December 5, 2016 Weather and Climate Report – December Update – Zonal Prevails

Written by Sig Silber

Global Warming takes a break at least for CONUS as cold is the forecast for the Northern Tier of CONUS (and points North). It first looked like this would be a meridional pattern bringing record cold down to the Southwest but the Jet Stream turned zonal in the nick of time. So the cold air is being distributed more equitably. Waiting for NOAA to walk back their incongruous La Nina Advisory…probably December 8.

First some housekeeping information. Working on a Glossary of Terms but right now it is only partially operational. It will be possible increasingly to look up acronyms etc by going to the GEI Weather Page Glossary. Also for those who want the forecasts beyond three months, we reported previously on the November 17 NOAA 15-Month Forecast and compared the first ten months of the NOAA Outlook with that of JAMSTEC in a special Update that you can get to by clicking here. We will of course publish a new 15 Month Update Report shortly after December 15, 2016. 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 December Outlook

NOAA has, as usual, issued an update for the month following the last day of the prior month. This update was issued on November 30 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 December to the Early Outlook for December issued on November November 17. 

Temperature

Prior Outlook Issued on November 17, 2016

Updated Outlook Issued on November 30, 2016

Precipitation

Prior Outlook Issued on November 17, 2016

Updated Precipitation Outlook Issued on November 30, 2016

Below is the discussion issued with this update.

30-DAY OUTLOOK DISCUSSION FOR DECEMBER 2016

THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR DECEMBER 2016 ARE BASED ON THE LATEST DYNAMICAL MODEL GUIDANCE, WPC TEMPERATURE AND PRECIPITATION FORECASTS DURING THE FIRST WEEK OF DECEMBER, THE CPC 6-10/8-14 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, AND CPC’S EXPERIMENTAL WEEKS 3-4 TEMPERATURE AND PRECIPITATION OUTLOOKS. SINCE THE FUTURE MJO EVOLUTION AND ITS POTENTIAL INFLUENCE ON THE EXTRATROPICAL CIRCULATION PATTERN ARE NOT CERTAIN DURING THE NEXT MONTH, THE MJO WAS NOT CONSIDERED A MAJOR FACTOR IN THE REVISED OUTLOOKS.

LARGE CHANGES WERE NECESSARY IN THE TEMPERATURE OUTLOOK, DUE TO A HIGHLY AMPLIFIED RIDGE FORECAST OVER THE BERING SEA WITH A DOWNSTREAM AMPLIFIED TROUGH ACROSS THE CONTINENTAL U.S. LIKELY PERSISTING THROUGH THE FIRST HALF OF DECEMBER. THIS LONGWAVE PATTERN YIELDS A MUCH COLDER OUTLOOK ACROSS THE CONTINENTAL U.S. AND ALASKA THAN WHAT THE DYNAMICAL MODEL GUIDANCE INDICATED AT MID-MONTH. TEMPERATURES ARE EXPECTED TO AVERAGE 5 TO 10 DEGREES F, OR MORE, BELOW NORMAL ACROSS MUCH OF THE WESTERN U.S. DURING THE FIRST WEEK OF DECEMBER. ALSO, POSITIVE ANOMALIES IN SNOW COVERAGE CURRENTLY EXIST ACROSS THE GREAT BASIN AND INTERMOUNTAIN WEST, RAISING CONFIDENCE IN BELOW-NORMAL TEMPERATURES FOR THESE AREAS. THEREFORE, BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN U.S. IN THE REVISED OUTLOOK. THE HIGHEST PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE FORECAST FOR THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS WHERE ARCTIC HIGH PRESSURE IS EXPECTED TO RESULT IN THE LARGEST NEGATIVE TEMPERATURE ANOMALIES DURING EARLY DECEMBER AND BELOW-NORMAL TEMPERATURES ARE MOST LIKELY TO PERSIST INTO THE SECOND WEEK OF DECEMBER. INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES EXTEND EAST TO THE GREAT PLAINS WHERE THE CPC 6-10/8-14 DAY OUTLOOKS FAVOR BELOW-NORMAL TEMPERATURES AS MODIFIED ARCTIC AIR IS FORECAST TO AFFECT THIS REGION AT LEAST EARLY IN THE MONTH. FORECAST CONFIDENCE IS LOWEST ALONG THE EAST COAST DUE TO VARIABLE TEMPERATURES FORECAST DURING EARLY DECEMBER, FOLLOWED BY MORE UNCERTAINTY IN THE LONGWAVE PATTERN ACROSS EASTERN NORTH AMERICA LATER IN THE MONTH. SINCE THE EAST COAST IS EXPECTED TO RESIDE ON THE RELATIVELY WARM SIDE OF MULTIPLE LOW PRESSURE SYSTEMS TRACKING ACROSS THE EAST-CENTRAL U.S. EARLY IN THE MONTH, A SLIGHT TILT IN THE ODDS FOR ABOVE-NORMAL TEMPERATURES IS FORECAST FOR THE NORTHEAST AND PARTS OF FLORIDA.[Editor’s Note:Chances are this cold air will work it’s way to the East Coast and  NOAA will gradually recognize this.]

BASED ON SHORT-TERM AND CPC’S 6-10/8-14 DAY PRECIPITATION OUTLOOKS, INCREASED CHANCES FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS THE PACIFIC NORTHWEST, NORTHERN GREAT BASIN, AND NORTH-CENTRAL ROCKIES/HIGH PLAINS. ARCTIC HIGH PRESSURE SHIFTING SOUTH FROM WESTERN CANADA EARLY IN THE MONTH IS EXPECTED TO ENHANCE UPSLOPE FLOW AND PRECIPITATION ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS. DOWNSTREAM OF THE AMPLIFIED UPPER-LEVEL TROUGH EARLY IN THE MONTH, ABOVE-MEDIAN PRECIPITATION IS FAVORED ALONG THIS PREDICTED STORM TRACK. THE HIGHEST ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS SOUTHEAST TEXAS AND LOUISIANA WHERE THE PRECIPITATION TOTALS PREDICTED DURING THE FIRST WEEK OF DECEMBER ARE NEAR OR ABOVE THE DECEMBER NORMAL. THE MOST LIKELY AREA FOR BELOW-MEDIAN PRECIPITATION EXISTS ACROSS THE FLORIDA PENINSULA DUE TO RIDGING ALOFT DURING EARLY DECEMBER AND IT IS CONSISTENT WITH THE LOW-FREQUENCY BASE STATE.

ARCTIC HIGH PRESSURE WITH ANOMALOUS NORTHERLY FLOW IS EXPECTED TO RESULT IN LARGE NEGATIVE TEMPERATURE ANOMALIES ACROSS MOST OF MAINLAND ALASKA AND THE ALASKA PANHANDLE DURING EARLY DECEMBER. BASED ON THESE LARGE NEGATIVE TEMPERATURE ANOMALIES, BELOW-NORMAL TEMPERATURES ARE FAVORED IN THE REVISED TEMPERATURE OUTLOOK. ABOVE-NORMAL SSTS CONTINUE TO FAVOR ABOVE-NORMAL TEMPERATURES ACROSS THE ALEUTIANS AND COASTAL SOUTHWEST ALASKA. ENHANCED ODDS FOR BELOW-MEDIAN PRECIPITATION PREDICTED FOR COASTAL SOUTHERN ALASKA ARE CONSISTENT WITH RECENT DAILY RUNS OF THE CFS MODEL AND ANOMALOUS OFFSHORE FLOW EARLY DURING DECEMBER.

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

December plus December 2016  –  February 2017 Outlook

A. Focus on Alaska and CONUS (all U.S. except Hawaii) – Let’s Focus on the Current (Right Now to 5 Days Out) Weather Situation.

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

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

The explanation for the coding used in these maps, i.e. the full legend, can be found here although it includes some symbols that are no longer shown in the graphic because they are implemented by color coding.

U.S.  3 Day to  7 Day Forecasts

Below is a graphic which highlights the forecasted surface Highs and the Lows re air pressure on Day 3. The Day 6 forecast can be found here.

You can enlarge the below daily (days 3 – 7) weather maps for CONUS only by clicking on Three Day or  Four Day or Five Day or Day Six or Day Seven

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

The map below is the mid-atmosphere 7-Day chart rather than the surface highs and lows and weather features. In some cases it provides a clearer less confusing picture as it shows only the major pressure gradients.This graphic auto-updates so when you look at it you will see NOAA’s latest thinking. The speed at which these troughs and ridges travel across the nation will determine the timing of weather impacts. This graphic auto-updates I think every six hours and it changes a lot. Because “Thickness Lines” are shown by those green lines on this graphic, it is a good place to define “Thickness” and its uses. The 540 Level general signifies equal chances for snow at sea level locations. Remember that 540 relates to sea level.

The graphic below is the Eastern Pacific a 24 hr loop of recent readings. It does a good job of showing what is going on right now.

The graphic below (which is a bit redundant with the above) updates automatically so it most likely will look different by the time you look at it as the tropical weather patterns unlike the patterns north of 30N are generally moving from east to west but right now are moving from west to east. This graphic highlights tropical activity. Unlike the above which shows recent history, the below graphic is a satellite image with the forecast of tropical events superimposed on the satellite image. There is no significant “new” tropical activity that would appear to impact CONUS forecast for the beginning of this week.

We can track tropical storms here.

Below is the current water vapor Imagery for North America.

Looking at the current activity of the Jet Stream.

First the current situation. 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. The sub-Jetstream level intensity winds shown by the vectors in this graphic are also very important in understanding the impacts north and south of the Jet Stream which is the higher-speed part of the wind circulation and is shown in gray on this map. In some cases however a Low-Pressure System becomes separated or “cut off” from the Jet Stream. In that case it’s movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream. This usually is more significant for the lower half of CONUS i.e. further south than the Jet Stream.

Now looking at the 5 Day Forecast

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Putting the Jet Stream into Motion and Looking Forward a Few Days Also

To see how the pattern is projected to evolve,  please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.

This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.

When we discuss the jet stream and for other reasons, we often discuss different layers of the atmosphere. These are expressed in terms of the atmospheric pressure above that layer. It is kind of counter-intuitive to me. The below table may help the reader translate air pressure to the usual altitude and temperature one might expect at that level of air pressure. It is just an approximation but useful.

Re the above, H8 is a frequently used abbreviation for the height of the 850 millibar level, H7 is the 700 mb level, H5 is the 500 mb level, H3 is the 300 mb level. So if you see those abbreviations in a weather forecast you will know what they are talking about.

Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on “earth” adjusting the parameters and then clicking again on “earth” to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns. This amazing graphic covers North and South America. It could be included in the Worldwide weather forecast section of this report but it is useful here re understanding the wind circulation patterns.

Four- Week Outlook

I am going to show the three-month DJF Outlook (for reference purposes although I do not have a lot of confidence in it), the Updated Outlook for the single month of December,  the 6 – 10 Day and 8 – 14 Day Maps and the Week 3 –  4 Experimental 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

Here is the Three-Month DJF Temperature Outlook issued on November 17, 2016:

Here is the Temperature Outlook for December Issued on November 30, 2016

 6 – 10 Day Temperature Outlook Issued Today

8 – 14 Day Temperature Outlook Issued Today  

Looking further out.

Prior forecast

This week’s forecast (I usually only show the current forecast but this week I also showed the forecast made last week)

Now – Precipitation

Here is the three-month DJF Precipitation Outlook issued on November 17, 2016 that I do not have much confidence in.

And here is the Updated Precipitation Outlook for December Issued on November 30, 2016

6 – 10 Day Precipitation Outlook Issued Today

8 – 14 Day Precipitation Outlook Issued Today

Looking further out.

Last week’s forecast

This week’s forecast (I usually only show the current forecast but this week I also showed the prior forecast to allow comparison).

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Here is the NOAA discussion released today December 5, 2016.

6-10 DAY OUTLOOK FOR DEC 11 – 15 2016

TODAY’S MODELS EXHIBIT GOOD AGREEMENT ON THE PREDICTED 500-HPA HEIGHT PATTERN. ABOVE NORMAL HEIGHTS ARE PREDICTED OVER THE BERING STRAIT AND MOST OF THE SOUTHERN TIER OF THE CONUS. TROUGHING OVER CANADA AND THE NORTHERN CONUS ARE ALSO AGREED UPON IN THE MODELS. THE MODELS SHOW SOME DISAGREEMENT IN THE HEIGHTS OVER THE GREAT PLAINS, WITH THE 500-HPA HEIGHTS IN THE EUROPEAN ENSEMBLE MEAN A LITTLE LOWER THAN IN THE GEFS, AND THE 500-HPA HEIGHTS IN THE CANADIAN ENSEMBLE MEAN MUCH HIGHER OVER THE SOUTHERN CONUS. DESPITE THOSE DIFFERENCES, THE OVERALL PATTERNS AGREE ON A BLOCK OFF THE CENTRAL PACIFIC AND AN ENHANCED JET OVER THE CONUS.  

PREDICTED RIDGING OVER THE BERING STRAIT FAVORS BELOW AVERAGE TEMPERATURES AS COLD AIR IS FORECAST TO FUNNEL SOUTHWARD OVER MOST OF ALASKA AND ACROSS CANADA TO THE NORTHERN ROCKIES, GREAT PLAINS AND GREAT LAKES REGION. ABOVE NORMAL SSTS FAVOR ABOVE NORMAL TEMPERATURES FOR PORTIONS OF NORTHERN COASTAL ALASKA AND THE ALEUTIANS. ABOVE AVERAGE HEIGHTS AND LOW-LEVEL HIGH PRESSURE IMPLY ABOVE NORMAL TEMPERATURES FOR THE SOUTHERN TIER OF THE CONUS. 

THE RIDGING OVER THE BERING STRAIT FAVORS A DRIER PATTERN OVER ALASKA AS STORMS WOULD BE DEFLECTED SOUTHWARD. THE SOUTHWARD DISPLACED STORM TRACK, ALIGNED WITH THE SOUTHERN PERIPHERY OF THE TROUGH OVER CENTRAL CANADA, FAVORS ABOVE MEDIAN  PRECIPITATION FOR THE CENTRAL AND NORTHERN ROCKIES, AND FROM THE TENNESSEE VALLEY TO THE GREAT LAKES REGION. THE SLIGHT RIDGING FORECAST OVER THE SOUTHWEST FAVORS BELOW MEDIAN PRECIPITATION FROM SOUTHERN CALIFORNIA TO TEXAS.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  GOOD OVERALL AGREEMENT AMONG THE VARIOUS MODELS AND TOOLS, AND GENERALLY LOW TO MODERATE SPREAD AMONG THE ENSEMBLE MEMBERS

8-14 DAY OUTLOOK FOR DEC 13 – 19 2016 

DURING THE 8-14 DAY PERIOD, MODEL AGREEMENT REMAINS GOOD, ALTHOUGH DISCREPANCIES GROW COMPARED TO THE 6-10 DAY PERIOD. A BLOCKING STRUCTURE IS STILL PREDICTED OVER THE CENTRAL PACIFIC WITH TROUGHING NEAR HAWAII AND RIDGING OVER THE BERING SEA. TROUGHING IS PREDICTED OVER CENTRAL CANADA. THE MODELS DISAGREE ON THE SOUTHERN EXTENT OF THE TROUGHING, WITH THE EUROPEAN ENSEMBLE MEAN DROPPING HEIGHTS OVER THE SOUTHEAST CONUS AND RAISING 500-HPA HEIGHTS OVER THE WESTERN CONUS. THE GFS MAINTAINS A BROAD TROUGH OVER MUCH OF THE CONUS WITH ONLY A MODERATE RAISING OF HEIGHTS FROM THE 6-10 DAY PERIOD. THE CANADIAN  ENSEMBLE MEAN DRAMATICALLY RAISES HEIGHTS OVER THE WESTERN CONUS. THE 500-HPA MANUAL BLEND INCORPORATES THE EUROPEAN ENSEMBLE AND THE GFS BASED SOLUTIONS.

THE RESULTANT BLEND FAVORS BELOW NORMAL TEMPERATURES OVER MUCH OF ALASKA AND THE NORTHERN CONUS AS COLD AIR IS LIKELY TO FLOW SOUTHWARD, EAST OF THE PREDICTED RIDGE OVER THE BERING SEA. THE COLDER AIR IS EXPECTED TO WORK 

SOUTHWARD TO THE GREAT PLAINS, GREAT LAKES REGION, THE ENTIRETY OF THE MISSISSIPPI VALLEY, MID-ATLANTIC AND THE NORTHEAST. WITH THE HEIGHTS PREDICTED TO RISE SLIGHTLY OVER THE WESTERN CONUS, TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL OVER THE GREAT BASIN AND SOUTHWEST. 

RIDGING PREDICTED OVER THE SOUTHWEST FAVORS BELOW NORMAL PRECIPITATION. THE  ACTIVE STORM TRACK IS PREDICTED FROM THE PACIFIC NORTHWEST TO THE GREAT LAKES REGION, FAVORING ABOVE MEDIAN PRECIPITATION IN THOSE REGIONS. FRONTS ASSOCIATED WITH THE STORM TRACK FAVOR ABOVE MEDIAN PRECIPITATION FOR PORTIONS OF THE SOUTHEAST, ALTHOUGH PROBABILITIES ARE LOWER BECAUSE UNCERTAINTY IS HIGHER OVER THAT REGION.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO GOOD MODEL AGREEMENT, TEMPERED BY DISAGREEMENTS IN THE PREDICTED HEIGHTS OVER THE SOUTHEAST CONUS.

Some might find this analysis 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.

(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 November 18 to December 18 which is 31 days which is similar to 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 December 2. These analogs are centered on 3 days and 4 days ago (November 30 or December 1). So the analogs could be considered pretty much in sync with the calendar meaning that we will be getting weather that normally would occur at about this time of year.

For more information on Analogs see discussion in the GEI Weather Page Glossary.

There are two El Nino Analogs (why are there any?), five La Nina Analogs and one ENSO Neutral Analog. The phase of the ocean cycles in the analogs points strongly towards McCabe Condition B. There are some aspects of the 6 – 14 Day Forecast that are consistent with McCabe Condition B.

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.

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 November 26, 2016

And the 30 Days ending December 3, 2016

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

Near Term

World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click Here you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the “Back Arrow” usually found top left corner of your screen to the left o the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool.

Although I can not display the interactive control panel in my article, I can display any of the graphics it provides so below are the current worldwide precipitation and temperature forecasts for three days out. They will auto-update and be current for Day 3 whenever you view them. If you want the forecast for a different day Click Here

Precipitation

Temperature

Looking Out a Few Months

This is the new precipitation forecast from Queensland Australia.

But the above is based on October/November having a rapid rise in SOI which was not the case so I used the option where you can change the assumption to a relatively stable SOI and generated a second forecast.

Here is the JAMSTEC three month Temperature Forecast.
 

And here is the three month JAMSTEC  Precipitation Forecast.

And then to get more focus, I extracted and enlarged an image for Europe on the left and CONUS on the right.

There is a short JAMSTEC discussion that relates the seasonal outlook to their El Nino and El Nino Modoki forecasts and this was issued on Tuesday November 22, so here it is:

Nov. 23, 2016 Prediction from 1st Nov., 2016

ENSO forecast:

According to the SINTEX-F prediction, the current La Niña Modoki/La Niña state will continue until spring. [Editor’s Note: They explain what they mean by this being a Modoki rather than a true La Nina in a very long detailed explanation which focuses on the Modoki aspects of this Cool Event. We will discuss that next Monday but the simple explanation is that the cool anomaly is not well connected to the coast of South America]. That state will then start decaying and the tropical Pacific will return to a normal state by summer. The model prediction appears to be consistent so far with the observed evolution of the sea surface temperature (SST) anomalies

Indian Ocean forecast:

The negative Indian Ocean Dipole will keep decaying and disappear in winter. The Ningaloo Nino will appear off the west coast of Australia in late austral summer and persist until late austral fall.

Regional forecast:

On a seasonal scale, most part of the globe will experience a warmer-than-normal condition, while some parts of northern Brazil, Australia, and Mongolia will experience a colder-than-normal condition in the boreal winter.

According to the seasonally averaged rainfall prediction, most parts of southern China, southeastern Africa, southern Europe, and eastern/western U.S. will experience a drier condition during boreal winter, while most parts of Brazil, western Central Africa, and South Africa will experience a wetter-than-normal condition. Australia will receive above normal rainfall during austral summer. Northern parts of Japan (including Hokkaido) will be cooler and drier than normal while southern parts of Japan will generally be warmer than normal in winter. However, we note that fluctuating mid- and -high latitude climate in winter may not be captured well by the current model.

Additional forecasts from JAMSTEC including future time periods can be found at this link.

Sea Surface Temperature (SST) Departures from Normal for this Time of the Year i.e. Anomalies

And when we look at the current Sea Surface anomalies below, we see a lot of them not just along the Equator related to ENSO.

Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.

Look at the Western Pacific in Motion.`

Below is an analysis of projected tropical hazards and benefits over an approximately two-week period. This graphic is scheduled to update on Tuesday and I am reading the November 29, 2016 Version and looking at Week 2 of that forecast.

C. Progress of the Cool ENSO Event

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 below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. The two rows just below that break point contribute to ENSO Neutral and after another break, the rows are associated with La Nina conditions. I have changed the reference date to May 23, 1016.

I calculate the current value of the ONI index (really the value of NINO 3.4 as the ONI is not reported as a daily value) each week using a method that I have devised. To refine my calculation, I have divided the 170W to 120W Nino 3.4 measuring area into five subregions (which I have designated from west to east as A through E) with a location bar shown under the TAO/TRITON Graphic). I use a rough estimation approach to integrate what I see below and record that in the table I have constructed. Then I take the average of the anomalies I estimated for each of the five subregions.

So as of Monday December 5, in the afternoon working from the December 4 TAO/TRITON report, this is what I calculated. [Although the TAO/TRITON Graphic appears to update once a day, in reality it updates more frequently.]

From Tropical Tidbits.com

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.

In recent weeks I have stopped showing the below graphic which is more focused on the Equator but looks down to 300 meters rather than just being the surface. There has until this week been almost no change from the prior week but over the last month there has been sufficient change to warrant including this graphic this week.

Let us look in more detail at the Subsurface Water Temperatures.

Equatorial Subsurface Analysis

We are now going to change the way we 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.

Current Sub-Surface Conditions.  Notice by the date of the graphic (dated November 29, 2016) that the lag in getting this information posted so the current situation may be a bit different than shown although this graphic was updated today so it is more current than usual. The date shown is the midpoint of a five-day period with that date as the center of the five-day period.

And now the pair of graphics that I regularly provide.

The above pair of graphics showing the current situation has an upper and lower graphic. 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) and how both measures are useful but for different purposes.

The bottom half of the graphic (Absolute Values which highlights the Thermocline) is now more useful as we track the progress of this new Cool Event.

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

Although I did not fully discuss the Kelvin Waves earlier, now seems to be the best place to show the evolution of the subsurface temperatures which remains relevant. What we have is only the upwelling phase of the series of Kelvin waves last winter.

And now Let us look at the Atmosphere.

Low-Level Wind Anomalies near the Equator

Here are the low-level wind anomalies.

And now the Outgoing Longwave Radiation Anomalies which tells us where convection has been taking place. 

And Now the Air Pressure which Shows up Mostly in an Index called the SOI.

This index provides an easy way to assess the location of and the relative strength of the Convection (Low Pressure) and the Subsidence (High Pressure) near the Equator. Experience shows that the extent to which the Atmospheric Air Pressure at Tahiti exceeds the Atmospheric Pressure at Darwin Australia when normalized is substantially correlated with the Precipitation Pattern of the entire World.

Below is the Southern Oscillation Index (SOI) reported by Queensland, Australia. The first column is the tentative daily reading, the second is the 30 day moving/running average and the third is the 90 day moving/running average.

The 30-day average, which is the most widely used measure, as of December 5 is reported at -1.30 which is not much changed since last week. The 90-day average at +2.52 is less La Nina-ish than last week. Usually but not always the 90 day average changes more slowly than the 30 day average but it depends on what values drop out. The disparity between the two is one reason why we look at both. (Sustained values over +7 are usually associated with La Nina and less than -7 are usually associated with El Nino). To some extent it is the change in the SOI that is of most importance. It had been increasing but may now be stabilizing or going down. That could change but for now the SOI is not signaling a La Nina but ENSO Neutral.

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. November has not been particularly favorable for La Nina development and most likely neither will be December in terms of the MJO.The forecasts of the MJO are all over the place and not suggesting a strong Active or Inactive Phase of the MJO any time soon.The MJO being Inactive is more favorable for La Nina than the MJO being Active. But the MJO goes back and forth from being Active, Inactive, strong and weak so it has mostly a short-term impact. It is possible that a weak Inactive Phase of the MJO might give this dying La Nina a little reprieve. .

Lately, the impact has been fairly muted. But the change in the SOI recently and some other changes suggest that we are having an Active Phase of the MJO even if such is not being reported and what we have is not the MJO but something else that is impacting the cool pool in a similar way as an Active MJO would. The forecast for the MJO is updated weekly and can be found here. If the MJO is not in its Active Phase then perhaps some other pattern is impacting the SOI and also shifting the cool pool to the east. We are also having a non-split fairly strong Jet Stream which is also consistent with an Active MJO. So I am calling it a Stealth MJO.

The MJO tends to be more important when the situation is ENSO Neutral and the MJO can start the process of an El Nino getting started. It is less significant re the initiation of a La Nina but is a factor. It is surprising how weak the MJO has been for months. But it may account for what seems like a cycling of the estimate of Nino 3.4 as the cool water is blown first to the west and then to the east. This impacts the upwelling also.

Forecasting the Evolution of ENSO

The below is first the early-month report from CPC/IRI which I call the reading of the tea leaves in that it is based on a combination of model results and a survey of the views of meteorologists. Recently the early month analysis has been more favorable for a la Nina than the later in the month model-based analysis.I think meteorologists like action so they prefer either El Nino or La Nina to Neutral. But the models are dispassionate about it.

And now we have the more recent fully model-based version .

There is not a lot of difference but the preference for La Nina conditions in NDJ is a bit less than a week earlier when the report was based mainly on a survey of meteorologist. When I see DJF I notice that January is the middle month in the DJF three-month period. Thus it seems that January is probably the last month that will have Nino 3.4 values equal to or under -0.5. When I look at the slightly higher probability for Nino 3.4 to be -0.5 or less as compared to Nino 3.4 to be in the Neutral Range, I am not blown away by the probability that we will be in La Nina condition into 2017..We are now past mid-November so to me the story-line should be the imminent end of the Cool Event rather than upgrading the Status of the Cool Event.

Here is the daily PDF and Spread Corrected version of the NOAA CFSv2 Forecast Model.

The full list of weekly values can be found here.

Forecasts from Other Meteorological Agencies.

Here is the Nino 3.4 report from the Australian BOM (it updates every two weeks)

Discussion (notice their threshold criteria are different from NOAA but also their actuals are higher than recorded by NOAA and yet Nino 3.4 is standard. So someone is incorrect OR WORSE.)

La Niña no longer likely in the coming months

The El Niño–Southern Oscillation (ENSO) in the tropical Pacific Ocean remains neutral (neither El Niño nor La Niña). Although some very weak La Niña-like patterns continue (such as cooler than normal ocean temperatures and reduced cloudiness in the central and eastern Pacific), La Niña thresholds have not been met. Climate models and current observations suggest these patterns will not persist. The likelihood of La Niña developing in the coming months is now low, and hence the Bureau’s ENSO Outlook has shifted from La Niña WATCH to INACTIVE.

The Indian Ocean Dipole (IOD) also remains neutral (neither positive nor negative), as is typical at this time of year. When ENSO and the IOD are neutral they have limited impact on Australian climate.

The climate of Australia, and other countries around the tropical Indian Ocean and western Pacific Ocean, has been strongly influenced during the second half of 2016 by both a strong negative IOD in the tropical Indian Ocean (that ended in November) and the weak La Niña-like pattern in the tropical Pacific (which has eased). This combination of climate drivers contributed to Australia observing its wettest May to September on record in 2016.

We also have the most recent JAMSTEC November 1 ENSO forecast. There should be a new version in a week or so.

The model continues to show ENSO Neutral for the next two years (after what they call a weak La Nina Modoki ends). But the potential for an El Nino has been taken out of the forecast. The JAMSTEC Discussion is shown earlier in this report.

Indian Ocean IOD (It updates every two weeks)

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

Discussion

Indian Ocean Dipole outlooks

The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 4 December was −0.02 °C.

The influence of the IOD on Australian climate is weak during the months of December to April. This is because the monsoon trough shifts south over the tropical Indian Ocean changing wind patterns, which prevents an IOD pattern from being able to form.

However, the continued presence of much warmer than average water to the north and northwest of Australia may see continued influence on Australia, including enhanced rainfall.

D. Putting it all Together.

Looks like this Cool Event is no longer even properly described as La Nina Conditions Apply.

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.

E. Relevant Recent Articles and Reports

Weather in the News

Arctic Oscillation and Polar Vortex Analysis and Forecasts

What does it mean? hard to say. The above link takes you to Jonah Cohen’s latest blog. Last week he said: “low Arctic sea Ice is also related to a Northwestward espansion of the Siberian High”. Whenever the location, size, strength etc of a semi-permanent High or Low is changed, that will impact weather. So that is what I found to be most interesting. The rest is forecasts and forecasts are made and updated on an ongoing basis. I  read the November 30 edition of the blog this evening but now there is a new version and I have not yet read it. I do think this is a very good meteorologist. And I could have listed this under the Global Warming category. I list it hear as I think the AO could be important this winter.

Weather Research in the News

Nothing to report.

Global Warming in the News

My unhappy Life as a Climate Heretic

Antarctic Rift What is that About?

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

Useful Background Information

With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.

ONI Recent History

The Aug/Sept/Oct reading has been issued and is currently listed as -0.7. The Sep/Oct/Nov preliminary estimate is -0.8 so there would now need for there to be two more periods of -0.5 or colder for this to be eligible to be formally recorded as a La Nina. I suspect there will be one more but not two. NOAA seems to be determined to make that happen. THEIR FUNDING MAY DEPEND ON THAT.

The full history of the ONI readings can be found here. The MEI index readings can be found here.