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posted on 01 August 2017

July 31, 2017 Weather and Climate Report - NOAA Rethinks August Outlook

Written by Sig Silber

All signs of El Nino are gone. A short period of La Nina conditions is expected but too short to be considered a La Nina. Today NOAA issued their usual end of month update for the following month - in this case August. We report on that and the very large changes conjured up by NOAA in just 11 days.  We also provide our usual update of current conditions and forecasts worldwide with a focus on CONUS and Alaska.


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The Seasonal Outlook Update Report was published on Saturday July 22 and can be accessed 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. This is our regular weekly Weather and Climate Report with the addition of a report on NOAA's August Update.

Forecast Summary with a Focus on the Southwest Monsoon.

  Temperature Precipitation
 6 - 10 Day  6- 10 Day Temperature Forecast.  6 - 10 Day
 8 - 14 Day 6 - 14 Day Temperature Forecast  8 - 14 Day precipitation forecast

 

This is what I am looking at Monday Night. It might be different if you do not read my report until after 10 am to 11 am EDT on Tuesday as the above maps will have updated and may look a little different. I thought of freezing these graphics (so they would not update and change) but decided against it. What you can see is a West/East divide re temperature with the southern border agreeing to some extent with the West and for precipitation a North/South divide but the wet anomaly is far larger than the dry anomaly.

NOAA Update of their Outlook for August

NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on July 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 August to the Early Outlook for August issued on July 20, 2017. 

Temperature

Prior Outlook Issued on July 20, 2017

August Early Temperature Outlook Issued on July 18, 2017

Updated Outlook Issued on July 31, 2017

Temperature August, 2017 Outlook Updated on July 31, 2017

This is a huge change in just eleven days with the West and Alaska remaining warm but from CONUS west east there is first a large cool anomaly and then EC except for New England and South Florida which remain as being forecast to be warm.

Precipitation

Prior Outlook Issued on July 20, 2017

August Precipitation Early Outlook Issued on July 20,  2017

Updated Precipitation Outlook Issued on July 31, 2017

August Precipitation Outlook Updated on July 31, 2017

This also is a large change with a dry anomaly in the Northwest and the wet anomaly is extended all the way to the East Coast and the area of highest probability of being wet has shifted from the Four Corners area to extreme Southeast New Mexico and Southwest Texas. 

30-DAY OUTLOOK DISCUSSION FOR AUGUST 2017

THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR AUGUST 2017 ARE BASED ON THE LATEST DYNAMICAL MODEL GUIDANCE, WPC TEMPERATURE AND PRECIPITATION FORECASTS DURING THE FIRST WEEK OF THE MONTH, THE CPC 6-10/8-14 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, CLIMATE LINKAGES TO CURRENT SOIL MOISTURE CONDITIONS, AND POTENTIAL INFLUENCE FROM AN ATMOSPHERIC KELVIN WAVE (KW) [Editor's Note: This is a very complicated subject and is different than an Equatorial Ocean Kelvin Wave which we often talk about]. ALTHOUGH THE MADDEN-JULIAN OSCILLATION (MJO) STRENGTHENED DURING LATE JULY WITH ITS ENHANCED PHASE OVER THE MARITIME CONTINENT AND WEST PACIFIC, IT IS FORECAST TO WEAKEN. A ROBUST KW EMERGED FROM THE WEST PACIFIC RECENTLY AND IS CURRENTLY PROPAGATING EAST ACROSS THE WESTERN HEMISPHERE. THIS KW IS EXPECTED TO PROVIDE A FAVORABLE ENVIRONMENT FOR TROPICAL CYCLONE (TC) DEVELOPMENT OVER THE EAST PACIFIC DURING THE FIRST WEEK OF AUGUST. TCS ACROSS THE EAST PACIFIC MAY ENHANCE MOISTURE ACROSS THE SOUTHWESTERN U.S. DURING EARLY AUGUST.

THE MAJOR REVISION TO THE TEMPERATURE OUTLOOK IS A LARGE REDUCTION IN THE COVERAGE OF INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE CENTRAL AND EASTERN U.S. THE GFS AND ECMWF ENSEMBLE MEANS INDICATE AN AMPLIFYING 500-HPA TROUGH DEVELOPING OVER THE EAST-CENTRAL U.S. DURING THE FIRST WEEK OF AUGUST WITH NEAR- TO BELOW-NORMAL 500-HPA HEIGHTS PERSISTING THROUGH AT LEAST THE FIRST TEN DAYS OF THE MONTH. BELOW-NORMAL TEMPERATURES ARE MOST LIKELY ACROSS THE CENTRAL AND SOUTHERN GREAT PLAINS WHERE TEMPERATURES ARE FORECAST TO AVERAGE NEAR 10 DEGREES F BELOW NORMAL DURING THE FIRST WEEK OF AUGUST AND WEEK-2 TEMPERATURE TOOLS HAVE THE HIGHEST PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS THIS REGION. INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE WESTERN U.S. DUE TO ANOMALOUS RIDGING EARLY IN THE MONTH ALONG WITH A CONSISTENT SIGNAL AMONG RECENT MONTHLY TEMPERATURE FORECASTS FROM THE CFS MODEL. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE HIGHEST ACROSS THE PACIFIC NORTHWEST SINCE TEMPERATURES ARE FORECAST TO AVERAGE NEAR 15 DEGREES F ABOVE NORMAL THROUGH THE FIRST WEEK OF AUGUST. ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES INCLUDE THE NORTHERN HIGH PLAINS, BASED IN PART ON EXCEPTIONALLY LOW SOIL MOISTURE. AS OF JULY 30, SOIL MOISTURE IS BELOW THE 5TH PERCENTILE ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA. ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON JULY 25, NEARLY ALL OF WESTERN NORTH DAKOTA IS DESIGNATED WITH EXTREME (D3) TO EXCEPTIONAL (D4) DROUGHT.

ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE MAINTAINED ACROSS THE SOUTHWESTERN U.S. AND EXPANDED TO INCLUDE PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS, GULF COAST, AND SOUTHEASTERN U.S. THE HIGHEST ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST FOR SOUTHEAST NEW MEXICO AND THE RIO GRANDE VALLEY DUE TO SHORT-TERM RAINFALL AND A CONSISTENT SIGNAL AMONG RECENT MONTHLY PRECIPITATION FORECASTS FROM THE CFS MODEL.  THE EXPANSION OF INCREASED CHANCES FOR ABOVE-MEDIAN PRECIPITATION ACROSS PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS, GULF COAST, AND SOUTHEASTERN U.S. IS BASED ON LOCALLY HEAVY RAINFALL EXPECTED DURING THE FIRST WEEK OF AUGUST ALONG WITH GOOD AGREEMENT AMONG PRECIPITATION TOOLS AT ALL TIME RANGES. AS OF 11AM ON JULY 31, TROPICAL STORM EMILY IS NEAR TAMPA BAY, FLORIDA. EMILY IS FORECAST TO CROSS THE FLORIDA PENINSULA AND TRACK AWAY FROM FLORIDA AT THE BEGINNING OF THE MONTH. ALTHOUGH MOST OF THE RAINFALL ASSOCIATED WITH EMILY IS EXPECTED TO OCCUR BEFORE THE START OF THE MONTH, THE MOST RECENT DAILY RUN OF THE CFS MODEL INDICATES ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ACROSS FLORIDA. LITTLE OR NO PRECIPITATION IS LIKELY ACROSS THE PACIFIC NORTHWEST, NORTHERN ROCKIES, AND NORTHERN HIGH PLAINS DURING THE FIRST WEEK OF AUGUST. SINCE THE PAST THREE DAILY RUNS OF THE CFS MODEL HAVE A DRY SIGNAL, ENHANCED ODDS FOR BELOW-MEDIAN PRECIPITATION WERE ADDED TO THESE AREAS IN THIS UPDATED OUTLOOK.  DUE TO CONFLICTING OR WEAK PRECIPITATION SIGNALS AT DIFFERENT TIME RANGES, EQUAL CHANCES FOR BELOW-, NEAR-, OR ABOVE-MEDIAN PRECIPITATION ARE NECESSARY FOR THE MIDWEST AND NORTHEAST.

ONLY MINOR CHANGES ARE REQUIRED TO THE PREVIOUS TEMPERATURE AND PRECIPITATION OUTLOOKS ACROSS ALASKA. THE HIGHEST CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS NORTHWEST ALASKA WHERE SEA SURFACE TEMPERATURE ANOMALIES ARE AVERAGING MORE THAN 2.5 DEGREES C ABOVE NORMAL. ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE EXPANDED TO INCLUDE MORE OF THE ALASKA MAINLAND BASED ON THE LATEST PRECIPITATION TOOLS.

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

July Plus July  -  September  2017 Outlook

August and ASO 2017 Updated on July 31, 2017

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

For temperature The difference between August and the three-month map is very different from the Rocky Mountains on East with a total reversal in the Great Plains. Thus if you assume these colors are assigned correctly, it is a simple algebra equation to solve August/September  probability for a given location = (3XThree-Month Probability - August Probability)/2*. So you can derive the September/October forecast this way. You can do that calculation easily for where you live.
Re precipitation, the spatial distribution of precipitation probabilities in Alaska has changed a bit but the major change is the expansion to the East of the Northwest dry anomaly and the the expansion to the East of the Southwest wet anomaly and change in where the precipitation has the highest probability from the Four Corners Areas and a second center of highest probabilities located in East Texas to a single large area with highest Probabilities in Southwest Texas. So if you assume these colors are assigned correctly, it is a simple algebra equation to solve September/October probability for a given location = (3XThree-Month Probability - August Probability)/2*. So you can derive the September/October forecast this way. You can do that calculation easily for where you live.
One has to keep in mind that we are now subtracting an August Map issued on July 31 from a three-month map issued on July 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 July 20 would not change if it was updated on July 31. The results in the box above might be an indication of how September and October 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 August Outlook is a better predictor of the three-month outlook than the three-month maps issued on July 20.  From the discussion released by NOAA on July 31,  the changes mentioned would appear to extend to the Three-Month and even beyond the three-month forecast so I would be inclined to look at these changes as being more than simply to the month of August. I will not go so far as to say the NOAA and JAMSTEC Seasonal Outlooks are best stored in the circular file but I am tempted to say that.
* 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 July 31, 2017, as I am looking at the above graphic, I see the Tropical Activity in Florida and Monsoonal Activity in New Mexico which is having difficulty extending to the north.

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 is again way north in Canada.

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 do not see very much activity. Irwin and Hilary are doing the Fujiwhara (merger imminent with Irwin being the survivor for the short period of time before it disappears). There is moisture crossing Florida and North of the Border in Canada.

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

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.  At this point in time, no tropical events are expected to significantly impact CONUS beyond today (Emily departing from South Florida today Monday). If that changes, we will provide an update.

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 certainly no longer a Winter Pattern. 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. In the Day 6 forecast there is a large low in over the Eastern Aleutians spitting it seems and moving both to the north and south. It has in the Gulf of Alaska a surface central pressure of 1012 hPa. That does not sound very low but it is all relative.
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 large and has a surface central pressure of 2024 hPa in both of the Centers where the pressure is the highest. Remember this is the Day 6 pattern not the current pattern. Also notice that this is the summer position of that semipermanent High  Moisture entering from the Pacific related to the Polar Jet Stream is less likely with this pattern. There is an interesting Arctic Low.
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. You can see the Jet Stream and Great Lakes Low interacting. Remember this is a H3 view meaning a view at 30,000 feet which is about six miles high.
If  you look closely you can attempt to see the Four Corners high by observing that the small arrows there are indicating clockwise movement. I can't find it.

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 (which is intended to represent the atmosphere above the Boundary Layer most impacted by surface conditions), 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 a dry Northwest and everything else wet but not as extreme as shown last Monday. The border between New Mexico and Texas still looks problematical especially further south. The Gulf Coast and Florida also seem to be forecast to receive a lot of precipitation. Southwest of the Great Lakes is another area projected to be wet.

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 very pronounced Great Lakes Trough. There is a ridge in front of (downstream) of that trough on the East Coast about to be shoved into the Atlantic. There is also a small ridge in the west and the question there is whether it is far enough north to allow the Monsoon to proceed as normal. Notice there is no Four Corners High and the High shown is over Baja California which can bring in moisture from the Pacific but not from 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. Sometimes Meteorologists work with the 500 mb heights which provides somewhat similar readings to the "Thickness" lines but IMO provide slightly less specific information. The Southwest Heat Wave appears to have relented to some extent as more clouds have moved in.

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 also provide the forecast map for the current or soon to be current full month and the three-month forecast map. These are issued and updated less frequently than the first three maps shown.

small Images of Temperature Maps
6 to 10 Days 8 to 14 Days Weeks 3 and 4
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. But this set of three maps paints a pretty good picture of what the forecast is.

 

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 July 31, 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 July 31, 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 July 31, 2017

August 6 to August 14 August 12 to August 25

Days 6 - 10: Most of CONUS West plus Southern Florida is warm. To the the east it is cool.  Alaska is warm.

For CONUS, the Southern Tier and the East Coast are warm.  Most of Alaska is warm except for the Northeast which is EC.

The transition to the pattern shown in the Week 3 - 4 Forecast from the pattern shown in the 8-14 Day forecast does not appear to be feasible.

Week 2:  As the period evolves, the pattern does not change very much. But the Northeast EC anomaly expands.
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.

Below 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.

August Temperature Outlook Updated on July 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.

ASO 2017 Temperature Outlook Issued on July 20, 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 with the three small images, you can find the larger maps and a discussion and for reference purposes I then also provide the forecast map for the current or soon to be current full month and the three-month forecast map. These 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
The above shows the progression of forecasts from six days out through four weeks out. Larger maps with discussion appear below. But this set of three maps paints a pretty good picture of what the forecast is.

 

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 July 31, 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 July 31, 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 July 31, 2017

August 6 to August 14  August 12 to August 25, 2017

Days 6 -10: Generally for CONUS it is dry in the Northwest and wet in the Monsoon States extending to the east and even into New England but not Florida. Alaska is wet to the north and Panhandle but dry to the west.

For CONUS, the Northwest is dry. A wet anomaly extends from Texas to Virginia but does not include the southern tip of Florida.  Southern Alaska and the Panhandle is dry possibly connected to the weather pattern forecast to have CONUS Northwest dry.

The transition to the pattern shown in the Week 3 - 4 Forecast from the pattern shown in the 8-14 Day forecast appears to be feasible.

Week 2: For CONUS, there is not much change but in places the probability of being wet become less. For Alaska, the Panhandle becomes dry.

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.

Below 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.

August 2017 Precipitation Updated on July 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.

ASO 2017 Precipitation Outlook Issued on July 15, 2017

Here is the NOAA discussion released today July 31, 2017

6-10 DAY OUTLOOK FOR AUG 06 - 10 2017

TODAY'S DYNAMICAL MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED MID-TROPOSPHERIC CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN. THE OFFICIAL BLENDED 500-HPA HEIGHT FIELD DEPICTS MEAN TROUGHS OVER THE GULF OF ALASKA/EAST PACIFIC AND EAST-CENTRAL NORTH AMERICA, AND MEAN RIDGES OVER THE NORTHWESTERN CONUS AND WESTERN CANADA. THE VARIOUS SPAGHETTI MAPS SHOW LOW TO MODERATE SPREAD AMONG THE INDIVIDUAL ENSEMBLE MEMBERS OVER THE CONUS, WITH THE GREATER UNCERTAINTY REGARDING THE PREDICTED DEPTH OF THE EAST-CENTRAL CONUS TROUGH. AT HIGHER LATITUDES (5640 METER LEVEL), THE SPAGHETTI MAPS REVEAL HIGH SPREAD AND MUCH UNCERTAINTY ACROSS THE BERING SEA, ALASKA, AND GULF OF ALASKA REGION.

ODDS OF ABOVE NORMAL TEMPERATURES ARE ELEVATED ACROSS ALASKA, THE WESTERN CONUS, THE FLORIDA PENINSULA. THIS IS GENERALLY DUE TO THE PREDICTED PRESENCE OF 500-HPA RIDGES AND ASSOCIATED ABOVE NORMAL HEIGHTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE CENTRAL AND EASTERN CONUS (EXCLUDING FLORIDA AND EXTREME SOUTHERN TEXAS). THIS IS DUE TO THE PREDICTED PRESENCE OF A NEARBY 500-HPA TROUGH AND LIKELIHOOD FOR ENHANCED RAINFALL, AND IS CONSISTENT WITH VARIOUS DYNAMICAL MODEL TEMPERATURE FORECASTS, AND THE CPC CONSOLIDATION TEMPERATURE FORECAST.

ABOVE NORMAL PRECIPITATION IS FAVORED IN NORTHERN ALASKA, CENTRAL AND SOUTHERN PORTIONS OF THE INTERMOUNTAIN REGION, THE CENTRAL AND SOUTHERN ROCKIES, THE CENTRAL AND SOUTHERN PLAINS, AND THE EASTERN CONUS. THIS IS ATTRIBUTED TO THE EXPECTATION OF APPROACHING 500-HPA TROUGHS AND ASSOCIATED WIDESPREAD ASCENT OF AIR, AND IN THE SOUTHWESTERN CONUS, A COMBINATION OF THE SOUTHWEST SUMMER MONSOON. BELOW NORMAL PRECIPITATION IS FAVORED OVER THE NORTHERN INTERMOUNTAIN  REGION, THE NORTHERN ROCKIES, AND THE NORTHERN PLAINS. THIS FAVORED AREA OF BELOW NORMAL PRECIPITATION IS ASSOCIATED WITH AN ANTICIPATED 500-HPA RIDGE AND THE SUBSIDENCE AREA ASSOCIATED WITH THE EASTERN CONUS TROUGH.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO FAIRLY GOOD MODEL AGREEMENT, AND REASONABLE AGREEMENT AMONG THE VARIOUS  TEMPERATURE AND PRECIPITATION TOOLS, OFFSET BY THE SPREAD ASSOCIATED WITH MEAN TROUGH OVER THE BERING SEA.

8-14 DAY OUTLOOK FOR AUG 08 - 14 2017 

TODAY'S MODELS ARE IN FAIR AGREEMENT ON THE PREDICTED WEEK-2 500-HPA CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN. THE OVERALL CIRCULATION PATTERN THAT IS EXPECTED FOR WEEK-2 IS SIMILAR TO THAT PREDICTED FOR DAYS 6-10, THOUGH WITH A SLIGHTLY WEAKER TROUGH ANTICIPATED OVER THE EAST-CENTRAL CONUS. HEAVIEST WEIGHTING WAS ASSIGNED TO THE 00Z ECMWF ENSEMBLE RUNS TODAY IN THE MANUAL BLENDED HEIGHT FORECAST BASED ON THE RECENTLY MODEL SKILL. ENSEMBLE SPREAD IS MODERATE OVER MUCH OF THE FORECAST DOMAIN, BUT HIGH ACROSS THE BERING SEA, ALASKA, AND THE GULF OF ALASKA REGION.

THE PREDICTED WEEK-2 TEMPERATURE PATTERN IS SIMILAR TO THAT ANTICIPATED DURING THE 6-10 DAY PERIOD, THOUGH WITH SEVERAL ADJUSTMENTS. ONE ADJUSTMENT IS TO REDUCE THE AREA OF FAVORED BELOW NORMAL TEMPERATURES ACROSS PARTS OF THE EASTERN CONUS. THIS IS DUE TO AN ANTICIPATED ABOVE NORMAL SSTS ALONG THE ATLANTIC COAST. THE PRIMARY MODIFICATION MADE WITH THE PRECIPITATION OUTLOOK IS SLIGHTLY REDUCED PROBABILITIES OF FAVORED ABOVE NORMAL PRECIPITATION ACROSS TEXAS, BASED ON WEAKENING ANTICIPATED GULF MOISTURE INFLOW ACROSS THIS REGION.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE  TO FAIR MODEL AGREEMENT, OFFSET BY THE PREDICTION OF WEAK SIGNALS AMONG THE  PRECIPITATION 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

Jul 18, 1956 Neutral - - After a La Nina
Jul 24, 1959 Neutral - (t) N  
Aug 3, 1981 Neutral + -  
Aug 9, 1996 Neutral - N  
Aug 12, 1996 Neutral N(t) N  
Aug 14. 1996 Neutral N(t) N  
Jul 13, 1998 La Nina -(t) + Following the MegaNino
Jul 14, 1998 La Nina -(t) + Following the MegaNino
Aug 12, 1998 La Nina - + Following the MegaNino
Aug 13, 1998 La Nina - + Following the 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 July 13 to August 13 which is 31 days which is the same as last week. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, is about July 29. These analogs are centered on 3 days and 4 days ago (July 27 or July 28). So the analogs could be considered to be in sync with the calendar meaning that we will be getting weather that we would normally be getting this time of the year. For more information on Analogs see discussion in the GEI Weather Page Glossary.

There are six ENSO Neutral Analogs and four La Nina analogs. The phases of the ocean cycles of the analogs are most consistent with McCabe D which is the drought scenario for the Southwest and Great Lakes area. Thus I am less confident than NOAA about their 6 - 14 day outlook and of course NOAA is not very confident about the latter part of that Outlook assigning a confidence level of 2 out of 5 to it.

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.

Looking Out Beyond Three Months.

The Monthly Seasonal Outlook Update which we published Saturday June 17 can be accessed by clicking here. It looks out 15 months for NOAA (the next month plus 14 more) and for JAMSTEC three three-month periods which right now is through February 2018. So it is a very useful reference and it gets updated each month. We will publish an Update on Saturday July 22. 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.

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 July 22, 2017

July 22, 2017 30 Day Temperature and Precipitation Departures

The East is a bit less wet and the Southeast is a bit more wet. The extreme Western Heat has moderated. Remember, this is a 30 average so the most distant seven days are removed and the most recent seven days are added.

And the 30 Days ending July 29, 2017

July 29, 2017 30 Day Temperature and Precipitation Departures

 Fairly similar to the report from the prior week with a bit less drought in the Northwest. Remember, this is a 30 average so the most distant seven days are removed and the most recent seven days are added.

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 which 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 are now headed into August so we are 1/6 between the set of positions shown above for July and the ones shown for January. For CONUS the seasonal repositioning of the Bermuda High and the Pacific High are very significant. Notice the Summer position of the Pacific High.

Forecast for Today

Temperature at 2 Meters

Notice that below the map there is a tabulation of magnitude of the current anomalies by region. Notice the cool CONUS Southeast.

Maine Reanalyer

This graphic is actuals not anomalies as is the case in the temperature map. We again see the dry area from North Africa through Asia (other than Southeast Asia). Much of Europe is wet. South America south of the ITCZ is dry. Africa south of the Equator and the ITCZ is dry. 

Additional Maps showing different weather variables can be found here.

Forecast  for Day 6 (Currently Set for Day 6 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  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

Temperature

BOM Current Temperature Wedensday

Please remember this graphic updates every six hours so the diurnal pattern can confuse the reader.

Precipitation

BOM World Preciptation  Wednesday

Notice that in the Day 6 Forecast, we again see the Atlantic and Pacific dominated by High Pressure but this week the Pacific is more complex than last week. The westward extension of the Bermuda High is very impressive and probably will have a significant impact on CONUS Southern Tier weather both the Southeast directly and the Southwest Monsoon indirectly.

Looking Out a Few Months

Here is the precipitation forecast from Queensland Australia:

Falling SOI  forecast for July to September 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 change from a rising SOI  to a falling SOI. It is more like an El Nino forecast than a La Nina forecast.

JAMSTEC Forecasts

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. 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.

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 Caspian Sea is very warm.

Warm.

Warm south of Mainland Alaska

Warm off Baja and in Sea of Cortez

Cool off Northwest but a bit offshore

.

Warm.

Western Gulf of Mexico slightly warm

Hudson Bay very warm

Warm
The Tropical Pacific

Neutral but warmish

Africa West of Australia North, South and East of Australia

West of South America

East of South America

Mostly Neutral. Cool off of Gulf of Guinea

Slightly cool to the west and southwest Slightly warm to the east. Neutral Warm south of  20S. Cool at 10S

 

What you see in the below graphic is the change in the anomaly over the last four weeks 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. It is important to understand the distinction between these two graphics. The top one shows the recent conditions, the bottom one shows the direction of change.

July 31, 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

Western Mediterranean and Black Seas is cooling. The Caspian Sea is warming.

Overall intense warming.

Arabian Sea slight warming

Red
Sea cooling hard to see the Persian Gulf but it may be cooling

Intense warming west of Baja California and in Gulf of California.

Cooling offshore of the Northwest

Warming.

Warming in the Central  GOM extending to Yucatan and Greater Antilles

Cooling.
The Tropical Pacific Cool to the West. Neutral to the east with more of a La Nina cast.
Africa West of Australia North, South and East of Australia West of South America East of South America

Cooling off Northwest Coast.

Slight warming in Gulf of Guinea

Slight cooling to the south and southeast.

Cooling to the east and beyond Madagascar

Small area of cooling to the Southwest

Warming to the north and northeast

Cooling off of Ecuador.

Cooling to the north of 20S,

 

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 +0.10 +0.23  0.0
February +0.04 +0.23 +0.2
March +0.12 +0.17 +0.0
April +0.52 +0.29 +0.2
May +0.31 +0.32 +0.2
June +0.17 +0.31  0.0

 

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 July 31 for what is shown as Week Two, the period August 2 to August 8, 2017 we see wet conditions* over the western part of the Maritime Continent, in Africa just north of the Equator and the Lesser Antilles. We see dry conditions* impacting part of India.
* 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.

Current SST and wind anomalies

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

 

If one were to track this day by day over the past month one would see both the northern intrusion from south of the Equator strengthening (temperature) but being squeezed from both the east and the west. We now see it gradually being squeezed but not south as I had anticipated but to the north. Most like soon it will be totally out of the Nino 3.4 Measurement Area. There is now also some cooler water in the eastern end of the Nino 3.4 Measurement Area and also just to the west.

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)

LAND

LAND

0

0

+0.5C to +1C (marginal)

120W

LAND

25

0

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

170E

145W

35

25

0C or cooler Anomaly (coolish neutral)

145W

130W

15

15

These Rows Below Show the Extent of La Nina Impacts on the Equator.
-0.5C or cooler Anomaly

130W

120W

10

10

 

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 July 31, in the afternoon working from the July 30 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 +0.3
B. 160W to 150W +0.6 +0.3
C. 150W to 140W +0.7 +0.2
D. 140W to 130W +0.4 +0.1
E. 130W to 120W -0.1 -0.3
Total +2.2 +0.6
Total divided by five i.e. the Daily Nino 3.4 Index (+2.2)/5 = +0.4 (+0.6)/5= +0.1

 

My estimate of the daily Nino 3.4 SST anomaly tonight is  +0.1 which is an ENSO Neutral Value.  NOAA has reported the weekly Nino 3.4 to be +0.0 which is dead Neutral and much lower than last week which ended a fairly long string of weekly values +0.5 or higher.
Nino 4.0 is reported lower than last week at +0.2. Nino 3 is lower at +0.1. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is reported a bit higher at 0.0. I believe it was up there close to 3 at one time so this index has been declining quite a bit and also fluctuating quite a bit which is not surprising as it is the area most impacted by the Upwelling off the coast. So it is an indication of the interaction between surface water and rising cool water. Thus it is subject to larger changes. Most likely it will be neutral to negative for a while.
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. Notice that Nino 4.0 and 3.4 have been declining and this week dramatically. The same data in table form but going back a couple of more years can be found here.

July 31, 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.

July 31, 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 shows the current readings is 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. But the cool area east of 100W has expanded and we see another cool area perhaps at 120W. These are not in the Nino 3.4 Measurement Area but are important never-the-less. The bottom sentence in the legend to the left of the graphic proper says it all.

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.

July 31, 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 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 was a warm area shown between 145W and 130W which created the marginal El Nino values of the Nino 3.4 Index. It is no longer showing. We also see to the far left a white area and more white to the right of that. That needs to be brown or red for there to be an El Nino. No El Nino!

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). 

.July 31, 2017 Kelvin Wave Analysis.

We now have very little warm water near the surface. There is another graphic that shows it better. There is not enough cool water either to flip the situation to La Nina other for a month or so which is not long enough to be a La Nina but simply to create La Nina conditions for a month or two.

Now for a more detailed look (there is some redundancy with the above graphic). Notice by the date of the graphic (dated July 27, 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 for other purposes.

Subsurface Heat Anomalies

Re the top graphic, let us first look at surface temperature anomalies. There is an area of neutral water off the coast of Ecuador.There is Neutral to Warm water from 100W to 150W. There is cool water at 160W. Subsurface Temperature Anomalies: There is east of 170W no warm water below 50 meters and almost no warm water west of 150W. There is no way the Nino 3.4 Index can remain at the current level. There is a lot of cool water but not much cooler than -0.5C. But there is a pod of cool water at moderate depth from 165W to 125W so Nino 3.4 readings of more negative than -0.5C might occur for a short period of time in a month or so. 
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 further west at about 165W. This graphic does not show a 27.5C anomaly which might more precisely indicate where convection is likely to occur. The 27C isotherm is now also west of 140W a big change from last week. The 25C Isotherm reaches the surface at 130W. What we have is ENSO Neutral but almost La Nina.
The flattening of the Isotherm Pattern is an indication of ENSO Neutral just as the steepening of the pattern indicates La Nina or El Nino depending on where the slope shows the warm or cool pool to be. That flattening has occurred. At this point, we have gone to ENSO Neutral but not El Nino although the situation is essentially the dividing line between La Nina and ENSO Neutral.
The conditions to create an El Nino simply do not exist. The conditions t create a sustainable La Nina also do not appear to exist.  

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 westerlies all over the Equator which should be favorable for the development of an El Nino but do not seem to be having much of an impact.

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) but we again see enhanced OLR at 120E ( 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 July 31 was reported as +6.97 which is an ENSO Neutral value with a cool bias i.e. close to a La Nina value. The 90 Day Average was reported at -0.50 which is an ENSO Neutral value. Looking at both the 30 and 90 day averages is useful and right now both are in agreement. They seem to be tracking the Nino 3.4 Index pretty well and reflect the downturn in marginal El Nino Conditions and short-term conditions in the Western Pacific where there there had been a long string of negative values for a while. Now the 30 day average is actually positive i.e. in the direction of a La Nina but still in the Neutral Range.

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 Ocean Equatorial 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

The newly issued on July 19 CPC/IRI  fully model-based report is shown on the right. The earlier July 13 IRI/CPC Meteorologist survey is shown on the left.

July 20. 2017 CPC/IRI Update two graphics side by side.

There is not much difference between the two.

Here is the primary NOAA model.

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 about 0.5 for July which is a borderline El Nino/Neutral value but it heads pretty much straight down from there. But we are starting to see this model flirting with La Nina conditions for a short period of time this winter. Click here to see  a month by month version of the same model but without some of the correction methodologies applied. It gives us a better picture of the further out months as we are looking at monthly estimates versus three-month averages. 

From Tropical Tidbits.com

CDAS Legacy System

The above is from a legacy "frozen" NOAA system meaning the software is maintained but not updated. Notice since mid-July the collapse of Nino 3.4 values from the range of 0.5C to 0.5C down to near Zero C but rebounding just a bit.

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 Issued July 30, 2017

Tropical Pacific remains ENSO-neutral

The El Niño-Southern Oscillation (ENSO) remains neutral. All climate models surveyed by the Bureau indicate the tropical Pacific Ocean is likely to stay ENSO-neutral for the rest of 2017.

Sea surface temperatures (SSTs) in the central tropical Pacific have cooled over the past fortnight, but remain slightly warmer than average, and well within the neutral range. The 30-day Southern Oscillation Index (SOI) has been somewhat volatile over the past two months, but remains neutral. Other indicators

Here is the JAMSTEC June 1 forecast of the Nino 3.4 values which are the most looked at index used to forecast El Nino.

JAMSTEC July 1, 2017 ENSO Forecast.

As you can see this is now a totally ENSO Neutral pattern. It is a shocking critique of the models that they got this wrong when it was obvious from the beginning that this was not going to be an El Nino winter.

Here is the discussion that corresponds to the JAMSTEC July 1 Nino 3.4 Forecast. We will issue our analysis of the NOAA and JAMSTEC Seasonal Outlooks on Saturday July 22.

Jul. 13, 2017

Prediction from 1st Jul., 2017

ENSO forecast:

A slightly warmer-than-normal sea surface temperature is predicted for the whole tropical Pacific. This condition will persist until boreal winter. Then, it will return into a neutral state by next spring.

Indian Ocean forecast:

All ensemble members of SINTEX-F continue to predict a positive Indian Ocean Dipole [Editor's Note: The Australian BOM disagrees see BOM graphic and discussion below] ; the ensemble mean prediction suggests that it peaks in boreal fall. In accord to the positive IOD evolution, sea level anomalies are expected to be negative (positive) in the eastern (western) tropical Indian Ocean.

Regional forecast:

On a seasonal scale, most part of the globe will experience a warmer-than-normal condition, while some parts of central Russia and central U. S. will experience a colder-than-normal condition in the boreal fall.

As regards to the seasonally averaged rainfall, a wetter-than-normal condition is predicted for some parts of East Africa and West Africa during the boreal fall, whereas most parts of Indonesia, Australia, eastern China, and Brazil will experience a drier condition during the boreal fall. Those are partly due to the positive Indian Ocean Dipole.

Most parts of Japan will experience moderately warmer-than-normal and drier-than-normal conditions in the boreal fall. The wind and pressure anomalies averaged in September-November suggest that Japan might be covered by an equivalent barotropic high. Those may be due to the combined effect of "the monsoon-desert mechanism" of the positive Indian Ocean Dipole and "the Silk Road pattern" along the Asian jet.

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 Issued July 30, 2017

The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 30 July was +0.1 °C.  Four out of six climate models used by the Bureau predict the IOD will remain neutral for winter–spring of ENSO, such as cloudiness near the Date Line and trade winds also remain at neutral levels.

Two of the six climate models suggest positive IOD thresholds could be reached in the coming months but only one model maintains these values long enough to be considered a positive IOD event. Positive IOD events are typically associated with below average winter and spring rainfall over central and southern Australia.

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 reduced interest as to whether or not this Summer and Fall will be El Nino situations. 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.

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.

The odds of a climate shift for the Pacific taking place has significantly increased. It may be in progress. JAMSTEC was suggesting that if there is an El Nino in the winter of 2017/2018 this could signify that the PDO had 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 was suggesting it might occur very soon. But their strong El Nino forecast appears to have been premature. So our assessment that the standard time for Climate Shifts in the Pacific are likely to prevail and it most likely will be a gradual process with a speed up in less than five years but more than two years.

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 July 10, 2017

The Apr/May/Jun preliminary was reported as +0.5. This means that we would still need four 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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