posted on 16 February 2016
Written by Sig Silber
This ENSO event records as an El Nino but behaves like a La Nina with respect to CONUS, especially in January, and it would appear most if not all of February. Is it simply because it is a bit westerly displaced? Is it because it is so strong that it has forced the Jet Stream north rather than south as a normal El Nino would do? Is it Climate Change? It may be that the Jet Stream it is so far north that CONUS will receive precipitation from the Southern Branch of the Jet stream - sort of a winter Monsoon - until the situation returns to normal for an El Nino. I am a bit skeptical of that part of the forecast. All of this is discussed in the report this week.
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.
Some may wonder what I mean when I say this El Nino is westerly displaced. Perhaps this graphic will help explain what I mean.
NOAA via one of their lead consultants has issued an update on the current El Nino. It is very informative so I have decided to post most of it. The full article can be found here.
Let's Now Focus on the Current (Right Now to 5 Days Out) Weather Situation.
A more complete version of this report with daily forecasts is available in Part II. This is a summary of that more extensive report. This link Worldwide Weather: Current and Three-Month Outlooks: 15 Month Outlooks will take you directly to that set of information but it may take a few seconds for your browser to go through the two-step process of getting to Page II and then moving to the Section within Page II that is specified by this link.
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.This graphic auto-updates so when you look at it you will see NOAA's latest thinking. The speed at which these troughs and ridges travel across the nation will determine the timing of weather impacts. This graphic auto-updates I think every six hours and it changes a lot.
The level of storm activity in the Western Pacific had picked up when the MJO transitioned to its active phase but that then slowly shifted to its inactive phase. But the MJO may be shifting back to its active phase this week and peaking in about two weeks. Hopefully NOAA will take this into account in their next seasonal update to be released on February 18. The MJO is thought to be relatively unimportant during the winter but perhaps a strong El Nino increases the relevance of the MJO: another research question for NOAA.
Notice the Northern Pacific is like a giant anticyclone with clockwise motion so that which gets sent west due to El Nino is to some extent returned to North America but at higher latitudes.
As I am looking at the below graphic Monday evening February 15, I still see a northern shifted weather pattern.This is the opposite of what one would expect with a strong El Nino so that again is something that needs to be explained. This graphic updates automatically so it most likely will look different by the time you look at it as the weather patterns are moving from west to east.
Below is an analysis of projected tropical hazards and benefits over an approximately two-week period. This graphic is scheduled to update on Tuesday and I am reading the Feb 9, 2016 Version and looking at Week 2 of that forecast.
Below is a graphic which highlights the forecasted surface Highs and the Lows re air pressure on Day 6 (the Day 3 forecast is available on Page II of this Report). This graphic also auto-updates.
Looking at the current activity of the Jet Stream one can certainly see how the Jet Stream is meandering but entering North America north of CONUS.
And here is the forecast out five days.
To see how the pattern is projected to evolve, please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.
This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.
Here is a very flexible computer graphic. You can adjust what is being displayed by clicking on "earth" adjusting the parameters and then clicking again on "earth" to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns.
And when we look at Sea Surface anomalies below,
We see a lot of them not just along the Equator related to El Nino.
Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.
6 - 10 Day Outlook
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 always available in Part II of this report but in the winter I often show both maps as the forecasted weather patterns change during that nine day period.
To put the forecasts which NOAA tends to call Outlooks into perspective, I am going to show the three-month FMA and the updated single month of February forecasts and then discuss the 8 - 14 day Maps and the 6 - 14 Day NOAA Discussion within that framework.
First - Temperature
Here is the Three-Month Temperature Outlook issued on January 21, 2016:
Here is the updated February Temperature Outlook.
Below is the current 6 - 10 Day and 8 - 14 Day Temperature Outlook Maps which will auto-update and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that all winter as the patterns are moving from west to east fairly rapidly.
6 - 10 Day Temperature Outlook
8 - 14 Day Temperature Outlook
Now - Precipitation
Here is the three-month Precipitation Outlook issued on January 21, 2016:
Here is the updated February Precipitation Outlook.
Below are the current 6 - 10 Day and 8 - 14 Day Precipitation Outlook Maps which will auto-update and thus be current when you view them. It covers the nine days following the tail end of the current week. I have included both today and probably will continue to do that all winter as the patterns are moving from west to east fairly rapidly.
6 - 10 Day Precipitation Outlook
8 - 14 Day Precipitation Outlook
Here are excerpts from the NOAA discussion released today February 15, 2016. It covers the full nine-day period and this week I have shown both the 6 -10 Day and the 8 - 14 Day Maps.
Some might find this analysis interesting as the organization which prepares it looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of this El Nino.
Analogs to 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 thing that jumped out at me right away was the very tight spread among the analogs from January 31 to February 15 which is just a bit more than two weeks. It may simply indicate that we are in the heart of winter or suggest that there is a strong basis for this forecast.
1977 showed up a lot in the analogs. That was a particularly dry El Nino. It is somewhat consistent not surprisingly with the 6 - 14 Day Outlook.
It was followed by a wet El Nino Modoki, which is not in the forecast but could happen if this El Nino is slow retreating to the West - which I think is possible. So next winter might be the wet one. Perhaps I should mention that this was when the Pacific "Shifted" to PDO Positive and weather patterns in the U.S. especially the West Coast changed to a wetter phase which started the following year and lasted until at least 1998. You can read about that here and many other places.
The phases of the ocean cycles in the analogs are clearly indicating McCabe Condition A which suggests that our weather may be wetter than suggested in the 6 - 14 Day Forecast but perhaps not until March. The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time.
You may have to squint but the drought probabilities are shown on the map and also indicated by the color coding with shades of red indicating higher than 25% of the years are drought years (25% or less of average precipitation for that area) and shades of blue indicating less than 25% of the years are drought years. Thus drought is defined as the condition that occurs 25% of the time and this ties in nicely with each of the four pairs of two phases of the AMO and PDO.
Historical Anomaly Analysis
When I see the same dates showing up often I find it interesting to consult this list.
With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.
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/running average.
The Inactive Phase of the MJO is weakening and switching over to its active phase so we are beginning to see some SOI values which are more negative. The 30-day average, which is the most widely used measure, as of February 15 is reported at -9.80 which although it is definitely a reading that is associated with an El Nino (usually required to be more negative than -8.0 but some consider -6.0 value good enough) it is much lower (smaller negative number) than last week. The 90-day average remains in El Nino territory at -12.11 little change from last week. The SOI continues to be indicative of an El Nino Event in progress but it is pretty much passed the time of year where it is very meaningful.
Low-Level Wind Anomalies
Here are the low-level wind anomalies. In October, the area from 180W to 160W was of interest and quite intense. There then was an area of interest at 160W which also was quite intense. Now, calm appears to prevail but there recently was a WWB (Westerly Wind Burst) in January near and east of the Date Line related to Tropical Storm Pali which has long since dissipated. But look at the intensity of the wind anomaly associated with that WWB: 14 That might be "all she wrote" for this El Nino as calm winds prevail.
In the below graphic, you can see how the convection pattern recently appeared to be shifting ever so slightly a bit to the east but not as far east as we would expect with a strong El Nino. Now that slight movement to the East has reversed. You can also see convection firing up in the Indian Ocean which may or may not be significant.
Let us now take a look at the progress of Kelvin Waves which are the key to the situation. You can see all five of the Kelvin Waves which created this El Nino in this Hovmoeller graphic. From the earliest to the most recent they can be named #1 through #5, a new episode of warming from 150W to 100W. But this Kelvin Wave appears to be less intense than Kelvin Waves #3 and #4 and is already beginning to leave the NINO 3.4 Measurement Area. This El Nino is dying but not without a fight. I have been wrong before on Kelvin Wave #4 so I am hesitant to say this but it does look to me like Kelvin Wave #5 will not make it very far east and is already in its decline phase. But it does slow the retreat to the west of the Eastern Pacific Subsurface Warm Pool. That is why I believe the transition to ENSO Neutral will proceed more slowly than some have predicted.
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. This El Nino appears to be fading slowly from west to east. The real decline will be from east to west.
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 still 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 no longer extends to 180W but only to 170W which is an indication that the El Nino is losing ground.The 3C anomaly still extends to 160W but now exists only over to 130W. So I am viewing the 3C anomaly as encompassing only about 40% of the Nino 3.4 Measurement Area for the ONI along the Equator but even there not the full area from a latitude perspective which extends five degrees latitude to the north and south of the Equator. It explains why NOAA is coming up with lower ONI estimates. The 4C anomaly is not not even close to intersecting the surface. The 6C anomaly is now almost completely gone and some with more current data are reporting that it is gone. One sees a small 0C anomaly at depth at about 100W. Water temperatures off the Coast of South America near the Equator are returning to normal.
Bottom Graphic (Absolute Values which highlights the Thermocline)
The bottom half of the graphic may soon become more useful in terms of tracking the progress of this Warm Event as it converts to ENSO Neutral and then La Nina. It shows the thermocline between warm and cool water which pretty much looks like this as shown here during a Warm Event. You can see that the cooler water is not yet fully making it to the surface to the east along the coast of Ecuador. In fact, the 25C Isotherm no longer reaches the surface but the 26C isotherm now reaches the surface. We now will pay more attention to the 28C Isotherm as west of that temperature is where convection is more easy to occur. The 28C Isotherm has pretty much remained in the same place for months now but now appears to be migrating west consistent with this El Nino fading.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
Let us compare the situation as reported on October 4 to the most recent graphic. Remember each graphic has two parts the top part is the average values, the bottom part is those values expressed as an anomaly compared to the expected values for that date. Generally I am mainly discussing the bottom of the pairs of graphics namely the anomalies
First the October 4 version which I am providing for purposes of comparison. I "flash froze" the daily value that day so that it would not auto-update.
And then the December 14 version which I also "flash froze" to stop it from updating.
And then the current version of the TAO/TRITON Graphic.
And an earlier but recent reference point re the bottom half of the TAO/TRITON Graphic.
The below table tracks the changes. It only addresses the situation right on the Equator so visually the TAO/TRITON graphic contains more information. But the below table turns visual information into quantitative information so it may be useful. The degrees of coverage shown in the rightmost two columns shows that the extent of the warm water directly on the Equator has been reduced in the past few weeks. The way I constructed the table, the 2.0 anomaly as an example includes water warmer than 2.0C so the 2.5C anomaly is included within it which you can tell by the way I recorded the westward and eastward coordinates. I could have constructed this table in a different way. Note the 3C anomaly no longer exists.
I calculate the ONI each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W ONI measuring area into five subregions (which I have designated from west to east as A through E) with a location bar shown under the TAO/TRITON Graphic). I use a rough estimation approach to integrate what I see below and record that in the table I have constructed. Then I take the average of the anomalies I estimated for each of the five subregions. So as of Monday February 15 in the afternoon working from the February 14 TAO/TRITON report, this is what I calculated.
This is summarized in the following NOAA Table. I am only showing the currently issued version as the prior values are shown in the small graphics on the right with this graphic. Notice that other than NINO 4.0 (which has been propped up by Kelvin Wave #5), the other indices are trending lower and in the far end of the Tropical Pacific this decline rate has increased.
Is this El Nino a Modoki?
It did not evolve as a Modoki unless you consider it to be a continuation of the Faux El Nino Modoki of 2014/2015 which is a possible interpretation. But the Walker Circulation appears to be much like that of a Modoki. These graphics help explain this.
Although I discussed the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures.
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. A major advantage of the Hovmoeller method of displaying information is that it shows the history so I do not need to show a sequence of snap shots of the conditions at different points in time. Nevertheless this Hovmoeller provides a good way to visually see the evolution of this El Nino and later track its demise. One can easily see the historical evolution of this El Nino and the "hot spots" that existed in December and which resulted in the very high ONI readings. But one can also see the western edge of the warm anomaly starting to shift to the East. You can see at the very bottom of this graphic, which shows the most recent readings, the easing of the extreme temperature anomalies in the Nino 3.4 Measurement area (see the scale on the right: red is less warm than dark red) namely 170W to 120W. That explains the slight reduction in NOAA ONI estimate. That is likely to continue to be the trend. You also see the decay in the anomalies from the east between 80W and 110W and even over to almost 140W but they are difficult to see with the resolution of this graphic.You can clearly see the peak anomalies occurred in December.
Recent Impacts of Weather Mostly El Nino but possibly Also PDO and AMO Impacts.
Below are snapshots of 30 Day temperature and precipitation departures over the life of this El Nino. The end date of the 30 day period is shown in the graphic. It is a way of seeing how the impacts of this El Nino have unfolded.
I realize this is a lot of graphics but one needs to look at the history of an event to assess it. As you can see, so far we are not having the expected El Nino Impacts in CONUS.
El Nino in the News
Some think this El Nino resembles the 82/83 El Nino and after the end of that El Nino there was a major flooding event in Arizona in the Fall.
View from Australia
Here is the discussion just released:
IOD (Indian Ocean Dipole)
The graphic comes with only a very short discussion and here is that discussion:
Putting it all Together.
The subsurface reservoir of warm water in the Eastern Pacific has reached its maximum and is now beginning to discharge. This would have occurred earlier if not for Kelvin Waves #4 and now #5. This El Nino has peaked in intensity and is now in rapid decline. We are beginning to speculate on the winter of 2016/2017 which now according to the models seems increasingly likely to be a La Nina.
The below is the CPC/IRI forecast issued on January 21, 2016 followed by the forecast issued on February 11, 2016. It is important to remember that the first report in each month is based on a survey of meteorologists and the second report later in the month is based on the analysis of the forecast models. It is a minor difference but a difference.
Two weeks ago we suggested that it is possible the models will be wrong about how fast the Eastern Pacific Warm Pool moves back towards its La Nina location and it may well be that next winter will be more of a Neutral year or even have some characteristics of an El Nino Modoki and thus be wetter than a typical year as the Warm Pool may still be more in the Central Pacific than shifted all the way west to its La Nina position. This new update from CPC/IRI suggests that his concept is not entering into their thinking. But the early and late month forecasts are based on different methodologies (forecasters early in the month and computer model results later in the month) so small differences may not be significant. This however is a big difference from what was presented two weeks ago
Forecasting Beyond Five Years.
So in terms of long-term forecasting, none of this is very difficult to figure out actually if you are looking at say a five-year or longer forecast. The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS. It includes decade by decade predictions through 2050. Predicting a particular year is far harder.
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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