What happens when near-Winter and near-Summer conditions occur on the same day? To find out, read the news on Tuesday morning. Because this article is published on Monday nights but usually read by most on Tuesdays, I will not have the answer to that question by the time I publish so I also will be reading the news on Tuesday morning especially related to the Gulf States and again on Wednesday related to the East Coast. But let's not forget Alaska and the Northwest as they will be having unusual weather also.
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Wind Power Overcomes Solar Power in Australia Cyclone Debbie March 27
Source: AAP: Sarah Motherwell More coverage in the News Section of this Report.
Boats washed ashore and damaged, roofs lifted off, and trees uprooted and broken off and strewn about were the typical causes of damage of Cyclone Debbie as it went ashore in Northeast Australia.
Mocoa Columbia April 1
Typically, moving water causes more damage than wind and when water causes mud/debris slides, the higher density and abrasive properties multiply the damage enormously..initial reports are of over 250 dead.
Photo Source: AFP
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.
Severe Weather is of Concern in many Places including the Gulf States.
NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on March 31 and rather than have a Special Update that covers simply the next month, we combined that report with our Regular Weekly Report and we will discuss that first by comparing the Updated Outlook for April to the Early Outlook for April issued on March 16, 2017.
Prior Outlook Issued on March 16, 2017
Updated Outlook Issued on March 31, 2017
Not much change. The Southern Warm Anomaly highest probability area is now more centered in South Central CONUS and extends further north.
Prior Outlook Issued on March 16, 2017
Updated Precipitation Outlook Issued on March 31, 2017
The only major change is the Northwest Coast is now a wet rather than dry anomaly.
Below is the discussion issued with this update.
30-DAY OUTLOOK DISCUSSION FOR APRIL 2017
THE UPDATE TO THE APRIL TEMPERATURE AND PRECIPITATION OUTLOOKS IS MADE USING THE LATEST GUIDANCE FOR THE MONTH FROM THE CFS, AS WELL AS DYNAMICAL MODEL GUIDANCE FOR WEEK 2, AND WEEKS 3 AND 4, AND TEMPERATURE AND PRECIPITATION FORECASTS FOR WEEK 1 FROM NUMERICAL WEATHER PREDICTION MODELS. OVERALL, ENSO NEUTRAL CONDITIONS CONTINUE FOR THE TROPICAL PACIFIC, AND THE MJO REMAINS INACTIVE, AS INDICATED BY THE WHEELER AND HENDON RMM INDICES. DYNAMICAL MODELS GENERALLY INDICATE THAT MJO WILL REMAIN INACTIVE THROUGH MUCH OF APRIL. THEREFORE THE UPDATE RELIES PRIMARILY ON DYNAMICAL MODEL GUIDANCE.
THE UPDATED TEMPERATURE OUTLOOK FOR APRIL IS VERY SIMILAR TO THE PREVIOUSLY RELEASED HALF MONTH LEAD OUTLOOK, WITH PROBABILITIES OF ABOVE NORMAL TEMPERATURES INCREASED OVER THE SOUTHWEST INCLUDING SOUTHERN CALIFORNIA, AS WELL AS INCREASED PROBABILITIES ACROSS THE SOUTHEAST, AND FOR SOUTHERN ALASKA. THIS UPDATE FOLLOWS THE LATEST GUIDANCE FROM THE CFS MONTHLY FORECAST. ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES CONTINUE FOR MUCH OF THE EASTERN CONUS.
THE UPDATED PRECIPITATION OUTLOOK FOR APRIL HAS LARGELY CHANGED BASED ON RECENT NUMERICAL WEATHER PREDICTION FOR THE FIRST WEEK IN APRIL, AS WELL AS CONSIDERATION OF THE RECENT CFS MONTHLY FORECASTS, AND FORECASTS FOR WEEK 2 FROM THE ECMWF AND GEFS MODELS, AND FOR WEEKS 3 AND 4 FROM THE ECMWF MODEL. THE PRECIPITATION FORECAST NOW INDICATES AN INCREASED CHANCE OF ABOVE MEDIAN PRECIPITATION FOR COASTAL REGIONS OF NORTHERN CALIFORNIA, OREGON, AND WASHINGTON STATE, WHERE MODEL FORECASTS NOW INDICATE INCREASED PRECIPITATION FOR THE MONTH. WHILE THE AREA OF ABOVE MEDIAN PRECIPITATION OVER PARTS OF EASTERN TEXAS, THE LOWER MISSISSIPPI VALLEY, AND CENTRAL GULF COAST IN THE UPDATED FORECAST IS SIMILAR TO THE HALF MONTH LEAD FORECAST, FORECASTS FOR WEEK 2, AS WELL AS WEEKS 3 AND 4 COMBINED, NOW INDICATE INCREASED PROBABILITIES OF BELOW MEDIAN PRECIPITATION. HOWEVER, FORECASTS FOR THE FIRST WEEK OF THE MONTH OF APRIL INDICATE A HIGH LIKELIHOOD OF SIGNIFICANT PRECIPITATION, SUCH THAT THE PROBABILITIES OF ABOVE MEDIAN PRECIPITATION ARE ENHANCED FOR THE FULL MONTH OF APRIL.
Sometimes it is useful to compare the present month outlook to the three-month outlook
April Plus April - June 2017 Outlook
One can mentally subtract the April Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely May and June 2017. If one does that you might conclude that:
For temperature there is very little difference between the April Map and the three-month Map from a spacial perspective but the probabilities of being warmer than normal are higher in the three-month map than in the April Map for the East Coast States. This means the three-month probabilities for those areas where the maps are different will be different for the combined May/June map if such was created in order for the probabilities in the three-month map to be correct. Thus if you assume these colors are assigned correctly, it is a simple algebra equation to solve May/June probability for a given location = 3XThree-Month Probability - April Probability*. So you can derive the May/June forecast this way. You can do that calculation easily for where you live.
Re precipitation, there is only one area which changes dramatically. In the April Map there is a Northwest Coastal wet anomaly which does not show up in the three-month map. So if you assume these colors are assigned correctly it is a simple algebra equation to solve May/June probability for a given location = 3XThree-Month Probability - April Probability*. So you can derive the May/June forecast this way. You can do that calculation easily for where you live.
One has to keep in mind that we are now subtracting an April Map issued on March 31 from a three-month map issued on March 16. So it is less reliable than the exercise we went through in the special Update Report. We are assuming that the three-month outlook issued on March 16 would not change if it was updated on March 31. The results in the box above might be an indication of how May and June will differ from the three-month outlook or it might alternatively indicate how the three-month outlook might be modified if issued today. So the discussion in the paragraph above this may be overruled by a conclusion that the three-month outlook is no longer correct and the updated April Outlook is a better predictor of the three-month outlook than the three-month maps issued on March 31. From the discussion released by NOAA on March 31, the changes mentioned would appear to be specific to April and not apply to May and June. Thus the procedure described above would appear to have some validity this month..
* Math calculation explained at end of this report.
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 April 3, 2017, as I am looking at the above graphic, we see the storm which was impacting the Central Gulf States already becoming an East Coast Storm but also curving around to impact the Great Lakes. We also see a storm impacting mostly Colorado.
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 and then diving south. Also notice the Split Jet Stream but with the Southern Branch into Mexico.
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 or if you want more theoretical information by clicking here. The idea is that we have now concluded that moisture often moves via narrow but deep channels in the atmosphere (especially when the source of the moisture is over water) rather than being very spread out. This raises the potential for extreme precipitation events.
Mostly this evening we see the flow of moisture into the system which as been impacting the Gulf States and will soon transform into an East Coast Storm.
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 split low with the larger lobe located in the Gulf of Alaska with central air pressure of 980 hPa which is quite low for this time of the year. There is another part of the system over by Kamchatka with central surface pressure of 980 hPa and it appears to be strengthening. 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 is pretty much not there but there is what may be a third lobe of the Aleutian Low there instead with central surface pressure of 996 hPa. Further south you can see above average Sea Level Air Pressure but there is no circulation so it has little impact. It is not clear exactly how this formation functions but there is no block to Pacific Storms entering CONUS or Canada from the Pacific.
You can also see a Low Pressure System centered on Ohio. One might have thought the current storm would be gone by Day 3 but not in this forecast map.
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 further south than recently due to the High Pressure system that would normally block or push the entry point further north not positioned to do that. 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 we see for Day 7 is a deep Western Trough and a very robust East Coast Ridge.
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.
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 April 3, 2017 was 4 out of 5)
8 - 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on April 3, 2017 was 3 out of 5)
Looking further out.
Consolidation of 6 - 10, 8 - 14 and Experimental Week 3-4 Forecasts
(Interpreted on April 3, 2017
April 9 to April 17
April 15 to April 28
The period starts very cool in the West and very warm in the East and also Northern Alaska and also the Panhandle. As the period evolves both the cool and warm anomalies moderate and progress to the East.
Alaska including the Panhandle is warm. The extreme Northern part of New England is cool. Looks like a trapezoid in the center of CONUS is warm. Everywhere else, which is not a large area, 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 unlikely.
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 April 3, 2017 was 4 out of 5)
8 - 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on April 3, 2013 was 3 out of 5)
Looking further out.
Consolidation of 6 - 10, 8 - 14, and Week 3-4 Forecasts
Interpreted on April 3, 2017
April 9 to April 17
April 15 to April 28, 2017
Alaska and the Panhandle are dry. CONUS starts wet except for the East Coast which is dry. The wet anomaly gradually progresses east. The EC anomaly expands.
Southwest Alaska including the Panhandle is dry. The Southeast Quadrant of CONUS is projected to be dry. A narrow swath of the Northern Tier extending into the Great Lakes is projected to be wet. In between the dry and wet anomalies is 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 unlikely particular with respect to the Southeast.
Remember the W
eek 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 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.
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 April 3, 2017.
6-10 DAY OUTLOOK FOR APR 09 - 13 2017
TODAY'S DYNAMICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA CIRCULATION PATTERN PREDICTED OVER NORTH AMERICA FOR THE 6-10 DAY PERIOD. ENSEMBLE MEANS FORECAST TROUGHS OVER THE ALEUTIAN ISLANDS INTO THE GULF OF ALASKA AND OVER THE WESTERN CONUS, WHILE MODELS FORECAST RIDGES OVER EASTERN ALASKA AND THE EASTERN CONUS. TODAY'S MANUAL 500-HPA HEIGHT BLEND INDICATES NEGATIVE HEIGHT ANOMALIES OVER THE ALEUTIAN ISLANDS AND THE WESTERN CONUS AND POSITIVE ANOMALIES OVER REMAINING AREAS OF ALASKA AND OVER THE EASTERN CONUS.
ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR WESTERN ALASKA AND THE ALEUTIAN ISLANDS, AS WELL AS THE ALASKA PANHANDLE, UNDER PREDICTED ANOMALOUS SOUTHERLY FLOW. BELOW NORMAL TEMPERATURES ARE MOST LIKELY FOR MUCH OF THE WESTERN HALF OF THE CONUS UNDER A PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR THE EASTERN CONUS, WHERE HEIGHT ANOMALIES ARE POSITIVE UNDER A FORECAST RIDGE.
ABOVE MEDIAN PRECIPITATION IS MOST LIKELY FOR MOST OF THE CONUS FROM THE PACIFIC COAST TO THE APPALACHIAN MOUNTAINS, EXCLUDING CLIMATOLOGICALLY DRY AREAS OF THE SOUTHWEST, AHEAD OF STRONG PACIFIC FLOW. PROBABILITIES OF ABOVE MEDIAN PRECIPITATION ARE GREATEST IN PARTS OF EASTERN TEXAS AND THE LOWER MISSISSIPPI VALLEY, WITH NORTHWARD FLOW FROM THE GULF OF MEXICO AHEAD OF THE PREDICTED TROUGH. BELOW MEDIAN PRECIPITATION IS MOST LIKELY TO THE EAST OF THE APPALACHIAN MOUNTAINS EAST OF THE PREDICTED RIDGE AXIS. THE PROBABILITIES OF BELOW MEDIAN PRECIPITATION ARE ENHANCED FOR MUCH OF ALASKA UNDER POSITIVE MID-LEVEL HEIGHT ANOMALIES.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE DYNAMICAL MODELS ON THE FORECAST 500-HPA HEIGHT PATTERN, AND GOOD AGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR APR 11 - 17 2017
THE PREDICTED 500-HPA HEIGHT PATTERN FOR THE WEEK-2 PERIOD IS SIMILAR TO THE 6-10 DAY PERIOD FORECAST BUT IS MUCH LESS AMPLIFIED AND INDICATES SOME EASTWARD PROGRESSION. HEIGHT ANOMALIES ASSOCIATED WITH THE PREDICTED TROUGH OVER THE WESTERN CONUS ARE MUCH CLOSER TO ZERO, AND WHILE POSITIVE ANOMALIES ARE STILL PRESENT IN THE 8-14 DAY FORECAST PERIOD OVER THE EASTERN CONUS AND ALASKA, THEY HAVE WEAKENED SIGNIFICANTLY FROM THE 6-10 DAY PERIOD FORECAST. IN THE MANUAL BLEND 500-HPA HEIGHTS, POSITIVE ANOMALIES ARE NOW PRESENT OVER THE FAR WESTERN CONUS.
FOLLOWING THE DEAMPLIFICATION OF THE CIRCULATION PATTERN IN THE WEEK 2 FORECAST, THE TEMPERATURE AND PRECIPITATION ANOMALY PATTERNS ARE SIMILAR TO THE 6-10 DAY PERIOD WITH SOMEWHAT WEAKER PROBABILITIES. BELOW NORMAL TEMPERATURES ARE MUCH LESS LIKELY OVER THE WESTERN CONUS, WHERE THE PREDICTED TROUGH HAS WEAKENED. BELOW NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY IN PARTS OF THE CENTRAL ROCKIES AND CENTRAL PLAINS. AVERAGE ABOVE NORMAL TEMPERATURES ARE NOW MORE LIKELY THAN BELOW NORMAL FOR PARTS OF SOUTHERN CALIFORNIA AND ARIZONA FOR THE 8-14 DAY PERIOD, WHERE MID LEVEL HEIGHTS ARE RISING.
THE PROBABILITIES OF ABOVE MEDIAN PRECIPITATION HAVE DECREASED OVER REGIONS OF THE ROCKY MOUNTAINS AND THE CENTRAL PLAINS, WHERE NEAR MEDIAN PRECIPITATION IS NOW FAVORED. WITH THE EASTWARD PROGRESSION OF THE CIRCULATION PATTERN, NEAR MEDIAN PRECIPITATION IS NOW MORE LIKELY ALONG MUCH OF THE ATLANTIC COAST.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE TO WEAK 500-HPA ANOMALIES AND SOME DISAGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION TOOLS.
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 16, 1970
Just after a Traditional El Nino
Mar 17, 1970
Just after a Traditional El Nino
Mar 29, 1980
Tail end of Marginal Modoki Type II
Mar 22, 1984
Mar 25, 1984
Mar 14, 1996
Mar 15, 1998
Mar 16, 1998
(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 14 to March 29 which is 15 days which is a very tight 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 29 or March 30). 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 earlier in the calendar. That is the opposite of the case last week.
There are three El Nino Analogs, four ENSO Neutral Analogs and one La Nina analog. 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 Condition A which is fairly consistent with the 6 to 10 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 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.
And the 30 Days ending April 1, 2017
The Southern Tier drought is much less pronounced. The temperature anomalies are somewhat similar but the cool anomaly in the Northeast is much more pronounced. Remember this is a 30 day average with 7 more recent days added and 7 more distant days removed so it 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 positive number for the Arctic..
This graphic is actuals not anomalies. Western CONUS, Central America, Africa and Asia and Australia are particularly uniformly dry. South America is wet.
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. Northern South America is wet. A large low pressure system dominates the Northeastern 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 from the forecast last month due to the rising SOI. It is a big change. .
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 by clicking 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 but has had some update issues. It will probably update by the time you read this report but I can't comment on that which I can not see so I am leaving the weekly graphic in the report but commenting on the daily graphic. . .
Remember this discussion is all about anomalies not absolute temperatures so it is deviation from seasonal norms.
because the weekly report from NOAA is being posted in a less than timely manner, I have added the daily product which I will comment on this evening.
The Tropical Pacific is overall NEUTRAL. The waters off of South America are very warm. This looks like how an El Nino originates. You can see the warm water extending west but not much into the key area of 170W to 120W. Also it extends 5 degrees south of the Equator but not 5 degrees north so it is so far a strange looking anomaly and some think wind driven rather than reflecting the top 300 meters of the ocean.
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 is 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 0.12 and February was reported at +0.08 but now revised to 0.04 and March just released at 0.08 i.e Neutral. 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 but just along the coast. The North Atlantic is warm. The list of Atlantic Multidecadal Oscillation (AMO) values can be found here.
The Caspian Sea and Black Sea are Neutral. The Mediterranean is slightly warm. The Persian Gulf is warm extending out into the Arabian Sea.
The waters at mid-latitude East of South America are now quite warm. The big story is the warm South Pacific. Is this a new flavor of El Nino? Australia and Peru, Ecuador and Australia experienced that this past week.
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.
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 is the flirst derivative of the sea surface temperature (SST) and the graphic below is the second derivatives of the sea surface temperature(SST) but not exactly.
What I see is the warming along the Equator in the Eastern Pacific is increasing but cooling closer to Ecuador which may surprise some. We remain in full ENSO Neutral. The anomalies in the Pacific in the Northern Hemisphere are mostly warming to the east and cooling to the west. I do not see a PDO pattern at all in the Eastern Pacific. There is warming off of the U.S. West Coast. The waters off the East Coast of North America are cooling. At the southern end of South America, the anomalies are cooling both off their west coast and east coast. South and east of Africa the anomaly continues to cool. The entire Indian Ocean is cooling except along the Equator and in the Arabian Sea. The waters west of Australia are cooling consistent with a positive IOD.
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 April 3 for what is shown as Week Two, the period April 5, 2017 to April 11, 2017, has wet conditions* north of the Maritime Continent but including the Philippines and possibly impacting Indochina with a small area of tropical cyclone activity* in Northwest Australia and wet conditions* for Peru.
* 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 or water in the El Nino category from 150W to 120W.Along the Equator, that is currently split 25 degrees Neutral with a Warm Bias and 5 degrees of water warmer than 0.5C i.e. El Nino water.
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. Today we have 5 degrees of water along the Equator that meet that criteria. 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 April 3, in the afternoon working from the April 2 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
(+2.0)/5 = +0.4
(+2.5)/5 = +0.5
My estimate of the daily Nino 3.4 SST anomaly is +0.5 which is borderline El Nino. NOAA has reported the weekly Nino 3.4 to be an ENSO Neutral value at +03 which is on the El Nino Side side of Neutral but slightly warmer 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 slightly warmer than last week at 0.0.. Nino 3 is also reported slightly warmer at 0.8. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is reported cooler at +1.8 which is still a 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 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 from 120W east but the reds are no longer showing at the bottom of the chart. However this lukewarm pattern weakened again last week but has spread out further west. 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 substantial change. If anything the pattern is fairly stable. Further west the surface is less warm. Basically there is on balance 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. OMG I forget to mention last week that now NOAA is reporting two Kelvin waves how could I have missed that. 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. 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. 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.
And one more.
I am not exactly sure of the area covered i.e. how much north and south of the Equator is included but you can see this warming has not progressed.
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. Hard to conclude that warm water is moving subsurface to the East with that blue cool blob 160W to 140W. 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 24, 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 The Dateline to 175W which is west of the Nino 3.4 Measurement Area. On the other hand warm water continues to extend from the Coast of Ecuador to 110W and slightly warm water all the way to 130W. Subsurface Temperature Anomalies: The cool water is almost all gone. Notice the warm water at depth but there is a big gap between the Dateline and 110W.
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 160E. 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 170E. We do not yet have ideal (El Nino) conditions for significant convection along the Equator east of the Dateline. What we have is still characteristic of a Cool Event. 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.
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 April 3 was reported as 2.69 which is ENSO Neutral. The 90 Day Average was reported at -0.59 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.
Math Calculation When Working with Multi-month Averages and Selected Months to Estimate what the Maps not Shown Might Look Like.
A three-month average probability is equal to (the probability for month 1 + probability for month 2 + probability for month 3)/3. We can not solve for each of Month 2 and Month 3 separately as we only have two data points and there are three variables i.e. three months in a three-month average. I have reorganized the equation where used in this report to make it more user friendly [and I have corrected an error in the process]. It is important to remember that we are solving for the probabilities for a two-month period which is the average of the probability for Month 2 and Month 3. I hope I have reduced rather than increased the confusion. If one actually attempts to solve the equation it should be fairly simple when you plug in real numbers. As an example if the average probability for a three-month period is 0.5 and the probability for the first month is 0.4 then the probability for months 2 and 3 must average 0.55 since 0.4 + 0.55 + 0.55 = 1.5 which divided by 3 to take the average for the three months gets you back to 0.5. Months 2 and 3 may not both have for the geographical area in question the probability of 0.55 but for the two-month period it must average 0.55 for the three-month average probability and the first-month probability to be as stated. I will show this footnote again the next time I compare a single month with the three-month average and thereafter I will probably put it in the Glossary.
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