posted on 13 January 2015
Written by Sig Silber
The "ImaginNiño" is not reviving but the ridge of high pressure that has blocked warm wet Pacific storms from entering the Southwest is forecast to dissipate and move inland at least temporarily. Thus the projected wet winter in the Southwest may begin but there is no guarantee that it will or how long it will persist. In the meantime, El Nino continues to fade and NOAA began to change their position on this in their Weekly ENSO Report by downgrading their forecast statement to "There is an approximately 50-60% chance of El Niño conditions during the next two months, with ENSO-neutral favored thereafter". It takes five consecutive three-month periods of El Nino Conditions to define an El Nino, so I take that statement as a formal concession that they have been wrong. This warm event most likely will not be recorded as an official El Nino due to insufficient duration. Today I also discuss the AMO and its impact on the Climate of the U.S.
A more compete report can be found here. This is a summary report.
Let us first take a look at the 6 - 14 day outlook that was issued today January 12, 2015. It will auto-update every day so it will be changing day by day (and thus be up to date whenever you elect to read this report) but my comments may become out of sync with the map since my comments do not auto-update.
I am only showing the "second week" namely the day 8 -14 outlook. The first week together with much additional information on current weather patterns and near-term forecasts can be found in Part II of my report, but 8 - 14 days covers most of the 6 - 14 day period.
Here is the 8 - 14 Day Temperature Outlook.
And here is the updated January Temperature Outlook issued on December 31, 2014.
The cold intrusion from the North projected in the January Outlook does not seem to be happening as our weather pattern becomes increasingly zonal. It does show up in the 8 - 14 Day Outlook but the discussion indicates it is expected to be temporary.
And here is the 8 - 14 Day Precipitation Outlook.
And here is the updated January 2015 Precipitation Outlook issued on December 31, 2014.
Precipitation in January does not appear to be developing according to the January Outlook. This may well be related to the continuation of the high-pressure ridge off the West Coast which is not supposed to be there during El Nino Conditions. Of course the real problem is there is no El Nino.
And excerpts from the NOAA discussion covering the January 12, 2015 6 - 14 Day Outlook.
Notice there is no mention of El Nino or Sea Surface Temperatures and the focus has now shifted to MJO, NO, NAO and other things. That is not an accident but journalism.
Analogs to Current Conditions
Now let us take a more 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.
I tried an experiment today and analyzed both today's analogs and yesterday's Analogs.
Here are yesterday's analogs:
And here are today's analogs:
I was pleased to see a lot of correspondence to the analogs from yesterday and those from today. That suggests stability in the ability to forecast. I was shocked that for both days all of the analogs were associated with a Negative PDO which is inconsistent with El Nino Conditions existing and is not favorable for the development of an El Nino. Today there are ten distinct analogs and three are associated with prior weather conditions that occurred during a La Nina and seven with ENSO Neutral. None of the analogs are associated with EL Nino Conditions.
Because of the recent appearance of anomalous AMO Negative in the analogs (not so much today but in recent weeks) I thought it useful to take a look at how the AMO impacts North American Weather. I discuss this also in Part II of my Report but today in Part I of the Report I am focusing on two specific studies.
First this paper focusing on winter impacts:
Imprint of the Atlantic multi-decadal oscillation and Pacific decadal oscillation on southwestern US climate: past, present, and future Petr Chylek, Manvendra K. Dubey, Glen Lesins, Jiangnan Li, Nicolas Hengartner
Special Note: This paper by Chylek et al. explains a common error in many climate studies including a recent analysis performed by the U.S. Bureau of Reclamation titled Upper Rio Grande Climate Assessment. It is likely that his sort of error is very prevalent in many reports because the researchers are not sufficiently familiar with what the IPCC calls internal variability. Recent focus on what has been called the Warming Hiatus has called attention for the need of researchers to become familiar with the impact of the major ocean cycles on climate or alternatively at least detrend the temperature data.
The Chylek et al paper is focused primarily on winter climate in the Southwest and to me it in many ways is a redo of the McCabe et al analysis but I do not believe the authors see it that way based on their reference list. I do believe their findings are similar which does not come as a surprise.
And this paper focuses on summer precipitation all across the U.S. but it has much of interest to say about the North American Monsoon.
Variations in North American Summer Precipitation Driven by the Atlantic Multidecadal Oscillation QI HU,SONG FENG, AND ROBERT J. O GLESBY
Some of the graphics from this paper are extremely interesting so I am showing them.
It is only one paper so it may not be correct but it certainly is provocative. Between the two papers it points out the need to be able to either:
A. Forecast the AMO and PDO or
B. Develop a set of reasonable scenarios for how they might vary over time.
So based on the following work by two Chinese Researchers, I connect their dots so to speak and use their information to project climate conditions in the U.S.
Predicting the State of Ocean Cycles Going Forward and the Impact on the Climate of the Lower 48 States.
The paper I want to discuss can be found here.
Joint statistical-dynamical approach to decadal prediction
Now I have modified the graphs in their paper where they project the succession of phases of the three main ocean cycles to line up some key dates in the graphics namely the beginning of decades starting from the one we are in and looking forward. The decades are numbered across the top as "1", "2", "3", "4".
The seminal work on the impact of the PDO and AMO on U.S. climate can be found here. The key maps which were presented earlier are repeated below:
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 two combinations of AMO and PDO phases i.e. four combinations.
In reality there are more than four combinations since for example AMO positive can cover years where the index is just barely positive to the years where the index is most positive. That may be possible to deal with using a software package but working with maps averaging the years where the indicated combination occurred makes for a more convenient way to display information but does not reflect that there is a continuum of combinations of two indices.
So combining the work of McCabe et al with the work of Lou and Li , what can we say about these beginning years in the decade which started in 2014 and subsequent decades out into our future?
This was clearly AMO+/PDO-. This is McCabe Condition D and full explains the approximately twice a century severe drought in the Southwest and also in the Great Lakes area.
This might be PDO+/AMO+ to AMO Neutral. This might be somewhere between McCabe A and McCabe C but closer to McCabe C. McCabe C is associated with extreme drought in the Northern Tier west of the Great Lakes. McCabe C also is associated with a high probability of drought in the South Atlantic Coast states extending into the Mid-West.
PDO-/AMO Neutral. This might be somewhere between McCabe B and McCabe D. Note the IPO (which I am using as a surrogate for the PDO) is forecast by Lou and Li to be less negative at its low point presumably due to the combination of subcycles with different amplitudes within the IPO. Also notice the significant difference between McCabe B and McCabe D. This illustrates the importance of the Atlantic SST's
PDO+/AMO Neutral. This might be somewhere between McCabe A and McCabe C. McCabe C seems to flip drought in the West from south to north. So McCabe A and McCabe B both spare the Southwest but the condition of the Atlantic may have a big impact on the Northern Tier west of the Great Lakes. McCabe C also is associated with a high probability of drought in the South Atlantic Coast states extending into the Mid-West.
5. And dare we project out to say 2050? This might be PDO?/AMO-. That might result in conditions intermediate to McCabe A and McCabe B. McCabe B would raise the risk for drought in the Southeast including moderate probability of drought in Florida and small areas of extreme drought in other places.
I DO NOT KNOW HOW TO MAKE IT ANY CLEARER. THE AMO WILL BE BECOMING LESS POSITIVE AND SHIFT TO AMO NEGATIVE AND THE PDO WILL SOON BECOME PDO POSITIVE IF IT HAS NOT ALREADY DONE SO.
Back to the Present:
Sometimes it is useful to take a look at the location of the Jet Stream or Jet Streams. You can see how the ridge of high pressure off the West Coast is currently still forcing the Jet Stream inland and then creating a large trough in the center of the Lower 48.
And sometimes the forecast is revealing. Below is the forecast out five days.
To see it in animation, click here. At the time this article was published, the animation shows a tendency for there again to be a Southern Branch of the Polar Jet Stream in addition to the usual Northern Branch. A southern stream can bring storms further south than usual. But you can see how the situation is becoming more zonal which should reduce the cold air intrusions from Canada.
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. One can imagine that attempting to forecast this 6 - 14 days out is quite challenging.
And below is a another view which highlights the highs and the lows re air pressure on Day 6.
This appears to show that the ridge of high pressure will in six days still be sitting off the West Coast but further south than recently. The Aleutian Low has become a monster. This appears to be a formula for a change in the weather pattern although it is not showing up in the 6 - 10 day forecast but a bit later.
A quick way of assessing the intensity of a high or low pressure area is simply to observe the distance between the isobar lines. When they are coiled tightly, this signifies a strong high or low. So you can see that this high is not that strong. But the winds in highs in the Northern Hemisphere are clockwise and lows are counterclockwise so you can see the channel that is created at the surface which corresponds with the jet stream in this case providing the path of lest resistance for storm systems. They should soon be directed into mid-California.
Computer models have the ability to predict these conditions but the graphics I present reflect either current conditions or the predicted conditions and make it fairly easy to interpret the implications of what the current readings and the computer models imply for our weather. Professional meteorologists look at much more information than I present here and know more than I do but they are also skilled at converting their knowledge into graphics that a lay person can understand. So that is what I attempt to do in my weekly report with the ultimate goal of being able to translate the weather and climate into economic impacts. There is a learning curve here.
El Nino Discussion
Now let us look at the latest NOAA Hovmoellers.
There are many graphics that NOAA provides every Monday but I focus on three and today I thought I would start with what probably is the most important one that I call the Kelvin Wave graphic but it is really the Upper Ocean Heat Anomaly along the Equator which is caused in many cases primarily by Kelvin Waves.
There is quite a bit of change since last week. The most recent Kevin Wave is no longer a factor. The upwelling phase has started to display a cooling anomaly as it moves east. The next Kelvin Wave has not yet become a factor in the near term.
Now let us look at the Sea Surface Temperatures
Again there is significant change since last week as you can see less warm water along the Equator.
Of most interest to NOAA is 120 W to 170 W as that is where the ONI Index is measured. More information can be found here. If you look at the color coding in the above Hovmoller they are looking for shades where the redder the better re conditions being El Nino but so far it is just showing shades of tan and brown i.e. marginal especially when averaged over the entire area of interest. But that explains why we have a situation where some of the factors are in place for an El Nino but so far it is marginal at best and fading fast.
And now the low-level wind anomalies.
This shows quite a bit of change from last week especially over towards Ecuador. The westerly anomaly discussed in the above NOAA Graphic is between Indonesia and Africa. It may impact the U.S. this summer. The Southern Oscillation Index (SOI) has not at all been cooperating this week to preserve let alone reinvigorate the "ImaginNiño". You can find the daily and 30 and 90 day averages here. The 30 day average of -6.0 is not even marginal for El Nino conditions (a 30 day average of -8.0 or more negative is considered to be consistent with El Nino conditions). Today's reading is +0.2. You can see the impact of this in one of the above Hovmoellers and in the TAO/Triton graphic further down in this Report.
And finally the latest model results released by NOAA and these are as of Saturday January 10.
This graphic is a modified version of the graphic that appears on Page II of this Report. It is modified by NOAA to be consistent with the maps on the right which can be found here. Those maps have been processed to adjust for the observed skill of the models. As you can see, December was the peak of this El Nino and January is already sub-El Nino on the ONI scale and future months look even less like an El Nino. The correct term for the current situation is ENSO Neutral on the warm side. There is for anyone with normal vision absolutely no prediction of El Nino in this graphic. Although these models are not reliable further out, there are signs that this warm event will last beyond the April/May timeframe that is suggested by the recently released NOAA Seasonal Outlook maps which can be found in Page II of this Report. Those maps cover the NOAA Outlook for 14 months.
Here is another graphic that confirms that we are not in an El Nino. I probably should have divided this graphic into two pieces and only showed the bottom piece but I got lazy and perhaps the two together are more useful anyway. The top graphic shows conditions along the Equator, 10 degrees north to 10 degrees south of the Equator and this is one of the most up to date sources of information available. The top graphic shows surface temperatures and wind direction and speed. The bottom graphic shows anomalies.The bottom graphic shows the deviation from average conditions. You can see two things in that graphic. First of all you can see the pockets of warm water which are in some cases greater than 1C above average and in other cases below 0.5C above average conditions. Looking between 170W and 120W on the Equator, you see a larger area where the anomaly is under 0.5C than you see an area above 0.5C. Also the anomaly analysis of the winds generally point to the West meaning a strengthening rather than a weakening of the Easterlies.
From Australia starting with their most recent proprietary model run followed by their commentary.
They do use a different and probably more realistic threshold value in Australia as their interest is how ENSO impacts their weather. But it is fairly clear that whatever was going on in December 2014, it did not continue on into January 2015.
Pulling it All Together. .
So this continues to look to me like a warm event that is not a full fledged El Nino this year but which may last longer than NOAA thinks and have different impacts than they think also. So far that has certainly been the case. We shall see if that continues. I am still thinking the Japanese sized this up from the start and that this is really more like a Modoki than a traditional El Nino and that weather patterns are shifted some number of degrees further west than would be the case for a traditional El Nino. The Australians have consistently been skeptical that this would develop into an El Nino of any strength.
I do not see a traditional El Nino of any significant strength likely to happen this winter although a "near" El Nino appears to be making its presence known to a limited extent but mainly outside of the U.S. It appears to be a very complicated situation mostly because of the at least temporary shift of the configuration of the Pacific with respect to the location of warm and cold water to a configuration which is called PDO Positive (+) combined with the Blocking Ridge off the West Coast.
An El Nino Watch for next year might be in order as there remains a lot of warm water but usually it takes a few years for that to built up sufficient for another warm event to get under way.
Click Here for the Econointersect Weather and Climate Page (which I call Page II) where you will find:
For now this is all in one article which may be a little difficult to navigate but that will soon change and there will be two links: one to the weather and climate information and a second link to the Global Warming information.
>>>>> Scroll down to view and make comments <<<<<<
|.... and keep up with economic news using our dynamic economic newspapers with the largest international coverage on the internet|
|Asia / Pacific|
|Middle East / Africa|
This Web Page by Steven Hansen ---- Copyright 2010 - 2017 Econintersect LLC - all rights reserved