posted on 15 June 2015
Written by Sig Silber
Hurricane Carlos is thwarted by the Subtropical Ridge but may produce a mini-Monsoon. El Nino is revving up but overall CONUS may be drier in the short-term due to the Bermuda High and the Eastern Pacific High. Japan has issued a three-season forecast which is dire for India but good news for U.S. Ski resorts so those planning such trips might want to make their travel plans for this Winter early. Depts of transportation might want to stock up on salt, sand and gravel.
This is the Regular Edition 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.
You have seen this before [Author D. Windrim]
We tend to think of Planet Earth as divided into six zones: three in the Northern Hemisphere and three in the Southern Hemisphere. It all starts at the Equator where warm air rises. That air cannot travel into outer space so it moves toward one or the other of the Poles. At some point, the air cools and subsides creating what is called the Subtropical Ridge. It is another way of describing the Hadley Circulation. But the location of this Subtropical Ridge moves to some extent as part of its seasonal cycle but it is also influenced by the phase of the ENSO Cycle. Since we are in an El Nino Phase now, which will for sure last through the summer, there is a tendency for the subsidence process to occur closer to the Equator than usual. We will see how this might impact our weather this summer. It is most likely to impact the Southwest but it should also have impacts in the Southeast as well.
Here is some background information on the Subtropical Ridge.
This from Thursday's forecast from the Albuquerque NWS.
The point is simply that the location of certain semipermanent features such as the Eastern Pacific Subtropical High (sometimes called the North Pacific High or the RRR) and the Bermuda High (Sometimes called NASH or the Azores High) impact our weather. The Bermuda High has a 60 year cycle namely the AMO which is gradually increasing the western extension of the Bermuda High year by year at this point in its cycle. Not totally sure about the movement of the Eastern Pacific Subtropical High but you can learn a lot from this slide presentation. And this graphic tells a story.
Basically this is saying that with PDO Negative, Modokis are more likely and the Hadley Cell is stronger. But right now we have something much more like a traditional Eastern Pacific El Nino and we may have PDO Positive but for sure the Pacific Subtropical High is shifted to the East. Thus we have the Pacific High shifted or extending to the East and the Atlantic High extending to the West which puts two Highs close to each other. That is not the usual way things happen as there normally is H - L - H - L - H etc. not H - H or H - H - H. When you have adjacent clockwise systems, they do not get along well together. Thus the interesting excerpts above from the Thursday Technical Discussion released by the Albuquerque Office of the NWS. Another way of putting it is "we are not sure what will happen to the moisture from Hurricane Carlos". Also there may be a tendency for the two highs to tend to rotate around each other. I think that would most likely cause the Pacific High to move around the Bermuda High. I think I have detected what I have called "rotation" in the past. I am not talking about anything dramatic but something subtle.
We are talking about a Spring and Summer pattern that might show up frequently over the next few decades with the AMO shifting into its Neutral and then Negative Phase and be more exaggerated in El Nino years. Wouldn't it be nice if water planners understood this sort of thing?
Current (Now to 5 Days) Weather Situation:
For daily forecasts it is better to consult your local weather service or the weather service where you are traveling as these will be more specific. But I do have daily forecasts on Page II of the Report so you can always look at those as they auto-update. What I present here is information that normally is not made available via local weather forecasts and which can help you understand what some of the major drivers are for the local forecast.
First here is a national 12 hour to 60 hour forecast of weather fronts shown as an animation. Beyond 60 hours, the maps are available in Part II of the Global Economic Intersection Weather and Climate Report.
The explanation for the coding used in these maps, i.e. the full legend, can be found here.
That animation goes by pretty fast so this might be an easier way to view the current situation.
This map 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.
Along the Southern Tier, right now you may see one, two or even three Highs and are not likely to see a Low. But this graphic updates every six hours so what you see will not be exactly what I am looking at. You can see the ridge which right now is projected for Day 7 to be extended north towards Wyoming and Montana.
There have been two Pacific Hurricanes and the second one had a major impact on CONUS particularly in the Southwest. Now we have Carlos and it is not clear where Carlos can go and where the moisture associated with Carlos can go. It is pretty well blocked so it is likely to die in place. Those right under the storm may not be having a good time. Notice the stream of moisture moving north into Texas on the extreme western edge of the influence of the Bermuda High. Some are calling this a monsoon-like pattern. Is it temporary or truly and early start to the Southwest Monsoon? I am not sure. I suspect not.
Since these storms are not likely to come onshore north of Mexico as intact cyclones, the wind intensity is less important than the extent and location of the cloud pattern in terms of the impact on CONUS. So we can monitor the below to see how this is playing out. There is always the possibility that the outer circulation can enter the circulation of a High or Low over CONUS and provide moisture to that feature. Notice the strange pattern of clouds moving from Mexico into Texas. As that moisture rotates around to the Great Plains and then the Midwest and even the Great Lakes, there could be flooding events.
You can see that the U.S. is overall pretty well supplied with water vapor right now. That is partially due to the warm water off the West Coast - But the Gulf of Mexico has also been a source of moisture. And the Warm Event along the Equator also enhances the level of atmospheric moisture. But the current well supplied situation is likely to change over the next 6 - 14 Days as we have a probably brief break from a more active weather pattern.
Below is another view which highlights the surface highs and the lows re air pressure on Day 3. The Aleutian Low is as I am looking at this graphic is now weak and no longer a major factor other than with respect to Siberia. In fact you have to look hard to find it. The RRR which normally is not active in an El Nino year but is active in an El Nino Modoki Type II year is still in the picture but further north than recently as the Aleutian Low has moved to the west. The RRR still has the ability to keep the Northwest toasty warm and dry by blocking storms from the Pacific. It also appears to have a large North to South Axis. In this graphic as I am looking at it on Monday afternoon, it has split into two separate Highs. It is having a tremendous impact on North American weather.
And here is Day 6. Where is Carlos? Look's like Carlos has been defeated by the army of Highs it needed to navigate.
Outlook Days 6 - 14 (but only showing the 8 - 14 Day Maps)
Here is a graphic of the monthly outlook issued May 31.
And here is the 8 - 14 Day Temperature Outlook issued today June 15, 2015. It covers the week following the coming week.
Today's Outlook is just nine days of the month and the map of the 8 to 14 day Outlook only shows seven days but it does seem substantially different from the month outlook issued on May 31. The Monthly Outlook projected a warming of the CONUS Northern Tier and that does not appear to be happening.
And here is the full month Precipitation Outlook issued May 31, 2015.
Here is the 8 - 14 Day Precipitation Outlook issued today June 15, 2015.
And again remember that this map shows only seven days and the full 6 - 14 Day Outlook only covers nine days. There are 30 days in June. It is now clear how the Bermuda High which is related to the evolving shift in the AMO is playing a role in how this Spring has been evolving. NOAA may want to pay more attention to that.
Here are excerpts from the NOAA release today June 15, 2015.
Analogs to Current Conditions
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 analyzing this second set of information. This first set applies to the 5 and 7 day observed pattern prior to today. The second set which I am not using relates to the forecast outlook 6 - 10 days out to similar patterns that have occurred in the past during the dates covered by the 6 - 10 Day Outlook. That may also be useful information but they put this set of analogs in the discussion with the other set available by a link so I am assuming that this set of analogs is the most meaningful.
It is interesting that we are in an El Nino Condition and have only one El Nino analog which dates back to 1953. There are five ENSO Neutral analogs and two La Nino analogs so it is not surprising that the 6 - 14 Day Outlook is pretty much a neutral forecast. The ocean phases associated with the analogs also do not easily yield a lot of clues. The seminal work on the impact of the PDO and AMO on U.S. climate can be found here.
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.
Progress of the Warm Event
Here are the low-level wind anomalies
The above graphic is not as compact as the graphic provided by the weekly NOAA ENSO Report (more white space) but this version auto-updates so you will always have the latest version of this Hovmoeller. As you can see, the wind gust of a several weeks ago at 160E is over and a subsequent less intense wind gust at 160W to 140W has also played out. The Eastern Pacific now seems to be the only place to have the Easterly wind anomalies and they appear to be moderating.
Here is another graphic that is less compact than the prettied up version published by NOAA on Mondays but which has the advantage of auto-updating.
You can see how the convection pattern (really cloud tops has in May shifted to the East from a Date Line (180) Modoki pattern to a 170W to 120W Traditional/Canonical El Nino Pattern. Prior to May, it was a Modoki and I believe best described as a Modoki Type II. Now it is an out-of-season Traditional El Nino. Hopefully the above graphic will be updated fairly soon as it is a bit out of date.
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 running average and the third is the 90 day average.
This past week, for the third week in a row, the SOI has been very negative for the development of or confirmation of the existence of an El Nino. Usually -8 is considered El Nino Conditions. Sometimes -6 is used for local forecasting in Australia. The 30 average, which is the most widely used measure, on June 15 was reported as being +0.74 which is clearly not an El Nino reading. The 90 day average also is not longer in El Nino territory at -6.38. We may have El Nino Sea Surface Temperatures but the SOI is not in sync which I interpret as indicating that the El Nino is now in the decline phase. It may be a slow decline. This continues to be a very perplexing Warm Event.
Let us now take a look at the progress of the Kevin wave which is the key to the situation. You can see below in the graphic which shows temperature along the Equator as a function of depth, both the magnitude of the anomalies and their size. You can now see where 2C (anomaly) water is impacting the area where the ONI is measured i.e. 170W to120W. The 2C anomaly now extends to about 135W and there is a blip at about 170W. This will be apparent when we discuss the TAO/TRITON graphic and my crude estimation of the ONI value that that I develop from that graphic.
The bottom half of the graphic is not that useful in terms of tracking the progress of this Warm Event as it simply shows the thermocline between warm and cool water which pretty much looks like this as shown here during a Warm Event except now the cooler water is not making it to the surface to the east along the coast of Equator.
Here is an animation that covers a larger area but with the same information. Do not be concerned about the gray streaks. The two in the center are on the left Australia and on the right Central America and the the extreme left and right are Africa with 30E splitting Africa. Not sure exactly why they display this the way they do but I assume it is because the wish to focus on the Equatorial Pacific since that is what counts for the ENSO Cycle. It really shows that when the Kevin Wave crashes into Ecuador, the warm water in this case has gone quite deep and if I had a 3D graphic it would show that it heads north also. But you can see the colder water to the west of this Kevin Wave which is what makes me think the computer models are simply WRONG to the extent that they in some cases are forecasting this Warm Event to continue past year end into 2016. But perhaps it will. .
I like this animation a lot. You can see with regards to 170W to 120W where NOAA measures the ONI how first the water near the surface was under 1C in terms of the anomaly. Then you can see water warmer than 1C rising to the surface. You can see the 2C+ zone of subsurface water which if it rises into the Nino 3.4 zone would signify a very powerful El Nino. Does it look like that will happen? Not to me although I could see it in the eastern end of the 170W to 120W measurement zone. On the other hand, it looks like the 0.5C to 1C anomaly will reach 170W at some point which will then be followed by a decline in the measured ONI. It has certainly moved more slowly than I expected. But it has no choice but to move in that direction. So when that happens, the ONI readings will begin to decline.
Now we will take a look at the the surface anomalies starting with the Daily Sea Surface Temperature anomalies.
The warm areas off the West Coast of the U.S. appear to be somewhat less intense or at least less continuous than as viewed in the seasonal analysis. The situation in the Indian Ocean is clear. It is moving either towards IOD Neutral or IOD Positive which has implications for Australia and most likely is related to our Warm Event. The IOD is defined as the difference between SST anomaly in a western area (60E-80E,10S-10N) and an eastern area (90E-110E,10S-0S).
I think you can see that this index is now either positive or more positive than in the seasonal average. It is not a huge difference.
And how does the IOD impact Australia? This is discussed here.
To what extent are the ENSO and IOD related? That is discussed here.
And there are variations of IOD. So if one wants to really delve into the subject you could read this article.
And here is the monthly. Notice that once you start averaging data, the image become less distinct.
And here is the three-month. You can see the PDO+ Pattern and the El Nino combination of a Modoki Type II and a Canonical/Traditional El Nino and the warm Gulf of Mexico and the Neutral IOD in the Indian Ocean which is gradually becoming Positive. You also see cooler water off of West Africa that suggests a weak Atlantic Hurricane Season.
As you can see, the situation in the Indian Ocean is changing and that does not show up correctly in the three-month graphic. When you look at all three you can see the warmer water shifting to the west.
For my own amusement, I thought I would recalculate the ONI again as I have been doing recently. To refine my calculation I have totally changed my approach and rather than having the anomalies be the way I organized the data, I have divided the 170W to 120W ONI measuring area into five subregions and have mentally integrated what I see below and recorded that in the table I have constructed. Then I take the average of the anomalies I estimated for each of the five subregions. So now I am applying more subjectivity but it should produce a better estimate.
So as of Monday June 15 in the afternoon working from the June 14 TAO/TRITON report, this is what I calculated.
My estimate of the Nino 3.4 ONI is now 1.45. NOAA has today reported the weekly ONI as being 1.3.which I think is an underestimate as in they are not able to keep up as the surface temperature changes on a day to day basis. I was a bit surprised that NOAA was not reporting a slightly higher number today. My calculations however do not auto-update so I may decide to add this analysis to Page II of my Report and update it mid-week. You can already see (in my calculation table) the gradient from West to East that has formed with the higher values in the East and the Western part of the Zone having a smaller anomaly which I believe will soon decline slightly.
Here is another way of looking at it
This Hovmoeller shows a lot of useful information. I could copy it into MSPaint and draw some lines on it but then it would not autoupdate so I do not wish to do that. But take a lot at 140E 160E, 165E, 175E, 120W and 90W. Remember reading from top to bottom one is reading the earlier times to the more current times. So you can see how this Warm Event started at 140E, has moved to 160E and then to 165E and lately you can see movement towards 175E but very slowly. You can also see that suddenly the entire Equator is warmer. You can especially see the impact east of 90W where the Kelvin Wave is crashing into Ecuador. Also more warmer water has expanded towards 120 W. The eastern progress has been slower than I had anticipated. Leaving aside the SOI issue which no longer is consistent with an El Nino this is clearly an El Nino type seas surface temperature (SST) pattern right now. But to me it seems to be a pattern that will play out as it does not appear to be going to be reinforced. It may well play out more slowly that I have anticipated. But it is playing out.
You will not see the ONI decline until the warm water over at 175E has moved to 170W. Until then, the ONI could easily continue to rise but probably not by very much although some models are predicting it will peak at about 2.0. Once the warm surface water no longer extends west of 170W the ONI should begin to decline. I hesitate to offer a new estimate of when that will happen as I have not had the time to play those animations enough times to make an estimate. Plus it depends on the way the subsurface pod of warm water behaves and I do not know enough to predict how that will work its way through. The size of the deep water anomaly may have a bearing on the rate of movement to the east which is slower than what I read in the literature as being more usual. It may also impact where it rises. It has to go somewhere or mix or come to the surface and experience evaporative cooling. We will watch the progress of this Warm Event together because I have provided the graphics that will allow us to do that.
And here is one more way of looking at the situation. I like this Hovmoeller a lot but I have not been able to find a version that autoupdates. You can see the Kelvin Wave that got started in February which started this Warm Event. There have been earlier such events that proved to be not very strong. On the left you see what might be a reverse process called an upwelling wave of cooler water that NOAA refuses to recognize and so far that cooler water has not progressed very far to the East so perhaps NOAA has been correct not to call it an upwelling wave. NOAA has also clearly declared a reinforcing follow-up downwelling Kelvin Wave. It is consistent with the data. So one can see why the computer models have extended the life of this El Nino through the period of time it will take for this reinforcing Kelvin Wave to clear the area where the ONI is calculated. The SOI has at least temporarily ceased to support the development of this El Nino. So the question is no longer does this Warm Event have one more boost to carry it through this coming winter but how much of a boost will this be? Unfortunately, we can not wind this Hovmoeller forward to see what it will look like in a month. We will just have to wait and watch. .
Greater than single Northern Hemisphere winter warm events are fairly rare. I looked at the NOAA list of El Ninos declared since 1950 and there are 19 of them and only two lasted through two winters. One started at the time of year that this Warm Event first reached a ONI 0.5 level and one started later in the season. Both were during a period later recognized as PDO+. So I am just wondering if there is a reason to assume that this particular Warm Event has the staying power of the former champions. The PDO is currently positive but not as positive as recently and what has occurred so far re this Modoki Type II in terms of geographical coverage of warmer water has been minimal so the dissipating impact of the Faux El Nino may have been sufficiently minimal to allow this event to make it through this winter. I will be surprised if that happens but I have been surprised before. There is also the question of when this El Nino started. NOAA shows it starting in SON 2014 which would make it a two-winter event. I do not agree with that classification and I do not think the Asian weather services agree with NOAA either. So I believe they will record this as a single-winter event i.e. the El Nino of 2015/2016. That will also fit a lot better with weather impacts and make scientific analysis more accurate.
Current El Nino Impact
For the Southwest, given that this is normally a dry time, a substantial percentage increase is usually not a major factor in the overall full-year precipitation budget which is why I say that what happens in the winter is more important.....unless this translates into a powerful Monsoon Season which it might. The temperature departures are clear but with all things weather, it is rarely possible to be 100% sure one is attributing the result to the proper cause. But the result is fairly impressive.
The 90 day analysis of temperature and precipitation "departures" is beginning to be impressive. But note that on a 90-day basis California has not really benefited. Most of the precipitation was still south of the Border with Mexico.
But the 30 day analysis is really impressive. You can see the extreme impact of the two Pacific Cyclones on Baja California and the temperature "departures" are pretty dramatic. One can really see the difference between a Faux El Nino Modoki which really only significantly impacted Mexico and the real thing which we have had now for only about six weeks.
View from Japan
Wow.. 2 a.m. Monday Morning and I see a lot of new data from Japan. I have not had a chance to study it carefully. But I see no need to withhold this information from readers so I am presenting it with minimal comments. NOAA issues their Seasonal Update Thursday so next Monday I will compare the two. For now you have the Japanese SINTEX - F forecasts. .
El Nino Index Forecast
Note the forecasted peak ONI of about 2 and the decline starting right before New Year's Eve. This is important because some studies may be showing that the impacts are not just related to the magnitude of the ONI but the rate of change of the ONI. I do not have a reference on that handy but the Queensland precipitation forecast model is based on the rate of change of the SOI Index. There are also lags and perhaps leads as the ENSO changes to the Atmosphere teleconnect to other parts of the World.
Sea Surface Temperature Anomaly June - July - August 2015
Finally it looks like a traditional El Nino Pattern.
Sea Surface Anomaly Forecast Sept - Oct - Nov 2015
Some significant changes are shown here in the Indian Ocean.
Sea Surface Anomaly Forecast Dec 2015, Jan - Feb 2016
They are still showing El Nino into 2016. But it is looking more like ENSO Neutral in terms of the connection of the warm water with the South American Coastline.
June - July - August 2015
A cool summer for the U.S. but warm essentially everywhere else except part of Siberia.
Sept - Oct - Nov 2015
Still cool in the U.S. but not the East Coast. Check out the difference between Eastern Siberia and Alaska. I am just guessing but I would not be surprises if they were projecting a strong Aleutian Low. Check out Chile and Argentina. The Antarctic Shelf Ice might be a problem for shipping this winter which will be summer in that area.
Dec 2015, Jan -Feb 2016
Not everywhere but still basically cold in the U.S. and now also Europe. A negative NAO perhaps. Again I am guessing perhaps the Aleutian Low will be weakening as the El Nino fades away.
June - July - August
Wet in the U.S. Dry in India and Australia. Japan looks wet. Central America dry. The geography between perhaps 90E and the Date Line is very interesting with a wet band further north of a dry band. Exactly where these bands end up could impact Indonesia and other places.
If you know where you live or plan to visit you can probably locate that place on this forecast map.
Sept - Oct - Nov
Still wet in the U.S. and dry in India and part of Australia. Equatorial Africa is wet. Eastern South America is dry. It looks like Indonesia is dry.
Dec 2015, Jan - Feb 2016
Looks like the impacts of the El Nino begin to fade away in this time period. But Southern Europe is wet corresponding to them being cold. India returns to normal. I think Australia is dry but I am having trouble locating it under all those colors. I think you can see the warm water moving back to the Neutral ENSO position getting ready for the next La Nina.
Pulling it All Together.
We are in El Nino conditions now. It is probably influencing the IOD to tend towards being positive thus providing a double whammy for parts of Asia and Australia. The length and intensity of this El Nino is still not clear to me mostly in terms of whether or not it will extend into the early part of 2016. All the models except mine predict that it will. The disagreement is in terms of a couple of months but a couple of months makes a difference in terms of agriculture and other economic impacts. We may or may not have a Pacific Climate Shift as the PDO+ may be simply related to the Warm Event (and quite frankly at this point appears to be). But for now we do have PDO+. The AMO being an overturning may be more predictable so the Neutral status moving towards AMO- is probably fairly reliable but not necessarily proceeding in a straight line. So none of this is very difficult to figure out actually if you are looking at say a five-year forecast.The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report which you can get to below. It includes decade by decade predictions through 2050. Predicting a particular year is far harder.
Click Here for the Global Economic Intersection Weather and Climate Report. Page II where you will find:
My Editor tells me that he will show me how to create a Table of Contents for Part II to make it easier to navigate.
Click Here for Page III which deals with Global Warming.
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