posted on 05 October 2015
Written by Sig Silber
NOAA has released their end of month update of the following month i.e. October. There are some but not major changes. Although there is an obsession with El Nino, CONUS weather right now is being controlled by both oceans. Both coasts are being significantly impacted by their adjacent oceans, but the Atlantic may be keeping the Jet Stream further north than the Pacific prefers which may be delaying El Nino Impacts. The center of CONUS is simply following the calendar but the 6 - 14 Day Temperature Outlook suggests that Fall may be a bit slow to show itself.
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.
At the end of each month, NOAA updates its "Early Release" of the following month outlook which had been released with the full Seasonal Outlook on the Third Thursday of the month. So we now have an updated October Outlook to consider. To do that I like to compare the Updated Outlook with the Prior Outlook.
Prior Temperature Outlook:
New Temperature Outlook:
There is a lot less warmer than climatatology area and that is addressed in a somewhat unsatisfactory way in the NOAA discussion. This was issued on Wednesday and the 6 -14 Outlook on Thursday still showed a much larger warm area and the subsequent 6 - 14 day outlooks through today also show a much larger warmer than climatology area. Thus the outlook is for overall warmer than climatology for half the month of October. I guess if the second half of the month is cooler than climatology, it can blend out to EC. But that does not appear to be likely.
Prior Precipitation Outlook:
New Precipitation Outlook:
The drier than climatology area that was in the Northeast shifted to the west which allowed a wetter than climatology pattern to replace it. The alternative explanation is that tropical activity moved a low-pressure pattern over the East Coast which pushed the high-pressure west. Since everything is connected, both explanations are probably correct but the Atlantic storm story is easier to relate to and it did not take long to see the impact of this updated Outlook. .
Here is the NOAA discussion which mostly describes the maps rather than explaining why the anomalies are where they are. To me simply saying they are there because that is what the models are forecasting is not a very enlightening discussion:
Shifting Focus 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 more extensive 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. During the summer, 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. Looking at the below map it is the Low that is of most importance The current forecasted position of this Low on Day 7, as I am finalizing my report, was shown way to the south in the western part of Mexico which is positioned to draw up subtropical moisture into CONUS (kind of a Fall Monsoon) but probably mostly into Texas. 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 coming down from the Great Lakes. This and the Low off of Baja California appear to be the dominant features 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 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 thickness lines do not yet indicate winter conditions which might be thickness levels below 540 for most areas. The above uk.sci.weather link is is an explanation for the U.K. The levels for CONUS might be slightly different. Obviously these thickness lines do not tell you about mountain peaks. The particular definition of "thickness" on this graphic may not be the best way to define the snow line and this is discussed in the link provided but it is I believe the older method and gives a first approximation which can be further refined as per the discussion in the link. This graphic indicates normal west to east movement of air masses for the most part except along the coasts.
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.
There are no storms currently showing in the below graphic as of the time I am publishing but most likely more will appear as October progresses. It is a dynamic situation with a strong El Nino.
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 pretty good subtropical moisture tap streaming into CONUS with many complicated features to the east and west of the moisture tap.
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 each updates on a different day of the week so when you look at them both carefully you might see some differences due to the exact day when they were updated. More information can be found here. The discussion at that link may update on Tuesdays. I am not sure.
Looking at the first graphic (and as I am looking at it it is the most recently updated but they will take turns being the most recently updated) what stands out to me, at the time of publication, is the dry conditions in Panama and the wetter area that crossed the northern part of Central America last week and is not shown in the below forecast graphics and now extends over to the Southeast of CONUS where it gets tangled up with the East Coast tropical activity.
This graphic below 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. At the time of publication, the above graphic was more current for North and South America. It gets confusing. I realize that.
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 the Aleutian Low returning as one would expect in the winter but very large and tending to locate towards the East which is typical of an El Nino year. The atmospheric pressure systems off the West Coast are complicated and appear in some cases to be forcing the tropical storms moving up the coast off of Mexico inland. The RRR is not present which is a change from the situation the last three or four years. The Aleutian Low is on certain days extended to the south like a trough. So for the short term we have a situation which is more favorable for precipitation entering CONUS from the Pacific but NOAA's interpretation is that this is most likely to occur in the Northwest or Southwest i.e. not in California which still has a mini-version of the RRR "protecting" it.
We now need to monitor the Jet Stream to see if it is shifting to the South. This is the forecast out five days.
To see how the pattern is projected to evolve, please click here. The activity still appears to be mostly north rather than south but we are starting perhaps to see that changing a bit with a southern branch of the Jet Stream reappearing so far sporadically. Is this the beginning of the shifting to the south of the Jet Stream which one would expect with an El Nino? We will see but it would be reasonable for that to occur now.
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. 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. The warm anomalies are not evenly distributed around the world. There is more in the Northern Hemisphere possibly related to there being more land in the Northern Hemisphere. So there may be a connection to the ratio of land to water and the heating of the water surface. The warm water off of California is a wild card in the impacts of this El Nino.
The two graphics below show first the changes over the four weeks (ending September 16) as compared to the above graphic which shows the current SST anomalies and then the changes over the four weeks ending on September 30. Looking at both of these change in anomaly graphics is helpful in putting the current situation shown above into perspective.
In both graphics you can see the increasing change of the warm anomaly in the Nino Area but the pattern is slightly different in the more recent graphic. Of note is the warming of the part of the Atlantic where hurricanes develop. That has impacted the U.S. Southeast and the Bahamas. Also the warm water off the west coast of Australia is very evident and cancels out the IOD. The water west of the U.S. is not as warm as previously. It is less of a PDO positive pattern. The water off of West Africa is warmer. The water south of South America is cooler.
Remember these are four-week averages and graphic above the two four-week average of the changes in the anomalies is the daily readings of the anomalies which auto-updates. You can get a better feel there for the current impacts. It is difficult to relate the actuals to the four week changes but it paints a picture. Remember the actuals are anomalies which is the change from climatology (normal) so we are talking in these two bottom two graphics about the change in the change. It is kind of like the first derivative of the "anomalies" which to confuse things NOAA interchanges the word "anomaly" and "departures" which are the same thing.
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 Updated October Temperature Outlook issued on September 30, 2015.
Below is the current 8 - 14 Day Temperature Outlook Map 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 October 5 (it updates each day) it appears that October will start out defying Fall.
Here is the three-month Precipitation Outlook which was issued on September 17, 2015:
And here is the Updated October Precipitation Outlook Update Issued on September 30, 2015.
Below is the current 8 - 14 Day Precipitation Outlook Map 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 covers seven days of the nine. The 6 - 10 Day Map (the two maps overlap) is available on Page II of this report. As I view this map on October 5 (it updates each day) it appears that CONUS is a bit drier than suggested by the full-month outlook especially in the Plains States all the way down through Texas.
Here are excerpts from the NOAA discussion released today October 5, 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 that there were four 2008 analogs. There were two La Nina analogs and two El Nino and five neutral analogs. Right now the analogs are not reflecting this El Nino. What message is that delivering? The phases of the ocean cycles were most consistent with McCabe Condition D which is associated with Southwest drought and a wet Northwest and East Coast. Both the Atlantic and the Pacific are in control. The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. My take away from this and other information presented in this report 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 and seems to be doing that gradually now. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time.
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 October 5 was reported as being -22.6 which is a very high (negative) level and is clearly a reading associated with an El Nino and much higher than last week. The 90-day average also is solidly in El Nino territory at -17.71. 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. There have been some really high readings this past week.
Here are the low-level wind anomalies. It has been fairly calm although there was recent activity around 160E which turned out to be more significant than I originally thought it would be. But now it again looks like that wind burst has played out but the SOI continues to record extreme negative values. Could there be yet another Kelvin Wave? The area from 160W to 120W is now of interest but we will better understand it in a week.
In the below 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. For sure the SOI is behaving like it would be expected to behave in a strong El Nino. The Easterlies in the Pacific along the Equator are suppressed. So if this is all that is meant, that part has fallen into place. But the Walker Circulation may not be consistent with a standard El Nino. That is my point.
The interconnection with the Indian Ocean seems to be unusual to say the least. The convection in the Pacific along the Equator 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. But it may not be in the direction of more convection further east. The September 30 Update, which is what I am looking at on Monday October 5, suggests that the area of anomalies in convection is strongest over by the Date Line and has not expanded to the east as one might have expected. This is not your standard El Nino.
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 130W. The intense activity between just west of 120W and extending to just east of 100W is no longer evident. Kelvin waves move east so the most intense part of the Kelvin Wave is gradually moving east of the Nino 3.4 measurement area. But there is a hint of something new at 175W to 170W. This could be another Kelvin Wave but I think it is simply the warm water rising in that area. Until recently we were able to see the cooling down of the water east of 90W but that has filled in recently as this latest and perhaps last Kelvin Wave moves east. 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 recently, 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 slightly larger amount of warm 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. This El Nino appears to be fading from west to east.
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 180W which is interesting as this is further west than it has been. The subsurface warm water is making its way to the surface in the Eastern Pacific especially in the vicinity of 110W but also to some extent working its way deeper. The 3C anomaly is over to 150W which again is very impressive and which now encompasses at least 50% of the Nino 3.4 Measurement Area for the ONI. One can see how the ONI has continued to increase.
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. The size of the 6C anomaly is reduced from last week but I do not know if that is real or the way the base used for computing anomalies adjusts with the calendar. The 4C anomaly is no longer intersecting the surface or if so is barely doing so but again I do not know if that is real or the way the anomalies are calculated, displayed etc. but it looks a bit different than last week.This El Nino is peaking now 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 to be 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 has been the case for some time.
Taking a close look at the bottom half of the TAO/TRITON graphic, notice that things are continuing to show significant warm anomalies but not quite as strong as recently. I no longer see the small 3C+ area. But the warm anomaly extends further west. I will "freeze this auto-updating graphic today so that in a week we can compare the two. So far there are few if any impacts on CONUS other than those related to the Pacific Cyclones. So this raises real questions about how we measure an El Nino and how we do regression analysis on historical El Ninos. The weakening of the Easterlies now extends all the way to 130W and further west at the Date Line north of the Equator the Easterlies have changed to Westerlies. So this is a very extreme situation. But there is no longer any warm water left in the Pacific Warm Pool to reinforce this El Nino so it will fade as the heat is transferred into the atmosphere. We should see a spike in global temperatures.
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 October 5 in the afternoon working from the October 4 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 after rounding remains at 2.3 with less of a gradient from west to east. NOAA has today reported the weekly ONI as being 2.4 and that is certainly a very high level for an ONI even though it is a weekly value not a three-month average. It is slightly higher than the 2.3 reported last week. The increase in the NOAA estimated ONI is I believe mostly due to the surface warm anomalies extending further west in the Nino 3.4 Measurement Area. The base used to calculate the anomalies changes with the calendar 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 again 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 2.8 which is high. 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.
This is summarized in the following NOAA Table which has changed only slightly since last week. You can also see the trends in this table which now seem to be back in the increase mode. 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.
One wonders about these calculations as they appear to not be related to the "adjusted" version of the NOAA forecast model which was discussed last week. So it is not clear to me how this El Nino will be officially recorded. July-August-September has been recorded as having an ONI of 1.5. In the above graphic eyeballing it you might conclude that the three months were observed as being 1.6, 2.0 and 2.3. So the impact of adjusting these observed values to what is considered "adjusted" is not obvious to me.
SST Surface Anomaly Hovmoeller
Here is another way of looking at it: Unlike the Upper Ocean Heat Anomaly Hovmoeller (I call it the Kelvin Wave Hovmoeller) which takes an average down to 300 meters, this just measures the surface temperature anomaly. It is the surface that interacts with the atmosphere. As you can see the warm water rising off the South American Coast had (or at least the value of the anomaly when calculated) worked its way all the way over to beyond 170W so it fully contributes to the increasing ONI but is showing some signs of stalling. One can see the anomaly getting more intense at 100W. Until recently, 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 2.4 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. To a large extent this Hovmoeller is the historical record of the TAO/TRITON data that I present.
El Nino in the News
This may be a useful link for understanding what took place in South Carolina but I have not had the time to go through all the articles. It is not clear that this was an El Nino impact but everything is connected.
Here is an article on the Bahamas which were impacted by the same storm.
Here is information on forecasts difficulties related to Hurricane Joaquin. A question now is will this storm as it curves impact Europe? Even a weakened storm can cause a lot of precipitation.
It may be some time before we can discuss this storm on a scientific basis. It is still a news event.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
First the Temperature and Precipitation Departures from four 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).
And again four weeks later (Ending Date October 3, 2015)
This provides a four-month sequence of snapshots of the four-week departures from normal as this El Nino has progressed.
You can see these four graphics as well as I can and it is difficult to describe the changes that have taken place over four periods of time because of the large number of changes. Currently we see:
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. Last week we had serious flooding in South Carolina and the Bahamas but it is not clear that this event was related to this El Nino but everything is connected. The El Nino 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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