Written by Sig Silber
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.
Please share this article – Go to very top of page, right hand side for social media buttons.
Wind Power Overcomes Solar Power in Australia Cyclone Debbie March 27
Source: AAP: Sarah Motherwell More coverage in the News Section of this Report.
Mocoa Columbia April 1
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.
This detailed description click to read might help with reading NWS reports. Haby Hints are always useful and since Helicity is of concern right now this Haby Hint click to read is very pertinent. The best place to get information on CONUS storms is the NOAA Storm Prediction Center (SPC). I do not know to upload their graphics into my report but you can access their web page by clicking here.
NOAA Update of their Outlook for April
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.
Temperature
Prior Outlook Issued on March 16, 2017
Updated Outlook Issued on March 31, 2017
Precipitation
Prior Outlook Issued on March 16, 2017
Updated Precipitation Outlook Issued on March 31, 2017
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:
* 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.
Water Vapor.
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.
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.
This graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.
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.
Now looking at the 5 Day Jet Stream Forecast
.
Putting the Jet Stream into Motion and Looking Forward a Few Days Also
To see how the pattern is projected to evolve, please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.
This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.
When we discuss the jet stream and for other reasons, we often discuss different layers of the atmosphere. These are expressed in terms of the atmospheric pressure above that layer. It is kind of counter-intuitive to me. The below table may help the reader translate air pressure to the usual altitude and temperature one might expect at that level of air pressure. It is just an approximation but useful.
Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on “earth” adjusting the parameters and then clicking again on “earth” to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns. This amazing graphic covers North and South America. It could be included in the Worldwide weather forecast section of this report but it is useful here re understanding the wind circulation patterns.
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.
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.
Four- Week Outlook
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.
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.
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.
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.
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.
.
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.
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.
Day | ENSO Phase | PDO | AMO | Other Comments |
Mar 16, 1970 | Neutral | + | – | Just after a Traditional El Nino |
Mar 17, 1970 | Neutral | + | – | Just after a Traditional El Nino |
Mar 29, 1980 | El Nino | + | -(t) | Tail end of Marginal Modoki Type II |
Mar 22, 1984 | Neutral | + | – | |
Mar 25, 1984 | Neutral | + | – | |
Mar 14, 1996 | La Nina | + | N | |
Mar 15, 1998 | El Nino | + | + | MegaNino |
Mar 16, 1998 | El Nino | + | + | MegaNino |
(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.
For more information on Analogs see discussion in the GEI Weather Page Glossary.
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.
McCabe Condition | Main Characteristics |
A | Very Little Drought. Southern Tier and Northern Tier from Dakotas East Wet. Some drought on East Coast. |
B | More wet than dry but Great Plains and Northeast are dry. |
C | Northern Tier and Mid-Atlantic Drought |
D | 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
And the 30 Days ending April 1, 2017
B. Beyond Alaska and CONUS Let’s Look at the World which of Course also includes Alaska and CONUS
Todays Forecast
Additional Maps showing different weather variables can be found here.
Near Term (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
Precipitation
Temperature
Looking Out a Few Months
Here is the new precipitation forecast from Queensland Australia:
JAMSTEC Forecasts
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
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. . .
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.
Below I show the changes over the last four weeks in the Sea Surface Temperature (SST) anomalies.
Below is an analysis of projected tropical hazards and benefits over an approximately two-week period.
Now let us look at the Western Pacific in Motion.
C. Progress of ENSO
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 found here. 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.
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.
———————————————— | A | B | C | D | E | —————– |
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. 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.
Subareas of the Anomaly | Westward Extension | Eastward Extension | Degrees of Coverage | |||||
As of Today | May 23, 2016 | As of Today | May 23 2016 | As of Today | In Nino 3.4 | Dec 12, 2016 | May 23, 2016 | |
These Rows below show the Extent of El Nino Impact on the Equator | ||||||||
+0.5C to +1C | 125W | ? | LAND | ? | 30 | 5 | 0 | 0 |
These Rows Below Show the Extent of ENSO Neutral Impacts on the Equator | ||||||||
0.5C or cooler Anomaly | 150W | 155E | 125W | 155W | 25 | 25 | 95 | 50 |
0C or cooler Anomaly | 175W | 155W | 150W | Land | 25 | 20 | 85 | 60 |
These Rows Below Show the Extent of the La Nina Impacts on the Equator | ||||||||
-0.5C or cooler | LAND* | 145W | LAND | Land | 0 | 0 | 65 | 50 |
-1C or cooler Anomaly | LAND | 140W | LAND | 105W | 0 | 0 | 40 | 35 |
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.]
Anomaly Segment | Estimated Anomaly | |
Last Week | This Week | |
A. 170W to 160W | +0.0 | +0.1 |
B. 160W to 150W | +0.2 | +0.3 |
C. 150W to 140W | +0.4 | +0.5 |
D. 140W to 130W | +0.6 | +0.7 |
E. 130W to 120W | +0.8 | +0.9 |
Total | +2.0 | +2.5 |
Total divided by five i.e. the Daily Nino 3.4 Index | (+2.0)/5 = +0.4 | (+2.5)/5 = +0.5 |
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.
And one more.
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).
.
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.
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.
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.
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.
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. |
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
El Nino | La Nina | MJO Active Phase | MJO Inactive Phase | |
---|---|---|---|---|
Eastern Pacific Easterlies |
|
|
|
|
Western Pacific Westerlies |
|
|
|
|
MJO Active Phase |
|
|
| |
MJO Inactive Phase |
|
|
|
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.
Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.
The full list of weekly values can be found here.
From Tropical Tidbits.com
The above is from a legacy “frozen” NOAA system meaning the software is maintained but not updated. It seems to show a cycle in the Nino 3.4 Index Values. I see that as I monitor the TAO/TRITON graphic. My best guess is that it is related to the MJO but it certainly is intriguing. 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
ENSO forecast:
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.
Regional forecast:
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.
Discussion
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.
The research on Ocean Cycles is fairly conclusive and widely available to those who seek it out. I have provided a lot of information on this in prior weeks and all of that information is preserved in Part II of my report in the Section on Low Frequency Cycles 3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS. It includes decade by decade predictions through 2050. Predicting a particular year is far harder. Parts of that discussion are in the beginning section of this week’s Report.
E. Relevant Recent Articles and Reports
Weather in the News
Cyclone Debbie Wreaks Havoc on Australia
Coastal El Nino Devastates Columbia
Weather Research in the News
Nothing to report
Global Warming in the News
Nothing to report
F. Table of Contents for Page II of this Report Which Provides a lot of Background Information on Weather and Climate Science
The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page II where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)
2. Medium Frequency Cycles such as ENSO and IOD
3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.
4. Computer Models and Methodologies
5. Reserved for a Future Topic (Possibly Predictable Economic Impacts)
G. Table of Contents of Contents for Page III of this Report – Global Warming Which Some Call Climate Change.
The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page III where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
2. Climate Impacts of Global Warming
3. Economic Impacts of Global Warming
4. Reports from Around the World on Impacts of Global Warming
Useful Background Information
With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.
El Ninos | La Ninas | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Start | Finish | Max ONI | PDO | AMO | Start | Finish | Max ONI | PDO | AMO | |
DJF 1950 | J FM 1951 | -1.4 | – | N | ||||||
T | JJA 1951 | DJF 1952 | 0.9 | – | + | |||||
DJF 1953 | DJF 1954 | 0.8 | – | + | AMJ 1954 | AMJ 1956 | -1.6 | – | + | |
M | MAM 1957 | JJA 1958 | 1.7 | + | – | |||||
M | SON 1958 | JFM 1959 | 0.6 | + | – | |||||
M | JJA 1963 | JFM 1964 | 1.2 | – | – | AMJ 1964 | DJF 1965 | -0.8 | – | – |
M | MJJ 1965 | MAM 1966 | 1.8 | – | – | NDJ 1967 | MAM 1968 | -0.8 | – | – |
M | OND 1968 | MJJ 1969 | 1.0 | – | – | |||||
T | JAS 1969 | DJF 1970 | 0.8 | N | – | JJA 1970 | DJF 1972 | -1.3 | – | – |
T | AMJ 1972 | FMA 1973 | 2.0 | – | – | MJJ 1973 | JJA 1974 | -1.9 | – | – |
SON 1974 | FMA 1976 | -1.6 | – | – | ||||||
T | ASO 1976 | JFM 1977 | 0.8 | + | – | |||||
M | ASO 1977 | DJF 1978 | 0.8 | N | ||||||
M | SON 1979 | JFM 1980 | 0.6 | + | – | |||||
T | MAM 1982 | MJJ 1983 | 2.1 | + | – | SON 1984 | MJJ 1985 | -1.1 | + | – |
M | ASO 1986 | JFM 1988 | 1.6 | + | – | AMJ 1988 | AMJ 1989 | -1.8 | – | – |
M | MJJ 1991 | JJA 1992 | 1.6 | + | – | |||||
M | SON 1994 | FMA 1995 | 1.0 | – | – | JAS 1995 | FMA 1996 | -1.0 | + | + |
T | AMJ 1997 | AMJ 1998 | 2.3 | + | + | JJA 1998 | FMA 2001 | -1.6 | – | + |
M | MJJ 2002 | JFM 2003 | 1.3 | + | N | |||||
M | JJA 2004 | MAM 2005 | 0.7 | + | + | |||||
T | ASO 2006 | DJF 2007 | 0.9 | – | + | JAS 2007 | MJJ 2008 | -1.4 | – | + |
M | JJA 2009 | MAM 2010 | 1.3 | N | + | JJA 2010 | MAM 2011 | -1.3 | + | + |
JAS 2011 | JFM 2012 | -0.9 | – | + | ||||||
T | MAM 2015 | AMJ 2016 | 2.3 | + | N | JAS 2016 | NDJ 2016 | -0.8* | + | + |
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.