September 12, 2016 Weather and Climate Report – Frozen in Time

Written by Sig Silber

There is a lot of uncertainty about details of the forecast for the next two weeks.  But the pattern for CONUS has remained remarkably the same other than for the occasional Tropical Event. The Southwest has been cooler than climatology and almost everywhere else has been warmer than climatology. The Northwest has been dry and a wet anomaly anchored in New Mexico and Texas expanded and contracted northeast towards the Great Lakes. This pattern is expected to continue for at least another month.

A. Focus on Alaska and CONUS (all U.S. except Hawaii)

I have never presented the below graphic before but I am showing it today to support the statement in the lead paragraph to this report.

Let’s Focus on the Current (Right Now to 5 Days Out) Weather Situation.

First, 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 the link provided above.

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

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

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 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. I am leaving this explanation in the report but it may not be very significant until next October or so which now is less than two months away. .

The graphic below is similar to the above but with more detail which has pros and cons. It highlights the forecasted surface Highs and the Lows re air pressure on Day 6 (the Day 3 forecast is available on Page II of this Report. It you go there, hit your return button to get back to this report). This graphic also auto-updates.

This graphic (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 weather patterns, except for the Southwest Monsoon, are moving from west to east. It highlights the tropical activity

Looking at the current activity of the Jet Stream.

Re the above, H8 is 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.

Also the ideal situation is for the mid-level to be cooler than the Boundary Level. You need to have a steep decline in temperature at higher altitudes for the atmosphere to be unstable and create a significant number of healthy clouds and storms. The Devil is in the details. So there can be very higher PWATs i.e. the amount of moisture in the water column at a particular location but still no precipitation if there is no convection. A PWAT of 1.2 inches of water is sort of a summer trigger point,  Levels much higher than 1.2 inches of water could lead to hail. But in the absence of instability, nothing happens. Those westerlies are one reason why there has been less instability than optimal for the Southwest Monsoon to be productive. And now with September almost here the PWAT’s are down under 1.2 inches so we not only have a “low Grade Monsoon” we also have a “Dry Monsoon”.

Below is the forecast out five days.

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.

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.

Four- Week Outlook

I am going to show the three-month SON Outlook (for reference purposes), the Updated Outlook for the single month of September, the 6 – 10 Day and 8 – 14 Day Maps and the Week 3 –  4 Experimental Outlook. 

First – Temperature

Here is the Three-Month SON Temperature Outlook issued on August 18, 2016:

Here is the Temperature Outlook for September which was updated on August 31, 2016

 6 – 10 Day Temperature Outlook

8 – 14 Day Temperature Outlook   

Looking further out.

 Now – Precipitation 

Here is the three-month SON Precipitation Outlook issued on August 18, 2016 21, 2016:

And here is the Updated Outlook for September Precipitation Issued on August 31, 2016

6 – 10 Day Precipitation Outlook

8 – 14 Day Precipitation Outlook 

.

Here is the NOAA discussion released today September 12, 2016.

6-10 DAY OUTLOOK FOR SEP 18 – 22 2016

TODAY’S NUMERICAL MODEL SOLUTIONS ARE IN RELATIVELY POOR AGREEMENT ON THE 500-HPA FLOW PATTERN PREDICTED OVER THE FORECAST DOMAIN. THE ENSEMBLE MEAN SOLUTIONS FROM THE GFS, CANADIAN, AND ECMWF PREDICT A TROUGH NEAR THE BERING STRAIT AND BELOW NORMAL HEIGHTS OVER MOST OF ALASKA. FARTHER TO THE SOUTH, THE ECMWF-BASED SOLUTIONS FEATURE AN ENHANCED JET AND BELOW NORMAL HEIGHTS NEAR THE PACIFIC NORTHWEST WHILE THE GFS- AND CANADIAN-BASED SOLUTIONS FORECAST ABOVE NORMAL HEIGHTS ACROSS THE NORTHWESTERN CONUS. FARTHER DOWNSTREAM, MOST MODEL SOLUTIONS FORECAST THE WESTERLIES TO BE NORTH OF THEIR CLIMATOLOGICAL POSITION, RESULTING IN PREDICTED ABOVE NORMAL HEIGHTS ACROSS THE NORTHERN TIER OF THE CONUS. SUBTROPICAL RIDGING AND NEAR NORMAL HEIGHTS ARE FORECAST ACROSS MUCH OF THE SOUTHERN TIER OF THE CONUS. ENSEMBLE SPREAD IS VERY HIGH OVER MUCH OF THE CONUS INDICATING LARGE DIFFERENCES AMONG INDIVIDUAL ENSEMBLE MEMBERS. DUE TO THIS UNCERTAINTY, TODAY’S MANUAL 500-HPA HEIGHT BLEND IS COMPOSED PRIMARILY OF THE ENSEMBLE MEAN SOLUTIONS. THE GREATEST WEIGHTS WERE GIVEN TO THE GFS ENSEMBLE MEANS DUE, IN PART, TO RELATIVELY HIGH ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE FORECAST PATTERN MATCHES CASES THAT HAVE OCCURRED IN THE PAST.

ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER MUCH OF THE CONUS UNDERNEATH PREDICTED ABOVE NORMAL HEIGHTS. HOWEVER, NEAR NORMAL TEMPERATURES ARE FAVORED  FOR PARTS OF THE SOUTHERN HIGH PLAINS AND SOUTHWEST DUE TO THE POTENTIAL FOR INCREASED CLOUD COVER AND PRECIPITATION TO AFFECT THIS REGION. THERE ARE ENHANCED PROBABILITIES FOR BELOW NORMAL TEMPERATURES FOR PARTS OF NORTHERN ALASKA UNDERNEATH PREDICTED BELOW NORMAL HEIGHTS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF SOUTHERN ALASKA (ESPECIALLY FOR COASTAL LOCATIONS) IN ASSOCIATION WITH ABOVE NORMAL SEA SURFACE TEMPERATURES IN ADJACENT WATERS. 

THERE ARE ENHANCED PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION FOR SOUTHERN  AND EASTERN ALASKA IN ASSOCIATION WITH TROUGHS PREDICTED OVER THE BERING STRAIT AND THE GULF OF ALASKA. BELOW MEDIAN PRECIPITATION IS FAVORED ACROSS MUCH OF THE NORTHERN TIER OF THE CONUS FROM THE GREAT LAKES WESTWARD UNDERNEATH  PREDICTED ABOVE NORMAL HEIGHTS. CONVERSELY ABOVE MEDIAN PRECIPITATION IS  FAVORED ALONG THE EASTERN SEABOARD EXTENDING TO THE SOUTHERN PLAINS DUE TO A  PREDICTED FRONTAL BOUNDARY AND ASSOCIATED SHORTWAVE ENERGY.   

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO  VERY HIGH MODEL SPREAD OVER MUCH OF THE CONUS.

8-14 DAY OUTLOOK FOR SEP 20 – 26 2016 

TODAY’S WEEK-2 ENSEMBLE MEAN SOLUTIONS CONTINUE TO FORECAST A TROUGH NEAR THE BERING STRAIT AND BELOW NORMAL HEIGHTS OVER WESTERN ALASKA. DOWNSTREAM OF THIS TROUGH, RIDGING IS FORECAST OVER PARTS OF WESTERN NORTH AMERICA RESULTING IN PREDICTED ABOVE NORMAL HEIGHTS OVER MUCH OF NORTHWESTERN CONUS. SHALLOW, CYCLONIC FLOW IS FORECAST DOWNSTREAM OF THIS RIDGE ACROSS MUCH OF THE NORTHERN  TIER OF THE CONUS. HOWEVER, MODELS DISAGREE AS TO THE LOCATION OF THE MEAN TROUGH AXIS AS THE CANADIAN ENSEMBLE MEAN FORECASTS THE TROUGH AXIS NEAR THE GREAT LAKES WHILE THE GFS ENSEMBLE MEANS HAVE IT MUCH FARTHER TO THE WEST OVER THE NORTHERN PLAINS. SUBTROPICAL RIDING AND NEAR NORMAL HEIGHTS ARE FORECAST OVER MUCH OF THE SOUTHERN TIER OF THE CONUS. AGREEMENT AMONG SUCCESSIVE RUNS OF THE DETERMINISTIC GFS IS POOR TODAY AND ENSEMBLE SPREAD IS HIGH. DUE TO THESE DISAGREEMENTS, TODAY’S WEEK-2 500-HPA MANUAL HEIGHT BLEND CONSISTS PRIMARILY OF THE ENSEMBLE MEAN SOLUTIONS. THE GREATEST WEIGHT WAS GIVEN TO THE 0Z CANADIAN ENSEMBLE MEAN DUE, IN PART, TO RELATIVELY HIGH ANALOG CORRELATIONS.

THERE ARE ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONUS UNDERNEATH PREDICTED ABOVE NORMAL HEIGHTS. HOWEVER, NEAR NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE SOUTHERN HIGH PLAINS AND SOUTHWEST CONSISTENT WITH BIAS CORRECTED TEMPERATURES FROM THE CANADIAN, GFS, AND ECMWF ENSEMBLE MEMBERS. THERE ARE ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR SOUTHEASTERN MAINLAND ALASKA AHEAD OF A TROUGH FORECAST NEAR THE ALASKA PENINSULA AND FOR SOUTHERN COASTAL ALASKA FROM THE ALEUTIANS TO THE PANHANDLE DUE TO ABOVE NORMAL SSTS.

ABOVE MEDIAN PRECIPITATION IS FAVORED FOR MUCH OF THE EAST-CENTRAL CONUS UNDERNEATH PREDICTED CYCLONIC FLOW. CONVERSELY, BELOW MEDIAN PRECIPITATION IS  FAVORED FOR MUCH OF THE NORTHWESTERN CONUS IN ASSOCIATION WITH PREDICTED RIDGING AND ABOVE NORMAL HEIGHTS. ENHANCED PROBABILITIES FOR BELOW MEDIAN PRECIPITATION ARE INDICATED FOR PARTS OF THE NORTHEASTERN CONUS CONSISTENT WITH GEFS REFORECAST GUIDANCE. ABOVE MEDIAN PRECIPITATION IS FAVORED FOR MUCH OF SOUTHERN ALASKA IN ASSOCIATION WITH A TROUGH PREDICTED NEAR THE ALASKA PENINSULA.

 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE TO HIGH MODEL SPREAD AND UNCERTAINTY.

THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON  SEPTEMBER 15

Some might find this analysis interesting as the organization which prepares it 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 August 30 to September 23 which is just three days over three weeks which is a small spread. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, is about September 11 These analogs are centered on 3 days and 4 days ago (September 8 or 9). So the analogs could be considered pretty much in sync with the calendar perhaps three or four days later (meaning that we will be getting weather that normally would occur three or four days later than it is forecasted to occur) with a small spread which to me adds some confidence in the forecast in the sense only that it is not very inconsistent with the time of the year and the analogs if correctly selected (a big assumption) are also reasonably consistent with this time of the year.

There is this time two El Nino Analogs (why are there any?), two La Nina Analogs, and four ENSO Neutral Analogs. The phases of the ocean cycles in the analogs are suggestive of McCabe Condition A and D which are opposites which is consistent with the difficulty NOAA has indicated with their 6 – 14 Day Outlook.

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 in recent months. Because it is now September, I have now removed the June and June – April – May – June 90 Day Graphics. They are available in Part II of this Report – If you click to go there and take a look, hit your “Return Key” to return to this article. 

Let’s look at the temperature and precipitation anomalies for the 30 days ending July 30, 2016

And now we looking at August. Here are the 30 Days ending September 3.

And the 90 days

And now the 30 days ending September 10, 2016.

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

Click Here for a World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the map only so to see it you have to click where I said “click here”. You can adjust the settings to show Temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. 

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 September 6, 2016 Version and looking at Week 2 of that forecast.

Forecast from Japan

Aug. 17, 2016 Prediction from 1st Aug., 2016

ENSO forecast:

The SINTEX-F model initialized with the SST condition observed on July 31st predicts a weak La Niña/La Niña Modoki state in coming months.  [Editor’s Note: This article is already running too long so we will not discuss La Nina Modoki tonight but here is a good article to read for those with an interest in the topic]. Although the NCEP GODAS shows an anomalously cold subsurface condition almost all the way from central Pacific to eastern Pacific along the equator in July, the prediction has not picked the strong La Niña/La Niña Modoki signal yet. This might be a model bias due to the simple SST data assimilation scheme used in the initialization. However, we have noted similar prediction results in several other climate models.

Indian Ocean forecast:

As predicted earlier, the negative Indian Ocean Dipole (IOD) has actually emerged in the June-July SST anomalies of the NCEP GODAS data. The model continues predicting the negative IOD for the boreal fall; this will bring a wetter-than-normal (drier-than-normal) condition over the eastern (western) side of the Indian Ocean. There is high possibility of floods in the region near Sumatra and Java, and drought in East Africa. The negative IOD seems to have brought temporary relief to a hot summer over East Japan normally expected in an evolving La Niña year.

Regional forecast:

In boreal fall, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while northern Brazil will experience a colder-than-normal condition.

According to the seasonally averaged rainfall prediction, U.S., Korea, eastern China, Indo-China and East Africa will experience a drier condition during boreal fall, while most parts of Indonesia and northwestern South America (including Colombia, Ecuador, and western Brazil) will experience a wetter-than-normal condition; this may be mostly due to the negative IOD and the evolving weak La Niña. Also, because of those climate conditions in Indian and Pacific Oceans, Australia is expected to receive above normal rainfall during austral spring and summer. The active South Pacific Convergence Zone (SPCZ) may play a role in this, too However, we expect a weak dry condition in the southwestern coastal region of Western Australia because of the evolution of weak Ningaloo Niña. [ Editor’s Note: Click for Explanation and even more detail on the Ningaloo Niña]

Most part of Japan will experience above normal temperature from summer through winter. We expect above normal precipitation in most part of Japan in September-October. However, it may be noted that the forecast skills in those mid- and high-latitudes on regional scales are still limited.+

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.

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 ONI 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 September 12, in the afternoon working from the September 11 TAO/TRITON report, this is what I calculated.

My estimate of the daily Nino 3.4 ONI has declined to -0.6 which is now a  La Nina value.  NOAA has reported the weekly ONI to be again -0.7 which is a La Nina value.

All the reported values by NOAA this week are the same as last week. They must have known that the theme of my article this week would be “Frozen in Time”. How did they know that?

But I question the accuracy of their calculation. It is entirely possible that the TAO/TRITON system is not reporting accurately or that I have made an error in my estimation of the value for Nino 3.4 from the TAO/TRITON graphic. The difference between -0.6 and -0.7 is not substantial this week.

Nino 4.0 is reported as being the same as last week at and the week before at  -0.1.  Nino 3 is being reported as unchanged at -0.3  Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported unchanged at +0.3.  ACCORDING TO NOAA WE REMAIN IN ENSO Neutral BUT WE HAVE HAD OUR ninth straight LA NINA value of Nino 3.4 reported in the NOAA WEEKLY REPORT.  The Australian Bureau of Meteorology two weeks ago announced that their estimate of the value for NINO 3.4 for August was -0.4. IT IS THE SAME OCEAN. They are forecasting that the value for NINO 3.4 will decline to about-0.6 for September.  I believe my rough estimation approach is providing a more realistic ONI value right now than NOAA. There may also be a cyclical variation in the Nino 3.4 reading which impacts what you get based on what day you calculate it but I think these -0.7 values are biased low (more extreme) by about 0.1C. 

Nine weeks are not definitive (the NOAA criteria for declaring an El Nino or La Nina includes five overlapping three-month periods with the appropriate conditions) especially without confirmation from the SOI which we may have now finally. These index measurements are not definitive but they suggest the direction things are headed but other information strongly suggests the ONI readings will soon (NOAA) or after September (Australia BOM) be less negative than they are this week. I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in graphical form but going back a couple of more years can be found here.  NINO 1+ 2 stubbornly remains positive and determines the weather of Ecuador and Peru.

Sea Surface Temperature and Anomalies

It is the ocean surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. So we are interested in the actual ocean surface temperatures and the departure from seasonal normal temperatures which is called “departures” or “anomalies”. Since warm water facilitates evaporation which results in cloud convection, the pattern of SST anomalies suggests how the weather pattern east of the anomalies will be different than normal.

A major advantage of the Hovmoeller method of displaying information is that it shows the history so I do not need to show a sequence of snap shots 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 autoupdates daily because the SST Depatures on the Equator do not change rapidly and the prettied up version is so much easier to read.

Let us look 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 to the view from the surface down.

Current Sub-Surface Conditions.   Notice the lag in getting this information posted so the current situation may be a bit different than shown.

And now the pair of graphics that I regularly provide and which as I publish are currently able to be accessed from the NOAA website. There was a period of time when that website was up and down but it appears to be functioning well recently.

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.

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 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 a comparison between Air Pressure at Tahiti and Darwin Australia 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 September 12 is reported at +8.21 which is up fairly considerably from last week and is a La Nina level. The 90-day average at +5.36 is essentially unchanged from last week and is again borderline but clearly trending towards La Nina. These may be the high water marks for the SOI re this cycle. 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. Different agencies use a different range to classify the SOI as being El Nino or La Nina. The tightest range (I have referred to that as “strictest” but that may not be a clear way of putting it)  is -5 for El Nino and +5 for La Nina. Some meteorological agencies sometimes use -8 or +8. So the range +5 to -5 is clearly neutral and above +8 is clearly La Nina and below -8 is clearly El Nino and between -8 and -5 and +5 to + 8 is somewhat marginal but suggestive of El Nino if negative and La Nina if positive. For many purposes the trend is more important than the absolute level. So clearly the Upper Atmosphere has a slight trend right now towards La Nina.

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. August has not been particularly favorable for La Nina development and neither will be September in terms of the MJO. The MJO being Inactive is more favorable for La Nina than the MJO being Active. It is complicated in that some models predict a strong active MJO for September which normally means westerlies which is negative for the development of the La Nina. But the MJO goes back and forth from being Active, Inactive, strong and weak so in has mostly a short-term impact. Right now the impact is fairly muted. It 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.

Forecasting the Evolution of ENSO

The below is  (Mid-Month) Model- Based forecast issued on August 18, 2016 followed by Early Month Consensus-Based forecast issued on September 8, 2016.  It is important to remember that the first report in each month is based on a survey of meteorologists and the second report later in the month is based on the analysis of the forecast models. It is a minor difference but a difference.

First the Model-Based Forecast published on August 18, 2016.

And now the Early September “Probabilistic Forecast which includes a large component of input from meteorologists as compared to the second forecast in the month which is more tied to model results without interpretation. It is not a big difference but it is a difference. I assume they do it this way as to avoid forcing meteorologists to have to run their computers twice a month (some sarcasm expressed there).

We have suggested that it is possible that some of the models and in particular NOAA’s model will be wrong about how fast the Eastern Pacific Warm Pool moves back towards its La Nina location and it may well be that next winter will be more of a Neutral year or even have some characteristics of an El Nino Modoki and thus be wetter than a typical year as the Warm Pool may still be more in the Central Pacific than shifted all the way west to its La Nina position.

The full list of weekly values can be found here.

Forecasts from Other Meteorological Agencies.

View from Australia

El Nino

Below is the discussion just released. Notice the discussion re forecasting a La Nina for next winter. POAMA is not currently predicting a La Nina. POAMA is the Australian Bureau of Meteorology (BOM) proprietary forecasting model. BOM also consults the other international forecasting models and after that consultation is not forecasting a La Nina at this point in time as per below. Notice they use a different standard than NOAA namely + or – 0.8 rather than the + – 0.5 that NOAA sues. But even with the NOAA Standard, POAMA would not be forecasting a La Nina. BOM is reporting a value of NINO 3.4 of -0.4 while NOAA reports it at -0.7. How that can be is a mystery. And with NOAA criteria,  the duration must be five overlapping three month periods which is about the same as seven months but with some leeway to not meet the criteria for a particular month.

Outlooks from the eight international climate models surveyed by the Bureau have eased back slightly in terms of the chance of La Niña, compared to two weeks ago. However, many of the models continue to show borderline cool conditions to be likely and most models include ensemble members which exceed La Niña thresholds. Overall, only one of the surveyed models indicates a clear La Niña is likely to develop and persist across the outlook period.

If La Niña does form, models suggest it will be weak, potentially short-lived, and well below the strength of the significant 2010–12 event.

During La Niña, northern and eastern Australia typically experience above average spring rainfall, with the first rains of the wet season typically arriving earlier than average in northern Australia. At present, warmer than average seas surrounding Australia—which more typically occur during La Niña—mean some La Niña–like impacts may occur even if thresholds are not exceeded.

IOD (Indian Ocean Dipole)

The graphic comes with discussion that is usually very short but longer tonight for obvious reasons, Here is that discussion:

The negative Indian Ocean Dipole (IOD) event continues, and has strengthened compared to two weeks ago as areas of cool anomalies have re-emerged in the western Indian Ocean adjacent to the coastline of Africa. Warm anomalies in the eastern Indian Ocean, between northwestern Australia and Indonesia, have also strengthened compared to two weeks ago. The weekly index value to 11 September was −1.19 °C.

The Indian Ocean Dipole (IOD) index has been below the −0.4 °C negative IOD threshold for sixteen weeks, peaking at −1.37 °C in early July. The July 2016 monthly IOD index value reported in the ERSSTv4 dataset was the strongest negative value in at least 50 years of record. 

International climate models indicate the negative IOD will steadily weaken during spring, as is typical of the lifecycle of IOD events. This means its influence on Australian rainfall may lessen in the coming months.

A negative IOD typically brings above average rainfall to eastern Australia during spring, cooler than normal daytime temperatures to southern Australia, and warmer daytime and night-time temperatures to northern Australia.

Information on the impact of a negative IOD on Australia can be found here

We have the JAMSTEC August 1 ENSO forecast and are waiting for the updated forescast which should be very soon.

Aug. 17, 2016 Prediction from 1st Aug., 2016

ENSO forecast:

The SINTEX-F model initialized with the SST condition observed on July 31st predicts a weak La Niña/La Niña Modoki state in coming months.  [Editor’s Note: This article is already running too long so we will not discuss La Nina Modoki tonight but here is a good article to read for those with an interest in the topic]. Although the NCEP GODAS shows an anomalously cold subsurface condition almost all the way from central Pacific to eastern Pacific along the equator in July, the prediction has not picked the strong La Niña/La Niña Modoki signal yet. This might be a model bias due to the simple SST data assimilation scheme used in the initialization. However, we have noted similar prediction results in several other climate models.

Indian Ocean forecast:

As predicted earlier, the negative Indian Ocean Dipole (IOD) has actually emerged in the June-July SST anomalies of the NCEP GODAS data. The model continues predicting the negative IOD for the boreal fall; this will bring a wetter-than-normal (drier-than-normal) condition over the eastern (western) side of the Indian Ocean. There is high possibility of floods in the region near Sumatra and Java, and drought in East Africa. The negative IOD seems to have brought temporary relief to a hot summer over East Japan normally expected in an evolving La Niña year.

Regional forecast:

In boreal fall, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while northern Brazil will experience a colder-than-normal condition.

According to the seasonally averaged rainfall prediction, U.S., Korea, eastern China, Indo-China and East Africa will experience a drier condition during boreal fall, while most parts of Indonesia and northwestern South America (including Colombia, Ecuador, and western Brazil) will experience a wetter-than-normal condition; this may be mostly due to the negative IOD and the evolving weak La Niña. Also, because of those climate conditions in Indian and Pacific Oceans, Australia is expected to receive above normal rainfall during austral spring and summer. The active South Pacific Convergence Zone (SPCZ) may play a role in this, too However, we expect a weak dry condition in the southwestern coastal region of Western Australia because of the evolution of weak Ningaloo Niña. [ Editor’s Note: Click for Explanation and even more detail on the Ningaloo Niña]

Most part of Japan will experience above normal temperature from summer through winter. We expect above normal precipitation in most part of Japan in September-October. However, it may be noted that the forecast skills in those mid- and high-latitudes on regional scales are still limited.

D. Putting it all Together.

Last winter’s El Nino has officially ended in terms of currently satisfying the criteria. We are now speculating on the winter of 2016/2017 which now according to some of the models seems likely to be a La Nina or Neutral with a La Nina bias. But Australia and Japan do not see it that way and are not calling for a La Nina at this point in time. So NOAA is a bit the Odd Man Out but it is mostly a question of degree. NOAA is calling for a borderline La Nina and the others are forecasting a La Nina-ish event that does not quite meet the criteria for being labeled a La Nina and does not last long enough to meet the criteria.

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

Newton takes a toll

Weather Research in the News

Peak Hurricane

Global Warming in the News

Impact of carbon dioxide increases on grasslands may be more complex than first thought.  Full Paper

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 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 official reading for Jun/Jul/Aug is now reported as -0.3. As you can see this recent El Nino peaked in NDJ and has now ended and depending on what system you use it is either the 2nd or 3rd strongest El Nino since modern records were kept which is considered to be 1950. You could argue for it being #1 based on a week of readings but few are buying that argument. Still #2 or #3 means it is one of the strongest ever based on the way these events are measured. I will be writing more about that soon in a separate article. I believe the measurement system is inadequate re being useful in forecasting Worldwide weather impacts. The JJA is not a La Nina Value. So there would need for there to be five periods of -0.5 or colder starting with JAS. It is not even clear that JAS will record as -0.5 or less. So the chances of this event being an official La Nina are very low.

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