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posted on 06 June 2017

June 5, 2017 Weather and Climate Report - NOAA Significantly Updates June Outlook

Written by Sig Silber

As is usually the case at the end of each month, NOAA updates its next month outlook which means June. This month the update is very extensive even though it was only 13 days after the May 18 release. In a similar vein, the 6 - 10 day forecast and 8 - 14 day forecast have also been changing day by day so it is an interesting situation. 


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First some housekeeping information. For those who want the forecasts beyond three months, we recently reported on the recent NOAA and JAMSTEC Seasonal Forecasts and compared them in a Special Update that you can get to by clicking here. We have also a couple of months ago provided an Update on the possible El Nino this Winter that many meteorological models until recently have been forecasting. We think it is implausible and our report can be accessed by clicking here. It seems that NOAA and BOM (Australia) are coming around to our way of thinking on this but JAMSTEC (Japan) is still bullish on an El Nino this winter. 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.

NOAA Update of their Outlook for June

NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on May 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 June to the Early Outlook for June issued on May 18, 2017. 

Temperature

Prior Outlook Issued on May 18, 2017

June Early Temperature Outlook Issued on May 18, 2017

Updated Outlook Issued on May 31, 2017

Updated Temperature June 2017 Outlook Updated on May 31, 2017

The warm anomaly has shrunk especially on the East Coast and the cool anomaly is much further east and larger. That is a big change in thirteen days.

Precipitation

Prior Outlook Issued on May 18, 2017

June Precipitation Early Outlook Issued on May 18,  2017

Updated Precipitation Outlook Issued on May 31, 2017

June Precipitation Outlook Updated on May 31, 2017

The prior outlook never made any sense to me. It seemed not possible to work out that way. The new outlook looks more feasible and is interesting as it does not seem to depend on Pacific Moisture for the most part. Where the moisture originates for the West-North central part of the wet anomaly is a mystery. The Gulf of Mexico plays a larger part in the updated Precipitation Outlook. The forecast for Alaska is very different in the updated Outlook.

Below is the discussion issued with this update.

30-DAY OUTLOOK DISCUSSION FOR JUNE 2017

THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JUNE 2017 ARE BASED ON THE LATEST FORECASTS FOR DAYS 1-7 (FROM WPC), DAYS 6-10, WEEK-2, WEEK 3-4, THE GFS, CFS, AND ECMWF DYNAMICAL MODEL RUNS, SOIL MOISTURE CONSIDERATIONS, COASTAL SEA-SURFACE TEMPERATURES (SSTS), AND CLIMATOLOGY. THOUGH SOME OF THE PREDICTED ANOMALY AREAS REMAIN UNCHANGED FROM THE 0.5-MONTH LEAD OUTLOOK (ISSUED 18 MAY), THERE ARE OTHER AREAS THAT HAVE CHANGED SIGNIFICANTLY.

THE UPDATED MONTHLY TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL MEAN TEMPERATURES OVER WESTERN ALASKA, MUCH OF THE FAR WESTERN AND FAR SOUTHERN CONUS, AND NEW ENGLAND. HOWEVER, THE ABOVE-NORMAL TEMPERATURES THAT WERE PREDICTED OVER THE REMAINDER OF THE ATLANTIC SEABOARD REGION IN THE 0.5-MONTH LEAD OUTLOOK NO LONGER HAVE THE SUPPORT OF MOST MODELS. RELATIVELY WARM COASTAL SSTS ALSO PLAY SOME ROLE IN THE TEMPERATURE OUTLOOK FOR WESTERN ALASKA. ANOTHER SIGNIFICANT CHANGE FROM THE TEMPERATURE OUTLOOK RELEASED 18 MAY IS THE PLACEMENT AND COVERAGE OF PROBABILITIES FAVORING BELOW-NORMAL TEMPERATURES. THE UPDATED OUTLOOK DEPICTS A SOMEWHAT LARGER, AND EASTWARD DISPLACED, AREA OF FAVORED BELOW-NORMAL TEMPERATURES, WHICH NOW FOCUSES ON THE CENTRAL PLAINS, THE CENTRAL THIRD OF THE MISSISSIPPI VALLEY, THE SOUTHWESTERN OHIO VALLEY, THE TENNESSEE VALLEY, AND INTERIOR PORTIONS OF THE SOUTHEAST. THIS AREA IS INDICATED BY DYNAMICAL MODEL FORECASTS AND IS ALSO WELL SUPPORTED BY THE 6-10 DAY AND WEEK-2 TEMPERATURE OUTLOOKS, AND HAS SOME SUPPORT FROM RECENT SOIL MOISTURE OBSERVATIONS. ELSEWHERE, IN AREAS WHERE CLIMATE SIGNALS ARE EITHER CONFLICTING OR OF VERY MODEST MAGNITUDE, EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-NORMAL MEAN TEMPERATURES ARE INDICATED.

THE UPDATED MONTHLY PRECIPITATION OUTLOOK HAS DRAMATICALLY CHANGED FROM THE 0.5-MONTH LEAD PRECIPITATION OUTLOOK. ABOVE-MEDIAN PRECIPITATION IS FAVORED FROM THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS SOUTHEASTWARD ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS, AND THEN EASTWARD AND NORTHEASTWARD ACROSS MOST OF THE SOUTHERN HALF OF THE MISSISSIPPI VALLEY, THE OHIO AND TENNESSEE VALLEYS, THE MID-ATLANTIC, AND MOST OF THE SOUTHEAST, WITH THE EXCEPTION OF FLORIDA. IN A BROAD SENSE, THIS AREA HAS THE SUPPORT OF RECENT CFS RUNS, AND PRECIPITATION FORECASTS ON ALL TIME-SCALES OUT TO ONE MONTH IN ADVANCE. FOR THE NORTHERN ROCKIES, AND THE NORTHERN AND CENTRAL HIGH PLAINS, MUCH OF THE EXPECTED PRECIPITATION FOR JUNE MAY COME WITHIN THE FIRST WEEK OF THE MONTH, ESPECIALLY IN AREAS WHERE THE CLIMATOLOGY IS RELATIVELY DRY. THERE ARE ELEVATED ODDS FOR BELOW-MEDIAN PRECIPITATION OVER MUCH OF WASHINGTON, OREGON, AND NORTHERN CALIFORNIA, AND ALSO OVER NORTHWESTERN ALASKA. THESE ANOMALY AREAS INDICATE WHERE THERE IS A GENERAL CONSENSUS BETWEEN THE VARIOUS PRECIPITATION OUTLOOKS AND MODEL RUNS NOTED EARLIER. ELSEWHERE, IN AREAS WHERE CLIMATE SIGNALS ARE EITHER CONFLICTING OR OF VERY MODEST MAGNITUDE, EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-MEDIAN PRECIPITATION ARE INDICATED.

Sometimes it is useful to compare the present month outlook to the three-month outlook

June Plus  June  -  August  2017 Outlook

June and JJA 2017

One can mentally subtract the June Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely July and August 2017. To  do that you need to take into account that:

For temperature there is much reduced coverage of the warm anomaly in June compared to the three-month period and the cool anomaly shown in June is not in the three-month forecast. Thus if you assume these colors are assigned correctly, it is a simple algebra equation to solve July/August probability for a given location = (3XThree-Month Probability - June Probability)/2*. So you can derive the July/August forecast this way. You can do that calculation easily for where you live. The three-month probabilities for the warm anomaly in the east would have to be even higher for July and August for the three-month probabilities to work out.
Re precipitation, in the March 18 map for June there was a North Central wet anomaly that extended south to and beyond  the New Mexico/Texas border. Now that wet anomaly for June is skewed to the east further south and extends all the way to the East Coast. The June Northwest dry anomaly is not shown in the three-month forecast. Alaska is wet in the three-month map and mostly dry in the updated June Map but that is not a big change from the May 18 map.  So if you assume these colors are assigned correctly, it is a simple algebra equation to solve July/August probability for a given location = (3XThree-Month Probability - June Probability)/2*. So you can derive the July/August forecast this way. You can do that calculation easily for where you live. A July/August May would have to show a dry anomaly for the West Coast to make the EC probability in the three-month map work.
One has to keep in mind that we are now subtracting a June Map issued on May 31 from a three-month map issued on May 18. 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 May 18 would not change if it was updated on May 31. The results in the box above might be an indication of how July and August 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 June Outlook is a better predictor of the three-month outlook than the three-month maps issued on May 18.  From the discussion released by NOAA on May 31,  the changes mentioned would appear to be fairly likely. I have a low level of confidence in the three-month forecast.

* The concept is that the probabilities of a deviation from climatology in the First Month and the combined Month Two and Three forecast that one derives must average out to the probabilities shown in the three-month maps.

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.

Eastern Pacific Animation

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.

 Water Vapor Imagery

Tonight, Monday evening June 5, 2017, as I am looking at the above graphic, we see storm activity in Wyoming moving to the east.

Looking at the current activity of the Jet Stream.

Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems especially in the winter The sub-Jet Stream 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. Some basic information on how to interpret the impact of jet streams on weather can be found here and here.

Current Jet Stream

One sees the current jet stream above. It again seems to be up and over a ridge and showing up again in the Eastern Part of the U.S.

This graphic provides a good indication of where the moisture is. It is a bit different than just moisture imagery as it is quantitative.

 Center for Western Weather and Water Extremes, Scripps/UCSD.

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.
This evening we see moisture entering from the Gulf of Mexico and moisture approaching the West Coast.

You can convert the above graphic in to a flexible forecasting tool by clicking here.  One can obtain views of different geographical areas by clicking here

60 Hour Forecast.

Here is a national animation of weather fronts and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. Beyond 60 hours, additional maps are available at links provided below.

current highs and lows

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.

Tropical Activity

But let's not forget the upcoming Hurricane Season. It may be getting off to an early start. So we need to start watching this graphic again.

Eastern Pacific Two Day Tropical Weather Outlook

When there is activity and I have not provided the specific links to the storm of interest, one can obtain that information at this link.

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 6. The Day 3 forecast can be found here. I used to present the Day 3 with a link to Day 6 but showing Day 6 may be more useful.

Day 6 Weather Forecast

When I look at this Day 6 forecast, it is a split Low with the Kamchatka portion having a surface central air pressure of 1000 hPa. The Low near Alaska also has a surface central air pressure of 1000 hPa. The Aleutian Low has turned from a semi-permanent feature into a train of Lows which one expects this time of the year. Remember, this is a forecast for Day 6 not the current situation.
The High Pressure off of the West Coast, the familiar RRR or more properly called the Eastern Pacific Semi-tropical High or the Hawaiian High is strong west and south of the Alaska Low. It has a surface central air pressure of 1028 hPa. There is thus now for Day 6 a significant block on Pacific Storms entering CONUS south of the extreme Northeast. Thus everything is shifted to the north other than storms that undercut (come in at lower latitudes than) the large Pacific High.
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 6. It is not the current situation.

Now looking at the Day 5 Jet Stream Forecast

Jet Stream Five Days Out .

This is a Day 5 forecast by one model. The activity is a trough diving deep but not all the way to Southern California. Arizona and New Mexico. The velocity of the winds in the Jet Stream are pretty low. 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.

air pressure and altitude
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.

Short term forecasts

Here is the seven-day cumulative precipitation forecast. More information is available here.

Seven Day WPC Quantitative precipitation forecast

We see some Northern Tier cumulative precipitation plus a more extreme situation in the Southeast especially Florida.

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.Thickness of 600 or more suggests very intensely heat and fire danger.

7 Day 500 MB Geopotential Forecast

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 West Coast/Rocky Mountains Trough and a Great Lakes/East Coast Ridge. There is also a trough forming in the southeast below the ridge but it is not very visible right now. Look for where the 582 and 588 thickness lines move away from each other.  We might even see the Monsoonal Ridge building over Mexico.
Remember this is a forecast for Day 7. Note the 540 Thickness Line re the above discussion of thickness and snow likelihood. Thickness lines near or over 600 tend to suggest very warm temperatures. So that is what we will be focusing on now re the need for heat warnings. We  do not see that in the forecast which is good news for Southern California and Arizona.

 Four- Week Outlook

I use "EC" in my discussions although NOAA sometimes uses "EC" (Equal Chances) and sometimes uses "N" (Normal) to pretty much indicate the same thing although "N" may be more definitive. 

First - Temperature

I am starting 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 June and three-month JJA maps which are issued and updated less frequently than the first three maps shown.

mall Images of Temperature Maps
6 to 10 Days 8 to 14 Days Weeks 3 and 4
6 to 10 Day 8 - 14 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 June 5, 2017 was 4 out of 5)

6 - 10 Day Temperature Outlook

8 - 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on June 5, 2017 was 2 out of 5) 

8-14 Day Temperature Outlook

Looking further out.

Experimental Week 3-4 Temperature Outlook

Consolidation of 6 - 10, 8 - 14 and Experimental Week 3-4 Temperature Forecasts

Interpreted on June 5, 2017

June 11 to June 19 June 17 to June 30

Days 6 - 10: CONUS is cool in the Western 1/3rd and warm in the Eastern 2/3rds. Alaska is warm in the north and cool in the south and the Panhandle.

The West is warm except for the extreme Northwest. Along a narrow strip of the East Coast it is warm. Alaska is warm. There is a large Great Lakes cool anomaly. The transition to the pattern shown in the Week 3 - 4 Forecast from the pattern shown in the 8-14 Day forecast seems to be feasible.

Week 2:  As the period evolves, the Alaska pattern does not change very much but the CONUS Western cool anomaly moderates and retreats north and most of CONUS becomes warm.
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. For all three time periods, in between the cool and warm anomalies it is usually EC i.e. the boundary is usually not sharp.

 

Reference Forecasts Full Month and Three Months.

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 shown at the beginning of this discussion on temperature 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.

June Temperature Outlook Updated on May 31, 2017

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 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 (6  10 Days, 8 - 14 Days, and recently Weeks 3-4) and statistical models (Monthly and Three-Months) 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.

JJA 2017 Temperature Outlook Issued on May 1, 2017

Now - Precipitation

I am starting 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 June and three month JJA maps which are issued and updated less frequently than the first three maps shown.

 Small Images of Precipitation Maps
6 to 10 Day 8 to 14 Day Weeks 3 and 4
6 to 10 Day 8 - 14 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 June 5, 2017 was 4 out of 5)

6 - 10 Day Precipitation Outlook

8 - 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on June 5, 2017 was 2 out of 5)

Current 8 - 14 Day Precipitation Outlook

Looking further out.

Weeks 3 and 4 Experimental Forecast..

Consolidation of 6 - 10, 8 - 14, and Week 3-4 Precipitation Forecasts

Interpreted on June 5, 2017

June 11 to June 19  June 17 to June 30, 2017
Days 6 -10: For CONUS, the Northern Tier is wet over to and including most of the Great Lakes and then extends down the Mississippi River Valley and and into the Southeast based on the forecast trough undercutting the Northeast Ridge. To the east and west of the wet anomaly it is dry. Alaska is wet except for the Northeast which is dry.

For CONUS, The Northwest is dry and this extends down and through Utah. The Middle Mississippi River Valley is wet and that anomaly extends all the way to the East Coast and in the other direction into the Great Plains.   Central Alaska is dry. The transition to the pattern shown in the Week 3 - 4 Forecast from the pattern shown in the 8-14 Day forecast seems to be feasible.

Week 2: The CONUS wet anomaly progresses to the east and the Southern Rockies dry anomaly shifts to the northwest.

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. In between the dry and wet anomalies, it is usually EC i.e. the boundary is usually not sharp.

Reference Forecasts Full Month and Three Months.

Her 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 shown at the beginning of this discussion about precipitation 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.

June 2017 Precipitation Outlook Updated on May 31, 2017

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 (6 - 10 Days, 8 - 14 Days and recently Weeks 3-4) and statistical models for longer-term forecasts (Month and three months) 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.

JJA 2017 Precipitation Outlook Issued on May 18, 2017

Here is the NOAA discussion released today June 5, 2017.

6-10 DAY OUTLOOK FOR JUN 11 - 15 2017

TODAY'S DYNAMICAL MODEL SOLUTIONS FOR THE 6-10 DAY PERIOD ARE IN GOOD AGREEMENT ON THE 500-HPA CIRCULATION PATTERN PREDICTED OVER NORTH AMERICA. TROUGHS ARE ANTICIPATED OVER THE ALEUTIANS  AND THE WESTERN CONUS, WHILE A RIDGE IS EXPECTED OVER THE NORTHEASTERN CONUS. THERE ARE SOME SHORT WAVES WITH A TROUGH OVER THE SOUTHEAST CONUS. TODAY'S 500-HPA BLEND CHART DEPICTS BELOW NORMAL HEIGHTS OVER THE WESTERN CONUS, MOST OF ALASKA, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE ANTICIPATED OVER THE EASTERN CONUS, AND NORTHWESTERN ALASKA. 

ABOVE NORMAL HEIGHTS ENHANCE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE EASTERN AND CENTRAL CONUS. BELOW NORMAL HEIGHTS TILT THE ODDS TO NEAR TO BELOW NORMAL TEMPERATURES FOR MUCH OF THE WESTERN CONUS FROM THE HIGH PLAINS TO THE WEST COAST. NEAR TO ABOVE NORMAL TEMPERATURES ARE FAVORED FOR WESTERN ALASKA AND THE ALEUTIANS, WHILE NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED FOR EASTERN ALASKA AND THE ALASKA PANHANDLE, CONSISTENT WITH THE GEFS BIAS-CORRECTED TEMPERATURE FORECAST TOOL.

A TROUGH OVER THE WESTERN CONUS ENHANCES PROBABILITIES FOR NEAR TO ABOVE MEDIAN  PRECIPITATION FOR THE NORTHWEST, THE CENTRAL AND NORTHERN GREAT PLAINS, AND THE GREAT LAKES. ABOVE MEDIAN PRECIPITATION IS EXPECTED OVER THE SOUTHEASTERN CONUS RELATED TO THE SHORT WAVES. BELOW MEDIAN PRECIPITATION IS FORECAST FOR PARTS OF THE SOUTHERN GREAT PLAINS AND THE MIDDLE AND NORTHERN ATLANTIC COAST STATES, WHICH IS CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLE MEMBERS. THE TROUGH NEAR THE ALEUTIANS TILTS THE ODDS TO NEAR TO ABOVE MEDIAN PRECIPITATION FOR CENTRAL AND SOUTHERN ALASKA, WHILE ABOVE MEDIAN PRECIPITATION ENHANCED OVER THE NORTHERN ALASKA.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODEL SOLUTIONS AND THE FORECAST TOOLS. 

8-14 DAY OUTLOOK FOR JUN 13 - 19 2017 

TODAY'S ENSEMBLE MEAN DYNAMICAL MODEL FORECASTS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA FOR THE WEEK-2 PERIOD.  A TROUGH IS ANTICIPATED OVER THE ALEUTIANS. DOWNSTREAM A WEAK TROUGH IS FORECAST OVER THE WESTERN CONUS.  ANOTHER TROUGH IS ANTICIPATED OVER THE SOUTHEASTERN CONUS, WHILE WEAK RIDGING IS INDICATED OVER THE NORTHEASTERN CONUS. TODAY'S 500-HPA BLEND CHART DEPICTS WEAK BELOW NORMAL HEIGHTS OVER MUCH OF THE WESTERN CONUS EXCEPT THE WEST COAST, WHILE WEAK ABOVE NORMAL HEIGHTS ARE FORECAST OVER THE CENTRAL AND EASTERN CONUS. 

CORRESPONDING TO THE TROUGHS OVER THE ALEUTIANS AND THE WESTERN CONUS, BELOW NORMAL HEIGHTS FAVOR BELOW NORMAL TEMPERATURES FOR SOUTHEASTERN ALASKA, THE ALASKA PANHANDLE, AND THE PACIFIC NORTHWEST. ENHANCED PROBABILITIES FOR NEAR TO ABOVE NORMAL TEMPERATURES ARE INDICATED FOR THE REMAINDER OF THE CONUS AND WESTERN ALASKA CONSISTENT WITH MOST OF THE DYNAMICAL TEMPERATURE FORECAST TOOLS.

TROUGHS PREDICTED OVER THE SOUTHEASTERN CONUS LEAD TO ENHANCED PROBABILITIES  FOR NEAR TO ABOVE MEDIAN PRECIPITATION FOR THE EASTERN CONUS. ENHANCED PROBABILITIES FOR BELOW MEDIAN PRECIPITATION ARE FORECAST FOR THE WESTERN CONUS, WHICH IS CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLE MEMBERS. ABOVE MEDIAN PRECIPITATION IS FAVORED FOR SOUTHERN ALASKA AND THE ALASKA PANHANDLE, AND NORTHWEST WASHINGTON AHEAD OF THE TROUGH OVER THE ALEUTIANS, WHILE  BELOW MEDIAN PRECIPITATION IS FAVORED FOR NORTHERN ALASKA. 

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE MODEL SOLUTIONS AND POOR AGREEMENT AMONG THE FORECAST TOOLS.

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.

Centered

Day

ENSO

Phase

PDO AMO

Other Comments

Jun 13, 1971 La Nina - -  
May 22, 1976 Neutral - - Between a La Nina and El Nino
May 31, 1988 La Nina + +  
Jun 1, 1988 La Nina + +  
May 24, 1990 Neutral + -  
May 15, 1994 Neutral + -  
Jun 2, 2004 Neutral + + Just before an El Nino Modoki Type II
Jun 3, 2004 Neutral + + Just before an El Nino Modoki Type II
May 21, 2005 El Nino + + Tail end of above described El Nino

(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 May 15 to June 13 which is strangely very similar to last week and 29 days which is a reasonable 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 May 29. These analogs are centered on 3 days and 4 days ago (June 1 or June 2). So the analogs could be considered to be just a bit out of in sync with the calendar meaning that we will be getting weather that we would normally have two or three days earlier in the year. The question is what if anything does this mean. For more information on Analogs see discussion in the GEI Weather Page Glossary.

There are three La Nina analogs, one El Nino Analog, and five ENSO Neutral Analogs. The phases of the ocean cycles of the analogs are consistent with McCabe Condition C which is associated with Northern Tier and Mid-Atlantic drought. So it is not a surprise that NOAA's models are not able to see out to Days 8 - 14 with much confidence. I think this is seasonal transition at work with a lot of movement of the Eastern Subtropical High that is switching from its winter position to its summer position and back again.

The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. Water Planners might usefully pay attention to the low-frequency cycles such as the AMO and the PDO as the media tends to focus on the current and short-term forecasts to the exclusion of what we can reasonably anticipate over multi-decadal periods of time. One of the major reasons that I write this weather and climate column is to encourage a more long-term and World view of weather.

McCabe Maps modified to include the subtitles

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 Conditions from 2007 report with labels corrected with authors permission

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 May 27, 2017

May 27  2017  30 Day temperature and precipitation departures.

Not a lot of change in the precipitation pattern. The temperature warm anomaly on the East Coast continues to moderate. Remember this is a 30 day average with seven more recent days added and seven more distant days removed.

And the 30 Days ending June 3, 2017

June 3, 2017 30 Day Temperature and Precipitation Departures

Re precipitation the pattern is similar but more muted. Re temperature, the pattern is now reversed with the East now showing neutral rather than warm and the West now showing a bit more warm.              Remember this is a 30 day average and seven days recent days are added and seven distant days are removed.

B. Beyond Alaska and CONUS Let's Look at the World which of Course also includes Alaska and CONUS

Same as above but for July

I will be including the above two graphics regularly as they really help with understanding why things are happening the way they are. I think the (at least intermediate Source is The Weather Channel and I was able to download the full presentation with difficulty and you can attempt the same thing by clicking here.
I think these two slides are from a much larger set but these two really highlight the position of the Bermuda High which they are calling the Azores High in the January slide and is often called NASH and it has a very big impact on CONUS Southeast weather and also the Southwest. You also see the north/south migration of the Pacific High what also has many names and which is extremely important for CONUS weather and it also shows the change of location of the ITCZ which I think is key to understanding the Indian Monsoon. A lot of things become much clearer when you understand these semi-permanent features some of which have cycles within the year, longer period cycles and may be impacted by Global Warming.
We arein Mid-June right now so we are very close to the set of positions shown above for July. For CONUS the seasonal repositioning of the Bermuda High and the Pacific High are very significant.

Todays Forecast

Temperature at 2 Meters

Notice that below the map there is a tabulation of magnitude of the current anomalies by region. There is a large negative anomaly in Antartica. The warm anomaly for Africa covers the entire continent.

Maine Reanalyer

This graphic is actuals not anomalies. We again see the dry area from North Africa through Asia except for Southeast Asia as well as most areas south of the Equator. Most of North America is dry also.

Additional Maps showing different weather variables can be found here.

Near Term Forecast (Currently Set for Day 6 but the reader can change that) [For several months I set this variable for Day 3 but tonight it is showing Day 6 which may be of more interest]

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  and 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. Below are the current worldwide precipitation and temperature forecasts for six days out. They will auto-update and be current for Day 6 whenever you view them. If you want the forecast for a different day Click Here

Precipitation

BOM World Preciptation  Wednesday

Notice that the Bermuda High isis now a split High. The Pacific is a High for each coast with the Aleutian Low in between. Central America and Northern South America are wet. Southeast Asia and the Maritime Continent are wet.

Temperature

BOM Current Temperature Wedensday

The pattern of hot from North Africa through India continues. Please remember this graphic updates every six hours so the diurnal pattern can confuse the reader.

Looking Out a Few Months

Here is the precipitation forecast from Queensland Australia:

Rising SOI  forecast for June to August 2017.

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 continuation of the  rising SOI. It is more like a La Nina forecast than an El Nino forecast.

JAMSTEC Forecasts

This month, JAMSTEC issued their ENSO forecasts and climate maps in early May. We issued a Special Update on May 20 that you can get to by clicking here.  Remember if you leave this page to visit links provided in this article, you can return by hitting your "Back Arrow", usually top left corner of your screen just to the left of the URL box. 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. We will be publishing a new Update on June 17 of the new JAMSTEC and NOAA seasonal outlooks.

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.[NOAA may be having problems updating their daily SST Anomaly Report so I am working with the latest version that I have]

Daily SST Anomalies

First the categorization of the anomalies.

Mediterranean, Black Sea and Caspian Sea Western Pacific West of North America East of North America North Atlantic
The Black Sea, Caspian Sea and the Mediterranean are warm. Warm west of North Korea, around Japan and around Kamchatka. There is a large cool area straddling the Dateline but now mostly east of the Dateline. Warm in Bering Straights. Cool off the Southern Baja. Warm but cool out to sea off Newfoundland. Cool
The Tropical Pacific

Cool from Ecuador out to 110W. Neutral with warm bias from 110W to Malaysia.

Africa West of Australia North, South and East of Australia West of South America East of South America
Warm North of Northwest Africa i.e. off Spain and the U.K. Warm west of and southwest of Africa. A but cool off Southwest Coast. Warm off the Southeast Coast. Cool off of Peru. Cool off of 20S. Very warm south of 30S.

 

What you see in the below graphic is the change in the anomaly over the last four weeks [*very important re Peru which is showing cool today (actually yesterday) but has been warming which shows that one day does not make a trend] . So you have to refer to the graphic above this one to really interpret the below graphic as what we are seeing here is the change in the anomalies. So blue means a trend that is either cooler or less warm than four weeks ago. Red means a trend that is warmer or less cool than four weeks ago. So this graphic is a way of understanding how the anomalies shown in the above graphic have changed over the past four weeks.

June 5, 2017 four week change is SST Anomalies

The categorization of the four week change in the anomalies.

Mediterranean, Black Sea and Caspian Sea Western North Pacific West of North America East of North America North Atlantic

Not much changing

Warming around Japan.

Slight warming west and east of India; cooling to the south.

Stable in Bering Straits. Cooling from California to the Equator. Cooling at 40N but not as intense as off West Coast. Warming east of Florida Stable
The Tropical Pacific Cooling east and for the Maritime Continent. Mostly stable in between.
Africa West of Australia North, South and East of Australia West of South America East of South America
Warming Bay of Guinea Stable Mostly stable. Slight warming to the north. Cooling north of 30S. Extensive cooling further out to sea. Cooling north with significant cooling between 10N and 20S. Warming south of 30S

 

This may be a good time to show the recent values to the indices most commonly used to describe the overall spacial pattern of temperatures in the (Northern Hemisphere) Pacific and the (Northern Hemisphere) Atlantic and the Dipole Pattern in the Indian Ocean.

Most Recent Six Months of Index Values PDO Click for full list

AMO click for full list.

Indian Ocean Dipole (Values read off graph)
October -0.68 +0.39 -0.3
November +0.84 +0.40  0.0
December +0.55 +0.34 -0.1
January +0.12 +0.23  0.0
February +0.04 +0.23 +0.2
March +0.08 +0.17 +0.0
April +0.52 +0.29 +0.2
May NA NA +0.2

 

Switching gears, below is an analysis of projected tropical hazards and benefits over an approximately two-week period.

Tropical Hazards

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 June 12 for what is shown as Week Two, the period June 14, 2017 to June 20, 2017, we see wet conditions* north of the Equator in West Africa  and also bridging from India to Myanmar. We see dry conditions* west of the Maritime Continent.
* 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.

Now let us look at the Western Pacific in Motion.

Western Pacific Tropical Activity

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. 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.

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.

Notice in the bottom graphic the big difference between temperature anomalies south of the Equator and north of the Equator. This creates a dynamic situation. The winds seem to be moving the warm water further south which reduces the level of recorded NINO indices. Notice the strong Easterlies.

Current SST and wind anomalies

Location Bar for Nino 3.4 Area Above and Below
------------------------------------------------  A       B       C      D       E       -----------------

 

The below table only looks at the Equator and shows the extent of anomalies along the Equator. The ONI Measurement Area is the 50 degrees of Longitude between 170W and 120W and 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.The top rows show El Nino anomalies. The two rows just below that break point contribute to ENSO Neutral.

Subareas of the Anomaly

Westward Extension

 

Eastward Extension

 

Degrees of Coverage

Total   

Portion in Nino 3.4 Measurement Area

These Rows below show the Extent of El Nino Impact on the Equator

1C to 1.5C*(strong)

WARM POOL

WARM POOL

0

0

+0.5C to +1C (marginal)

WARM POOL

155E

0

0

These Rows Below Show the Extent of ENSO Neutral Impacts on the Equator
0.5C or cooler Anomaly (warmish neutral)*

150E

LAND

110

50

0C or cooler Anomaly (coolish neutral)

LAND

LAND

0

0

 

* A warm anomaly exceeding +0.5C is showing South of the Equator in today's TAO/TRITON Five-Day Mean Graphic. This week it remains intruded north of the Equator as is shown in the Tao/Triton graphic. I have not recorded it that way in the above table but will do so if that warmer Southern Hemisphere water continues to show up North of the Equator. It would complicate the table so for now I am not showing it in the table.

My Calculation of the Nino 3.4 Index

I calculate the current value of the Nino 3.4 Index each Monday 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 June 5, in the afternoon working from the June 4 TAO/TRITON report [Although the TAO/TRITON Graphic appears to update once a day, in reality it updates more frequently.], this is what I calculated.

Calculation of ONI from TAO/TRITON Graphic
Anomaly Segment Estimated Anomaly
  Last Week This Week
A. 170W to 160W +0.6 +0.6
B. 160W to 150W +0.6 +0.6
C. 150W to 140W +0.6 +0.5
D. 140W to 130W +0.7 +0.5
E. 130W to 120W +0.7 +0.4
Total +3.2 +2.6
Total divided by five i.e. the Daily Nino 3.4 Index (+3.2)/5 = +0.6 (+2.6)/5 = +0.5

 

My estimate of the daily Nino 3.4 SST anomaly tonight is +0.5 which is a marginal El Nino Value. NOAA has again reported the weekly Nino 3.4 to be +0.6 which is an El Nino Value. The Nino 3.4 Measurement Area has been cooling a bit this week so it is not a surprise that my reading is a bit lower than the NOAA reading as they are covering a slightly longer period of time and a slightly earlier period of time.
Nino 4.0 is reported a bit higher at +0.4. Nino 3 is a bit lower at +0.5. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is reported lower at +0.2. I believe it was up there close to 3 at one time so this index has been declining quite a bit and is what I think has fooled the models and the meteorologists earlier this year and continues to create confusion.
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.

June 5, 2017 Nino Readings

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.

June 5, 2017 Equatorial Pacific SST Anomalies

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.
The bottom of the Hovmoeller which are the current readings are now light yellow which is not El Nino warm but clearly on the warm side of Neutral. 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.
Week to week there have been no substantial changes since the far East Pacific cooled down. It is ENSO Neutral with a warm bias.

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.

June 5, 2017 Upper Ocean Heat Anoma

The bottom of the Hovmoeller shows the current situation. The Cool Event is long gone. But what might be successive Kevin waves initiating an El Nino are still not very impressive. If you look from the bottom of the graphic up you can see that any La Nina conditions ended in December. There is not much change from the prior week but a cooler area is no longer in the picture.  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. There could be another weak Kelvin Wave getting started but we will need a couple of weeks to see if that is the case. So far there is no indication of this but not shown in this report the overall pattern of Easterlies has declined a bit so there is a bit more opportunity for a Kelvin Wave to get started. So far the change has been small. Mid-May is the time when the next Rossby Wave moves through and that will be the best opportunity to have a boost to this flagging incipient El Nino.
NOAA did draw in an Upwelling Wave in the graphic four weeks ago presumably to be ready to draw in a Downwelling wave which it did two weeks later. It has moved east to 130W. It generally is a pretty shallow layer. Two years there were five or six Kelvin waves the first ones quite strong.This is showing at 0.5C to 1.0C (orange color). No red and it covers a small area. Two weeks ago we said: "it almost looks like to the west you can see the passing of the wave i.e. it appears to have been not very wide more or less like the one in February". Today the graphic is even clearer on that.

 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). 

.June 5, 2017 Kelvin Wave Analysis.

The pattern has changed a bit since last week. The warm water to the west has hightailed it over into the Nino 3.4 Measurement Area but not at the surface where El Nino is measured. It is a fairly shallow warm anomaly and will mix out fairly quickly even though the specific heat of water makes it a pretty good insulator so the heat will not transfer out by contact very much but by currents mixing the water into other less warm water. That is why during the creation phases of an El Nino you need a constant stream of warm water coming in from the IndoPacific Warm Pool. There is shown in this graphic a decent warm anomaly between 165E and 175W but no reinforcements behind it i.e.to the west and a later graphic seems to show that warm anomaly has dissipated. 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 a lot of change. There is no indication of an El Nino of any significance forming.

Now for a more detailed look. Notice by the date of the graphic (dated June 7, 2017) that the lag in getting this information posted so the current situation may be a bit different than shown although this graphic was just updated this afternoon. 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.Subsurface Heat Anomalies

Re the top graphic, let us first look at surface temperature anomalies. In a change, cool to neutral water extends from the Coast of Ecuador to 100W and slightly warm to warm water all the way to 155W. Subsurface Temperature Anomalies: The cool water no longer blocks the arrival of warmer water. Below the Nino 3.4 Measurement Area there is a modest amount of moderately warm water (on an anomaly basis) enough to have the surface recorded as El Nino temperature for a month or so. Right now this warm water only reaches the surface at 135W and just barely and is neutral below 100 meters deep. The warm pocket of water that was centered on 175E at 125 meters has pretty much disappeared. A month or six weeks of Nino 3.4 values in excess of +0.5C will not be long enough for this event to be classified as an El Nino.
The bottom half of the graphic (Absolute Values which highlights the Thermocline) is now more useful as we track the transition from last winter's ENSO Cool Event to ENSO Neutral to ENSO Neutral with a warm bias which may possibly become an El Nino. More likely we will soon see the situation change to ENSO Neutral with a warm bias and then to just plain ENSO Neutral.
It shows the thermocline between warm and cool water. The 28C Isotherm is now located at the 150W. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm is again at 130W which is a lot further east than the 28C isotherm but no change from the last report. We do not yet have ideal (El Nino) conditions for significant convection along the Equator east of the Dateline. What we have is increasingly looking like ENSO Neutral which will record at El Nino levels for a month. The 25C isotherm no longer extends all to the way to Ecuador which is less El Nino-ish. The 20C Isotherm is depressed by warmer water all the way to Ecuador.
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.
It does not appear likely that the conditions exist to create an El Nino.

Here are the above graphics as a time sequence animation. You may have to click on them to get the animation going.

Equatorial Temperature Simulation

Isotherm Simulation

And now Let us look at the Atmosphere.

Low-Level Wind Anomalies near the Equator

Here are the low-level wind anomalies.

Low Level Wlind Anomalies

We now see easterly anomalies west of the Dateline which are not at all consistent with the formation of an El Nino.

And now the Outgoing Long wave Radiation (OLR) Anomalies which tells us where convection has been taking place. 

OLR Anomalies Along the Equator

The pattern has changed. We no longer see suppressed Outgoing Long Wave Radiation (OLR) at the Dateline (no longer dry) nor do we see enhanced OLR at 120E (no longer wet)

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 30 day and 90 day values.

Current SOI Readings

The 30 Day Average on June 5 was reported as 0.78 which is an ENSO Neutral value. The 90 Day Average was reported at -1.78 which is also ENSO Neutral. Looking at both the 30 and 90 day

 

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 (Negative SOI especially lower than -7 correlates with El Nino Conditions). During La Nina we expect the Warm Pool to be further east resulting in Positive SOI values greater than +7).       

To some extent it is the change in the SOI that is of most importance. 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.

Forecasting the Evolution of ENSO

We now have both the early May  (May 11) and Mid-May (May 18) reports 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.

May 18, 2017 CPC/IRI Update two graphics side by side.

First we look at graphic on the left which is the IRI/CPC Survey-Based Report issued on May 11, 2017. Then we look on the right at the most recent (May 18) fully model based report. Notice the new report has much higher probabilities for El Nino than the prior report.  The full discussion can be found at this link

The forecast of a strong El Nino never made any sense and we discussed that a couple of months ago and that report can be accessed by clicking here.  But now the latest forecast from NOAA has upped the probabilities a bit.

Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model. It does not agree with the CPC-IRI analysis.

CFSv2 spread and bias correct ENSO forecast

The estimated current value of the Nino 3.4 Temperature Anomaly after the adjustments have been applied is moving towards 0.6C or 0.7C for June which is an El Nino Value but it does not maintain that level into JJA. Looking ahead to Summer and Fall you see ENSO Neutral readings with a warm bias being the mean of the forecast ensemble. Moving into Winter the forecast is totally Neutral. But notice the wide spread among forecast members into the Fall and Winter. The forecasts have come down from a strong El Nino to what may be barely a near El Nino and most likely just ENSO Neutral. We discussed that recently in this article - click to read.

From Tropical Tidbits.com

CDAS Legacy System

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 yet 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)

Australia POAMA ENSO model run

Discussion (notice their threshold criteria are different from NOAA). Also the seasons in the Southern Hemisphere are the reverse of those in the Northern Hemisphere.

El Niño development pauses; ENSO Outlook remains at El Niño WATCH

The El Niño–Southern Oscillation (ENSO) remains neutral. The Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is around a 50% chance of El Niño developing in 2017—double the normal likelihood. However several indicators have shown little or no increase for several weeks, suggesting El Niño development has stalled for now.

Sea surface temperatures across the tropical Pacific remain warmer than average, though cooling has occurred in some areas over recent weeks in response to stronger than average trade winds. The Southern Oscillation Index has also eased to near zero values. All other ENSO indicators also remain neutral.

Four of eight international climate models suggest tropical Pacific Ocean temperatures may exceed El Niño thresholds during the second half of 2017, down from seven of eight models that were forecasting a possible event in April. Virtually all models have reduced the extent of predicted ocean warming compared to earlier in the year, indicating that if El Niño forms, it is likely to be weak.

El Niño is often, but not always, associated with a drier than average winter and spring over eastern Australia. If the tropical Pacific remains warmer than average, but El Niño thresholds are not quite met, some El Niño-like effects are still possible.

Here is the JAMSTEC forecast of the Nino 3.4 values which are the most looked at index used to forecast El Nino. This report was issued on May 8 or May 9. We should be able to access an updated version very soon.

JAMSTEC May 1, 2017 ENSO Forecast.

On Saturday May 20 we released our analysis of the NOAA and JAMSTEC seasonal outlook updates. As anticipated there was a lot of  disagreement in the further out months. You can access our analysis 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.

Indian Ocean IOD (It updates every two weeks)

The IOD Forecast is indirectly related to ENSO but in a complex way.

IOD POAMA Model Run

Discussion

Indian Ocean Dipole outlooks

The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 4 June was −0.08 °C.

Four of the six surveyed models indicate a positive IOD is likely to form during winter. However, model skill is low at this time of year, so caution should be exercised when using these forecasts.

A positive IOD typically brings below average winter–spring rainfall to parts of southern and central Australia.

Information on the impacts on Australia of the IOD can be found by clicking here.  But Australia is not the only nation impacted by the IOD. 

It is important to understand how and where the IOD is measured.

IOD Measurement Regions

IOD Positive is the West Area being warmer than the East Area (with of course many adjustments/normalizations). IOD Negative is the East Area being warmer than the West Area.  Notice that the Latitudinal extent of the western box is greater than that of the eastern box. This type of index is based on observing how these patterns impact weather and represent the best efforts of meteorological agencies to figure these things out. Global Warming may change the formulas probably slightly over time but it is costly and difficult to redo this sort of work because of long weather cycles.

D. Putting it all Together.

At this time there is now interest as to whether or not this Summer and Fall will be El Nino situations. Only the JAMSTEC model has really continued to be bullish on the El Nino scenario and they will be issuing a new outlook within the week. So we can not be sure but it would seem that the chances of other than a marginal El Nino are fairly low.

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.

E. Relevant Recent Articles and Reports

Weather in the News

Nothing to report

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.

1. Introduction

2. Climate Impacts of Global Warming

3. Economic Impacts of Global Warming

4. Reports from Around the World on Impacts of Global Warming

H. Useful Background Information

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.

El Nino Zones

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. 

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.

Western Pacific Warm Pool

Click for Source

Interaction between the MJO and ENSO

This Table is a first attempt at trying to relate the MJO to ENSO

  El Nino La Nina MJO Active Phase MJO Inactive Phase
Relationship of MJO and ENSO
Eastern Pacific Easterlies
  • Weaker
  • Stronger
  • Part of Decay Process
  • Counteracts Easterlies
  • Enhances Easterlies
Western Pacific Westerlies
  • Stronger
  • May Create or Stimulate the Onset of El Nino via Kelvin Waves
  • Weaker
  • Part of Decay Process
  • Strengthens Westerlies
  • Weakens Westerlies
MJO Active Phase
  • More  likely
  • Stimulates
  • Less likely and weak
  • Retards development of a new La Nina
  • Stimulates the Jet Stream
 
MJO Inactive Phase
  • Less Likely
  • Suppresses
  • 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. 

History of ENSO Events

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*  + +

 

*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

ONI History Updated on June 5, 2017

The Mar/Apr/May preliminary has just come out as +0.4. This means that we would still need five consecutive values of +0.5 or greater for this to be an El Nino and that is not going to happen. The full history of the ONI readings can be found here. The MEI index readings can be found here.

Click here for a list of Sig Silber's Weather Posts

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