Short-term the lower Mississippi Valley seems prone to flooding issues and tornadic activity. Some models are predicting an Active Phase of the MJO for April and May. This could consolidate the two branches of the Jet Stream and trigger Kelvin Waves. If there was warm water in the Indo-Pacific Warm Pool this could induce an El Nino.
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But there is very little warm water in the Indo-Pacific Warm Pool as there has not been enough time for the Sun to work its magic. But the feedback loops in ENSO are complex so anything can happen but we believe that the models are overreacting to the warm water off the Coast of South America. Betting on the MJO to deliver an El Nino requires having a lot of confidence in models that have not been very reliable re predicting the MJO. There is no doubt that there is already what some are calling a Coastal El Nino. Here is a photo of recent impacts.
Figure 1. Huachipa district, east of Lima, on March 19, 2017. Flash floods and landslides hit parts of Lima, where most of the water distribution systems have collapsed and people are facing drinking water shortages. Photo credit: ERNESTO BENAVIDES/AFP/Getty Images. Story Source:WunderBlog
Now some housekeeping information. For those who want the forecasts beyond three months, we recently reported on the March 16 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. More recently we provided an Update on the possible El Nino this Winter that many meteorological models are forecasting. We think it is implausible and our report 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.
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 view of the past 24 hours provides a lot of insight as to what is happening.
Below is the same graphic as above but without the animation to show the current situation with respect to water vapor imagery for North America. It also covers more of CONUS.
Tonight, Monday evening March 27, 2017, as I am looking at the above graphic, we see activity along the Northern Tier in the West and up from the Gulf of Mexico in the East.
Looking at the current activity of the Jet Stream.
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 especially in the winter 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 with the cutoff lows being further south than the Jet Stream.
One sees the current jet stream above. Notice the entry into CONUS along the West Coast. Also notice the Split Jet Stream but with the Southern Branch deep into Mexico. The entry point for the Northern Branch is fairly far north but the Jet Stream is bringing the storm track south.
This graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.
This graphic is about Atmospheric Rivers i.e. thick concentrated movements of water moisture. More explanation on Atmospheric Rivers can be found by clicking here. The idea is that we have now concluded that moisture often moves via narrow but deep channels in the atmosphere rather than being very spread out. This raises the potential for extreme precipitation events.
Mostly this evening we see the activity originating from the Gulf of Mexico and that probably is what is showing up in New England. We also see a tropical event north of the Antilles. There may be more moisture approaching the West Coast.
You can convert the above graphic in to a flexible forecasting tool by clicking here. One can obtain views of different geographical areas by clicking here.
60 Hour Forecast.
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.
The Aleutian Low is as I look at this Day 3 forecast is a single unified Low located south of the Aleutians with central air pressure of 972 hPa which is quite low for this time of the year. Remember this is a forecast for Day 3 not the current situation. The average sea level air pressure in the winter is 1001 hPa and 994 hPa for a non-split Low. This graphic changes every six hours.
The High Pressure off of the West Coast, the familiar RRR, on Day 3 has surface air pressure of 1028 hPa. The pattern now pretty much blocks Pacific Storms from entering CONUS. This raises questions about the NOAA 6 - 10 Day forecast.
I provided this K - 12 write up that provides a simple explanation on the importance of semipermanent Highs and Lows and another link that discussed possible changes in the patterns of these highs and lows which could be related to a Climate Shift (cycle) in the Pacific or Global Warming. Remember this is a forecast for Day 3. It is not the current situation but Day 3 is not very far out.
Now looking at the 5 Day Jet Stream Forecast
You can see that moisture is forecast to continue to stream into the West Coast but at a high latitude. Remember this is a H3 view meaning a view at 30,000 feet which is about six miles high.
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.
Re the above, H8 is a frequently used abbreviation for the height of the 850 millibar level, H7 is the 700 mb level, H5 is the 500 mb level, H3 is the 300 mb level. So if you see those abbreviations in a weather forecast you will know what they are talking about.
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.
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 cumulative precipitation forecast. More information is available here.
We see again a forecast for substantial precipitation along the Northern West Coast but less than recently. There is also plenty of moisture in the Eastern Half of CONUS. This has the potential for a lot of violent weather and flooding. The graphic shows the cumulative precipitation over a seven-day period.
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.
Thinking about clockwise movements around High Pressure Systems and counter- clockwise movements around Low Pressure Systems provides a lot of information.
What you can see in the above graphic (six hours ago) was a complicated pattern with the Northern Tier being pretty much zonal but a trough further south impacting on Day 7 New Mexico, Oklahoma and Texas with a ridge at the same longitude to the north. So that was a bit unusual. There was another trough entering CONUS which was shown impacting the Northwest. Upon returning from dinner, the forecast now is much less extreme and shows a more moderate trough in the center of CONUS with ridges on the West Coast and East Coast. What a difference six hours makes in NOAA-World. If you do not like the forecast, wait six hours.
Remember this is a forecast for Day 7. Note the 540 Thickness Line re the above discussion of thickness and snow likelihood. This week it looks like the 540 line will not impact CONUS other than where there are mountains except for possibly Northern Maine but that also has changed during the past six hours and no longer is shown as likely.
Four- Week Outlook
Census Bureau Regions and Sub-Regions are not always the best way to describe weather patterns but I am showing this map as I may sometimes use their terminology to describe regions.
I have changed my approach at the suggestion of a reader. I will first present the 6 - 10 Day and 8 - 14 Day Maps and the Week 3 - 4 Experimental Outlook. Then for reference purposes I will show first the Early Outlook for the single month of April followed by the three-month AMJ Outlook, The prior approach was to first provide the One Month and Three-Month maps for reference purposes and then the three more recently issued forecasts made by dynamical models. The new approach is to present the information in the sequence of the time frame to which the forecast applies. 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
I am staring with a summary of small images of the three short-term maps. This summary provides a quick look. I could have made it so you could click and enlarge the small images but for the moment I prefer that you go past the summary for the larger versions because if I set up such links, the chances increase that you will not back out of the link properly and get lost. For most people the summary with the small images will be sufficient. Following the graphic with the three small images, you can find the larger maps and a discussion and for reference purposes I then provide the April and three month AMJ maps which are issued and updated less frequently than the first three maps shown.
Small Images of Temperature Maps
6 to 10 Days
8 to 14 Days
Weeks 3 and 4
The above shows the progression of forecasts from six days out through four weeks out. Larger maps with discussion appear below.
Now the larger maps followed by a discussion that describes what is happening and any inconsistences that I see.
6 - 10 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on March 27, 2017 was 4 out of 5)
8 - 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on March 27, 2017 was 3 out of 5)
I thought this was interesting.
For Temperature, there was not a single "B" for belong normal shown in this forecast. There are seven "N" for normal shown. For those who think it is just a warm spell the definition of "N" is adjusted every ten years and the adjustments have all been higher. So I think it is significant. All the "N"s were in Alaska or New England.
Looking further out.
Consolidation of 6 - 10, 8 - 14 and Experimental Week 3-4 Forecasts
(Interpreted on March 27, 2017
April 2 to April 10
April 8 to April 21
The period starts warm except for small areas of EC the location of which has been changing from one forecast to the next. As the period unfolds, the warm anomaly extends almost everywhere except for Western Alaska and Northern New England which are EC.
Perhaps 2/3 of CONUS is projected to be warm. This covers the Eastern half of CONUS that in the precipitation maps is projected to be wet but also includes the Southeast which is projected to be dry and extends further to the west than the wet area. Alaska is projected to be warm. There is a small area of the Northwest projected to be cool. Everywhere else it is projected to 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 for reference purposes, here is the Temperature Outlook for the month shown in the Legend. This map is first issued on the Third Thursday of the Month for the following month and then updated on the last day of the month. The 6 - 10 day and 8 - 14 Day update daily and the Week 3/4 Map Updates every Friday so usually these are more up to date. Note that the three maps above may cover a slightly different time period since they update as the month progresses and the map below covers a particular month shown in the Legend. It is useful if one wants to understand how that month is forecast to play out.
Here is the Temperature Outlook issued on the date and for the three-month period shown in the Map Legend. Again this is provided for reference only. It is the same map that is included in our Saturday night report that follows NOAA third Thursday of the month Seasonal Outlook Update. It provides a longer time frame than the above maps. It uses a totally different methodology as it is not possible to use the dynamical models to project out three months. The dynamical models work by figuring out how the current conditions will evolve over a fairly short period of time. To look out three months or longer the approach is more statistical using the forecasted ENSO Phase and Climate Trends.
The theory behind using dynamical models for short-term forecasts and statistical models for longer-term forecasts makes perfect sense but sometimes we see that the short term forecasts and then the actuals do not match the statistical forecasts very well. This tells us that either the statistical forecasts were based on incorrect assumptions or that the actual weather patterns are different from what we might have expected. .
Now - Precipitation
I am staring with a summary of small images of the three short-term maps. This summary provides a quick look. I could have made it so you could click and enlarge the small images but for the moment I prefer that you go past the summary for the larger versions because if I set up such links, the chances increase that you will not back out of the link properly and get lost. For most people, the summary with the small images will be sufficient. Following the graphic that has the three small images, you can find the larger maps and a discussion that ties the three maps together. For reference purposes, I then provide the April and three month AMJ maps which are issued and updated less frequently than the first three maps shown.
Small Images of Precipitation Maps
8 to 14 Day
Weeks 3 and 4
Now the larger maps followed by a discussion that describes what is happening and any inconsistencies that I see.
6 - 10 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on March 27, 2017 was 4 out of 5)
8 - 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on March 27, 2013 was 3 out of 5)
Looking further out.
Consolidation of 6 - 10, 8 - 14, and Week 3-4 Forecasts
Interpreted on March 27, 2017
April 2 to April 10
April 8 to April 21, 2017
Alaska and the Panhandle are wet. CONUS starts wet except for the Extreme West and the Northern Great Lakes which are dry. The West Coast dry anomaly gradually rotates counterclockwise taking it south and east as the period unfolds. Between the wet and dry anomalies, it is EC. The overall wet coverage gradually declines as the period unfolds.
The Eastern Half of CONUS except for the Southeast is projected to be wet. A small part of the Alaska in the southeast but not the Aleutians is projected to be wet. Everything else is projected to 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 for reference purposes is the Precipitation Outlook for the month shown in the Legend. This map is first issued on the Third Thursday of the Month for the following month and then updated on the last day of the month. The 6 - 10 day and 8 - 14 Day update daily and the Week 3/4 Map Updates every Friday so usually these are more up to date. Note that the thee maps above may cover a slightly different time period since they update as the month progresses and the map below covers a particular month shown in the Legend. It is useful if one wants to understand how that month is forecast to play out.
Below is the Precipitation Outlook issued on the date and for the three-month period shown in the Map Legend. Again, this is provided for reference only. It is the same map that is included in our Saturday night report that follows the NOAA third Thursday of the month Seasonal Outlook Update. It provides a longer time frame than the above maps. It uses a totally different methodology as it is not possible to use the dynamical models to project out three months. The dynamical models work by figuring out how the current conditions will evolve over a fairly short period of time. To look out three months or longer, the approach is more statistical using the forecasted ENSO Phase and Climate Trends.
The theory behind using dynamical models for short-term forecasts and statistical models for longer-term forecasts makes perfect sense but sometimes we see that the short-term forecasts and then the actuals do not match the statistical forecasts very well. This tells us that either the statistical forecasts were based on incorrect assumptions or that the actual weather patterns are different from what we might have expected.
Here is the NOAA discussion released today March 27, 2017.
6-10 DAY OUTLOOK FOR APR 02 - 06 2017
TODAY'S DYNAMICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA CIRCULATION PATTERN PREDICTED OVER NORTH AMERICA. TROUGHS ARE EXPECTED OVER THE ALEUTIANS AND WESTERN ALASKA, AND THE SOUTH CENTRAL CONUS, WHILE RIDGES ARE FORECAST OVER PARTS OF EASTERN ALASKA AND WESTERN CANADA, AND OVER THE EASTERN CONUS. TODAY'S MANUAL BLEND DEPICTS NEGATIVE HEIGHT ANOMALIES OVER THE ALEUTIANS, WESTERN ALASKA AND PARTS OF THE SOUTH-CENTRAL CONUS WITH WEAK POSITIVE HEIGHT ANOMALIES ACROSS THE REMAINDER OF THE CONUS AND ALASKA.
ABOVE NORMAL HEIGHTS AND 500-HPA SOUTHWESTERLY FLOW ENHANCE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR MOST OF CENTRAL AND EASTERN ALASKA. AN ANOMALOUS RIDGE IN THE EASTERN U.S. ENHANCES THE LIKELIHOOD FOR ABOVE NORMAL TEMPERATURES OVER MOST OF THE EASTERN AND NORTH-CENTRAL CONUS. NEAR TO ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE WESTERN CONUS, CONSISTENT WITH CALIBRATED REFORECAST TEMPERATURE TOOLS FROM GFS ENSEMBLE FORECASTS.
MULTIPLE SHORTWAVE TROUGHS AND ENHANCED INFLOW FROM THE GULF OF MEXICO INCREASE CHANCES OF ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE CONUS, FROM THE ROCKIES TO THE EAST COAST. THE HIGHEST ODDS FOR ABOVE MEDIAN PRECIPITATION ARE FORECAST FOR THE SOUTH-CENTRAL CONUS. BELOW-MEDIAN PRECIPITATION IS FAVORED FOR PARTS OF CALIFORNIA AND THE SOME OF THE GREAT LAKES REGION DUE TO RIDGING UPSTREAM. ONSHORE FLOW FAVORS ABOVE MEDIAN PRECIPITATION FOR MOST OF ALASKA.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL SOLUTIONS AND AMONG THE FORECAST TOOLS.
8-14 DAY OUTLOOK FOR APR 04 - 10 2017
TODAY'S ENSEMBLE MEAN DYNAMICAL MODEL FORECASTS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA FOR THE WEEK-2 PERIOD. TROUGHS ARE FORECAST OVER THE ALEUTIANS AND PARTS OF THE WESTERN AND EASTERN CONUS, WHILE RIDGES ARE FORECAST OVER PARTS OF EASTERN ALASKA AND WESTERN CANADA. WEST-SOUTHWESTERLY ZONAL FLOW IS INDICATED OVER THE EASTERN SEABOARD. ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN.
ABOVE NORMAL 500HPA HEIGHTS AND/OR SURFACE ANOMALOUS SOUTHEASTERLY FLOW TILT THE ODDS TO NEAR TO ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CENTRAL AND EASTERN CONUS. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR NORTHERN ALASKA AND THE WESTERN CONUS, CONSISTENT WITH CALIBRATED REFORECAST TEMPERATURE TOOLS FROM GFS AND ECMWF ENSEMBLE FORECASTS.
SLIGHTLY NORMAL HEIGHTS TILT THE ODDS TO BELOW MEDIAN PRECIPITATION FOR THE SOUTH-CENTRAL CONUS. PRECIPITATION ESTIMATES FROM THE GEFS ENSEMBLE MEMBERS FAVOR ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE REMAINDER OF THE CONUS, CONSISTENT WITH A LONGWAVE TROUGH OVER THE CENTRAL CONUS. ONSHORE FLOW FAVORS ABOVE MEDIAN PRECIPITATION FOR THE MOST OF MAINLAND ALASKA, EXCEPT FOR THE WESTERN COAST.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL SOLUTIONS AND AMONG THE FORECAST TOOLS. OFFSET BY MODERATE SPREAD AMONG THE ENSEMBLE MEMBERS
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON APRIL 20
Some might find this analysis which you need to 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.
Mar 15, 1984
Mar 16, 1984
Apr 2, 1986
Apr 7, 1991
Just before a Modoki
Mar 22, 1993
Mar 16, 2003
Tail end Modoki Type 1
Mar 20, 2003
Tail end Modoki Type I
Mar 21, 2003
Tail end Modoki Type I
Mar 23, 2007
(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 March 15 to April 7 which is 23 days which is a fairly tight spread. 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 March 26. These analogs are centered on 3 days and 4 days ago (March 22 or March 23). So the analogs could be considered to be out of sync with the calendar meaning that we will be getting weather that we would normally get three or four days later in the calendar.
There are three El Nino Analogs, six ENSO Neutral Analogs and zero La Nina analogs. Looks like the analogs are suggesting that ENSO Neutral to El Nino Conditions apply. The phases of the ocean cycles of the analogs point clearly to McCabe Conditions A and C which are opposites calling into question the high confidence NOAA has in their 6 to 14 day forecast.
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.
Sometimes it is easier to work in black and white especially if you print this report so there is a black and white version from the later report by the same authors. Darker corresponds to red in the color graphic i.e. higher probability of drought.
Very Little Drought. Southern Tier and Northern Tier from Dakotas East Wet. Some drought on East Coast.
More wet than dry but Great Plains and Northeast are dry.
Northern Tier and Mid-Atlantic Drought
Southwest Drought extending to the North and also the Great Lakes. This is the most drought-prone combination of Ocean Phases.
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 March 18, 2017
The Great Plains Drought has really expanded into New Mexico. The temperature pattern is much muted. Remember this is a 30 day average so seven recent days have been added and seven more distant days have been removed so the map changes slowly.
And the 30 Days ending March 25, 2017
Wow the Southern Tier of the U.S. is really in drought. The Temperature anomalies have moderated especially on the East Coast. Remember this is a 30 Day Average so seven more recent days are added and seven more distant days are removed so the graphics changes slowly.
B. Beyond Alaska and CONUS Let's Look at the World which of Course also includes Alaska and CONUS
I will be including the above graphic regularly as it really helps with understanding why things are happening the way they are. I am trying to find the versions of the above that vary my month.
Notice that below the map there is a tabulation of magnitude of the current anomalies by region. That is a large number for the Arctic:
This graphic is actuals not anomalies. Notice the demarcation areas between wet and dry areas. The Southern Hemisphere is quite wet and the Northern Hemisphere is quite dry. CONUS, North Africa and Asia are particularly uniformly dry and it looks like Australia and South Africa and Southern South America want to join in.
Additional Maps showing different weather variables can be found here.
Near Term (Currently Set for Day 3 but the reader can change that)
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
Notice the wet belt along the Equator. Brazil continues to be wet. A large low pressure system dominates the North Pacific.
It is projected to be hot in much of Africa and India. That is a pretty dark red for India.
Looking Out a Few Months
Here is the new precipitation forecast from Queensland Australia:
It is kind of amazing that you can make a worldwide forecast based on just one parameter the SOI and changes in the SOI. Notice the change to a dry CONUS and the overall slightly dry orientation of the forecast except for much of Southern Africa.
JAMSTEC issued their ENSO forecasts and climate maps on March 15. We published a special Update Report on Saturday Night March 18 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 Report.
Sea Surface Temperature (SST) Departures from Normal for this Time of the Year i.e. Anomalies
My focus here is sea surface temperature anomalies as they are one of the two largest factors determining weather around the World.
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. I have switched over to the weekly analysis. It is less visually interesting but probably more meaningful and the Daily has have some update issues. . .
I switched to the weekly graphic as it is more stable than the daily view but it did not seem to update this week so I have added the daily product which I will comment on this week.
Remember this discussion is all about anomalies not absolute temperatures so it is deviation from seasonal norms.
The Tropical Pacific is overall NEUTRAL. The waters off of South America are very warm. This looks like how an El Nino originates.
The cool anomaly needed to have PDO+ is there but the horseshoe shaped warm anomaly around it is not there. The cool water to too far to the Northeast and the warm warm it south of it but not east and North of the cool water. The NOAA Pacific Decadal Oscillation (PDO) Index as reported by NOAA (Washington University also reports the PDO but using a different methodology which results in higher index numbers) has been 2016-January 0.79, 2016- February +1.25, 2016- March 1.55, 2016- April +1.62. 2016- May +1.45, 2016-June +0.78, 2016-July 0.15, 2016-August -0.87, 2016- September -1.06, 2016- October -0.68, 2016- November +0.84, 2016- December +0.55 and now January revised to 0.13 and February was recently reported at +0.08. The above reading for February is PDO Positive but not by much. Here is the full list of PDO values.
The Western Pacific in the Northern Hemisphere is cool.
The Gulf of Mexico is quite warm especially to the west. The waters off of North American are warm. The North Atlantic is warm especially north of Scandinavia. The list of Atlantic Multidecadal Oscillation (AMO) values can be found here.
The Caspian Sea and the Mediterranean are ever so slightly warm. The Black Sea is Neutral.
The waters at mid-latitude East of South America are now warm. The big story is the warm South Pacific. Is this a new flavor of El Nino?
The Indian Ocean is mostly cool especially to the East.
I have some additional commentary on this static analysis of the anomalies below where I examine the four-week change in these anomalies.
Since these are "departures" or "anomalies", it is not a seasonal pattern that is being shown it is the changes from what we would expect on a seasonal basis. It is important to understand that and interpret my comments above in the context of anomalies not absolute temperatures.
Below I show the changes over the last four weeks in the Sea Surface Temperature (SST) anomalies.
Comparing a four-week graphic to a prior four-week graphic is always tricky since only 25% of the data has changed and I am not showing the former graphic (it is in last week's report). I add the new one to my draft report, compare and comment on the change and then delete the old one to keep this report to a manageable size. Also it is important to recognize that what you see in this graphic is the change in the anomaly over the last four weeks. So blue means either cooler or less warm. Red means warmer or less cool. So you have to refer to the graphic above this one to really interpret this graphic as what we are seeing here is the change in the anomalies. What we see in this graphic is four weeks of change not the current absolute anomalies which are shown in the above graphic. It is not derivatives in the mathematical sense but deltas. They are somewhat similar. The graphic above this discussion is simply the current deviation from climatology and the graphic below shows the four week change in the deviation from climatology. So it is a bit like the graphic above and second below are the first and second derivatives of the sea surface temperature(SST) but not exactly. I take it a step further by comparing this week's version of the graphic below to the prior week and report on the differences below.the graphic.
What I see as I look at both last week's version of this graphic and the current one (before deleting the prior version) is the warming along the Equator in the Eastern Pacific has stabilized. (Remember warming with regards to this graphic is a change in an anomaly and can mean warmer or less cool and vice versa - you have to refer to the graphic above to know how to interpret a change in an anomaly.) We remain in full ENSO Neutral. The anomalies in the Pacific in the Northern Hemisphere are mostly warming. I do not see a PDO pattern at all in the Eastern Pacific. East of Japan the trend is now cooling but east of Kamchatka it is warming. There is warming off of the U.S. and Mexico West Coasts. The waters off the East Coast of North America are cooling. At the southern end of South America, the anomalies are cooling a bit off their west coast and a lot off their east coast. South and east of Africa the anomaly continues to cool. The entire Western Indian Ocean is cooling except along the Equator and one area southeast of Madagascar. The waters surrounding Australia are not showing a lot of change but the cooling to the west has intensified and the warm anomaly to the south is drifting to the west. Remember we are talking about changes in the anomalies something like a second derivative so you have to refer to the graphic above this one to know if blue is cool or less warm and if red is warm or less cool.
Below is an analysis of projected tropical hazards and benefits over an approximately two-week period.
This graphic updates on Tuesdays and I post on Monday which is almost a week later than when this graphic was last updated. So Week Two applies at the time I write this article on Monday but by the time you read it on Tuesday the Week Two that I am looking at is updated and becomes Week One. Mostly I see as I look at this on March 27 for what is shown as Week Two, the period March 29, 2017 to April 4, 2017, has dry conditions* for a few small parts of Africa and wet conditions** for Northwest Australia and the Maritime Continent with a small area of tropical cyclone activity* east of Indochina and dry conditions* for Eastern Brazil and wet conditions* for the Central Gulf of Mexico Coast. There is also a wet condition* shown for offshore of Ecuador and Northern Peru associated with their local El Nino.
* 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.
The above graphic which I believe covers the area from the Dateline west to 100E and from the Equator north to 45N normally shows the movement of tropical storms towards Asia in the lower latitudes (Trade Winds) and the return of storms towards CONUS in the mid-latitudes (Prevailing Westerlies). This is recent data not a forecast. But, it ties in with the Week 1 forecast in the graphic just above this graphic.Also you can see the break in the action of Pacific Storms headed east. Information on Western Pacific storms can be found by clicking here. This (click here to read) is an unofficial private source but one that is easy to read.
C. Progress of ENSO
A major driver of weather is Surface Ocean Temperatures. Evaporation only occurs from the Surface of Water. So we are very interested in the temperatures of water especially when these temperatures deviate from seasonal norms thus creating an anomaly. The geographical distribution of the anomalies is very important.
To a substantial extent, the temperature anomalies along the Equator have disproportionate impact on weather so we study them intensely and that is what the ENSO (El Nino - Southern Oscillation) cycle is all about.
Subsurface water can be thought of as the future surface temperatures. They may have only indirect impacts on current weather but they have major impacts on future weather by changing the temperature of the water surface.
Winds and Convection (evaporation forming clouds) is weather and is a result of the Phases of ENSO and also a feedback loop that perpetuates the current Phase of ENSO or changes it. That is why we monitor winds and convection along or near the Equator especially the Equator in the Eastern Pacific.
Starting with Surface Conditions.
The current conditions are measured by determining the deviation of actual sea surface temperatures from seasonal norms (adjusted for Global Warming) in certain parts of the Equatorial Pacific. The below diagram shows those areas where measurements are taken.
NOAA focuses on a combined area which is all of Region Nino 3 and part of Region Nino 4 and it is called Nino 3.4. They focus on that area as they believe it provides the best correlation with future weather for the U.S. primarily the Continental U.S. not including Alaska which is abbreviated as CONUS. The historical approach of measurement of the impact of the sea surface temperature pattern on the atmosphere is called the Southern Oscillation Index (SOI) which is the difference between the atmospheric pressure at Tahiti as compared to Darwin Australia. It was convenient to do this as weather stations already existed at those two locations and it is easier to have weather stations on land than at sea. It has proven to be quite a good measure. The best information on the SOI is produced by Queensland Australia and that information can be foundhere. SOI is based on Atmospheric pressure as a surrogate for Convection and Subsidence. Another approach made feasible by the use of satellites is to to measure precipitation over the areas of interest and this is called the El Nino–Southern Oscillation (ENSO) Precipitation Index (ESPI). We covered that in a weekly Weather and Climate Report which can be found here. Our conclusion was that ESPI did not differentiate well between La Nina and Neutral. And there is now a newer measure not regularly used called the Multivariate ENSO Index (MEI). More information on MEI can be found here. The jury is still out on MEI and it it is not widely used.
The below diagram shows the usual location of the Indo-Pacific Warm Pool. When the warm water shifts to the east we have an El Nino; to the west a La Nina.
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. The top part shows the actual temperatures, the bottom part shows the anomalies i.e. the deviation from normal.
Location Bar for Nino 3.4 Area Above and Below
Notice that part of what is left of the the cool anomaly is west of 165W and barely gets counted as being in the Nino 3.4 Measurement Area.
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. NOW i AM PUTTING THEM BACK IN. 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. I probably have more to do but one step at a time.
Comparing Now to May 23, 2016
Subareas of the Anomaly
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 below show the Extent of El Nino Impact on the Equator
+0.5C to +1C
These Rows Below Show the Extent of ENSO Neutral Impacts on the Equator
0.5C or cooler Anomaly
0C or cooler Anomaly
These Rows Below Show the Extent of the La Nina Impacts on the Equator
-0.5C or cooler
-1C or cooler Anomaly
It is useful to compare the current longitudinal extent of the water temperature anomalies with the situation on May 23, 2016 and the second checkpoint of December 12, 2016. What is new is that the part of the anomaly along the Equator which is cool enough to be ENSO Neutral or cooler has two components both ENSO neutral but one having a warm bias and one having a cool bias and the cool bias has 20 degrees of coverage. This means there is 50 - 20 or 30 degrees of ENSO Neutral Warm Bias water from 150W to 120W.
If you just look on the Equator, there are 50 degrees of Longitude of Neutral to La Nina anomalies which is the maximum possible as the ONI Measurement Area is 50 degrees of Longitude wide and that also is the maximum possible since the ENSO Measurement Area only stretches for 50 degrees. There are today 0 degrees of water anomalies cool enough to be a La Nina. Subtracting 0 degrees from the 50 degrees you end up with 50 degrees of ENSO Neutral and 0 degrees of water cool enough to qualify as La Nina i.e. temperature anomalies more negative than -0.5C. A new factor is we now begin to see water that is warmer (anomaly) than +0.5C which is El Nino water. The ONI Measurement Area extends 5 degrees of Latitude North and South of the Equator so the above table is just a guide and a way of tracking the changes. Away from the Equator it is generally warmer. The water from 3N to 5N and from 3S to 5S had until recently remained relatively warm.
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 March 27, in the afternoon working from the March 26 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.]
Calculation of ONI from TAO/TRITON Graphic
A. 170W to 160W
B. 160W to 150W
C. 150W to 140W
D. 140W to 130W
E. 130W to 120W
Total divided by five i.e. the Daily Nino 3.4 Index
(+2.1)/5 = +0.4
(+2.1)5 = +0.4
My estimate of the daily Nino 3.4 SST anomaly is again 0.4 which is an ENSO Neutral value but on the El Nino side within the Neutral Range. NOAA has reported the weekly Nino 3.4 to be an ENSO Neutral value at +0.2 which is on the El Nino Side side of Neutral but slightly cooler than last week. The cool anomaly has been moving around and NOAA reports a weekly value and I report an estimate of the daily value so that might explain the difference.
Nino 4.0 is also reported cooler than last week at -0.1.. Nino 3 is also reported cooler at 0.6. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is also reported cooler at +2.2 which is still an astoundingly high value. If it extended into Nino 3.4 it would represent a strong El Nino. It is worth mentioning that many Asian Meteorological Agencies work with Nino 3.0 rather than Nino 3.4 in which case we would be close to having El Nino Conditions with respect to Ocean Temperatures.
I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in table form but going back a couple of more years can be found here.
This is probably the best place to express the thought that this way of measuring an ENSO event leaves a lot to be desired. Only the surface interacts with the atmosphere and is able to influence weather. The subsurface tells us how long the surface will remain cool (or warm). Anomalies are deviations from "Normal". NOAA calculates and determines what is "Normal" which changes due to long ocean cycles and Global Warming. So to some extent, the system is "rigged". Hopefully it is rigged to assist in providing improved weather forecasts. But to assume that any numbers reported can be assumed to be accurate to a high level of precision is foolhardy. It is strange to me that the Asian forecasting services generally conclude that that this cool ENSO Phase is not a La Nina but a near La Nina and NOAA concludes it is a La Nina. It is the same ocean. The reported readings are very close but the Asian readings are generally slightly higher (less La Nina-ish) than the NOAA reading and their cut-off points for declaring a La Nina are a bit different and the parts of the Equator they look at are a bit different. It might be explained by what part of the ENSO pattern impacts their area of geography but it just seems to me that NOAA has been a bit over eager. And I wonder why.
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.
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 snapshots of the conditions at different points in time. This Hovmoeller provides a good way to visually see the evolution of this ENSO event. I have decided to use the prettied-up version that comes out on Mondays rather that the version that auto-updates daily because the SST Departures on the Equator do not change rapidly and the prettied-up version is so much easier to read.
You can see that the cool anomaly (bottom of the Hovmoeller has vanished with no blue in the Nino 3.4 Measurement Area), some white and now quite a bit of light yellow (still ENSO Neutral but on the warm side) and El Nino-ish dark yellows off and on from 155W east and browns tending towards reds from 100W east. However this lukewarm pattern weakened last week and has now returned to the situation two weeks ago. It is hard to tell if that is real or data irregularities/artifact. Remember the +5, -5 degree strip around the Equator that is being reported in this graphic. So it is the surface but not just the Equator. This is possibly the beginning of an El Nino pattern. But week to week there have been no change. If anything the pattern is fairly stable. Further west the surface is less warm. Basically there is no change from last week.
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 recently there has been sufficient change to warrant including this graphic. And now that we are back tracking a possible El Nino it is the graphic of choice.
The bottom of the Hovmoeller shows the current situation. The Cool Event is long gone. But what might be a Kevin wave initiating an El Nino is still not very impressive. If you look from the bottom of the graphic up you can see that any La Nina conditions ended in December. There is not much change from the prior week except for the small warm blip at about 125W which is no longer visible. But what I am really looking for is the left portion of the graphic the Pacific Warm Pool and I don't see much change other than a diminishment of the area around the Dateline that is warm. Reds are what is needed for an El Nino. The situation is a lot clearer this week and much less suggestive of a real El Nino brewing other than right off the coast of South America. But far too the left on the graphic there is some movement to the east of the very distant part of the surface warm water.
Let us look in more detail at the Equatorial Water Temperatures.
We are now going to 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 This graphic provides both a summary perspective and a history (small images on the right).
Usually we use this to track Kelvin Waves but you can see the progression of warm water streaming east but not very much of it. This may have been a Kelvin Wave. It is not clear but the consensus now is that yes it was. The reason this is important is what is called the Bjerknes Feedback Mechanism which you can read about here. It is an intricate set of interactions which determines the ENSO Cycle. Of course Jacob Bjerknes the son of the world renowned Norwegian meteorologist Vilhelm Bjerknes developed his theories in the sixties. There have been many modifications/improvements in his theories since then and this process continues. You can track the history of this graphic on the right. I think it shows the prior week and then every other week before then. There has not been much change. There is no indication of an El Nino forming. There is no real warm water flow from the Indo-Pacific Warm Pool to the Eastern Pacific.
Now for a more detailed look. Notice by the date of the graphic (dated March 19, 2017) that the lag in getting this information posted so the current situation may be a bit different than shown. The date shown is the midpoint of a five-day period with that date as the center of the five-day period.
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.
Re the top graphic, let us first look at surface temperature anomalies. The -1C water no longer shows anywhere. We only see -0.5 C water now from 175W to 165W and it probably will soon not be shown as sub -0.5C. On the other hand warm water now extends from the Coast of Ecuador to 110W. Subsurface Temperature Anomalies: The cool water is almost all gone. Notice the warm water at depth almost everywhere extending to the coast of Ecuador..
The bottom half of the graphic (Absolute Values which highlights the Thermocline) is now more useful as we track the transition to and ENSO Cool Event which may possibly become and El Nino.
It shows the thermocline between warm and cool water. The 28C Isotherm is now located at the 170E. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm is at the Dateline so we do not yet have ideal conditions for significant convection along the Equator east of the Dateline which is a characteristic of a Cool Event (which still has some influence) and also ENSO Neutral but it appears to be slowly changing. The 25C isotherm now extends all to the way to Ecuador. The 20C Isotherm is being increasingly depressed by warm water all the way to Ecuador. We are seeing the great swap where neutral and even warm water replaces the cooler water at the surface.
The flattening of the Isotherm Pattern is an indication of ENSO Neutral just as the steepening of the pattern indicates La Nina or El Nino depending on where the slope shows the warm or cool pool to be. That flattening has occurred. At this point, we have gone to ENSO Neutral but not El Nino although the trend is towards an El Nino.
Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.
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.
There is not much week to week change in the pattern.
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. At this point there seems to be no need to show the daily preliminary values of the SOI but we can work with the weekly values.
Current SOI Readings
The 30 Day Average on March 27 was reported as 4.25 which is ENSO Neutral but on the high side of pure neutral. The 90 Day Average was reported at 0.88 which is about 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.
SOI = 10 X [ Pdiff - Pdiffav ]/ SD(Pdiff) where Pdiff = (average Tahiti MSLP for the month) - (average Darwin MSLP for the month), Pdiffav = long term average of Pdiff for the month in question, and SD(Pdiff) = long term standard deviation of Pdiff for the month in question. So really it is comparing the extent to which Tahiti is more cloudy than Darwin, Australia. During El Nino we expect Darwin Australia to have lower air pressure and more convection than Tahiti. During La Nina we expect the Warm Pool to be further east.
To some extent it is the change in the SOI that is of most importance. It had been increasing in September but now from October through February the SOI has stabilized in the Neutral Range.
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. January accelerated the decline of this near La Nina development and most likely February will also be unkind in the opposite way in terms of the MJO as it does not deplete the cool pool but stimulates Kelvin Waves. .
This Table is a first attempt at trying to related the MJO to ENSO
MJO Active Phase
MJO Inactive Phase
Relationship of MJO and ENSO
Eastern Pacific Easterlies
Part of Decay Process
Western Pacific Westerlies
May Create or Stimulate the Onset of El Nino via Kelvin Waves
Part of Decay Process
MJO Active Phase
Less likely and weak
Retards development of a new La Nina
Stimulates the Jet Stream
MJO Inactive Phase
More likely but weak
Accelerates development of a new La Nina and the Decline of a mature La Nina
Slows the Jet Stream and can induce a Split Stream especially during a La Nina
Table needs more work. Is intended to show the interactions. What is more difficult is determining cause and effect. This is a Work in Progress.
Forecasting the Evolution of ENSO
We now have both the Mid-March and early-month report from CPC/IRI I am showing both as it is a way of seeing the trend in forecasts even though the methodology of the two forecasts are not identical.
First we look at the IRI/CPC March 16, 2017 fully model-based report.
Here is the one week earlier what I call the "Tea Leaves Report" issued on March 9, 2017. I call it the Tea Leaves Report as it is not clear how this report is prepared as it is some combination of model results and opinions of meteorologists and it is just not possible to really know how this report is prepared.
Notice that in one week the probabilities for an El Nino soared. Look at JAS as an example. On March 9th the Tea Leaves concluded that the chances of an El Nino were ever so slightly greater than the chances of ENSO Neutral. But one week later, the readers of the Tea Leaves looked at their model results and concluded that El Nino was an overwhelming favorite for JAS. That does not make any sense.
Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.
The estimated current value of the Nino 3.4 Temperature Anomaly after the adjustments have been applied is an ENSO Neutral Value now with a warm bias and shooting higher rapidly this month. Looking ahead to next summer you see El Nino readings being the mean of the forecast ensemble but it is before the Spring Prediction Barrier which means we need to wait a few months until May [click here to understand why] before getting excited about that. Notice the wide spread among forecast member into the summer. But we clearly are forecast to be in ENSO Neutral for the rest of this Winter. The question is the coming summer and next winter.
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. I do not need to draw in the lines for you to see that the Nino 3.4 Index as reported by CDAS has moved above the 0C line and is now reporting a warm anomaly but not an increasing warm anomaly.
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).
El Niño WATCH remains
The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Bureau's ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017.
Sea surface temperatures (SSTs) in the central and eastern tropical Pacific Ocean have steadily warmed since the start of the year. In waters near the South American coastline, some areas are now at least 3 °C above average. However, all indicators of ENSO remain within neutral levels. In the atmosphere, recent fluctuations in the Southern Oscillation Index (SOI) can be attributed to movements in the monsoon trough associated with severe tropical cyclone Debbie, and are not indicative of ENSO.
All international models surveyed by the Bureau suggest that the current steady warming of the tropical Pacific Ocean is likely to continue in the coming months. Seven of eight models indicate that sea surface temperatures will exceed El Niño thresholds during the second half of 2017. However, some caution must be exercised as models have lower accuracy at this time of year.
El Niño is often, but not always, associated with below average winter–spring rainfall over eastern Australia and warmer than average winter–spring maximum temperatures over the southern half of Australia.
Based on the Nino 3.4 projection, JAMSTEC is saying the Cool Event did not meet the criteria to have been declared a La Nina as was done by NOAA: Nino 3.4 being colder than -0.5 and the duration of being under -0.5 was not sufficient to qualify as a La Nina.
JAMSTEC is raising the possibility of an El Nino for the following winter. But it is too soon to make that prediction with a high degree of confidence.
The Discussion that goes with their Nino 3.4 forecast follows: Notice the suggestion that we might be having a Pacific Climate Shift to PDO Positive.
Mar. 21, 2017 Prediction from 1st Mar., 2017
The SINTEX-F predicts that a moderate-to-strong El Niño event may start in early summer this year and reach its peak in winter. If this happens, it 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. Such natural climate variability may double the global warming impact as we observed during the period from 1976 through 1998. We need to be prepared well to this possible decadal climate regime shift.
Indian Ocean forecast:
Occurrence of a positive Indian Ocean Dipole is also clearly predicted by the SINTEX-F seasonal prediction system; the ensemble mean prediction suggests its evolution in summer and its height in fall. We may observe co-occurrence of a positive Indian Ocean Dipole and an El Niño in the latter half of 2017; this is just as we observed in 1997 and 2015.
On a seasonal scale, most part of the globe will experience a warmer-than-normal condition, while some parts of southern Canada and northern U. S., and northern Brazil will experience a colder-than-normal condition in the boreal spring. In the boreal summer, most parts of the globe will experience a hotter-than-normal condition. On the other hand, some parts of Europe, central Russia, and northern Australia will experience a cooler-than-normal condition.
As regards the seasonally averaged rainfall, a wetter-than-normal condition is predicted for western part of Brazil during the boreal spring, whereas most parts of southeastern China, Indonesia, eastern Brazil, southern Australia and Europe will experience a drier condition during the boreal spring. In the boreal summer, most parts of Indonesia, India, Australia, southeastern China, Mexico, and northern Brazil will experience a drier-than-normal condition, due to co-occurrence of the El Niño and the positive Indian Ocean Dipole.
Most parts of Japan will be in a warmer and drier-than-normal condition in the boreal spring. In boreal summer, we expect a wetter-than-normal and slightly hotter-than-normal condition due to development of the positive Indian Ocean Dipole and El Niño; El Niño influences may be canceled due to development of the positive Indian Ocean Dipole and vice versa.
Indian Ocean IOD (It updates every two weeks)
The IOD Forecast is indirectly related to ENSO but in a complex way.
The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 26 March was +0.19 °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.
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 the Spring Predictability Barrier or SPB which was explained earlier but for the convenience of the reader I am repeating the link.
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.
JAMSTEC has raised the possibility of a Climate Shift in the Pacific and the implications of this are discussed in a prior GEI Weather and Climate Report which you can access by clicking here.
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.
The odds of a climate shift for CONUS taking place has significantly increased. It may be in progress. JAMSTEC is suggesting that if there is an El Nino in the winter of 2017/2018 this could signify that the PDO has entered its Positive Phase. The AMO is pretty much neutral at this point (but more positive i.e. warm than I had expected) so it may need to become a bit more negative for the "McCabe A" pattern to become established. That seems to be slow to happen so I am thinking we need at least a couple more years for that to happen. JAMSTEC is suggesting it might occur very soon.
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.
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.
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.
J FM 1951
*The GEI Weather and Climate Report does not accept this as a legitimate La Nina. It is not unusual for different Meteorological Agencies to maintain different lists of El Ninos and La Ninas. This is usually because the criteria for classification differ slightly. Obviously the GEI Weather and Climate Report has no standing but nevertheless for any analysis we do, we will either not include or asterisk this La Nina to indicate that NOAA has it on their list and we consider that to be Fake News. The alternative is to conclude that the other Meteorological Agencies are not able to measuring things correctly. .
ONI Recent History
The Dec/Jan/Feb preliminary has just come out as -0.4. Looks like NOAA chickened out re extending their farcical phony ONI record into the first three months of 2017. The full history of the ONI readings can be found here. The MEI index readings can be found here.
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