreme Northwest may start to change.
Here are excerpts from the NOAA discussion released today June 27, 2016.
6-10 DAY OUTLOOK FOR JUL 03 - 07 2016
TODAY'S MODEL SOLUTIONS ARE IN FAIR AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN ACROSS MOST OF THE FORECAST DOMAIN. A TROUGH IS FORECAST OVER THE NORTHEAST WHILE RIDGING IS PREDICTED OVER THE SOUTHWEST CONUS. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE LOW TO MODERATE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN. TODAY'S 500-HPA BLEND CHART DEPICTS BELOW NORMAL HEIGHTS OVER THE NORTHEASTERN CONUS, WHILE ABOVE NORMAL HEIGHTS ARE INDICATED OVER THE REST OF THE U.S. TODAY'S MANUAL 500-HPA HEIGHT BLEND IS COMPOSED PRIMARILY OF THE ENSEMBLE MEAN SOLUTIONS, BASED LARGELY ON CONSIDERATIONS OF RECENT SKILL AND ON ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE MODEL SOLUTIONS RESEMBLE CASES THAT HAVE OCCURRED IN THE PAST.
NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE MIDDLE MISSISSIPPI VALLEY, EASTWARD TO THE OHIO VALLEY, MID-ATLANTIC AND NORTHEAST, ASSOCIATED WITH PERSISTENT TROUGHING. ELSEWHERE IN THE U.S., ABOVE NORMAL TEMPERATURES ARE FAVORED WHERE HEIGHTS ARE ABOVE NORMAL. ABOVE NORMAL TEMPERATURES ARE MOST FAVORED FOR THE GULF COAST STATES, WHERE TEMPERATURE TOOLS ARE IN THE BEST AGREEMENT.
ABOVE NORMAL HEIGHTS INCREASE THE LIKELIHOOD OF BELOW MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST, SOUTHEAST TEXAS, AND LOUISIANA. NEAR TO ABOVE MEDIAN PRECIPITATION IS FAVORED FOR THE SOUTHEAST, THE TENNESSEE VALLEY, AND PARTS OF THE OHIO VALLEY IN ASSOCIATION WITH THE TROUGH PREDICTED OVER THE EASTERN CONUS. BELOW MEDIAN PRECIPITATION IS FAVORED FOR THE NORTHEAST, WHILE ABOVE MEDIAN PRECIPITATION PROBABILITIES ARE INDICATED FOR ALASKA, PARTS OF THE CENTRAL PLAINS, AND THE MIDDLE MISSISSIPPI VALLEY, CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GFS AND ECMWF ENSEMBLE MEMBERS.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE MODELS AND THE TOOLS.
8-14 DAY OUTLOOK FOR JUL 05 - 11 2016
THE 500-HPA PATTERN FORECAST FOR THE WEEK-2 PERIOD IS SIMILAR TO THE 6-10 DAY PERIOD, BUT MOST OF THE CONUS HAS VERY LOW MAGNITUDE HEIGHT ANOMALIES. NEAR NORMAL HEIGHTS ENHANCE PROBABILITIES FOR NEAR TO ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONUS. ABOVE NORMAL TEMPERATURES ARE MOST FAVORED FOR THE GULF COAST STATES, WHERE TEMPERATURE TOOLS ARE IN THE BEST AGREEMENT. ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE ALSO ANTICIPATED FOR ALASKA DUE TO PREDICTED ABOVE NORMAL HEIGHTS. FORECAST ABOVE NORMAL HEIGHTS INCREASE THE LIKELIHOOD OF BELOW MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST, EASTWARD TO THE NORTHERN ROCKIES. BELOW MEDIAN PRECIPITATION IS FAVORED FOR SOUTHEAST TEXAS AND LOUISIANA, WHILE ABOVE MEDIAN PRECIPITATION IS FORECAST FOR EASTERN ALASKA, THE GREAT LAKES, THE OHIO AND TENNESSEE VALLEY, THE UPPER AND MIDDLE MISSISSIPPI VALLEY, AND PARTS OF THE CENTRAL PLAINS AND SOUTHERN ROCKIES, CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GFS ENSEMBLE MEMBERS.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE MODELS AND THE TOOLS.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON JULY 21
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.
June 20, 1953
June 21, 1953
June 15, 1961
June 11, 1979
Followed by a mild El Nino Modoki Type II
June 21, 1979
Followed by a mild El Nino Modoki Type II
June 23, 1979
Followed by a mild El Nino Modoki Type II
June 6, 1996
After a La Nina
July 7, 2003
June 25, 2006
Followed by an El Nino
June 17, 2007
Followed by a strong La Nina
One thing that jumped out at me right away was the spread among the analogs from June 6 to July 7 which is four and a half weeks. I have not examined the centroid of this distribution carefully but if you take out the June 6 and July 7 analogs you end up with about June 15 and these analogs are centered on 3 days and 4 days ago (June 22 or 23). I am kind of concluding that current conditions (as represented in the historical analogs) are generally about a week earlier than for this time of the year. For subjective (difficult to make an analytic case) reasons, that gives me less confidence in the 6 - 14 Day Outlook. It also makes me suspicious of the call of an early start for the Southwest Monsoon.
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 zero El Nino Analogs, zero La Nina Analogs and ten 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 but it is true that we are in ENSO Neutral Conditions.
The phases of the ocean cycles in the analogs point to McCabe Conditions A and C which are opposites to some extent but both favor a wet Southern Tier. In the selection process for the analogs, those associated with a Positive PDO seemed to have a higher correlation with recent patterns of Highs and Lows so that is no big surprise. 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 Warm Event (Perhaps the title should change and it probably will next week)
Let us start with the SOI.
Below is the Southern Oscillation Index (SOI) reported by Queensland, Australia. The first column is the tentative daily reading, the second is the 30 day moving/running average and the third is the 90 day moving/running average.
90 Day Average
Looks like another week where I will have to complete this analysis on Tuesday as Queensland is behind in their website updating. But from the four days they have posted, The 30-day average, which is the most widely used measure, as of June 24 is reported at +2.29 which is now clearly Neutral but unchanged since last week. The 90-day average barely remains in El Nino territory at -5.61 not much changed from 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. The SOI is no longer associated with an El Nino (usually required to be more negative than -8.0 but some consider -6.0 or even -5.0 value good enough). Similarly +5 to +8 would be the values that different meteorological agencies would look for to conclude the 30 Day SOI was signaling La Nina. The 30 Day indicates current conditions which based on the SOI are neutral with a slight cool bias. The 90 day may be useful for assessed the lagged impacts.
Post publishing and fairly late in the week (I noticed it on Saturday but the Queensland website may have been updated a day or two earlier as I did not check every day) I was able to update the above table and can now say that as of June 27, the 30 day average was +3.23 (neutral but La Nina-ish) and the 90 Day average was -4.60 clearly remaining El Nino-ish but now in the Neutral Range. That pretty much raps up the El Nino as far as the SOI is concerned. We now focus on +5 to reach La Nina levels..
The MJO or Madden Julian Oscillation is an important factor in regulating the SOI and Kelvin Waves and other tropical weather characteristics. More information on the MJO can be found here. Here is another good resource.
Low-Level Wind Anomalies
Here are the low-level wind anomalies. We now see westerly anomalies which are retarding the development of the La Nina. This is an El Nino pattern.
And now the Outgoing Longwave Anomalies which tells us where convection has been taking place.
In the above graphic, the convection zone east of the Dateline has vanished. There no longer is any sign of El Nino except for dry conditions in the Western Pacific.
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 0.5 C anomaly now only shows up between 165E and the 170W all of which is west of the ONI Measurement Area. But the coolest water at the surface does not extend very far north and south of the Equator (not shown in this graphic) which is why we are in ENSO Neutral and not yet La Nina. Also the cold subsurface water appears to be somewhat slow to rise to the surface. There are some relatively warm areas at the surface east of 120W.
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 now 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 150W. The situation had actually become less La Nina-ish over the past couple of weeks probably due to the MJO. We should see more expansion of the cold water to the west soon and we are beginning to see that.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
We now have to change our focus from tracking the El Nino to tracking the transition to ENSO Neutral and most likely to ENSO La Nina. So I am deleting many of the TAO/TRITON graphics to show how the El Nino developed except one which was close to the maximum. It was not the maximum but it was the one that I froze which was the closest to the maximum that I saved. 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 warm anomaly is almost gone, the cool anomaly extends further into the Pacific but the cool anomaly near Ecuador is actually weaker. So the actual pattern may be more nuanced than is being measured by the models.
Location Bar for Nino 3.4 Area Above and Below
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows but I may not have mentioned that a couple of weeks ago when I did that. The two rows just below that break point contribute to ENSO Neutral and after another break the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016 and may not have announced that in the week when I did that. May 23, 2016 is about when I began to focus on the cool phase of ENSO rather than the warm phase.
Comparing Now to May 23, 2016
Subareas of the Anomaly
Degrees of Coverage
May 23, 2016
In Nino 3.4
May 23, 2016
These Rows Show the Extent of ENSO Neutral Impacts on the Equator
0.5C or cooler Anomaly
0C or cooler Anomaly
These Rows Show the Extent of the La Nina Impacts on the Equator
-0.5C or cooler Anomaly
-1C or cooler Anomaly
-1.5C or cooler Anomaly
If you just look on the Equator, there are 40 degrees of La Nina anomalies with 10 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 when just looking at the Equator. But away from the Equator it is generally warmer when a La Nina is trying to get started. That is why the more complete analysis that follows leads to an ONI value that is not yet cold enough to be considered a La Nina value. You can compare the situation to May 23 in this graphic and La Nina has made no progress but that is probably about to change.
I calculate the ONI each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W ONI measuring area into five subregions (which I have designated from west to east as A through E) with a location bar shown under the TAO/TRITON Graphic). I use a rough estimation approach to integrate what I see below and record that in the table I have constructed. Then I take the average of the anomalies I estimated for each of the five subregions. So as of Monday June 27, in the afternoon working from the June 26 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
(1.4)/5 = +0.3
(-1.1)/5 = -0.2
My estimate of the daily Nino 3.4 ONI has declined dramatically to -0.2 NOAA has reported the weekly ONI to be even lower at -0.4 which is almost in La Nina territory but still ENSO Neutral. Nino 4.0 is being reported slightly cooler 0.5 still raising questions about if and how fast the Warm Pool is migrating to the West as it dissipates. Nino 3.0 is being reported much cooler -0.3. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported as being much cooler at -0.1 and may be the most significant of the readings. WE REMAIN IN ENSO NEUTRAL. I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in graphical form but going back a couple of more years can be found here.
ONI Recent History
The official reading for Mar/Apr/May is now reported as 1.1. I have discussed before the mystery of how the Nino 3.4 (ONI) CFSv2 values above get translated into the ERSST.v4 values shown below and if NOAA feels that working with two sets of books is a good way to operate, who am I argue. Many businesses do the same thing. As you can see this El Nino peaked in NDJ and is now declining and depending on what system you use it is either the 2nd or 3rd strongest El Nino since modern records were kept which is considered to be 1950. You could argue for it being #1 based on a week of readings but few are buying that argument. Still #2 or #3 means it is one of the strongest ever based on the way these events are measured. I will be writing more about that soon in a separate article. I believe the measurement system is inadequate re being useful in forecasting Worldwide weather impacts.
The full history of the ONI readings can be found here. The MEI index readings can be found here.
Although I did not discuss the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures which remains relevant.
You can now see that the El Nino is totally gone. The coolest water, however, is only reaching the surface from 140W to 150W. Either this La Nina is shy or it is a Modoki. Or it is just not happening. I think it is not happening.
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.
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 now we start to track June.
Here is the most recent 30 day period which covers through June 25.
This El Nino has ended in terms of current satisfying the criteria. It is possible that officially it may not be declared dead until the end of June because the Mar - Apr - May value of the ONI at 1.1 satisfies the 0.5 cutoff and it is possible that the Apr - May - Jun average ONI may still meet the criteria even though the daily and weekly values no longer meet the criteria.
We are now speculating on the winter of 2016/2017 which now according to most of the models seems likely to be a La Nina or Neutral with a La Nina bias.
The below is the CPC/IRI forecast issued on June 16, 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.
Notice that in space of a week the probabilities for La Nina have been pushed out a a month. The methodology of these two graphics are different but I think the results are consistent with other information that is available. The La Nina is coming but not as quickly as some had thought.
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. The mean of the model ensemble has recently turned higher for next winter as you can see. You can see the same thing in the Australian POAMA model and the June 1 JAMSTEC model run.
Forecasting Beyond Five Years.
So in terms of long-term forecasting, none of this is very difficult to figure out actually if you are looking at say a five-year or longer forecast. The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS. It includes decade by decade predictions through 2050. Predicting a particular year is far harder.
The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. It may require one more La Nina 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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