Written by Sig Silber
The Near-La Nina is dead (RIP) but NOAA has not yet received authorization to bury it. Nevertheless we should now anticipate more robust MJO activity. In this week’s Report, in addition to the regular information that we provide, we also discuss the ESPI Index which is another way ENSO Events can be measured. It is a very interesting approach. For CONUS, only the Southwest will be dry and only the Northeast will be cool. Winter is over – There is no need to go to Punxsutawney, Pa. Winter ended last week.
AG (Artificial Groundhog)
Now some housekeeping information. For those who want the forecasts beyond three months, we recently reported on the January 19 NOAA 15-Month Forecast and compared the first nine months of the NOAA Outlook with that of JAMSTEC in a special Update that you can get to by clicking here. Remember if you leave this page to visit links provided in this article, you can return by hitting your “Back Arrow”, usually top left corner of your screen just to the left of the URL box. We will of course publish a new 15 Month Update Report shortly after NOAA issues their update on February 16, 2017.
ESPI
It has been suggested that I might understand why what appears to be ENSO Neutral is really a La Nina if I only understood the ESPI Index.
So let’s give it a go. The original paper by the developers of the Index was: “ENSO Indices Based on Patterns of Satellite-Derived Precipitation“ (Click here to read the full article); SCOTT CURTIS: Laboratory for Atmospheres, Goddard Space Flight Center, Greenbelt, Maryland, and Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, Maryland; ROBERT ADLER: Laboratory for Atmospheres, Goddard Space Flight Center, Greenbelt, Maryland; (Manuscript received 1 March 1999, in final form 20 September 1999)
ABSTRACT
In this study, gridded observed precipitation datasets are used to construct rainfall-based ENSO indices. The monthly El Nino and La Nina indices (EI and LI) measure the steepest zonal gradient of precipitation anomalies between the equatorial Pacific and the Maritime Continent. This is accomplished by spatially averaging precipitation anomalies using a spatial boxcar filter, finding the maximum and minimum averages within a Pacific and Maritime Continent domain for each month, and taking differences. The EI and LI can be examined separately or combined to produce one El Nino–Southern Oscillation (ENSO) precipitation index (ESPI). ESPI is well correlated with traditional sea surface temperature (e.g., Nino-3.4) and pressure indices [e.g., Southern Oscillation index (SOI)], leading Nino 3.4 by a month. ESPI has a tendency to produce stronger La Ninas [Editor’s note: “produce” is used in the sense of the index value indicating a stronger La Nina than the value of Nino 3.4. The actual weather pattern is not impacted by the method used to calculate an index]than does Nino-3.4 and SOI. One advantage satellite-derived precipitation indices have over more conventional indices is describing the strength and position of the Walker circulation. Examples are given of tracking the impact of recent ENSO events on the tropical precipitation fields. The 1982/83 and 1997/98 events were unique in that, during the transition from the warm to the cold phase, precipitation patterns associated with El Nino and La Nina were simultaneously strong. According to EI and ESPI, the 1997/98 El Nino was the strongest event over the past 20 years.
Here is the key calculation
Creation of the ESPI (This is a somewhat repetitive explanation but repetition often helps with understanding.)
The index is based on rainfall anomalies in two rectangular areas, one in the eastern tropical Pacific (10°S-10°N, 160°E-100°W) and the other over the Maritime Continent (10°S-10°N, 90°E-150°E). The first step of the procedure involves moving a 10° by 50° block around each box; the minimum and maximum values of all possible blocks is obtained for each box and these are combined to estimate an El Niño precipitation index (EI) and a La Niña precipitation index (LI) which are shown below in the plot below (after normalization). The EI and LI are in turn combined to create the ESPI index. Finally, the ESPI index is normalized to have zero mean and unit standard deviation. A new climatology and normalization factors were calculated in August 2014 from GPCP v2.2 precipitation from 1979 to 2013 (35 full years) and these are used in the present calculation of the ESPI.
- It is a 360 degree situation and ESPI only takes a look at two areas admittedly the two most important.
- The La Nina Pattern and ENSO Neutral pattern are similar in the areas measured with ESPI. So it is not easy for ESPI to separate La Nina from ENSO Neutral.
To explain the above assessment, we take a look at the Walker Circulation which is where the warm water causes evaporation and convection (cloud formation) and where these clouds tend to drop their precipitation which creates downwards air movements. The colors also reveal the location of warmer than climatology and cooler than climatology Sea Surface Temperatures (SST) which are used to define the pattern. Pay special attention to the water along the Equator.
It is difficult to see the difference between the La Nina (above) and Neutral conditions (below) but you should pay attention to the more pronounced (darker – thicker arrows) convection zone in the El Nino state as compared to the Neutral state and similarly the stronger subsidence zone in the La Nina state. Subsidence tends to warm and dry air masses.
It is a lot easier to see the difference between Neutral and El Nino shown below as the pattern tends to reverse with Convection Zones converting to Subsidence (drying) Zones.
A. Focus on Alaska and CONUS (all U.S. except Hawaii)
First Let us focus on the Current (Right Now to 5 Days Out) Weather Situation.
This graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.
Image credit: Center for Western Weather and Water Extremes, Scripps/UCSD. More explanation can be found at Atmospheric Rivers (Click to read full Weather Underground Dr. Bob Henson article)
To turn the above into a forecasting tool click here and you will have a dashboard for a short-term forecasting model.
Here is a national animation of weather fronts 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 links provided below.
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.
U.S. 3 Day to 7 Day Forecasts
Below is a graphic which highlights the forecasted surface Highs and the Lows re air pressure on Day 3. The Day 6 forecast can be found here.
You can enlarge the below daily (days 3 – 7) weather maps for CONUS by clicking on Day 3 or Day 4 or Day 5 or Day 6 or Day 7. These maps auto-update so whenever you click on them they will be forecast maps for the number of days in the future shown.
Here is the seven-day precipitation forecast. More information is available here.
The map below is the mid-atmosphere 7-Day chart rather than the surface highs and lows and weather features. In some cases it provides a clearer less confusing picture as it shows only the major pressure gradients.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. Because “Thickness Lines” are shown by those green lines on this graphic, it is a good place to define “Thickness” and its uses. The 540 Level general signifies equal chances for snow at sea level locations. Remember that 540 relates to sea level.
The graphic that I have been showing below was the Eastern Pacific a 24 hr loop of recent readings. When working, it does a good job of showing what is going on right now. When I published and in recent weeks, that graphic was not being displayed but the NOAA website indicated that was a temporary outage. So for the time being I have substituted a static version of that image which works almost as well. However you can obtain somewhat similar imagery loop image by clicking here. It actually provides more functionality than the either the previously or currently displayed version but you have to click to get it as I have not figured out how to get it to display otherwise. It is really cool imagery and explains a lot. For now you have the static image without clicking but can click to view a more elaborate loop image. The loop image provides a better feel for the speed at which things are taking place. But this Quasi-Polar view provides a lot of insight as to what is happening.
I have stopped showing the Tropical events graphic. We are still having tropical events even though it is January but we can track them with the other graphics that I am presenting including the graphic above and below. They are both the same graphic which you can tell by looking at the date and time stamp but the above graphic covers a larger area and is centered on the Eastern Pacific and the graphic below is centered on North America. That provides more resolution than trying to work with a single graphic that covers a larger fraction of Planet Earth.
Below is the current water vapor Imagery for North America. It is an enlargement of the graphic two above which covers the Eastern Pacific and CONUS and this is an enlargement of the CONUS portion.
Looking at the current activity of the Jet Stream.
First the current situation. Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems. The sub-Jetstream level intensity winds shown by the vectors in this graphic are also very important in understanding the impacts north and south of the Jet Stream which is the higher-speed part of the wind circulation and is shown in gray on this map. In some cases however a Low-Pressure System becomes separated or “cut off” from the Jet Stream. In that case it’s movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream. This usually is more significant for the lower half of CONUS i.e. further south than the Jet Stream.
Now looking at the 5 Day Forecast
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Putting the Jet Stream into Motion and Looking Forward a Few Days Also
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.
When we discuss the jet stream and for other reasons, we often discuss different layers of the atmosphere. These are expressed in terms of the atmospheric pressure above that layer. It is kind of counter-intuitive to me. The below table may help the reader translate air pressure to the usual altitude and temperature one might expect at that level of air pressure. It is just an approximation but useful.
Click here to gain access to 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. This amazing graphic covers North and South America. It could be included in the Worldwide weather forecast section of this report but it is useful here re understanding the wind circulation patterns.
Four- Week Outlook
I am going to show the three-month FMA Outlook (for reference purposes), the Early Outlook for the single month of February, the 6 – 10 Day and 8 – 14 Day Maps and the Week 3 – 4 Experimental Outlook. I use “EC” in my discussions although NOAA sometimes uses “EC” (Equal Chances) and sometimes uses “N” (Normal) to pretty much indicate the same thing although “N” may be more definitive.
First – Temperature
Here is the Three-Month FMA Temperature Outlook issued on January 19, 2017:
Here is the Temperature Outlook for February issued on January 19, 2017
6 – 10 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on January 30 was 3 out of 5)
8 – 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on January 30 was 4 out of 5)
Looking further out.
February 5 to February 13 | February 11 to February 24 |
Alaska will start mixed and become uniformly cool. The Northwest and Southern Tier will be warm. A Northern Tier cool anomaly will be fragmented.and gradually shift to the Northeast. Between the warm and cool anomalies it will be EC. | Alaska will be EC. It will be warm for CONUS more or less south of a line from Oregon to the Florida/Georgia border. A North Central cool anomaly is forecast Between the warm and cool anomalies it will be EC. The transition to the pattern shown in the Week 3 – 4 Forecast from the pattern shown in the 8-14 Day forecast seems to be feasible. |
Remember the Week 3-4 Experimental Outlook was issued last Friday and I am looking at the 6 – 10 and 8 – 14 day forecasts issued today i.e. Monday. So that explains the overlap of dates. Remember that the Week 3 – 4 Forecast covers two weeks so it can appear to not mesh perfectly but actually do so over the two-week period. |
Now – Precipitation
Here is the three-month FMA Precipitation Outlook issued on January 19, 2017
And here is the Updated Precipitation Outlook for February issued on January 19, 2017
6 – 10 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on January 30 was 4 out of 5)
8 – 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on January 30 was 3 out of 5)
Looking further out.
.
February 5 to February 13 | February 11 to February 24, 2017 |
Western Alaska is dry and Eastern Alaska and the Panhandle gradually become wet, CONUS starts mostly wet with a dry and slowly growing Southwest Anomaly. Between the wet and dry anomalies it will be EC. | Western Alaska is dry but the Alaskan Panhandle is wet. For CONUS there are two wet anomalies shown:one in the Northwest but smaller than during Feb 5 to Feb 13. The other dry anomaly is for the East Coast but extending west to the Ohio and Mississippi Rivers. Between the wet and dry anomalies it will be EC, The transition to the pattern shown in the Week 3 – 4 Forecast from the pattern shown in the 8-14 Day forecast seems to be feasible. |
Remember the Week 3-4 Experimental Outlook was issued last Friday and I am looking at the 6 – 10 and 8 – 14 day forecasts issued today i.e. Monday. So that explains the overlap of dates. Remember that the Week 3 – 4 Forecast covers two weeks so it can appear to not mesh perfectly but actually do so over the two-week period. |
Here is the NOAA discussion released today January 30, 2017
6-10 DAY OUTLOOK FOR FEB 05 – 09 2017
TODAY’S ENSEMBLE MEAN SOLUTIONS ARE IN VERY GOOD AGREEMENT ON THE FORECAST 500-HPA CIRCULATION OVER NORTH AMERICA. THE FORECAST BLOCKING PATTERN OVER ALASKA EARLY IN THE PERIOD IS FORECAST TO RETROGRADE TO FAR NORTHEASTERN ASIA DURING THIS PERIOD. THE CONFLUENCE ZONE DOWNSTREAM OF THE BLOCKING PATTERN IS FORECAST TO BE OVER THE ALASKA PANHANDLE INTO WESTERN CANADA. ANOMALOUS RIDGING IS FORECAST SOUTH OF THAT REGION,CENTERED OVER SOUTHERN CALIFORNIA. BROAD NEGATIVE HEIGHT ANOMALIES ARE EXPECTED OVER MUCH OF CANADA, WITH NEARLY CLIMATOLOGICAL TROUGHING FORECAST TO EXTEND SOUTHWARD INTO THE SOUTHEASTERN CONUS.
DUE TO AN INCREASED INFLUENCE FROM AIR MASSES OF PACIFIC ORIGIN, BELOW-NORMAL TEMPERATURES ARE ONLY FAVORED FOR PARTS OF THE NORTHERN PLAINS AND NORTHERN NEW ENGLAND OVER THE CONUS. ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM MOST OF THE WESTERN CONUS EASTWARD ACROSS THE CENTRAL AND SOUTHERN U.S. THIS REGION IS EXPECTED TO BE SOUTH OF THE MEAN FRONTAL ZONE INFERRED BY THE PERIOD-AVERAGE MSLP FORECASTS.
STRONG AND PERSISTENT ONSHORE FLOW IS FORECAST FOR THE PACIFIC NORTHWEST, AND THE ENHANCED MID-LEVEL WESTERLIES OVER THE NORTHERN TIER OF THE CONUS FAVOR A MORE ACTIVE STORM TRACK. OVER THE SOUTHWESTERN U.S., BELOW-MEDIAN PRECIPITATION IS MORE LIKELY DOWNSTREAM OF THE FORECAST RIDGE AXIS. NEAR AND EAST OF THE FORECAST TROUGH AXIS JUST EAST OF THE MISSISSIPPI RIVER, ABOVE-MEDIAN PRECIPITATION IS FAVORED.
OVER ALASKA, ANOMALOUS NORTHERLY MID-LEVEL FLOW IS EXPECTED TO LEAD TO A COOLING TREND DURING THE PERIOD. MUCH OF CENTRAL AND WESTERN ALASKA ARE MORE LIKELY TO SEE BELOW-MEDIAN PRECIPITATION IMMEDIATELY DOWNSTREAM OF THE 500-HPA BLOCKING PATTERN.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG FORECAST TOOLS.
8-14 DAY OUTLOOK FOR FEB 07 – 13 2017
MODELS REMAIN IN FAIRLY GOOD AGREEMENT FOR THE WEEK-2 PERIOD, WITH FURTHER RETROGRESSION OF THE BLOCKING PATTERN OVER THE NORTH PACIFIC AND NORTHEAST ASIA FORECAST ALONG WITH SOME SLIGHT EASTWARD PROGRESSION OF THE RIDGE-TROUGH PATTERN OVER THE CONUS. THE GEFS, INCLUDING THE LATEST 12Z RUN, CONTINUES TO DEPICT MORE ANOMALOUS TROUGHING OVER EASTERN CANADA AND NEW ENGLAND RELATIVE TO THE OTHER GUIDANCE. THE LATEST 12Z CANADIAN ENSEMBLE SYSTEM CONTINUES TO DIVERGE FROM THE GEFS LATER IN THE WEEK-2 PERIOD. TELECONNECTIONS UPON THE FORECAST HEIGHT CENTERS EXTENDING FROM NORTHEAST ASIA TO ALASKA TO SOUTH-CENTRAL CALIFORNIA, REVEAL A RATHER COHERENT PATTERN WITH EACH CENTER BEING WELL-TELECONNECTED TO THE OTHER TWO. THE CORRESPONDING HEIGHT FIELDS SUGGEST THAT A BLEND OF THE GEFS AND ECMWF ENSEMBLE MEANS IS THE MOST APPROPRIATE FORECAST.
BELOW-NORMAL TEMPERATURES ARE FAVORED FOR THE NORTHEAST CONUS AT VERY MODEST PROBABILITIES UNDER SLIGHTLY NEGATIVE 500-HPA HEIGHT ANOMALIES. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE REMAINDER OF THE CONUS, WITH PROBABILITIES EXCEEDING 80 PERCENT IN PARTS OF THE SOUTHWEST. BELOW-NORMAL TEMPERATURES ARE STRONGLY FAVORED OVER MAINLAND ALASKA WITH FORECAST NEGATIVE 500-HPA HEIGHT ANOMALIES EXCEEDING 150 M.
ABOVE-MEDIAN PRECIPITATION IS FAVORED FOR THE NORTHWESTERN CONUS UNDERNEATH PREDICTED ENHANCED PACIFIC FLOW AND IS CONSISTENT WITH TELECONNECTIONS FROM THE THREE AFOREMENTIONED HEIGHT ANOMALY CENTERS. DYNAMICAL MODEL GUIDANCE FROM THE GEFS AS WELL AS THE ECMWF AND CANADIAN ENSEMBLES FAVOR ABOVE-MEDIAN PRECIPITATION FOR THE EAST COAST NEAR THE FORECAST ANOMALOUS TROUGH. THERE ARE ENHANCED PROBABILITIES FOR BELOW-MEDIAN PRECIPITATION ACROSS MUCH OF THE SOUTHERN PLAINS AND SOUTHWEST DOWNSTREAM OF THE FORECAST RIDGE AXIS. WITH ANOMALOUS TROUGHING FORECAST TO BE CENTERED OVER CENTRAL ALASKA, BELOW-(ABOVE-) MEDIAN PRECIPITATION IS FAVORED OVER WESTERN (EASTERN) ALASKA.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY GOOD AGREEMENT AMONG FORECAST TOOLS, OFFSET BY DIVERGING SOLUTIONS AMONG THE VARIOUS ENSEMBLE MEANS LATE IN THE PERIOD.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON FEBRUARY 16
Some might find this analysis click to read interesting as the organization which prepares it focuses on the Pacific Ocean and looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of ENSO events.
Analogs to the Outlook.
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 regularly analyzing this second set of information. The first set which is what I am using today applies to the 5 and 7 day observed pattern prior to today. The second set, which I am not using, relates to the correlation of the forecasted outlook 6 – 10 days out with similar patterns that have occurred in the past during the dates covered by the 6 – 10 Day Outlook. The second set of analogs may also be useful information but they put the first set of analogs in the discussion with the second set available by a link so I am assuming that the first set of analogs is the most meaningful and I find it so.
Day | ENSO Phase | PDO | AMO | Other Comments |
Feb 4, 1954 | El Nino | – | + | Tail End |
Feb 5, 1954 | El Nino | – | + | Tail End |
Jan 25, 1955 | La Nina | – | +(t) | |
Feb 4, 1995 | El Nino | +(t) | -(t) | Modoki |
Feb 11, 1996 | La Nina | + | N | |
Feb 10, 2006 | Neutral | + | + | |
Jan 24, 2007 | El Nino | N | + | Tail End |
(t) = a month where the Ocean Cycle Index has just changed or does change the following month.
One thing that jumped out at me right away was the spread among the analogs from January 24 to February 11 which is 26 days again the same as last week. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, is about January 29. These analogs are centered on 3 days and 4 days ago (January 25 or January 26). So the analogs could be considered to be slightly out of sync with the calendar meaning that we will be getting weather just a little earlier than we would normally get for this time of the year. This is consistent with an early Spring.
For more information on Analogs see discussion in the GEI Weather Page Glossary.
There are four El Nino Analogs, two La Nina Analogs and one ENSO Neutral Analog. Looks like the analogs are suggesting that El Nino Conditions Apply. The phase of the ocean cycles is totally indecisive except that McCabe B is excluded. This suggests that the NOAA 6 – 14 Day Outlook and Experimental Week 3-4 Outlook are as good a guess as any other guess.
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. One of the major reasons that I write this weather and climate column is to encourage a more long-term and World view of weather.
McCabe Condition | Main Characteristics |
A | Very Little Drought. Southern Tier and Northern Tier from Dakotas East Wet |
B | More wet than dry but Great Plains Dry |
C | Northern Tier and Mid-Atlantic Drought |
D | Southwest Drought extending to the North and also the Great Lakes |
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.
Recent CONUS Weather
This is provided mainly to see the pattern in the weather that has occurred recently.
Here is the 30 Days ending January 21, 2017
And the 30 Days ending January 28, 2017
B. Beyond Alaska and CONUS Let’s Look at the World which of Course also includes Alaska and CONUS
Todays Forecast
Additional Maps showing different weather variables can be found here.
Near Term
World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click Here you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the “Back Arrow” usually found top left corner of your screen to the left of the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool.
Although I can not display the interactive control panel in my article, I can display any of the graphics it provides so below are the current worldwide precipitation and temperature forecasts for three days out. They will auto-update and be current for Day 3 whenever you view them. If you want the forecast for a different day Click Here
Precipitation
Temperature
Looking Out a Few Months
Here is the new precipitation forecast from Queensland Australia:
JAMSTEC
JAMSTEC issued their ENSO forecasts and climate maps on January 10. We published a special Update Report on Saturday Night January 21 which can be accessed by clicking here. Remember if you leave this page to visit links provided in this article, you can return by hitting your “Back Arrow”, usually top left corner of your screen just to the left of the URL box. One can always find the latest JAMSTEC maps at this link. You will find additional maps that I do not general cover in my monthly Update Repor.t
Sea Surface Temperature (SST) Departures from Normal for this Time of the Year i.e. Anomalies
And when we look at the current Sea Surface anomalies below, we see a lot of them not just along the Equator related to ENSO.
Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.
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 January 24, 2017 Version and looking at Week 2 of that forecast.
* Moderate Confidence that the indicated anomaly will be in the upper or lower third of the historical range as indicated in the Legend.
** High Confidence that the indicated anomaly will be in the upper or lower third of the historical range as indicated in the Legend
Look at the Western Pacific in Motion. NOAA is having problems with their web site so I have temporarily substituted a static image but you can find a somewhat similar loop version by clicking here. It actually provides more functionality than the displayed version but you have to click to get it as I have not figured out how to get it to display otherwise.
C. Progress of the Cool ENSO Event
Starting with Surface Conditions.
TAO/TRITON GRAPHIC (a good way of viewing data related to the part of the Equator and the waters close to the Equator in the Eastern Pacific where we monitor to determining the current phase of ENSO. It is probably not necessary to follow the discussion below, but here is a link to TAO/TRITON terminology.
And here is the current version of the TAO/TRITON Graphic.
———————————————— | A | B | C | D | E | —————– |
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. The two rows just below that break point contribute to ENSO Neutral and after another break, the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016.
Subareas of the Anomaly | Westward Extension | Eastward Extension | Degrees of Coverage | |||||
As of Today | May 23, 2016 | As of Today | May 23 2016 | As of Today | In Nino 3.4 | Dec 12, 2016 | May 23, 2016 | |
These Rows Show the Extent of ENSO Neutral Impacts on the Equator | ||||||||
0.5C or cooler Anomaly | 175E | 155E | Land | 155W | 90 | 50 | 95 | 50 |
0C or cooler Anomaly | 175W | 155W | LAND | Land | 80 | 50 | 85 | 60 |
These Rows Show the Extent of the La Nina Impacts on the Equator | ||||||||
-0.5C or cooler | 170W130W | 145W | 150W110W | Land | 40 | 30 | 65 | 50 |
-1C or cooler Anomaly | LAND | 140W | LAND | 105W | 0 | 0 | 40 | 35 |
-1.5C or cooler Anomaly | LAND | 135W | LAND | 120W | 0 | 0 | 0 | 0 |
I calculate the current value of the ONI index (really the value of NINO 3.4 as the ONI is not reported as a daily value) each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W Nino 3.4 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 January 30, in the afternoon working from the January 29 TAO/TRITON report, this is what I calculated. [Although the TAO/TRITON Graphic appears to update once a day, in reality it updates more frequently.]
Anomaly Segment | Estimated Anomaly | |
Last Week | This Week | |
A. 170W to 160W | -0.3 | -0.3 |
B. 160W to 150W | -0.5 | -0.4 |
C. 150W to 140W | -0.4 | -0.3 |
D. 140W to 130W | -0.1 | -0.3 |
E. 130W to 120W | +0.1 | -0.5 |
Total | -1.2 | -1.8 |
Total divided by five subregions i.e. the ONI | (-1.2)5 = -0.2 | (-1.8)/5 = -0.4 |
From Tropical Tidbits.com
The above is from a legacy “frozen” NOAA system meaning the software is maintained but not updated. It seems to show a cycle in the Nino 3.4 Index Values. I see that as I monitor the TAO/TRITON graphic. My best guess is that it is related to the MJO but it certainly is intriguing. If this was read like a stock chart one might conclude that there had been a triple bottom and an upside breakout. Below is a “frozen” version of this graphic that I updated two weeks ago with the trend lines for the highs and lows added. I think it is pretty clear that this method of analysis has value. One sees the Nino 3.4 value as reported by the CDAS system to be hovering at the 0C level. But the past few days showed a dip probably related to the MJO.
Sea Surface Temperature and Anomalies
It is the ocean surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. So we are interested in the actual ocean surface temperatures and the departure from seasonal normal temperatures which is called “departures” or “anomalies”. Since warm water facilitates evaporation which results in cloud convection, the pattern of SST anomalies suggests how the weather pattern east of the anomalies will be different than normal.
I had stopped showing the below graphic which is more focused on the Equator but looks down to 300 meters rather than just being the surface. But over the last month there has been sufficient change to warrant including this graphic.
Let us look in more detail at the Equatorial Water Temperatures.
We are now going to change the way we look at a three-dimensional view of the Equator and move from the surface view and an average of the subsurface heat content to a more detailed view from the surface down. Notice by the date of the graphic (dated January 23, 2017) that the lag in getting this information posted so the current situation may be a bit different than shown although this graphic was updated on late Monday so it is more current than usual. The date shown is the midpoint of a five-day period with that date as the center of the five-day period.
This graphic summarizes the situation without providing any detail as to where the warm or cool water is relative to depth.
Below is the pair of graphics that I regularly provide. 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. At different times and today in particular, I have discussed the difference between the actual values and the deviation of the actual values from what is defined as current climatology (which adjusts every ten years except along the Equator where it is adjusted every five years) and how both measures are useful but for different purposes.
The bottom half of the graphic (Absolute Values which highlights the Thermocline) is now more useful as we track the progress of this new Cool Event.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
Although I did not fully discuss the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures which remains relevant. What we had until this morning was only the upwelling phase of the series of Kelvin waves last winter. I guess NOAA has not clearly designated that upwelling phase as a new Kelvin Wave but they did put a “dash” through it in the graphic shown earlier.
And now Let us look at the Atmosphere.
Low-Level Wind Anomalies near the Equator
Here are the low-level wind anomalies.
And now the Outgoing Longwave Radiation Anomalies which tells us where convection has been taking place.
And Now the Air Pressure which Shows up Mostly in an Index called the SOI.
This index provides an easy way to assess the location of and the relative strength of the Convection (Low Pressure) and the Subsidence (High Pressure) near the Equator. Experience shows that the extent to which the Atmospheric Air Pressure at Tahiti exceeds the Atmospheric Pressure at Darwin Australia when normalized is substantially correlated with the Precipitation Pattern of the entire World.
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.
Date | Current Reading | 30-Day Average | 90 Day Average |
Jan 24 | -5.98 | +0.10 | -0.88 |
Jan 25 | +7.31 | ++0.38 | -0.57 |
Jan 26 | +6.32 | +0.64 | -0.10 |
Jan 27 | -3.53 | +0.62 | +0.22 |
Jan 28 | -3.53 | +0.69 | +0.41 |
Jan 29 | -4.28 | +0.46 | +0.42 |
Jan 30 | -0.56 | +0.11 | +0.31 |
The 30 Day Average on January 30 was reported as +0.11 (the same as last Monday) which is ENSO Neutral. The 90 Day Average was reported at -0.83 which is up a bit from last Monday but again as Neutral as an SOI reading can be. Looking at both the 30 and 90 day averages is useful and both are in agreement that we are in ENSO Neutral.
To some extent it is the change in the SOI that is of most importance. It had been increasing in September but now in October and November and December through essentially all of January has stabilized in the Neutral Range. The SOI is not signaling a La Nina but ENSO Neutral..
The MJO or Madden Julian Oscillation is an important factor in regulating the SOI and Kelvin Waves and other tropical weather characteristics. More information on the MJO can be found here. Here is another good resource. December was not particularly favorable for La Nina development and most likely neither will be January in terms of the MJO.The forecasts of the MJO are now suggesting an Inactive Phase. The MJO being Inactive is more favorable for the creation of a La Nina than the MJO being Active. But for a mature westerly displaced cool event the Inactive Phase of the MJO may be negative for that cool event.
The MJO tends to be more important when the situation is ENSO Neutral and the MJO can start the process of an El Nino getting started. It is surprising how weak the MJO has been for months. But it may account for what seems to be a cycling of the estimate of Nino 3.4 as the cool water is blown first to the west and then to the east. This impacts the upwelling also.
Relationship of MJO and ENSO
This Table is a first attempt at trying to related the MJO to ENSO
El Nino | La Nina | MJO Active Phase | MJO Inactive Phase | ||
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Eastern Pacific Easterlies |
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Western Pacific Westerlies |
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MJO Active Phase |
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MJO Inactive Phase |
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Forecasting the Evolution of ENSO
We now have the January both the early-month report from CPC/IRI which I call the reading of the tea leaves in that it is based on a combination of model results and a survey of the views of meteorologists and the mid-month model-based report. [here is an idea to save some taxpayer money – lose the Tea Leaves Report as the real report is issued just a week later].
First Last week;s Tea Leaves report.
The official CPC/IRI ENSO probability forecast, based on a consensus of CPC and IRI forecasters. It is updated during the first half of the month, in association with the official CPC/IRI ENSO Diagnostic Discussion. It is based on observational and predictive information from early in the month and from the previous month. It uses human judgment in addition to model output, while the forecast shown in the Model-Based Probabilistic ENSO Forecast relies solely on model output. This is updated on the second Thursday of every month.
As usual, the Tea Leaves Report tends to be bit more partial to La Nina than the second report of the month. Nevertheless the Tea Leaves Report shows the probability of ENSO Neutral is higher than the probability of La Nina for DJF and we are in the midpoint of that three month .And here is the discussion that was released with the graphic.
During early January 2016 the tropical Pacific SST anomaly was near -0.5C, the threshold for weak La Niña. Many of the atmospheric variables across the tropical Pacific have also remained consistent with weak La Niña conditions, although some have become only weakly so. The upper and lower atmospheric winds have continued to be weakly suggestive of a strengthened Walker circulation, and the cloudiness and rainfall have remain suggestive of La Niña conditions. The collection of ENSO prediction models indicates SSTs, now near the threshold of La Niña, will dissipate to neutral levels by February.
And now the January 19, 2017 fully model-based version
Here is the discussion released with the January 19 Graphic
Recent and Current Conditions
Since August 2016, the NINO3.4 SST anomaly has been near or slightly cooler than -0.5 C, indicative of a weak La Niña SST condition. For December the SST anomaly was -0.42, and for Sep-Nov it was -0.57 C. The IRI’s definition of El Niño, like NOAA/Climate Prediction Center’s, requires that the SST anomaly in the Nino3.4 region (5S-5N; 170W-120W) exceed 0.5 C. Similarly, for La Niña, the anomaly must be -0.5 C or less. The climatological probabilities for La Niña, neutral, and El Niño conditions vary seasonally, and are shown in a table at the bottom of this page for each 3-month season. The most recent weekly anomaly in the Nino3.4 region was -0.3, in the ENSO-neutral level. However, accompanying this ocean condition are atmospheric variables that mainly continue to indicate borderline or weak La Niña. The lower-level trade winds have been enhanced only weakly, while the upper level has shown slightly more convincing westerly anomalies. The Southern Oscillation Index (SOI) had been positive but has averaged just weakly so since November. On the other hand, convection anomalies across the equatorial Pacific have been suggestive of La Niña. Subsurface temperature anomalies across the eastern equatorial Pacific have essentially returned to average. Overall, given the SST and the atmospheric conditions, the diagnosis of weak La Niña remains appropriate but the event is thought likely to be in the process of dissipation.
Expected Conditions
What is the outlook for the ENSO status going forward? The most recent official diagnosis and outlook was issued one week ago in the NOAA/Climate Prediction Center ENSO Diagnostic Discussion, produced jointly by CPC and IRI; it carries a La Niña advisory but called for the weak La Niña to return to neutral by February. The latest set of model ENSO predictions, from mid-January, now available in the IRI/CPC ENSO prediction plume, is discussed below. Those predictions suggest that the SST is most likely to be in the ENSO-neutral range from January-March season forward through most of 2017, but with increased uncertainty from around May onward.
As of mid-January, 12% of the dynamical or statistical models predicts La Niña conditions for the initial Jan-Mar 2017 season, while 88% predict neutral ENSO. At lead times of 3 or more months into the future, statistical and dynamical models that incorporate information about the ocean’s observed subsurface thermal structure generally exhibit higher predictive skill than those that do not. For the Apr-Jun 2017 season, among models that do use subsurface temperature information, no model predicts La Niña conditions, 90% predicts ENSO-neutral conditions, and 10% predicts El Niño conditions. For all model types, the probabilities for La Niña are below 10% for from Feb-Apr through Sep-Nov 2017. The probability for neutral conditions is near or above 90% from Jan-Mar through Apr-Jun 2017, dropping to between 60 and 65% from Jun-Aug through Sep-Nov. Probabilities for El Niño are near zero initially, rise to 25% by May-Jul 2017, and to near 35% from Jun-Aug to Sep-Nov. Recent and Current Conditions
Since August 2016, the NINO3.4 SST anomaly has been near or slightly cooler than -0.5 C, indicative of a weak La Niña SST condition. For December the SST anomaly was -0.42, and for Sep-Nov it was -0.57 C. The IRI’s definition of El Niño, like NOAA/Climate Prediction Center’s, requires that the SST anomaly in the Nino3.4 region (5S-5N; 170W-120W) exceed 0.5 C. Similarly, for La Niña, the anomaly must be -0.5 C or less. The climatological probabilities for La Niña, neutral, and El Niño conditions vary seasonally, and are shown in a table at the bottom of this page for each 3-month season. The most recent weekly anomaly in the Nino3.4 region was -0.3, in the ENSO-neutral level. However, accompanying this ocean condition are atmospheric variables that mainly continue to indicate borderline or weak La Niña. The lower-level trade winds have been enhanced only weakly, while the upper level has shown slightly more convincing westerly anomalies. The Southern Oscillation Index (SOI) had been positive but has averaged just weakly so since November. On the other hand, convection anomalies across the equatorial Pacific have been suggestive of La Niña. Subsurface temperature anomalies across the eastern equatorial Pacific have essentially returned to average. Overall, given the SST and the atmospheric conditions, the diagnosis of weak La Niña remains appropriate but the event is thought likely to be in the process of dissipation.
Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.
The full list of weekly values can be found here.
Here is the NOAA statement on ENSO released on January 12.
EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION issued by CLIMATE PREDICTION CENTER/NCEP/NWS and the International Research Institute for Climate and Society
12 January 2017 ENSO Alert System Status: La Niña Advisory
Synopsis: A transition to ENSO-neutral is expected to occur by February 2017, with ENSO-neutral then continuing through the first half of 2017.
La Niña continued during December, with negative sea surface temperature (SST) anomalies continuing across the central and eastern equatorial Pacific (Fig. 1). The weekly Niño index values fluctuated during the last month, with the Niño-3 and Niño-3.4 regions hovering near and slightly warmer than -0.5°C (Fig. 2). [Editors note: If the Nino 3.4 Temperature Anomaly is warmer than -0.5C it is not La Nina Conditions]. The upper-ocean heat content anomaly was near zero when averaged across the eastern Pacific (Fig. 3), though near-to-below average subsurface temperatures were evident closer to the surface (Fig. 4). Atmospheric convection remained suppressed over the central tropical Pacific and enhanced over Indonesia (Fig. 5). The low-level easterly winds were slightly enhanced over the western Pacific, and upper-level westerly anomalies were observed across the eastern Pacific. Overall, the ocean and atmosphere system remained consistent with a weak La Niña.
The multi-model averages favor an imminent transition to ENSO-neutral (3-month average Niño-3.4 index between -0.5°C and 0.5°C), with ENSO-neutral lasting through August-October (ASO) 2017 (Fig. 6). Along with the model forecasts, the decay of the subsurface temperature anomalies and marginally cool conditions at and near the ocean surface portends the return of ENSO-neutral over the next month. In summary, a transition to ENSO-neutral is expected to occur by February 2017, with ENSO-neutral then continuing through the first half of 2017 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).
Even as the tropical Pacific Ocean returns to ENSO-neutral conditions, the atmospheric impacts from La Niña could persist during the upcoming months (NOAA’s 3-month seasonal outlook will be updated on Thursday January 19th). The current seasonal outlook for JFM 2017 favors above-average temperatures and below-median precipitation across much of the southern tier of the U.S., and below-average temperatures and above-median precipitation in portions of the northern tier of the U.S.
This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPC’s Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 9 February 2017. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: [email protected].
Climate Prediction Center
National Centers for Environmental Prediction
NOAA/National Weather Service
College Park, MD 20740
Forecasts from Other Meteorological Agencies.
Here is the Nino 3.4 report from the Australian BOM (it updates every two weeks)
Discussion (notice their threshold criteria are different from NOAA but also their actuals are higher (less La Nina-ish) than reported by NOAA and yet Nino 3.4 is standard. So someone is incorrect OR WORSE.)
Here is the discussion.
ENSO outlooks
Climate models surveyed by the Bureau indicate that ENSO-neutral conditions are likely for the remainder of the southern hemisphere summer and into autumn. All models indicate the central Pacific is likely to warm over the coming months, suggesting ENSO-neutral or El Niño are the most likely scenarios for winter/spring 2017.
A neutral ENSO state does not necessarily mean average rainfall or temperature for Australia. Rather it means that ENSO patterns are not driving Australia’s weather toward generally wetter or drier conditions. Other shorter-term or smaller-scale climate drivers may dominate and hence influence Australia’s climate.
Half the models surveyed suggest strong warming may occur during autumn, with five reaching El Niño thresholds by mid to late winter. It must be noted that this outlook straddles the autumn [Editor’s Note: Spring in the Northern Hemisphere] predictability barrier—typically the ENSO transition period—during which most models have their lowest forecast accuracy.
We now have the new JAMSTEC January 1, 2017 ENSO forecast.
The model shows that we are in ENSO Neutral. The potential for an El Nino next winter is shown but right now the duration is too short to be recorded as an El Nino. That may change but we are dealing with the Spring Predictability Barrier SPB so it is way too early to be predicting next winter.
The Discussion that goes with their Nino 3.4 forecast has been released.
Jan. 16, 2017 Prediction from 1st Jan., 2017
ENSO forecast:
The latest SINTEX-F prediction suggests the termination of the current weak La Niña Modoki/La Niña state in coming months. Majority of the ensemble members continue to indicate recurrence of a weak El Niño event in the latter half of 2017. It will be interesting if an El Niño event really evolves in 2017, which may suggest a decadal turnabout in the tropical Pacific climate condition to El Niño-like state after a long spell of La Niña-like state, which led to the global warming hiatus.
Indian Ocean forecast:
The predictions continue to suggest development of a positive Indian Ocean Dipole in coming boreal fall. We also expect the Ningaloo Niño off the west coast of Australia in austral fall.
Regional forecast:
On a seasonal scale, most part of the globe will experience a warmer-than-normal condition, while some parts of eastern Canada, northern Brazil, and western Australia will experience a colder-than-normal condition in the boreal spring.
According to the seasonally averaged rainfall prediction, a wetter-than-normal condition is predicted for eastern part of Brazil, western Australia and South Africa during the austral fall. Most parts of southeastern China, Indonesia, eastern Africa, western half of Europe, northern part of South America (including Colombia, Venezuela, and Guyana) will experience a drier condition during the austral fall, whereas the Philippines, Indochina, southern Mexico, and the eastern half of Europe will experience a wetter-than-normal condition. Most parts of Japan will be warmer and drier than normal in boreal spring. However, we note that highly fluctuating mid- and -high latitude climate may not be captured well by the current model.
Indian Ocean IOD (It updates every two weeks)
The IOD Forecast is indirectly related to ENSO but in a complex way.
Discussion
Indian Ocean Dipole outlooks
The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 29 January is +0.05 °C.
The influence of the IOD on Australian climate is weak during December to April. This is due to the monsoon trough shifting south over the tropical Indian Ocean and changing the overall wind circulation, which in turn prevents an IOD ocean temperature pattern from being able to form. Current outlooks suggest a neutral IOD for the end of autumn.
D. Putting it all Together.
Looks like this Cool Event is no longer even properly described as “La Nina Conditions Apply”. But it still is. Who knows when NOAA will figure it out but most likely they will declare this to be ENSO Neutral on February 9. At this time there is now some interest as to whether or not next Summer and Fall will be El Nino situations. The models are suggesting this as a possibility. But it is too soon to tell due to something called the Spring Predictability Barrier or SPB. There are many resources to learn about the SPB and what is being done to reduce the error rate of predictions at this time of the year and one of those resources can be accessed by clicking here .
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. Parts of that discussion are in the beginning section of this week’s Report.
E. Relevant Recent Articles and Reports
Weather in the News
Hotel rates to watch the Groundhogs are outrageous.
Save your money. Winter is over.
Weather Research in the News
Nothing to report.
Global Warming in the News
There will be a Climate Conference sponsored by Los Alamos National Laboratories (LANL) February 5 – 10 in Santa Fe, New Mexico and I will be giving a talk on Southwest Climate on February 10 and we will publish my talk on or about February 10..
F. Table of Contents for Page II of this Report Which Provides a lot of Background Information on Weather and Climate Science
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.
1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)
2. Medium Frequency Cycles such as ENSO and IOD
3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.
4. Computer Models and Methodologies
5. Reserved for a Future Topic (Possibly Predictable Economic Impacts)
G. Table of Contents of Contents for Page 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.
2. Climate Impacts of Global Warming
3. Economic Impacts of Global Warming
4. Reports from Around the World on Impacts of Global Warming
Useful Background Information
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.
El Ninos | La Ninas | |||||||||
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Start | Finish | Max ONI | PDO | AMO | Start | Finish | Max ONI | PDO | AMO | |
DJF 1950 | J FM 1951 | -1.4 | – | N | ||||||
T | JJA 1951 | DJF 1952 | 0.9 | – | + | |||||
DJF 1953 | DJF 1954 | 0.8 | – | + | AMJ 1954 | AMJ 1956 | -1.6 | – | + | |
M | MAM 1957 | JJA 1958 | 1.7 | + | – | |||||
M | SON 1958 | JFM 1959 | 0.6 | + | – | |||||
M | JJA 1963 | JFM 1964 | 1.2 | – | – | AMJ 1964 | DJF 1965 | -0.8 | – | – |
M | MJJ 1965 | MAM 1966 | 1.8 | – | – | NDJ 1967 | MAM 1968 | -0.8 | – | – |
M | OND 1968 | MJJ 1969 | 1.0 | – | – | |||||
T | JAS 1969 | DJF 1970 | 0.8 | N | – | JJA 1970 | DJF 1972 | -1.3 | – | – |
T | AMJ 1972 | FMA 1973 | 2.0 | – | – | MJJ 1973 | JJA 1974 | -1.9 | – | – |
SON 1974 | FMA 1976 | -1.6 | – | – | ||||||
T | ASO 1976 | JFM 1977 | 0.8 | + | – | |||||
M | ASO 1977 | DJF 1978 | 0.8 | N | ||||||
M | SON 1979 | JFM 1980 | 0.6 | + | – | |||||
T | MAM 1982 | MJJ 1983 | 2.1 | + | – | SON 1984 | MJJ 1985 | -1.1 | + | – |
M | ASO 1986 | JFM 1988 | 1.6 | + | – | AMJ 1988 | AMJ 1989 | -1.8 | – | – |
M | MJJ 1991 | JJA 1992 | 1.6 | + | – | |||||
M | SON 1994 | FMA 1995 | 1.0 | – | – | JAS 1995 | FMA 1996 | -1.0 | + | + |
T | AMJ 1997 | AMJ 1998 | 2.3 | + | + | JJA 1998 | FMA 2001 | -1.6 | – | + |
M | MJJ 2002 | JFM 2003 | 1.3 | + | N | |||||
M | JJA 2004 | MAM 2005 | 0.7 | + | + | |||||
T | ASO 2006 | DJF 2007 | 0.9 | – | + | JAS 2007 | MJJ 2008 | -1.4 | – | + |
M | JJA 2009 | MAM 2010 | 1.3 | N | + | JJA 2010 | MAM 2011 | -1.3 | + | + |
JAS 2011 | JFM 2012 | -0.9 | – | + | ||||||
T | MAM 2015 | AMJ 2016 | 2.3 | + | N |
ONI Recent History
The Aug/Sept/Oct reading has been issued and is now updated to be -0.8. The Sep/Oct/Nov preliminary estimate is -0.8 and the preliminary OND has just come out as -0.8 so there would now need for there to be only one more period of -0.5 or colder for this to be eligible to be formally recorded as a La Nina. I suspect there will be one more. NOAA seems to be determined to make that happen. THEIR FUNDING OR CAREER PATHS MAY DEPEND ON THAT.
The full history of the ONI readings can be found here. The MEI index readings can be found here.