Written by Sig Silber
Updated 4 PM EST October 12. Bermuda is not part of CONUS so the threat remaining for them is outside of CONUS. But Bermuda is in the Path of Nicole. Learn more here. Then hit return to return to this article. In general, according to NOAA, we have highly predictable weather ahead this week with a hint of a mild La Nina. Those who like snow may soon get their wish fulfilled. Overall according to NOAA this week will be about as normal as one can expect. The analogs raise some questions in my mind about the level of confidence that NOAA has expressed in their forecast but not enough to conclude that the forecast will not play out pretty much as issued.
This past week of intense tropical activity in the Pacific and Atlantic is pretty much over other than Hurricane Nicole which threatens Bermuda. Notice there is not a lot of separation between the storm track and Bermuda. Not sure if an out-to-sea storm also has a strong NE Quadrant as would be the case if such a storm was approaching the East Coast from further east of the Coast. There may also be some issues re the ability of existing models to predict the strength of storms in that area as they may not have been calibrated to do so.
If this map does not update you can get an updated map by clicking here.
We have been running an Update Report on the Status of Cyclonic Activity in the Atlantic and Pacific all week. Not sure how long we will continue to update that report but it can be found here. (If you wish to take a look, please after you have taken a look hit your Return Key to return to this Weekly Weather and Climate Report.) The weekly report is also updated as needed but rarely beyond Tuesday which is why we published a separate Storm Update Report this week. The way the web site works it is not easy to update the title of a report once published so you have to click on it to see what has changed as there are few clues in the title. The risk to Bermuda appears to be through Thursday and if that risk goes away and there are no new storms to be concerned about in the Atlantic or Pacific we will stop updating the Update Report and it will be repurposed soon after October 20 to cover the NOAA Seasonal Outlook. But for the next few days, if Bermuda remains in the track of Nicole, the Update Report will be updated. You can always be assured that GEI will attempt to keep its readers informed.
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.
Image credit:Center for Western Weather and Water Extremes, Scripps/UCSD. More explanation can be found at Atmospheric Rivers (Click to read full Weather Underground Dr. Bob Henson article)
To turn the above into a forecasting tool click here. and you will have a dashboard for a forecasting model.
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
I have changed things up a bit and the below is a Day 3 Forecast not the Day 6 Forecast I usually present. It 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. We now see the 540 line thinking about entering CONUS in the Extreme Northwest. Welcome to Fall. It is ski time. Remember that 540 relates to sea level. Inland from the Northwest you re above sea level so snow is likely.
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 southwest winds approaching Baja California are of some interest.
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. 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 forecast for this week that would appear to impact CONUS..
Below is the current water vapor Imagery for North America.
Looking at the current activity of the Jet Stream.
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.
When we discuss the jet stream and for other reasons, we often discuss different layers of the atmosphere. These are expressed in terms of the atmospheric pressure above that layer. It is kind of counter-intuitive to me. The below table may help the reader translate air pressure to the usual altitude and temperature one might expect at that level of air pressure. It is just an approximation but useful.
Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on “earth” adjusting the parameters and then clicking again on “earth” to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns. This amazing graphic covers North and South America.
Four- Week Outlook
I am going to show the three-month OND Outlook (for reference purposes), the Updated Outlook for the single month of October, the 6 – 10 Day and 8 – 14 Day Maps and the Week 3 – 4 Experimental Outlook.
First – Temperature
Here is the Three-Month OND Temperature Outlook issued on September 15, 2015, 2016:
Here is the Temperature Outlook for October which was updated on September 30, 2016
6 – 10 Day Temperature Outlook
8 – 14 Day Temperature Outlook
Looking further out.
Now – Precipitation
Here is the three-month OND Precipitation Outlook issued on September 15, 2016 :
And here is the Updated Outlook for October Precipitation Issued on September 30, 2016
6 – 10 Day Precipitation Outlook
8 – 14 Day Precipitation Outlook
.
As I view these maps on October 10 (two of the five update each day and one (the Week 3 – 4 Outlook) updates every Friday), it looks like precipitation leading up to November 4 is tending for the middle of October to be mostly a wet northern tier with the Northwest being the focal point and a mostly dry southern tier with the focal point being Oklahoma and Texas. The pattern is projected to evolve in the lost week of October heading into November to be one with a smaller Northwest wet anomaly, a Florida wet anomaly and a dry anomaly stretching from Eastern Texas north and slightly northeast to the Great Lakes. Alaska will start dry and morph to EC. Everywhere else is forecast to be EC.
Here is the NOAA discussion released today October 10, 2016.
6-10 DAY OUTLOOK FOR OCT 16 – 20 2016
TODAY’S ENSEMBLE MEAN FORECASTS ARE IN VERY GOOD AGREEMENT ON THE 500-HPA CIRCULATION PATTERN PREDICTED OVER THE FORECAST DOMAIN. ALL MODEL 500-HPA HEIGHT FORECASTS AGREE ON A DEEP TROUGH OVER THE GULF OF ALASKA, WITH NEGATIVE HEIGHT ANOMALIES EXTENDING ACROSS THE NORTHEAST PACIFIC INTO THE U.S. PACIFIC NORTHWEST. 500-HPA HEIGHTS ARE PREDICTED TO BE BELOW NORMAL ACROSS THE NORTH PACIFIC FROM JUST SOUTH OF THE ALEUTIAN ISLANDS, THROUGH THE GULF OF ALASKA INTO THE NORTHWESTERN CONUS. ABOVE NORMAL 500-HPA HEIGHTS ARE FORECAST BY ALL MODELS OVER NORTHWESTERN ALASKA AND REMAINING AREAS OF THE CONUS EXCEPT THE SOUTHERN FLORIDA PENINSULA. A RIDGE IS PREDICTED OVER THE EASTERN CONUS BY ALL ENSEMBLE MEAN FORECASTS AND VIRTUALLY ALL ENSEMBLE MEMBERS. UNDER BELOW NORMAL HEIGHTS ASSOCIATED WITH A PREDICTED TROUGH, BELOW NORMAL TEMPERATURES ARE PREDICTED OVER SOUTHERN ALASKA AND PARTS OF THE WESTERN CONUS. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR MOST OF THE CONUS UNDER A PREDICTED RIDGE AND ABOVE NORMAL 500-HPA HEIGHTS.
UNDER ANOMALOUS NORTHERLY FLOW BEHIND THE PREDICTED TROUGH AXIS, BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR ALASKA, EXCEPT FOR THE ALASKA PANHANDLE. AHEAD OF THE PREDICTED TROUGH OVER THE NORTH PACIFIC, ABOVE MEDIAN PRECIPITATION IS VERY LIKELY FOR THE WESTERN CONUS, AND MOST LIKELY FOR MOST OF THE NORTHERN HALF OF THE CONUS, FROM THE PACIFIC COAST TO THE GREAT LAKES REGION, AS WELL AS FROM THE WESTERN GULF COAST INTO THE CENTRAL PLAINS. AHEAD OF THE PREDICTED RIDGE, BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR THE EAST COAST AND SOUTHEAST.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: WELL ABOVE AVERAGE, 5 OUT OF 5, DUE TO VERY GOOD MODEL AND TOOL AGREEMENT.
8-14 DAY OUTLOOK FOR OCT 18 – 24 2016
THE 500-HPA CIRCULATION PATTERN FORECAST FOR THE WEEK-2 PERIOD IS FAIRLY SIMILAR TO THE 6-10 DAY PERIOD FORECAST, WITH WEAKER ANOMALIES DURING WEEK 2, DUE TO INCREASING UNCERTAINTY. ABOVE NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY FOR MUCH OF THE CONUS, UNDER ABOVE NORMAL HEIGHTS ASSOCIATED WITH A PREDICTED RIDGE, EXCEPT FOR PARTS OF THE WEST WHERE BELOW NORMAL TEMPERATURES ARE MORE LIKELY. PROBABILITIES OF ABOVE MEDIAN PRECIPITATION HAVE WEAKENED FOR THE WEST, AS FORECAST UNCERTAINTY INCREASES, BUT REMAIN MOST LIKELY ACROSS THE NORTHERN CONUS AND PARTS OF THE SOUTHERN AND CENTRAL PLAINS.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE TO GOOD AGREEMENT AMONG THE MODELS AND TOOLS, WITH INCREASING UNCERTAINTY APPARENT FROM GREATER ENSEMBLE AND MODEL SPREAD.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON OCTOBER 20
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.
Day | ENSO Phase | PDO | AMO | Other Comments |
Oct 17, 1951 | El Nino | – | – | |
Sept 30, 1954 | La Nina | +(t) | – | |
Oct 1, 1954 | La Nina | +(t) | – | |
Oct 19, 1957 | El Nino | +(t) | + | |
Oct 22, 1957 | El Nino | +(t) | +(t) | |
Oct 13, 1983 | La Nina | + | – | Following the strong 82/83 El Nino |
Sept 24 1984 | La Nina | +(t) | – | Following the strong 82/83 El Nino |
Oct 12, 2002 | El Nino | + | + | Modoki Type I |
(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 September 24 to October 22 which is twenty eight days which is a fairly large 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 October 8. These analogs are centered on 3 days and 4 days ago (October 6 or 7). So the analogs could be considered in sync with the calendar meaning that we will be getting weather that normally would occur this time of the year including that forecasted Western trough which is typical this time of the year.
There are this time four El Nino Analogs (why are there any?), four La Nina Analogs, and zero ENSO Neutral Analogs. The phases of the ocean cycles in the analogs point towards McCabe Conditions “A” and” C”. They are opposites and the 6 – 14 Day Forecast is not consistent with either one so I have less confidence in the 6 – 14 Day Forecast than NOAA. And having both El Nino and La Nina analogs raises many questions.
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 the beginning of October, I have now removed the July and August Graphics.
Here is the 30 Days ending October 1, 2016
And the 30 Days ending October 8, 2016
NOAA updated their Seasonal Outlook on September 15. We reported on that on Sunday Sept 18. You can read that report here. If you opt to go read my Report on NOAA’s Seasonal Outlook Update, please return from there to read this report which you can do by simply hitting your “backspace” button on your keyboard.
B. Beyond Alaska and CONUS Let’s Look at the World which of Course also includes Alaska and CONUS
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 hitting your “backspace” key which 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
But I know how to display the precipitation forecast from Queensland Australia and here it is.
JAMSTEC issued their Precipitation Forecast recently but it is based on the September 1 ENSO analysis. I show it because it is the most recent forecast we have received from JAMSTEC.
Just to be complete I will show their temperature forecast
Here is the discussion that does with it.
Sep. 21, 2016 Prediction from 1st Sep., 2016
ENSO forecast:
The SINTEX-F model predicts a La Niña Modoki/weak La Niña state [Editor’s Note: A La Nina State or Condition is not the same as a La Nina event because it takes a sufficient duration for a period of La Nina conditions to be declared to be a La Nina Event] will reach the peak in the boreal fall. Then, the tropical Pacific will return to a normal state by boreal spring. The model prediction is so far consistent with the observed evolution of the sea surface temperature (SST) anomalies.
Indian Ocean forecast:
The model has successfully predicted the negative IOD as observed in recent SST anomalies. The 2016 negative IOD will reach the peak in the boreal fall. It 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. On the other hand, we warn dry conditions in East African countries.
Regional forecast:
In boreal fall, as a seasonally averaged view, most part of the globe will experience a warmer-than-normal condition, while some parts of northern Brazil will experience a colder-than-normal condition.
According to the seasonally averaged rainfall prediction, eastern China, Indo-China, East Africa, and parts of southern Africa might experience a drier condition during boreal fall, while most parts of Indonesia, northern South America (including Colombia, Ecuador, and northwestern Brazil), southern West Africa, and western Central Africa will experience a wetter-than-normal condition; this may be mostly due to the negative IOD and the weak La Niña. Because of those climate conditions, Australia will receive above normal rainfall during austral summer. Most part of Japan will experience above normal temperature and above normal precipitation in fall, particularly in the western part of Japan.
Our monthly predictions fluctuate much in mid- and high- latitudes. The forecast skills in those latitudes on regional scales are still limited; predictions in those regions should be used carefully.
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. The graphic issued Sunday differs greatly along the Equator in the Eastern Pacific from what I saw Saturday so I do not know if the Oceans Changed or NOAA changed.
Below I show the changes over the last month in the Sea Surface Temperature (SST) anomalies.
x
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 October 4, 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.
———————————————— | A | B | C | D | E | —————– |
The below table which only looks at the Equator shows the extent of anomalies along the Equator. I had split the table to show warm, neutral, and cool anomalies. The top rows showed El Nino anomalies. When there were no more El Nino anomalies along the Equator, I eliminated those rows. 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.
Subareas of the Anomaly | Westward Extension | Eastward Extension | Degrees of Coverage | ||||
As of Today | May 23, 2016 | As of Today | May 23 2016 | As of Today | In Nino 3.4 | May 23, 2016 | |
These Rows Show the Extent of ENSO Neutral Impacts on the Equator | |||||||
0.5C or cooler Anomaly* | 160E | 155E | Land | 155W | 105 | 50 | 50 |
0C or cooler Anomaly | 170E | 155W | LAND | Land | 95 | 50 | 60 |
These Rows Show the Extent of the La Nina Impacts on the Equator | |||||||
-0.5C or cooler | 180W | 145W | LAND | Land | 85 | 50 | 50 |
-1C or cooler Anomaly | 170W | 140W | LAND | 105W | 75 | 50 | 35 |
-1.5C or cooler Anomaly | 165W | 135W | 150W | 120W | 15 | 15 | 0 |
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 October 10, in the afternoon working from the October 9 TAO/TRITON report, this is what I calculated. [Although the TAO/TRITON Graphic appears to update once a day, in reality it updates more frequently.]
Anomaly Segment | Estimated Anomaly | |
Last Week | This Week | |
A. 170W to 160W | -0.5 | -1.1 |
B. 160W to 150W | -0.4 | -1.1 |
C. 150W to 140W | -0.5 | -1.1 |
D. 140W to 130W | -0.3 | -0.9 |
E. 130W to 120W | -0.1 | -1.0 |
Total | -1.8 | -5.2 |
Total divided by five subregions i.e. the ONI | (-1.8)5 = -0.4 | (-5.2)/5= -1.0 |
My estimate of the daily Nino 3.4 SST anomaly has fallen to -1.0 which is an ENSO La Nina value. NOAA has reported the weekly ONI to be -0.9 which is slightly cooler than they reported last week and also very much a La Nina value. This week my estimate and their estimate are similar.Nino 4.0 is reported as being slightly cooler than last week at -0.6. Nino 3 is being reported a quite a bit cooler at -0.6. Nino 1 + 2 which extends from the Equator south rather than being centered on the Equator is being reported quite a bit cooler at +0.1. El Nino is not measured in Nino 1 + 2 but is part of the picture of the main change this week is the cooling of the Eastern Pacific.I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in table form but going back a couple of more years can be found here. NINO 1+ 2 stubbornly remains slightly 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.
I thought it would be useful to show this view which is more focused on the Equator but looks down to 300 meters rather than just being the surface. Here you can clearly see the cool blob (darker blue) at 170W to 155W which is the focus of this cool event. Does 10 to 15 degrees of Latitude make a La Nina? This could all be an issue of seasonal adjustments or the every five year trend adjustment. It is clear that the Eastern Pacific is cooling as the cool subsurface water rises but that does not enter into the Nino 3.4 Index measurement. But we can see a small blob at about 130W and that may be making the difference this week. It is subtle but makes a difference. One can also see the continual shift to the west which is also subtle.
Let us further 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 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 that the lag in getting this information posted so the current situation may be a bit different than shown. The date shown is the midpoint of a five-day period with that date as the center of the five-day period.
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 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.
Date | Current Reading | 30-Day Average | 90 Day Average |
Oct 4 | +4.51 | +12.92 | +7.99 |
Oct 5 | +11.47 | +13.22 | +8.15 |
Oct 6 | +12.25 | +13.66 | +8.31 |
Oct 7 | +10.12 | +14.03 | +8.42 |
Oct 8 | -0.84 | +13.76 | +8.33 |
Oct 9 | -2.52 | +13.32 | +8.16 |
Oct 10 | -2.58 | +12.79 | +7.95 |
The 30-day average, which is the most widely used measure, as of October 10 is reported at +12.79 which is about the same as last week and is definitely a La Nina level. The 90-day average at +7.95 is the same as last week and is again at a La Nina level. These may be the high water marks for the SOI re this cycle but I said that last week and the week before and the week before and the week before that. 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. To some extent it is the change in the SOI that is of most importance. It has been increasing but may now be stabilizing.
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. September was not particularly favorable for La Nina development and most likely neither will be October 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 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 the Early September CPC/IRI “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).
And then we have the recently released mid-month model-based report
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.
Here is the Nino 3.4 report from the Australian BOM
Here is the discussion:
Negative Indian Ocean Dipole eases; continued impacts likely
The tropical Pacific Ocean remains El Niño–Southern Oscillation (ENSO) neutral, however, some indicators have shifted closer to La Niña thresholds. Conversely, the negative Indian Ocean Dipole (IOD) has eased, though waters off Indonesia remain at near record temperatures. This may see continued IOD impacts for Australia.
Sea surface temperatures (SSTs) in the tropical Pacific Ocean have cooled over the past fortnight, consistent with a surge in the trade winds. The latest weekly NINO3.4 value of −0.6 °C—while still at neutral levels—is a value not seen since February 2012 (the end of the 2010–12 La Niña). Cloudiness near the Date Line and the Southern Oscillation Index have also shifted closer to La Niña-like levels. However, some forecasts suggest trade winds may return to near-normal soon. This could occur with the passage of the Madden–Julian Oscillation and would slow or cease any further La Niña development.
The majority of international climate models indicate the tropical Pacific is likely to remain at ENSO neutral levels through to the end of the 2016–17 summer. Two of the eight models suggest brief, weak La Niña levels are possible towards the end of 2016. The ENSO Outlook remains at La Niña WATCH.
With warmer than average sea surface temperatures to Australia’s north and east, some La Niña-like impacts remain likely even if an event doesn’t fully develop.
Negative IOD values have eased over the past fortnight, however this is mainly due to ocean warming off Africa. Waters off Indonesia remain very warm, and were second warmest on record for September. Models indicate the IOD will return to neutral levels by the end of spring. Spring in eastern Australia is typically wetter than average during a negative IOD or La Niña.
We also have the most recent JAMSTEC September 1 ENSO forecast.
The model shows ENSO Neutral for the next two years. The swings are a bit more intensified than in the prior model run. Indian Ocean IOD. The discussion was shown earlier as it contains a weather forecast.
Indian Ocean IOD
Not directly related to ENSO is the IOD Forecast:
Here is the discussion:
The negative Indian Ocean Dipole (IOD) event continues, although it has declined in strength over the past fortnight. The weekly index value to 9 October was −0.38 °C.
This is the first week since the latter part of May that the IOD index value has been outside the −0.4 °C negative IOD threshold. However, the eastern node of the IOD was second-warmest on record for September in the ERSSTv4 dataset, coming in just behind the exceptional value of September 2010.
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.
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 and in the end NOAA may turn out to have correct. 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
We have been covering the cyclones in the Atlantic and Pacific with a second article that is continually updated and can be found here.
Weather Research in the News
Nothing to report
Global Warming in the News
Southwest Mega-drought Risk – Needs to be read carefully. An important issue is the validity of RCP 8.5 as a benchmark. Here is a good article on that. It has page after page of comments so here may be a shorter version with somewhat fewer comments.
I need to really thoroughly review this very important article and that will take some time. But here are some initial thoughts.
I did want to mention that under the McCabe et al analysis, one of the four combinations of ocean phases was a drought phase so that suggested that for approximately 25% of the time the chances of drought were very good. Thus one would have expected a significant drought once a century. So that is not new information.
McCabe et al also calculated a change in the situation due to Warming. That is not new information either.
So although this new analysis is more recent than the older analysis which was just after the PDO and AMO were figured out, to me it is not very different. The main difference is this paper has scenarios for the future. One probably could have developed them from the McCabe et al analysis. And they are talking about 35 year droughts which is not all that different from the droughts we have had once per century. My quick reading of the article did not come across the mention of El Nino. Are they in the analysis? I need to read more.
The authors make things simple with basically 2C, 4C, and 6C scenarios. How the 2C is defined is important. Apparently it is mean warming from 2051 to 2100 compared to 1951 to 2000. I like to use simple approaches so my mind I will think about it as 2075 compared to 1975. There are other papers that use a different way of measuring 2C (and 4C and 6C). Some go back to 1750 or the beginning of the Industrial Revolution. Well if 1975 is the base even if the growth rate is steeper then linear there is still some room to get to 2C. We are about 40 years into the 100 year period used by the authors.
More when I have had a chance to really study this important paper.
The below is the key graphic:
James Hansen on the Paris Agreement Again this needs to be read carefully.
F. Table of Contents for Page II of this Report Which Provides a lot of Background Information on Weather and Climate Science
The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page II where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
1. Very High Frequency (short-term) Cycles PNA, AO,NAO (but the AO and NAO may also have a low frequency component.)
2. Medium Frequency Cycles such as ENSO and IOD
3. Low Frequency Cycles such as PDO, AMO, IOBD, EATS.
4. Computer Models and Methodologies
5. Reserved for a Future Topic (Possibly Predictable Economic Impacts)
G. Table of Contents of Contents for Page III of this Report – Global Warming Which Some Call Climate Change.
The links below may take you directly to the set of information that you have selected but in some Internet Browsers it may first take you to the top of Page III where there is a TABLE OF CONTENTS and take a few extra seconds to get you to the specific section selected. If you do not feel like waiting, you can click a second time within the TABLE OF CONTENTS to get to the specific part of the webpage that interests you.
2. Climate Impacts of Global Warming
3. Economic Impacts of Global Warming
4. Reports from Around the World on Impacts of Global Warming
Useful Background Information
With respect to relating analog dates to ENSO Events, the following table might be useful. In most cases this table will allow the reader to draw appropriate conclusions from NOAA supplied analogs. If the analogs are not associated with an El Nino or La Nina they probably are not as easily interpreted. Remember, an analog is indicating a similarity to a weather pattern in the past. So if the analogs are not associated with a prior El Nino or prior La Nina the computer models are not likely to generate a forecast that is consistent with an El Nino or a La Nina.
El Ninos | La Ninas | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Start | Finish | Max ONI | PDO | AMO | Start | Finish | Max ONI | PDO | AMO | |
DJF 1950 | J FM 1951 | -1.4 | – | N | ||||||
T | JJA 1951 | DJF 1952 | 0.9 | – | + | |||||
DJF 1953 | DJF 1954 | 0.8 | – | + | AMJ 1954 | AMJ 1956 | -1.6 | – | + | |
M | MAM 1957 | JJA 1958 | 1.7 | + | – | |||||
M | SON 1958 | JFM 1959 | 0.6 | + | – | |||||
M | JJA 1963 | JFM 1964 | 1.2 | – | – | AMJ 1964 | DJF 1965 | -0.8 | – | – |
M | MJJ 1965 | MAM 1966 | 1.8 | – | – | NDJ 1967 | MAM 1968 | -0.8 | – | – |
M | OND 1968 | MJJ 1969 | 1.0 | – | – | |||||
T | JAS 1969 | DJF 1970 | 0.8 | N | – | JJA 1970 | DJF 1972 | -1.3 | – | – |
T | AMJ 1972 | FMA 1973 | 2.0 | – | – | MJJ 1973 | JJA 1974 | -1.9 | – | – |
SON 1974 | FMA 1976 | -1.6 | – | – | ||||||
T | ASO 1976 | JFM 1977 | 0.8 | + | – | |||||
M | ASO 1977 | DJF 1978 | 0.8 | N | – | |||||
M | SON 1979 | JFM 1980 | 0.6 | + | – | |||||
T | MAM 1982 | MJJ 1983 | 2.1 | + | – | SON 1984 | MJJ 1985 | -1.1 | + | – |
M | ASO 1986 | JFM 1988 | 1.6 | + | – | AMJ 1988 | AMJ 1989 | -1.8 | – | – |
M | MJJ 1991 | JJA 1992 | 1.6 | + | – | |||||
M | SON 1994 | FMA 1995 | 1.0 | – | – | JAS 1995 | FMA 1996 | -1.0 | + | + |
T | AMJ 1997 | AMJ 1998 | 2.3 | + | + | JJA 1998 | FMA 2001 | -1.6 | – | + |
M | MJJ 2002 | JFM 2003 | 1.3 | + | N | |||||
M | JJA 2004 | MAM 2005 | 0.7 | + | + | |||||
T | ASO 2006 | DJF 2007 | 1.0 | – | + | JAS 2007 | MJJ 2008 | -1.4 | – | + |
M | JJA 2009 | MAM 2010 | 1.3 | N | + | JJA 2010 | MAM 2011 | -1.4 | + | + |
JAS 2011 | FMA 2012 | -0.9 | – | + | ||||||
T | MAM 2015 | NA | 1.0 | + | N |
ONI Recent History
The official reading for Jul/Aug/Sept is now reported as -0.5.The JAS reading is the first La Nina Value. So there would now need for there to be four more periods of -0.5 or colder for this to be eligible to be formally recorded as a La Nina. It is possible but it will be close.
The full history of the ONI readings can be found here. The MEI index readings can be found here.