November 19, 2018 Intermediate-Term Weather Report – Cold Turkey Day

Written by Sig Silber

It was tempting to say that we see signs of a transition from a wet north to a wet south in the West suggestive of the arrival of El Nino but it is too soon to draw that conclusion especially given the MJO forecast. What is more certain is that it will be cold for New England for the Thanksgiving Holiday and this might continue for a little while.  There is a transition taking place but the parameters of that transition are not yet clear.

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In our Monday night Weekly Weather and Climate Report, we mostly cover Days 6 – 14 and Weeks 3 – 4 which depending on when you read this article covers to about Day 25. We cover Days  1- 5 also but in most cases  readers will want to consult their local NWS Office for more detailed information that impacts them in the short term.

Here is the recent history.

It is not clear how much the MJO is contributing to the AO Negative (see later discussion) but the forecast calls for it to be doing so.  So that is one more factor that will keep the Northeast cooler than usual for this time of the year.

Here is the historical record for the NYC area. Will new records be set?

Summary of the Forecast

We now provide our usual summary first for temperature and then for precipitation of small images of the four short-term maps. You can click on these maps to see larger versions. The easiest way to return to this report is by using the “Back Arrow” usually found top left corner of your screen to the left of the URL Box. Larger maps are available later in the article with the discussion and analysis.

Sometimes it is useful to see the evolution of the forecasts from the 1 – 5 Day, 6 – 10 Day (which NOAA considers to be Week-1 of their intermediate forecast) , 8 – 14 Day (which NOAA considers to be Week-2) and Week 3 and 4 (which after being issued overlap with Week-2). I do not have comparable maps for the Day 1 – 5 forecast in the same format as the three maps we generally work with. What I am showing for temperature is the Day 3 Maximum Temperature and for precipitation the five-day precipitation: the latter being fairly similar in format to the subsequent set of the maps I present each week but showing absolute QPF (inches of precipitation) not QPF deviation from Normal.

First Temperature

This shows magnitude rather than probability of being higher or lower than Normal and shows the middle day of the five day period.	The pattern is now mostly zonal (west to east versus meridional north to south to north).  It is becoming more progressive as in the pattern is moving west to east a lot faster than it has been for weeks.		The transition from the 8 -14 day forecast shown above to the week 3/4 forecast seems likely.

And then Precipitation

The five day QPF is shown above. The units are different than the other maps i.e. in units of precipitation (inches) not probabilities of exceeding or being less than climatology.	Are we seeing a shift in the jet stream here? Not so much if we look ahead to the Week 3 – 4 forecast but it has not been updated since Friday.		The transition from the 8 -14 day forecast shown above to the week 3/4 forecast seems feasible. .

A. Now we will begin with our regular approach and focus on Alaska and CONUS (all U.S.. except Hawaii).

Water Vapor.

This view of the past 24 hours provides a lot of insight as to what is happening.

You can see from this animation that there has been moisture entering CONUS from the Pacific via Canada and traveling down the Great Basin. We also  see a small Pacific cut-off Low approaching California.

Tonight, Monday November 19, 2018, as I am looking at the above graphic, you see the  same pattern but weaker to the north and with the  Pacific cut-off low about to enter California.

This graphic is about Atmospheric Rivers i.e. thick concentrated movements of water moisture. More explanation on Atmospheric Rivers can be found by clicking here or if you want more theoretical information by clicking here. The idea is that we have now concluded that moisture often moves via narrow but deep channels in the atmosphere (especially when the source of the moisture is over water) rather than being very spread out. This raises the potential for extreme precipitation events. You can convert this graphic into a flexible forecasting tool by clicking here. One can obtain views of different geographical areas by clicking here.

And Now the Day One and Two CONUS Forecasts

Additional useful forecasts from the Storm Prediction Center and be found here. Storm events are covered by Met Watch which can be accessed here. Explanation of symbols can be found here.

60 Hour Forecast Animation

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.

The below makes it easier to focus on a particular day.  The best way to read them is from left to right on the first row and then from left to right in the row below it.

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What is Behind the Forecasts? Let us try to understand what NOAA is looking at when they issue these forecasts.

Below is a graphic which highlights the forecast surface Highs and the Lows re air pressure on Day 7. The Day 3 forecast can be found here. the Day 6 Forecast can be found here.

When I look at this Day 7 forecast, the Aleutian Low is quite strong with surface central pressure of 972 hPa and it is centered just south of the Eastern Aleutians not further into the Gulf of Alaska where it should be if this were an El Nino. But it extends into Canada which probably explains the Negative AO. The Hawaiian High is weak with surface central  pressure of 1020 hPa and closer to a summer position than a winter position. Further east there is a Canadian High with central surface pressure of 1032 hPa and much further east there remains that offshore Low with surface central pressure of 996 hPa. To the southwest of the offshore Low there is  a LOW just south of the Great Lakes with surface central pressure of 1008 hPa. In the Arctic, to the west there is a High with surface central pressure of 1032 hPa and over Greenland there is another High with surface central pressure of 1032 hPa. When the air pressure in the Arctic is higher than the air pressure in CONUS that is AO- and NAO- and an invitaiton for cold air to spill into CONUS. The boundary line between the Aleutian Low and the Hawaiian High provides an entry point for storms into CONUS and probably indicates where the Jet Stream is. There is a lot more one can glean from this single graphic.

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Looking at the current activity of the Jet Stream. The below graphics and the above graphics are very related.

Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems especially in the winter The sub-Jet Stream level intensity winds shown by the vectors in this graphic are also very important in understanding the impacts north and south of the Jet Stream which is the higher-speed part of the wind circulation and is shown in gray on this map. In some cases however a Low-Pressure System becomes separated or “cut off” from the Jet Stream. In that case it’s movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream. This usually is more significant for the lower half of CONUS with the cutoff lows being further south than the Jet Stream. Some basic information on how to interpret the impact of jet streams on weather can be found here and here. I have not provided the ability to click to get larger images as I believe the smaller images shown are easy to read.

Current	Day 5
You can see the current Central CONUS trough here.	The pattern shifts further to the east and is more zonal. We see the next Trough entering CONUS and also moving to the east.

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.

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.

500 MB Mid-Atmosphere View

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. Thinking about clockwise movements around High Pressure Systems and counter- clockwise movements around Low Pressure Systems provides a lot of information.

Here is the whole suite of similar maps for Days 3, 4, 5, 6 and repeated for Day 7. It is quite complicated. Read from left to right first  row and then left to right on the  second row. 

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Understand How the Jet Stream Impacts Weather

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We are showing both the situation on the surface and at mid-atmosphere 500 mb and the view is different so sometimes it is useful to simply be able to compare them.

Here is the seven-day cumulative precipitation forecast. More information in how to interpret this graphic is available here.

Four – Week Outlook: Looking Beyond Days 1 to 5, What is the Forecast for the Following Three + Weeks?

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

6 – 10 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on November 19, 2018 was 3 out of 5

8 – 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on November 19, 2018 was 2 out of 5).

–

Looking further out.

Now – Precipitation

6 – 10 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on November 19, 2018 was 3 out of 5)

8 – 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on November 19, 2018 was 2 out of 5)

Looking further out.

Here is the 6 – 14 Day NOAA discussion released today November 19, 2018

6-10 DAY OUTLOOK FOR NOV 25 – 29 2018

TODAY’S MODEL ENSEMBLE MEANS ARE IN FAIR AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA FOR THE 6-10 DAY PERIOD. A TROUGH IS FORECAST OVER THE EASTERN CONUS. A PREDICTED RIDGE IS LOCATED OVER THE WESTERN CONUS. TROUGHING IS PREDICTED OVER WESTERN MAINLAND ALASKA, THE BERING SEA AND THE ALEUTIANS. TODAY’S MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON ENSEMBLE MEANS FROM THE ECMWF AND GEFS MODELS. THE 500-HPA MANUAL BLEND INDICATES ABOVE NORMAL 500-HPA HEIGHTS OVER THE WESTERN CONUS, NORTHEASTERN MAINLAND ALASKA, AND THE ALASKA PANHANDLE, WHILE BELOW NORMAL 500-HPA HEIGHTS ARE FORECAST OVER THE CENTRAL AND EASTERN CONUS, SOUTHWESTERN MAINLAND ALASKA AND THE ALEUTIANS. 

TROUGHING AND ANOMALOUS NORTHERLY FLOW LEAD TO ENHANCED PROBABILITIES OF BELOW NORMAL TEMPERATURES OVER THE CENTRAL AND SOUTHEASTERN CONUS. RIDGING AND ABOVE NORMAL 500-HPA HEIGHTS OVER MUCH OF THE WESTERN CONUS INCREASE THE PROBABILITY OF ABOVE NORMAL TEMPERATURES OVER MOST THE WESTERN CONUS. THERE ARE ENHENCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHEAST AHEAD OF A TROUGH PREDICTED OVER THE GREAT LAKES.ABOVE NORMAL TEMPERATURES ARE FAVORED OVER SOUTHERN FLORIDA PENINSULA, DUE TO ABOVE NORMAL SST IN SURROUNDING AREAS AND ALSO CONSISTENT WITH DYNAMICAL MODEL FORECASTS. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY OVER CENTRAL AND SOUTHERN ALASKA, UNDER ANOMALOUS SOUTHERLY FLOW AND WITH ABOVE NORMAL SEA SURFACE TEMPERATURES IN THE GULF OF ALASKA, WHILE BELOW NORMAL TEMPERATURES ARE SLIGHTLY FAVORED FOR THE NORTH SLOPE OF ALASKA, CONSISTENT WITH DYNAMICAL MODEL FORECASTS. 

BELOW NORMAL PRECIPITATION IS MOST LIKELY OVER MOST OF THE SOUTHWESTERN CONUS AND PARTS OF THE NORTHERN ROCKIES, UNDER PREDICTED ABOVE NORMAL 500-HPA HEIGHTS. ABOVE NORMAL PRECIPITATION IS MOST LIKELY FOR MUCH OF THE NORTHERN AND CENTRAL PLAINS, THE GREAT LAKES, AND THE EASTERN CONUS IN ASSOCIATION WITH THE PREDICTED TROUGH OVER THE CENTRAL EASTERN CONUS. ABOVE NORMAL PRECIPITATION IS ALSO LIKELY FOR MUCH OF THE PACIFIC NORTHWEST AND THE NORTHERN INTERMOUNTIAN WEST, DUE TO PREDICTED MOIST SOUTHWESTERLY LOW LEVEL FLOW. BELOW NORMAL  PRECIPITATION IS FAVORED FOR PARTS OF THE SOUTHERN PLAINS NORTHEASTWARD TO  PARTS OF THE TENNESSEE AND OHIO VALLEYS, CONSISTENT WITH DYNAMICAL FORECAST  TOOLS. ABOVE NORMAL PRECIPITATION IS LIKELY FOR MOST OF ALASKA, AHEAD OF PREDICTED TROUGH. 

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT ON THE PREDICTED CIRCULATION PATTERN.  

8-14 DAY OUTLOOK FOR NOV 27 – DEC 03, 2018   

DURING THE WEEK 2 PERIOD, THE VARIOUS ENSEMBLE MEANS GENERALLY PREDICT DEAMPLIFICATION AND EASTWARD PROGRESSION OF THE CIRCULATION PATTERN OVER THE CONUS FROM THE 6-10 DAY PERIOD. THE 500-HPA MANUAL BLEND INDICATES POSITIVE  HEIGHT ANOMALIES FROM THE PACIFIC NORTHWEST ALONG THE CANADIAN BORDER INTO THE NORTHERN PLAINS, AND WEAK NEGATIVE HEIGHT ANOMALIES OVER MUCH OF THE EASTERN CONUS. 

NEAR TO BELOW NORMAL TEMPERATURES ARE LIKELY FOR MUCH OF THE EASTERN CONUS DUE TO FORECAST TROUGHING OVER EASTERN NORTH AMERICA. ABOVE NORMAL TEMPERATURES ARE LIKELY OVER MUCH OF THE THE WESTERN CONUS, DUE TO FORECAST RIDGING OVER THE REGION. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY OVER ALASKA UNDER ANOMALOUS SOUTHERLY FLOW.

ABOVE NORMAL 500-HPA HEIGHTS LEAD TO INCREASED PROBABILITIES OF BELOW NORMAL PRECIPITATION FOR MUCH OF THE NORTHERN ROCKIES IN WEEK 2. FORECAST PACIFIC FLOW ENHANCE PROBABILITIES OF ABOVE NORMAL PRECIPITATION OVER MUCH OF THE WEST COAST AND EXTENDING TO PARTS OF THE SOUTHWEST AND WESTERN GREAT BASIN. ABOVE NORMAL PRECIPITATION IS LIKELY OVER PARTS OF THE GREAT PLAINS, THE SOUTHEAST AND THE NORTHEAST, CONSISTENT WITH DYNAMICAL MODEL FORECAST TOOLS. BELOW NORMAL PRECIPITATION IS LIKELY OVER PARTS OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY,  THE GREAT LAKES AND THE OHIO VALLEY, ALSO CONSISTENT WITH DYNAMICAL MODEL FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR ALASKA DUE TO PREDICTED TROUGHING OVER THE REGION. 

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO  UNCERTAINTY AMONG FORECAST TOOLS.

Some Indices of Possible Interest: We should always remember that the forecast is driven by many factors some of which are conflicting in terms of their impacts. Please pay more attention to the graphics than my commentary which does not update on a regular basis once the article is published. The indices will continue to update. I provide these indices as they are important guidelines to the weather. It is in a way looking at the factors that are impacting the weather. There were developed  because weather forecasters found them to be useful.

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Madden Julian Oscillation (MJO)

The MJO is an area of convective activity along the Equator which circles the globe generally in 30 to 60 days. The location of the convective activity not only impacts the Equator but also the middle latitudes. Most people are not familiar with the MJO but at certain times it plays an important role Worldwide re weather and for CONUS.

There are a lot of models and I try to read the results from all of them. For access to a variety of models, I refer readers here. This weekly report summarizes things. Here is another useful source of information.

First we look at two models that I find very helpful. On the GFS graphic , the light gray shading shows the tracks which fit with 90% of the forecasts and the dark gray shading shows a smaller area that fits with 50% of the forecasts The large dot is the current location.

It is sometimes useful to look at the recent history  of the MJO.

Then the first of the two indices we typically present.

This shows the recent history. Movement to the east has begun

And then a forecast.

This tool allows one to translate the location of the forecast MJO to the impacts on CONUS. To make it easier for the reader I am displaying the highest probability interpretation for the time period in question namely October/November/December. I select this set of graphics since we are in November and November is the center month in OND. This (70% match) of course might miss some other impacts which have less statistical confirmation but may none-the-less be valid.

Remember we are interested in how the MJO impacts CONUS weather during the first half of November. So that is what I have displayed.

Temperature

Precipitation

Analogs to the NOAA 6 – 14 Day Outlook.

Now let us take a detailed look at the “Analogs”.

NOAA normally provides two sets of Analogs.

A. Analogs 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 the recent pattern is used to initialize the models to predict the 6 – 14 day Outlook.

B. There is a second set of analogs associated with the Outlook. It compares the forecast (rather than the prior period) to past weather patterns. I have not been regularly analyzing this second set of information. The first set applies to the 5 and 7 day observed pattern prior to today. The second set, relates to the correlation of the forecasted outlook 6 – 10 days out and 8 – 14 days out with similar patterns that have occurred in the past during a longer period that includes the dates covered by the 6 – 10 Day and 8 – 14 Day Outlook. The second set of analogs also has useful information as it indicates that the forecast is feasible in the sense that something like it has happened before. I am not very impressed with that approach. But in some ways both Approach A and B are somewhat similar. I conclude that if the Ocean Condition now are different then the analogs and if the state of ENSO now is different than the analogs that is a reason to have increased lack of confidence in the forecasts and vice versa.

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. But NOAA prefers the first set (A) as it helps them (or at least they think it does) assess the quality of the forecast.

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. It also helps the reader see the impact of the phases of the PDO and AMO which are shown. The first set (A) which is what I am using today applies to the 5 and 7 day observed pattern prior to today.

* I assign values that are consistent with the trend so I am doing some subjective smoothing with respect to the Phases of the AMO and PDO shown in this table. (t) = a month where the Ocean Cycle Index has just changed from a consistent pattern or does change the following month to a consistent pattern.

The spread among the analogs from November 6 to December 3 is 27 days which 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, and fairly accurate if the dates are reasonably evenly distributed, is about November 20. These analogs are centered on 3 days and 4 days ago (November 14 or November 15). So the analogs could be considered to be out of sync with respect to weather that we would normally be getting right now i.e. about a five to six days early.

For more information on Analogs see discussion in the GEI Weather Page Glossary. For sure it is a rough measure as there are so many historical patterns but not enough to be a perfect match with current conditions. I use it mainly to see how our current conditions match against somewhat similar patterns and the ocean phases that prevailed during those prior patterns. If everything lines up I have my own measure of confidence in the NOAA forecast. Similar initial conditions should lead to similar weather. I am a mathematician so that is how I think about models.

Including duplicates, there are five El Nino Analogs, three Neutral analogs and two La Nina Analogs. The pre-forecast analogs this week favor McCabe Condition A which is the wet scenario  McCabe C is least favored and that is the McCabe Condition associated with Northern Tier and Mid-Atlantic Drought Conditions i.e. these are suggested as being less likely. The Atlantic seems to be in control.

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Historical Anomaly Analysis

When I see the same dates showing up often I find it interesting to consult this list.

A Useful Read

Some might find this analysis which you need to click to read interesting as the organization which prepares it focuses on the Pacific Ocean and looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of ENSO events.

Recent CONUS Weather

This is provided mainly to see the pattern in the weather that has occurred recently.

And the 30 Days ending November 3, 2018	And the 30 Days ending November 10, 2018
More dry in California and Nevada. The Temperature departures are a bit less intense.	Re Precipitation the Western Dry Anomaly has become more intense and the Eastern Cool Anomaly has also become more intense.
Remember, these maps are a 30 average so the most distant seven days are removed and the most recent seven days are added.

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

It is Useful to Understand the Semipermanent Pattern that Control our Weather and Consider how These Change from Winter to Summer. These two graphics (click on each one to enlarge) are from a much larger set available from the Weather Channel. They highlight the position of the Bermuda High which they are calling the Azores High in the January graphic and is often called NASH and it has a very big impact on CONUS Southeast weather and also the Southwest. You also see the north/south migration of the Pacific High which also has many names and which is extremely important for CONUS weather and it also shows the change of location of the ITCZ which I think is key to understanding the Indian Monsoon. A lot of things become much clearer when you understand these semi-permanent features some of which have cycles within the year, longer period cycles and may be impacted by Global Warming. We are now moving into late November and we should be returning from the set of positions shown below for July back slowly to the Winter Pattern. For CONUS, the seasonal repositioning of the Bermuda High and the Pacific High are very significant.

World Forecasts

1. Today (Source: University of Maine)

2. Short-term set for day six but can be adjusted (BOM – Australia)

3. 8 – 14 Day (NOAA/Canada/Mexico Experimental NAEFS))

4 Tropical  Activity

1.  Forecast for Today (you can click on the maps to enlarge them)

And now precipitation

Additional Maps showing different weather variables can be found here.

2. Forecast for Day 6 (Currently Set for Day 6 but the reader can change that)

World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click Here and you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the “Back Arrow” usually found top left corner of your screen to the left of the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool. Below are the current worldwide precipitation and temperature forecasts for six days out. They will auto-update and be current for Day 6 whenever you view them. If you want the forecast for a different day Click Here

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

Now Precipitation

3. And now we have experimental 8 – 14 Day World forecasts from the NAEFS Model.

First Temperature

Then Precipitation

4. Tropical Hazards.

C. ENSO SUMMARY of Current Status. Our full report was published on November 9, 1018 and can be accessed here.

Current Status of ENSO

This section is organized into three parts.

1. Current Sea Surface Temperatures (SST)

2. Current Nino 3.4 Readings

3. The Surface Air Pressure Pattern that confirms the state of ENSO.

1. Current and Recent Sea Surface Temperatures (SST)

A major driver of weather is Surface Ocean Temperatures. Evaporation only occurs from the Surface of Water. So we are very interested in the temperatures of water especially when these temperatures deviate from seasonal norms thus creating an anomaly. The geographical distribution of the anomalies is very important. To a substantial extent, the temperature anomalies along the Equator have disproportionate impact on weather so we study them intensely and that is what the ENSO (El Nino – Southern Oscillation) cycle is all about. Subsurface water can be thought of as the future surface temperatures. They may have only indirect impacts on current weather but they have major impacts on future weather by changing the temperature of the water surface. Winds and Convection (evaporation forming clouds) is weather and is a result of the Phases of ENSO and also a feedback loop that perpetuates the current Phase of ENSO or changes it. That is why we monitor winds and convection along or near the Equator especially the Equator in the Eastern Pacific.

My focus here is sea surface temperature anomalies as they are one of the two largest factors determining weather around the World. If we want to have a good feel for future weather we need to look at the oceans as our weather mostly comes from oceans and we need to look at surface temperature anomalies (weather develops from the ocean surface

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.

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

First the categorization of the current daily SST anomalies.
Mediterranean, Black Sea and Caspian Sea	Western Pacific	West of North America	North and East of North America	North Atlantic
The Mediterranean. Black Sea and Caspian Sea are slightly warm.	Warm east of Japan	Warm Chukchi Sea, Bering Strait and Bering Sea Warm in Gulf of Alaska.	Hudson Bay slightly cool Slightly warm off Est Coast.	Slightly warm.
Equator	Looks like El Nino but fairly spread out.
Africa	West of Australia	North, South and East of Australia	West of South America	East of South America
Slightly cool off West Africa. Mixed south of South Africa Cool south of Madagascar.	Cool	Cool to the northwest and warm to the southeast and beyond New Zealand.	Fairly Neutral	Warm 40S Areas of South Atlantic are cool.

Then we look at the change in the anomalies. The SST anomaly is sort of like the first derivative and the change in the anomaly is somewhat like a second derivative. It tells us if the anomaly is becoming more or less intense.

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 graphic form but going back a couple of more years can be found here. The full table of values can be found here. NOAA considers N

ino 3.4 shown in the graphic as the best indicator of Equatorial Surface Temperature Anomalies associated with different phases of ENSO. There is a duration requirement to be a recorded El Nino or La Nina but to have El Nino Conditions the Nino 3.4 index needs to be +0.5C or warmer and to have La Nina Conditions the Nino 3.4 Index needs to be -0.5C or cooler.

This graphic brings the Nino 3.4 up to date and is easy to read.

Here is a daily version

3. The Surface Air Pressure that Confirms the Nino 3.4 Index

And of course Queensland Australia is the official keeper of the SOI measurements.

SOI = 10 X [ Pdiff – Pdiffav ]/ SD(Pdiff) where Pdiff = (average Tahiti MSLP for the month) – (average Darwin MSLP for the month), Pdiffav = long term average of Pdiff for the month in question, and SD(Pdiff) = long term standard deviation of Pdiff for the month in question. So really it is comparing the extent to which Tahiti is more cloudy than Darwin, Australia. During El Nino we expect Darwin Australia to have lower air pressure and more convection than Tahiti (Negative SOI especially lower than -7 correlates with El Nino Conditions). During La Nina we expect the Warm Pool to be further east resulting in Positive SOI values greater than +7).

D. Putting it all Together.

At this time, La Nina Conditions along the Equator have come to an end and we are solidly into ENSO Neutral and possibly entering into El Nino Conditions. But the drivers of a transition to El Nino are not solidly in place. In fact this is almost unprecedented in terms of the lateness of the arrival of a potential El Nino.

E. Relevant Recent Articles and Reports

High profile ocean warming paper gets correction

Here is the corrected graphic as published in RealClimate.org as a guest commentary.

Here is what we  published on November 5, 2018

Questions about the rate of Sea Temperature Warming. Is it happening faster than currently forecast by the IPCC?

From the BBC

From Journal of Nature

I  do not have access to the Journal of Nature article but they do provide this graphic for non-subscribers.

Since I do not have permission to read let alone publish the full article I can not really assess it but provide these links for those who wish to read what is accessible to me.

There may be more to come on this story

F. Useful Reference Information

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Standard Pressure Levels

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