posted on 03 August 2015
3 August 2015 Weather and Climate Report - NOAA Issues August Update - Perhaps Another Break in the Monsoon
Written by Sig Silber
NOAA updates their August Outlook with marginal changes. El Nino continues to strengthen but with no discernible impacts on CONUS despite heroic efforts by NOAA to conjure up such impacts. The Monsoon is at least temporarily ramping down. That may actually be to some extent an El Nino impact on Eastern Mexico but attribution is always difficult. El Nino provides increased Pacific moisture for the Monsoon but also reduces the differential between land and ocean temperatures so one might say that an El Nino can eat the Monsoon. Mostly it is pretty much normal summer weather for CONUS (usually contiguous U.S. but sometimes probably incorrectly interpreted to include Alaska). Indonesia is drying out. El Nino is a Worldwide Event and right now is mostly impacting other parts of the World.
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.
NOAA as usual at the end of a month updates their early update for the following month, in this case August, which they previously issued as is their normal schedule on the third Thursday of the month.
Here is the commentary that came with the update.
A useful way of looking at this is to compare the updated August outlook with the prior three - month outlook
One always wonders if the changes to the August Outlook suggest changes to the September and October Outlooks as the three month Outlook, which includes the early outlook for August, is not updated at the end of the month from their third Thursday issuance. We can see some minor changes in August that might carry over into September and October and you can see where they are by studying this graphic.
Switching from the Updated August Outlook to 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 fuller report. This link Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks will take you directly to that set of information but in some Internet Browsers it may just take you to the top of Page II where there is a TABLE OF CONTENTS and you may have to wait for a few seconds for your Browser to redirect to the selected section with that Page or if that process is very slow you can simply lick a second time within the TABLE OF CONTENTS to get to that specific part of the webpage.
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 at the link provided above.
The explanation for the coding used in these maps, i.e. the full legend, can be found here.
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. You can see the location of the Four Corners area where Utah, Colorado, Arizona, and New Mexico meet. At this time of the year there is typically a high pressure system near that area and it is called the Four Corners High. When the Four Corners High is centered directly over the Four Corners area, it creates pretty much a block for the Sonoran Monsoon which only visits its northern neighbor when the highs and lows are located in a way that draws the moist air north. Small changes in the location of that feature make a big difference in the weather of probably about ten or more states. Note the Day 7 location of the Four Corners High is now projected to be in Texas which is a bit east of the most favorable location for the circulation to bring up warm moist air from Mexico. But this High moves around a lot so by the time you view this report, it most likely it will be located somewhere else. The models are moving it around run to run and each location results in a different circulation pattern plus the jet stream is involved although I am not showing those graphics here (but they are available on Page II of this Report). If you know where the High is, you can always imagine the clockwise circulation and how that might impact the movement of moisture in from the Gulf of Mexico and up from Mexico and in from the Gulf of California. So this graphic can be very very useful. And it auto-updates, I think every six hours. Even without a weather map, you generally can figure it out. Wind to your back, High to your right, Low to your left.
In the Tropical Weather Outlook graphic below, notice that there is no Pacific Tropical Storm projected to be close enough to the coast to impact CONUS. That is why two weeks ago I raised the question as to a possible temporary break in the action. That is common in the Summer for CONUS. The Sonoran Monsoon which we commandeered and renamed the North American Monsoon or the Southwest Monsoon is a series of bursts and pauses in activity as it impacts the ten or so states in CONUS with the major impacts being with respect to New Mexico and Arizona. That break in the action occurred and after about a week or so the pause ended with the Monsoon regaining its impact on CONUS. But another weak period within the Monsoon may again occur in the near future. There seems to be an active debate on this within the meteorological community.
The below graphic is harder to look at but provides more detail on the water vapor being generated by these storms and the normal summer action of the Southwest Monsoon. It covers a much larger area within CONUS so you can see where the moisture currently is and is going. At this point in time one still sees Monsoonal Moisture entering CONUS via New Mexico and Texas but local forecasters are projecting that this flow of moisture will soon be greatly reduced without clear guidance as to when the flow might resume.
Looking at an even larger area, below is a view which highlights the surface highs and the lows re air pressure on Day 6 (Day 3 can be seen in Part II of this Report). The Eastern Pacific Subtropical High is no longer serving as a block to all storms attempting to move from the Pacific into CONUS. So for at least this week, we do not have to denigrate this feature by calling it the RRR. But it still plays a role in directing most of our weather north into Canada or along the Northern Tier of CONUS and it impacts the positioning of the Four Corners High and thus the strength and location of the Monsoon. The real action remains from the remnants of the cold air intrusion which first impacted the Great Lakes area and extended quite far south and this intrusion from Canada is to a large extent still dominating weather for a large part of CONUS. But this will gradually play out over the next two weeks.
Case Study of a Forecasting Fiasco this Past Week
I would like to discuss excerpts from the NOAA discussion from Wednesday July 29. I realize this is rehashing past history but I found it interesting and important.
And take a look at the analogs for that forecast.
And here is the 6 - 10 Day Precipitation Forecast on July 29
And here is the 6 - 10 Day Precipitation Forecast on July 30
Well in my way of thinking they kind of blew that forecast at last in the sense of lack of day to day consistency even recognizing that each day one day drops out of the 6 - 10 Day Outlook and another day gets included but I am shocked by some of what I read.
A.. ENSO is not properly described as a low-frequency cycle. It is a medium frequency cycle which repeats perhaps every 5 to 9 years on an irregular basis. The 60 year AMO and PDO are low-frequency cycles. This has been known since sometime in the nineties.
B. NOAA wants us to believe that ocean conditions on the days of the analog were consistent with El Nino conditions even though the dates of the analogs corresponded to dates when there was not an El Nino or in one case perhaps an El Nino Modoki. That is illogical.
C. There is no consistency in the analogs re the low-frequency cycles: the PDO and the AMO (which apparently NOAA is not even aware of or at least rarely mentions). Thus IMO the analogs were not suggestive of either El Nino Conditions or any of the McCabe Conditions. The information on the analogs is in the table that I created above the two maps. The analogs were suggestive of forecast difficulty more than anything else. And that is what has occurred with daily changes in the maps issued.
I do not think it was a very good job of forecasting. I hate to appear to be arrogant but really the NOAA forecasters need to learn about the impact of the PDO and AMO on weather patterns and the interconnection of the PDO with El Nino and the difficulty of really separating them when there is an El Nino and warm water off the Pacific Coast. It is better to simply indicate that one has low confidence in the ability to forecast on a particular day than to have a labile forecast which one day is rated as 3 out of 5 on their confidence scale and the next day after drastic changes is labeled as 4 out of 5 on their level of confidence scale. It demonstrates what happens when one starts with a hypothesis (that our weather is being controlled by the El Nino) and then makes forecasts that are consistent with the hypothesis rather than using the available tools and seeing what the analogs are telling us about days 6 - 14.
I recognize that it is not easy to make forecasts right now. Summer generally has less weather which "progresses" across the nation driven by well defined meteorological processes. And we have an unusual El Nino which unlike the Faux El Nino of last year is strong but has progressed so far to the East that it may not be impacting weather patterns in the Northern Pacific at this point in time. So I am not being critical of the ability of NOAA to make accurate forecasts but their effort to shoehorn our current weather into a particular hypothesis whether or not there is evidence that the hypothesis is actually impacting our weather in a significant way right now.
Outlook Days 6 - 14 (but only showing the 8 - 14 Day Maps)
Let's more ahead to today August 3.
Here is the Temperature Outlook for August that was released on July 16, 2015
And here is the updated August Temperature Outlook Issued on July 31, 2015. It is a bit different from the "Early Outlook" but not much.
Last week I compared both the NOAA temperature and precipitation forecasts with those of JAMSTEC. That comparison is still available on Page II of this Report.
And here is the current 8 - 14 Day Temperature Outlook which will auto-update and thus be current when you view it. It covers the week following the current week. Today's 6 - 14 Day Outlook is just nine days of the month and the map shown below of the 8 to 14 day Outlook only shows seven days. The 6 - 10 Day Map is available on Page II of this report. As I view this map on August 3 (it updates each day), it suggests that mid-August may be quite a bit warmer especially for the Southern Tier of CONUS than thought just three days ago. .
Here is the Precipitation Outlook for August that was released on July 16, 2015
And here is the Updated Precipitation Outlook for August released on July 31, 2015. There are some differences but not a lot.
Below is the current 8 - 14 Day Precipitation Outlook which will auto-update daily and thus be current when you view it. And again remember that this map shows only seven days and the 6 - 14 Day map is available on Page II of this report. As I view this map on August 3 (it updates each day), it suggests that Mid-August may have a very different precipitation pattern than anticipated just three days ago. .
Here are excerpts from the NOAA discussion released today August 3, 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.
The first thing I noticed is that today is August 3 and these are analogs centered on dates 3 or 4 days ago which for four of the non-duplicative analogs is a fairly narrow span from July 13 to July 17. Are we going to experience weather that normally would occur about two weeks earlier in the summer? The 1972 powerful El Nino is interesting as is the showing as an analog the powerful La Nina that occurred in the following year. Overall the analogs are slightly La Nina-ish not El Nino-ish. And the forecast reflects that. Again like last week, the analogs suggest to me that the current El Nino is not going to impact our weather significantly over the next two weeks. The ocean phases associated with the analogs this week lean towards McCabe Condition B and to a lesser extent McCabe Condition A. They are both associated with the Atlantic rather than the Pacific being in control. 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
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/rolling average.
This past week has been very favorable for the continued development of the current El Nino. The 30-day average, which is the most widely used measure, on August 3 was reported as being -13.29 which is clearly an El Nino reading although not quite as extreme as the prior week as some of the earlier very extreme values dropped out of the 30 day running average. The 90-day average also is solidly in El Nino territory at -13.64 and it is more negative than last week. The SOI is clearly indicative of an El Nino Event happening.
Here are the low-level wind anomalies. This 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. There has been another mid-Pacific wind burst in the Date Line to 160W area and yet again from 160E to the Data Line. This is consistent with an active SOI.
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 since May shifted to the East from a Date Line (180) Modoki pattern to a 170W to 120W Traditional/Canonical El Nino Pattern. But recently the signs of an El Nino are getting quite faint and shifting to the west. The probably impacts on CONUS are thus lessened. The impacts of an El Nino during the summer in the Northern Hemisphere are subtle.
Let us now take a look at the progress of the Kevin wave which is the key to the situation. I like this Hovmoeller a lot and I have now been able to find a version that autoupdates but is not prettied up. I will take the auto-update feature. 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. But if you look at the bottom of the Hovmoeller which represents the current situation, you can see that this latest Kelvin Wave is moving to the East fairly rapidly and we will see the impact of that on declining ONI estimates fairly soon. The strongest impact along the Equator is no longer shown on this graphic as it occurred a few weeks ago. The main impact of that Kelvin Wave is already close to 140W and about to exit the Nino 3.4 ONI measurement area.
But as you can see there is yet another Kelvin Wave. There is some other information that I will discuss later in this report that suggests this Kelvin Wave is weak so far re the subsurface impacts but it has occurred and is likely to extend the life of this El Nino at least into late Winter and perhaps as projected by the models into early Spring 2016. We do not know yet the intensity of the El Nino beyond its peak in late Fall. I think we can also see the beginning of the next upwelling wave off to the left and in other graphics which may signal the playing out of this series of Kelvin Waves. But continued SOI activity could create yet another Kelvin Wave although I think the Pacific Warm Pool at this point has been substantially depleted. The ENSO "battery" is weakening and will need a La Nina to recharge itself.
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 to 120W. The 2C anomaly now extends to beyond 140W but not quite to 150W. The subsurface warm water appears to be making its way to the surface to some extent in the Eastern Pacific and also over at 170W which is probably related to the new Kelvin Wave. In the Central Pacific we now see a relatively small pod of warm water at about 175E to 170W where the westerly wind burst occurred and where we see above the beginning of one more Kelvin Wave. So far it seems to be fairly minor compared to what has occurred in prior months but that might change. It certainly has delayed the movement of the leading edge of the warmer water to 170W. At that point we are likely to see the ONI decline week to week. We may get some additional insight when we discuss the TAO/TRITON graphic.
The big issue is where will the +6C and +5C anomaly water go as it reaches the beaches of Ecuador? To the extent it surfaces, it can create convection and impact the Walker Circulation which could then provide positive feedback to this El Nino. But that warm water might tend to go north or south or both. That is part of the phase out process for an El Nino and that is where we are in the life of this El Nino. It is peaking and will soon begin its decline. But it is certainly taking its sweet time probably because of the large amount of the subsurface warm water. Water is a very good insulator: I believe it has the second highest specific heat capacity of all known substances. So that means that other than by mixing, that warm water under the surface will stay warm until it rises to the surface where it can be cooled by evaporation (while making clouds) or moves to the north where it will impact Mexico and the the Southern Coast of the U.S. That is part of the basis for models predicting that the ONI of this El Nino will continue to rise but I am a bit skeptical because I see it as rising to the east of the ONI measurement area and not being counted.
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 and you can see that the cooler water is not making it to the surface to the east along the coast of Ecuador. However, one is beginning to see the increase in the slope of the thermocline (look at the 25C dividing line for example) and the increase in that slope would be the final change as the El Nino dies or turns back into a Modoki. I believe that process has already begun and will accelerate. We can now begin to monitor the 20C Isotherm which is often thought of as being the lower edge of the thermocline.
When I put all the information together I still conclude that I believe the ONI will soon peak and begin to decline. The possibility that there could be yet another Kelvin Wave forming, given the strength of the SOI, is a piece of information that at this point is difficult to assess. And there is the issue of how the Walker Circulation might extend the life of this Warm Event. The question of the Walker Circulation is not separate from the question of the forming of another Kelvin Wave. Pretty much all of the issues I am discussing are interrelated.
Back to the TAO/TRITON graphic below, notice that the 1.5C+ anomaly has just about reached 170W. When the leading edge of the warm water area moves beyond 170W, the anomalies in the western parts of Nino 3.4 are likely to start to decline. But at the same time, the subsurface warm water is coming to the surface and that makes the anomalies in the eastern part of Nino 3.4 larger.
To me, this being a summer El Nino, the near-term potential impacts on CONUS may currently be over-hyped since the real impacts will be felt this Fall and Winter. But on the other hand, there are signs that this may develop into a very powerful El Nino in the Fall. So we have to watch what happens carefully..
For my own amusement, 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 (that I have designated A through E (from west to east) with a location bar shown under the TAO/TRITON Graphic) 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 as of Monday August 3 in the afternoon working from the August 2 TAO/TRITON report, this is what I calculated which is basically the same as my calculation last week although the patterns of the anomalies have been changing around quite a bit but the changes have been cancelling each other out.
My estimate of the Nino 3.4 ONI is now 1.7. NOAA has today reported the weekly ONI as being 1.7 a slight increase from what was reported last week and identical with my rough calculation. The increase in the ONI is mostly due to the subsurface water in the Eastern Pacific backing up to the west as it comes to the surface. This warm water certainly impacts the weather in Ecuador and Peru but may not have a direct impact on weather in CONUS other than by spawning tropical cyclones which move north and enter the circulation of the Southwest Monsoon. That activity seems to have decreased recently.
Nino 4.0 is again reported as being 1.0. 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. But the new Kelvin Wave will arrive and then cause another rise in the ONI for the western part of the Nino 3.4 measurement area but so far that to me appears to me of smaller magnitude. This then may well result in a very complicated Walker Circulation pattern.
The real action is in Nino 1+2 which is reported as 2.7. The issue is how warm water off of Ecuador and Peru impacts CONUS weather. I think it has very little impact and that is what we are seeing right now.
Here is another way of looking at it:
This Hovmoeller shows a lot of useful information which I have discussed in previous weeks and I will not repeat the same interpretation over and over again. Today I see a slight tendency for the areas east of Nino 3.4 to be less warm than in prior weeks. That could be an indication of the process slowly working its way through the process of disposing of the subsurface very warm water.
You will not see the ONI substantially decline until the warm water over at 180, The International Date Line, has moved east of 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.or more. I personally believe they have overestimated the peak value of the ONI for this El Nino. Once the warm surface water no longer extends west of 170W, the ONI should begin to decline although apparently the seasonal pattern of sea surface temperatures along the Equator used to calculate the ONI declines into Fall (not sure why that is) and thus the reported ONI values might increase even as the sea surface temperatures (SST) decline. This of course in my mind suggests that there needs to be a seasonal adjustment made to the ONI for purposes of estimating the impacts.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
First the 90-Day
And the 30-Day which shows the more recent impacts
These are not the best graphics because the 90 day includes the most recent 30 days. I could have and perhaps should have displayed the 90 day graphic from a month ago and may consider doing that in the future. I am not sure I have them all saved.
But you can still see how the 30 differs if it does from the 90 day that includes the 30 day. I do not see much change. Parts of Texas and Mexico have dried up. The temperature anomaly has shifted a bit to the east but my friends on the East Coast do not seem to have observed that personally. Overall it is not much of a change but you can look at where you live and may notice more than I have as look at this graphic.
View from Australia
Here is the just released discussion:
IOD (Indian Ocean Dipole)
It comes with only a very short discussion and here it is:
Pulling it All Together
We are in El Nino conditions now. The actually impacts on CONUS are not clear. We have had wetter conditions than usual in the Southwest. But this is the Summer so El Nino impacts on Summer conditions in the Northern Hemisphere are muted even though this is a powerful El Nino. So it is somewhat of a confusing situation as the impacts are not currently proportional to the current strength of this El Nino.
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 mostly in terms of whether or not it will extend into the early part of 2016. All the computer models predict that it will last longer than my mental model suggests to me. 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. Actually the JAMSTEC model is not very different from my assessment. 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 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. But we are beginning to speculate on the winter of 2016/201 which I believe will tend to be ENSO Neutral. One thing is fairly certain for the U.S. it will be less wet and warmer than the winter of 2015/2016 which will be quite wet and cool. JAMSTEC is predicting that the Spring of 2017 will begin a mild La Nina.
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.
A. Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks (Usefully bookmarked as it provides automatically updated current weather conditions and forecasts at all times. It does not replace local forecasts but does provide U.S. national and regional forecasts and, with less detail, international forecasts)
1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)
D. Reserved for a Future Topic (Possibly Predictable Economic Impacts)
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.
D2. Climate Impacts of Global Warming
D3. Economic Impacts of Global Warming
D4. Reports from Around the World on Impacts of Global Warming.
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