posted on 21 September 2015
Written by Sig Silber
NOAA has issued a new Seasonal Update. It mostly extends the duration of the impact of this El Nino for about a month as compared to the prior Update issued on August 20. I am not sure exactly why they extended the duration of impacts (and the new NOAA maps are not fully in sync with the NOAA discussion) but clearly the strength of this El Nino, which for some time was known to be in the top five, now appears to most likely compete to be in the top three or even be recorded as having even greater strength than the 1997/98 El Nino. So the modifications to the Seasonal Outlook are logical. That does not mean they will prove to be correct. But it is clear that NOAA now has increased confidence in their analysis.
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 issued an updated Seasonal Outlook on September 17. The JAMSTEC (Japanese) analysis is also available now but other than the ONI forecast (which I show at the end of this report), I will wait until next week to compare the NOAA and JAMSTEC forecasts.
Lets start by looking at October and the three-month period October - November December..
Here are the prior three-month maps:
And here is the new version showing October on top and the three-month maps for OND of this year below the new October single-month maps
Comparing the two graphics, I come to the following conclusions:
A. Compared to the prior Outlook for that three-month period OND which was issued on August 20, 2015, the colder than climatology area in the Southwest has shifted to the west a bit and the warmer than climatology area across the northern tier and both coasts has expanded a bit. With respect to precipitation, the wetter than climatology area is more intense.
B. When looking at the new Outlook for the three-month period OND compared to just October (which allows us to draw some conclusions about November and December), the Lower Mississippi Valley is less warm and the Northwest gets drier in November and December and the wetter than climatology area expands. Both those changes with respect to November and December as compared to October are essentially the same as was presented in the Outlook Issued on August 20, 2015 for those months and are what one expects with a powerful El Nino.
Now let us look at the full set of three-month maps issued which extends to October-November-December 2016 i.e. the end of next year.
Here are the Prior Temperature Maps
And the New Temperature Maps:
What I see is a change in Mar - Apr - May with a larger cooler than climatology area in the Southwest extending to the Southeast which is what you would expect with a powerful El Nino. I also see in the maps extending further out in time that the Mid-Atlantic is no longer shown as being warmer than climatology. This change does not appear to be totally related to the El Nino because it continues through the entire sequence of three-month maps.
Here are the Prior Precipitation Maps
And the Newly Issued Precipitation Maps:
What I see again is a change in Mar - Apr - May with a larger area of wetter than climatology in the Southwest and Florida and also a change two months earlier in Jan - Feb - Mar with a larger and more intense drier than climatology area along the Northern Tier.
Excerpts from the NOAA Discussion Released with these maps. I have not changed any of the discussion but rearranged it a bit.
Now I want to shift focus and take a look at 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 click a second time within the TABLE OF CONTENTS to get to that specific part of the webpage.
First, here is a national animation of weather front 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. 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.
This High moves around a lot so by the time you view this report, it most likely it will be located somewhere else which results in a different circulation pattern. The current position as I am finalizing my report was shown way to the south which to some extent is consistent with the seasonal path of that feature as the Monsoon gets long in the tooth but now all of a sudden I see some additional Highs showing up in this graphic. Remember this is the mid-atmosphere High: the short-term location of the Surface High is shown in the above animation and it is in a more normal location but may not be very effective at influencing circulation that extends into Mexico. 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. You can clearly see the Trough off the West Coast. That appears to be the dominant feature projected to be determining CONUS weather on Day 7.
Because "Thickness Lines" are shown by those green lines on this graphic it is a good place to define "Thickness" and its uses. You can find a full uk.sci.weather style explanation (thorough) at that link or just remember that Thickness measures the virtual temperature (temperature plus moisture content) of the lower atmosphere and is very useful especially in the winter at identifying areas prone to snow and in the summer areas which are going to be hot and humid. Here is a U.S. style explanation of "Thickness" by Jeff Haby who is a valuable source of Haby Hints for anyone who wants an explanation of a meteorological term.
The level of storm activity in the Western Pacific has tapered off quite a bit.
At this time of the year, warm water off of the coast of Mexico, such as from an El Nino or a positive PDO reduces the ocean/land temperature differential and can weaken the Monsoon overall but the cyclones generated by that warm ocean water can enhance the Monsoon for short periods if those cyclones stay close enough to the Mexican coastline. So that is what is being watched now and there seems to be an endless sequence of the storms forming.
But each of these El Nino related tropical storms off the coast of Mexico has the potential, if they are close enough to shore, to introduce moisture into the circulation that enters CONUS and that has been the case this summer but it is sporadic. It also mostly benefits the western side of Mexico and the western reach in CONUS of the Southwest Monsoon but there has been a tendency for some of that moisture to also benefit New Mexico. But overall it has diminished the impact of the Southwest Monsoon as it has cut off any Gulf of Mexico involvement and generally has impacted a smaller number of states than is usually the case. For Mexico, an El Nino is a drought event.
But as shown below there is another storm (Sixteen-east) moving up the Mexican Coast which is already having an impact on CONUS weather but that should only last for a few days but will be significant and complicated as there is another Low-Pressure area that dropped down from the north (the west-coast trough previously mentioned) which might have combined with this tropical depression but now looks to follow it in from the Pacific or perhaps not. The prior storm, Linda, had only a brief impact but it was deadly. I provide some articles on that in the El Nino news section of this report.
The graphic below 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. This graphic is very good at pointing out the divisions between cloudy and not cloudy areas.
As I am looking at this graphic Monday evening, I see a storm (Sixteen-east) that had been over Baja California but now is entering the Southwest and right now there is a lot of dry area north and east of that storm but that most likely will change depending on where the remnants of Sixteen E go after their run-in with the Rocky Mountains. The storm has already encountered mountains in Mexico so it is dropping its moisture rapidly and will decline in importance rapidly. There is additional activity west of the tropical storm and that most likely is going to follow the tropical storm inland and will extend the period of unsettled conditions. But apparently the tropical wave (formerly a storm with counter clockwise circulation) is moving fast and will not persist in any one place for very long but will share its moisture with other weather patterns.
Here is a broader view of projected tropical hazards and benefits over an approximately two-week period. There are two views. One is more focused on the Pacific and one that includes the Indian Ocean and covers Asia more completely. Both graphics auto-update weekly but I think each update on a different day of the week so when you look at them both carefully you might see some difference due to the exact day when they were updated. More information can be found here. The discussion at that link there may update on Tuesdays. I am not sure.
Looking at the first graphic what stands out to me, at the time of publication, is the dry conditions in Central America and the two areas where conditions for the development to cyclones is moderately high both off the coast of Mexico but also off the coast of Florida and Georgia.
This graphic covers a larger part of the world. With this graphic, at the time of publication, you see more activity over by Asia including dry conditions in Indonesia and the Philippines and wet conditions in India in what they call Week 1 of their forecast.
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). We now see something very different than what we have been seeing for a long time and that is a low-pressure system centered on the Alaskan Panhandle which last week appeared to be moving east but which now appears to be a semi-permanent feature finally replacing the RRR. Last week I said:
At that time, I was thinking about the successor to Linda but as it turned out, the pattern of Highs and Lows was able to shear off a piece of Linda which then had tragic consequences for Los Angeles and probably the flooding along the Arizona/Utah border as well. Then the question became the track of the successor storm and now we know the answer to that question as Sixteen-E has moved inland and has entered the CONUS weather system.
We now need to monitor the Jet Stream to see if it is shifting to the South. This is the forecast out five days. The activity still appears to be mostly north rather than south but we are starting perhaps to see that changing a bit.
To see how the pattern is projected to evolve, please click here. Is this the beginning of the shifting to the south of the Jet Stream which one would expect with and El Nino? I think it is too soon to draw that conclusion but time will tell. Perhaps the second half of October.
And when we look at Sea Surface anomalies we see a lot of them not just along the Equator related to El Nino. But the extent of the warm water off the West Coast appears to be a bit less than recently. Also you can see along the Equator that the El Nino is less intense along part of the South American Coast. But the Atlantic has really heated up. But look at the colder water off of the U.K. You can tell a lot from this graphic.
This graphic below shows the changes over the past four weeks as compared to the above graphic which shows the current SST anomalies. Looking at both is helpful in putting the current situation shown above into perspective.
Here you can see the increasing change in the Nino Area which was not as evident last week indicating a big change since last week in that this is a four-week average. You can also see that the cool water west of the U.K. has gotten colder. The situation off of Japan and east into the Pacific to me is very interesting re impacts on precipitation. It has cooled considerably and the PDO nature of the distribution is less than it has been recently. We again see the warming south of Australia which to some extent has canceled out the IOD. We also see the warming in the Atlantic Hurricane Development Area.
6 - 14 Day Outlooks
Now let us focus on the 6 - 14 Day Forecast for which I generally only show the 8 - 14 Day Maps. The 6 - 10 Day maps are available in Part II of this report.
To put the forecasts which NOAA tends to call Outlooks into perspective, I am going to show the three-month OND and single month of October forecasts and then discuss the 8 - 14 day Maps and the 6 - 14 Day NOAA Discussion within that framework.
Here is the Three-Month Temperature Outlook issued on September 17, 2015:
And here is the October only "Early" Temperature Outlook issued on September 17, 2015.
Below 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 September 21 (it updates each day) it appears that October will start out warmer than the full month outlook.
Here is the three-month Precipitation Outlook which was issued on September 17, 2015:
And here is the October "Early" Precipitation Outlook Update Issued on September 17, 2015.
Below is the current 8 - 14 Day Precipitation 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 September 21 (it updates each day) it appears that October will start out drier than the full month outlook for the eastern half of CONUS but wetter for the Northern Tier west of the Great Lakes. This map to me is not showing significant El Nino impacts.
Here are excerpts from the NOAA discussion released today September 21, 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.
One of the first things I noticed was these analogs are all within a ten-year period and that ten-year period is more than fifty years ago. I do not know if this is significant but it jumps right out at you. In the decade of the fifties there were four El Ninos and two La Ninas. But the phases of the ocean cycles were consistent with McCabe Condition D which has been the dominant mode since probably 1998 and is highly correlated with Southwest drought The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. My take away from this is that the PDO has not changed phase and the current PDO plus is related to the current El Nino and the prior near El Nino. It most likely will return to PDO - or PDO neutral next winter.
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 significant. 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.
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.
The 30-day average, which is the most widely used measure, on September 21 was reported as being -14.64 which is clearly a reading associated with an El Nino but slightly lower than last week. The 90-day average also is solidly in El Nino territory at -17.57 which is marginally less negative than last week. The SOI is clearly indicative of an El Nino Event in progress. In fact it is so strong that it may be having impacts that are unusual.
Here are the low-level wind anomalies. It has been fairly calm although there is some new activity around 160E but it is not extreme.
In this graphic, 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 back to the west. You can see the lack of convection over at 120W which is Indonesia but the convection has withdrawn to the West not moved to the East as would be the case with a normal El Nino. That may still happen. In the 1997/1998 El Nino, that did not happen until 1998 which is why the Fall of 1997 was not wet for CONUS.
When I hear that with this El Nino the atmosphere is strongly coupled with the ocean, I really wonder what those meteorological agencies are smoking. It might be true on a worldwide basis but it does not appear to be the case as it impacts CONUS. The convection has not moved east. It has moved away from Indonesia which is an El Nino impact but it is remaining where one would expect it to be if this was a Modoki. This graphic may start to change soon.
Let us now take a look at the progress of the Kevin wave which is the key to the situation. Since February there have been three successive downwelling Kelvin Waves without really an upwelling Kelvin Wave of any consequence to counter their impact. The first wave which started in February was the most effective at getting this El Nino started. The second wave reinforced to some extent but not much and this third (and I believe last) downwelling Kelvin Wave has created an El Nino that will have a major peak coming soon and an extended life but at a diminished strength.
The main impact of this latest Kelvin Wave has already moved east to 150W. You also see the intense activity between just west of 130W and extending to just east of 100W. Perhaps one-third of that is in the area where the ONI is measured. Kelvin waves move east. You also see the cooling down of the water east of 90W but that has filled in recently. The maturation of this El Nino is a slow process and every El Nino has a different length. But if you think of an El Nino as typically lasting about a year or less, then this one is about half through its life.
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. When I examine the current situation as compared to the 1997/1998 El Nino which I described graphically last week, the current El Nino has developed more rapidly. This El Nino is a couple of months further along in its evolution than the 1997/1998 El Nino and will end earlier in the winter than the 1997/1998 El Nino. Also the 1997/1998 had a larger amount of slightly warmer subsurface water in the Eastern Pacific and that water takes time to surface, create convection, and thus cool. Something happens to allow the Easterlies to resume their strength and that in turn moves this water back towards the Western Pacific Warm Pool.
Current Sub-Surface Conditions
Top Graphic (Anomalies)
The above graphic 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 is the most useful of the two and shows where 2C (anomaly) water is impacting the area in which the ONI is measured i.e. 170W to 120W. The 2C anomaly now extends to 160W which is very impressive. There is also a small blip over at 175W. The subsurface warm water is making its way to the surface in the Eastern Pacific especially at 110W to 105W but also to some extent working its way deeper. The 3C anomaly is over to 140W which again is very impressive and which encompasses 40% of the Nino 3.4 Measurement Area for the ONI. One can see how the ONI can continue to increase for some time due to this warm subsurface water that is coming to the surface.
One big issue is where will the +6C and +5C anomaly water go as it reaches the beaches of Ecuador? To the extent it prevents cooler water from reaching the surface, it can enhance 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 and there is some indication that some of it is working its way deeper where it probably will mix with cooler water coming north from further south. 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.
It is important to differentiate between anomalies and actual temperature. The warm anomaly shown in the upper graphic is not covered by colder water as it might appear in the upper graphic but is shown as a warm anomaly because normally water at those depths is colder than it currently is. That is why this warm anomaly does not simply rise to the surface as warm water would normally do but it is preventing cooler water from entering the area as one would expect as summer transitions to Fall. That is why it takes time for this warm anomaly to dissipate.
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 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.
Bottom Graphic (Absolute Values which highlights the Thermocline)
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 yet fully making it to the surface to the east along the coast of Ecuador. However, one now can see the increase in the slope of the thermocline (look at the 25C dividing line for example which has now reached the surface). We can now begin to monitor the 20C Isotherm which is often thought of as being the middle of the thermocline where the slope is also steepening and looks like it may reach the surface fairly soon. I have been saying that for a while but there has been essentially no change. We may want to pay more attention to the 28C Isotherm as west of that temperature is where convection is more easy to occur. Right now that Isotherm intersects the surface near 130W which is a big change since last week.
Taking a close look at the bottom half of the TAO/TRITON graphic, notice that things are continuing to heat up. But so far there are few if any impacts on CONUS. So this raises real questions about how we measure an El Nino and how we do regression analysis on historical El Ninos.
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 September 21 in the afternoon working from the September 20 TAO/TRITON report, this is what I calculated which is bit higher than my calculation last week.
My estimate of the Nino 3.4 ONI has increased to 2.1 with again the gradient from west to east being accentuated. NOAA has today again reported the weekly ONI as being 2.3 and that is certainly a very high level for an ONI even though it is a weekly value not a three-month average. The increase in the NOAA estimated ONI is I believe mostly due to the subsurface water in the Eastern Pacific maintaining the surface temperatures in the Nino 3.4 Measurement Area. The base changes seasonally and I do not have those numbers so it is a little hard for me to tell if the surface is actually warming or if what is happening is that the surface temperature is remaining constant and the base declines as winter approaches so a constant surface temperature records as an increased anomaly. In theory I could compare the graphics from week to week and perhaps figure that out. This warm water or at least warmer than normal for this time of year 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. It gets complicated because it seems that north of the Equator the water is definitely warmer and that is where tropical storms form.
Nino 4.0 is reported as being 1.1. The action which I think is most important to track is in Nino 1+2 which is now reported as being up to 2.6 which is a big increase. One issue remains the extent to which 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. The other issue is that most El Ninos decay from east to west so it will be observed most clearly first in Nino 1+2 and we are not seeing that yet. The highest readings are in Nino 3.0 which some use as a better indicator of an El Nino than Nino 3.4. The reading there is now 2.7.
This is summarized in the following NOAA Table. You can also see the trends in this table. I believe that watching Nino 1+2 is the best way to track when this El Nino will begin to seriously decay. Curiously some of the warm water appears to be going deeper which I think accelerates the decline but I am not sure of that. The subsurface warm water has to be disposed of one way or another for ENSO to move back towards neutral or all the way to La Nina.
Here is another way of looking at it: Unlike the Upper Ocean Heat Anomaly 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. As you can see the warm water rising off the South American Coast has worked its way all the way over to beyond 170W so it fully contributes to the increasing ONI. You can see the anomaly getting more intense at 110W. Until this week we could see that the water immediately off the coast of South American was generally cooling down but that has reversed and that area is showing an increase in the SST anomalies. It is a dynamic process. There remains a lot of subsurface warm water to be disposed of. That is a slow process and will continue for some time. But there are some signs that the process is close to peaking. The projection is for the ONI to be a bit higher than where it stands at 2.3 so we will see if this makes it to 2.4 (for a three-month period) tying the 1997/1998 El Nino or sets a new record. The peak is likely to occur within the next two months but you need a three-month average for it to be an official peak. This suggests that to get an ONI of 2.5, there will need to be a period of time where the weekly ONI is higher than that.
When you break it down by the areas used to track ENSO you get values for each of the four Nino Regions and those values and their trend is shown in the graphic presented just prior to this Hovmoeller.
El Nino in the News
One could argue that this article is not about El Nino. But it is about ocean cycles.
I will report next week on Sixteen-E as I will then be able to discuss the impacts of this Pacific Tropical Depression moving inland.
Might this also be related to the initial impacts of an El Nino and in this case Linda in particular? Some say yes. This tragedy should also remind us that weather events sometimes are given religious significance. That might be a good topic for me to address sometime in the future.
It may or may not be directly related but predicting where a wildfire will move is very important. Read more here.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
First the Temperature and Precipitation Departures from three months ago (Ending Date June 13)
Then the same graphic one month later (Ending Date July 11)
And then the same graphic (Ending Date August 8).
So this gives us a three-month sequence of monthly departures and that series of graphics showed a drying trend which is not exactly what you would expect with an El Nino arriving. For many parts of CONUS, it was a cooling trend also which may be associated with an El Nino.
And now the view from September 19 which is about six weeks later.
As you can see Linda changed the situation a bit for Mexico. But overall there has not been much change from what I presented last week which is a big change from the 30 days ending August 8, 2015.
View from Japan
Putting it all Together.
We are in El Nino conditions now. The actual impacts on CONUS are not clear. We started in the Spring by having wetter conditions than usual in the Southwest but that has tapered off quite a bit. It is probably influencing the IOD to tend towards being positive thus providing a double whammy for parts of Asia and Australia but this is projected above to continue for only a month or two. That by itself should make us wonder what exactly is going on.
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. There does not seem to be an obvious match to any prior El Nino in the modern era which to me means there is no model to use to predict 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 and may be moving back to PDO Negative. 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 as indeed the storm track for hurricanes in the Atlantic is suddenly unusually warm.
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.
We are beginning to speculate on the winter of 2016/2017 which I believe will tend to be ENSO Neutral but I am not so sure that it will not lean towards being a cool event or at least closer to a La Nina than 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 but perhaps for a shorter portion of the winter than NOAA has been predicting. JAMSTEC is predicting that the Spring of 2017 will begin a mild La Nina. That is a long way to make a prediction for a number of reasons including the Spring Prediction Barrier.
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
D,4. Reports from Around the World on Impacts of Global Warming.
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