posted on 27 April 2015
Written by Sig Silber
Spring is proceeding but in a strange way and apparently not impacted much or at all by the "advertised" El Nino. Because of the hiatus between major releases of information by NOAA, I am focusing today on Ocean Cycles and how they are likely to impact weather over the next few decades. I also better document the differences in seasonal forecasts between NOAA and JAMSTEC.
This is the Regular Edition of my weekly Weather and Climate Update Report. Additional information can be found here on Page II of the Global Economic Intersection Weather and Climate Report.
Last week I made the point that the NOAA precipitation forecasts for the US were different from those made by JAMSTEC and also Queensland Australia. But I do not think I made it easy for the reader and I was struggling with the issue that JAMSTEC had computer problems and as I was going to press were only partially through updating their website. Well, since then their forecasts have been brought up to date and they have also now posted their discussion of their sea surface temperature (SST) forecast (which includes their projections on the Warm Event) which I published last week but for which JAMSTEC had not yet updated their discussion. The updated discussion which I show below has not changed much from the prior month but has changed some.
Since last Monday, I have had the time to compile a composite of the forecasts issued by JAMSTEC and NOAA.
First let us start with precipitation
You can compare the forecast for the U.S. on the left side provided by JAMSTEC with the forecast by NOAA on the right side of this graphic. They are very different. One wonders why the substantial difference. I do not have a good explanation for it. I will say that the JAMSTEC forecast seems to put more weight on the situation in the Pacific and the NOAA forecast more weight on the situation in the Atlantic but I am not sure of that and if it explains the major difference between the two forecasts.
Now let us look at the temperature forecasts and I apologize for having skewed the graphic of the U.S. a bit but it is not easy to create a composite in MSPAINT.
Larger versions of these graphics can be found here, here, here and here. Again you can the differences which are extreme in the second period covered. I did not compare the summer forecasts mostly because summer for the U.S. is very difficult to forecast. The JAMSTEC discussion above however presents their views relative to this summer.
Let's Talk Ocean Cycles Especially Longer Term.
From the Thursday April 16 NOAA Seasonal Update:
"ANOTHER IMPORTANT FEATURE THAT IMPACTED THE OUTLOOK IS THE PATTERN OF SSTS ACROSS THE EXTRATROPICAL PACIFIC WHICH CONTINUES TO SHOW LARGE POSITIVE ANOMALIES (BETWEEN 2-3 DEGREES ABOVE NORMAL IN SOME AREAS) FROM JUST SOUTH OF ALASKA EASTWARD AND SOUTHWARD ALONG THE WEST COAST OF NORTH AMERICA TO HAWAII. THIS SST PATTERN CONTINUES TO PROJECT VERY STRONGLY ONTO A POSITIVE PDO PATTERN. IN FACT THE MARCH 2015 VALUE WAS +2.0, CONTINUING A TREND OF RECORD AND NEAR RECORD MONTHLY POSITIVE PDO VALUES SEEN THIS PAST WINTER AND EARLY SPRING. THE ATLANTIC MULTIDECADAL OSCILLATION (AMO) INDEX CALCULATED AT NOAA/ESRL/PSD IS -0.109, WHICH IS THE LOWEST SINCE APRIL"
I want to explore the implications and the following is information that I have presented before. I apologize for repeating information but understanding our Ocean Cycles is important and something that is not widely presented in the press or taught at universities in the U.S.
Here goes. For the moment ignoring the Indian Ocean, we need to understand how the phases of the cycles in the Pacific and Atlantic are related. It is not a hard and fast relationship but the two cycles tend to be out of sync with each other. Some believe that changes in the Atlantic are significantly responsible for subsequent changes in the Pacific but the mechanism to effect these changes takes time and based on empirical data it takes longer than is suggested by the computer model runs.
Some have attempted to calculate the lead and lag between the peaks and valleys of these two cycles and this is shown in the following table.
Some of these papers are difficult to read so I am pretty sure that if I had interpreted the graphics correctly in the Wu et al paper, I would have concluded that there was a minus sign in front of the lead estimate meaning that all three authors came to essentially the same conclusion in their analysis. If you have some confidence in these lead and lag estimates you can to some level of confidence project the peaks and valleys of each cycle into the future.
The paper I want to discuss next and which I have discussed before can be found here.
Joint statistical-dynamical approach to decadal prediction
The authors have projected the three ocean cycles out through 2040 and in their graphics below I have added vertical lines to highlight the situation for certain 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 are shown 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 each of the four pairs of two phases of the AMO and PDO.
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-. For CONUS, this is McCabe Condition D and fully 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. For CONUS, 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. For CONUS, 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. For CONUS, 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-. For CONUS, 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.
The above applies mainly to Winter conditions in the U.S. CONUS. But what about summers? 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. OGLESBY
Some of the graphics from this paper are extremely interesting so I am showing them. You can enlarge them here and here. The way to look at this graphic is that the situation for the AMO being in its warm phase is shown on the left and the situation for the AMO being in its cool phase is shown on the right. The top graphic represents the upper troposphere and the bottom graphic the lower troposphere.
It is amazing to me that the patterns in the upper and lower troposphere can be so different but the easiest explanation perhaps is that the stronger/larger/and 20 degrees of longitude further west Bermuda High (also known as NASH, Azores High) associated with AMO- results in the jet stream being shifted further north and creating a counter-clockwise/cyclonic curvature which is conducive to storm formation.
The AMO has been positive since the mid nineties and peaked around 2010 or a bit earlier and is now pretty much neutral but we will be in AMO negative soon and for a long time. It might be useful to better understand how the Atlantic Multidecadal Oscillation presents itself and the following table presents some information which comes from an excellent paper by Iris Grossmann and Philip J. Klotzbach which can be found here.
* These locations are really associated with the NAO rather than the AMO but I think they are fairly similar and I will continue to research this. But the key point is that both the AMO and NAO tend to show up as a tripole i.e. three different areas of temperature anomalies. At any rate it is more complicated than some presentations that describe it as a uniform warming or cooling of the Atlantic. There is a third cycle called the Atlantic Meridional Mode AMM which relates mostly to the differential strength of the Trade Winds north and south of the Equator. One can understand why Climate Change models have difficulty incorporating these ocean and air pressure cycles. Of course that means these models are not very reliable for forecasting intervals shorter than 100 years.
I have not extended my analysis to the rest of the World but I have developed the following table that sheds some light on this. This table is still a Work in Progress.
This may also help:
My goal is to be able to predict the economic impacts of these changes in ocean cycles and air pressure cycles and other meteorological cycles. Of course we must also be able to integrate the secular temperature change called Global Warming. The IPCC is just beginning to incorporate the two phenomena in their models. The general Press has no clue nor do politicians as it is way over their heads. But that does not prevent them from attempting to develop policies that are climate related. The Bureau of Reclamation (BOR) is one of the worst offenders in this regard as their lack of knowledge about the climate of the United States is astounding for an agency that manages water.
We will now shift timeframes dramatically. Current (Now to 5 Days) Weather Situation:
For daily forecasts it is better to consult your local weather service or the weather service where you are traveling as these will be more specific. But I do have daily forecasts on Page II of the Report so you can always look at those as they auto-update. What I present here is information that normally is not made available via local weather forecasts and which can help you understand what some of the major drivers are for the local forecast.
First here is a national 12 hour to 60 hour forecast of weather fronts shown as an animation. Beyond 60 hours, the maps are available in Part II of the Global Economic Intersection Weather and Climate Report.
The explanation for the coding used in these maps i.e. the full legend can be found here.
Sometimes it is useful to take a look at the location of the Jet Stream or Jet Streams. This and the following graphic update every six hours. The split jet stream may be related to the Warm Event.
And sometimes the forecast is revealing. Below is the forecast out five days.
To see it in animation, click here.
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 NOAA is having fits attempting to guess how this will play out over a 14 day period especially for the Southwest.
And below is another view which highlights the surface highs and the lows re air pressure on Day 3.
And here is Day 6. The RRR remains in place. California continues to be cut off from Pacific moisture. We still see "incoming" cold waves but at this time of year they mostly result in April Showers.
Outlook Days 6 - 14
Let us take a look at what was issued today April 27, 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 as well as the comments of NOAA may become out of sync with the map since these comments do not auto-update.
Generally I only show the "second week" namely the 8 -14 Day Outlook. The first week (6 - 10 Day Outlook) 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. There are however some significant shifts projected within the nine day 6 -14 period but I decided not to show the early set of forecasts which as mentioned are available in Part II of this Report.
Here is the Early Outlook May Temperature Outlook
And here is the April 8 - 14 Day Temperature Outlook issued today April 27, 2015. It covers most of the second week of May.
Remember that the 8 - 14 day outlook only covers 9 days not the full month and the map shown only covers seven days. But May already appears to be developing somewhat differently and warmer than indicated in the May Outlook which will be updated on Thursday.
And here is the Early May Precipitation Outlook Issued on April 16, 2015.
Here is the 8 - 14 Day Precipitation Outlook issued today April 27, 2015.
And again remember that this map shows only seven days and the full 6 - 14 Day Outlook only covers nine days. There are 30 days in May. But the month of May looks to start out differently than the full-month Outlook. The Atlantic and Gulf of Mexico influence appears to be a correct call by NOAA but perhaps their influence was underestimated in the monthly outlook.
And here are excerpts from the NOAA release today April 27, 2015.
Analogs to Current Conditions
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 analyzing this second set of information. This first set applies to the 5 and 7 day observed pattern prior to today. The second set which I am not using relates to the forecast outlook 6 - 10 days out to similar patterns that have occurred in the past during the dates covered by the 6 - 10 Day Outlook. That may also be useful information but they put this set of analogs in the discussion with the other set available by a link so I am assuming that this set of analogs is the most meaningful.
This week there are four ENSO Neutral and five La Nina and zero El Nino analogs. NOAA provides me with two groups of five and I discard the duplicates and this week there was one duplicate. The Ocean Phases of the analogs this week are somewhat consistant with McCabe Condition B and D. The graphic that explains the four different McCabe conditions was shown earlier in this report. Both B and D are consistent with the weather pattern shown in the 6 - 14 Day Outlook but neither are patterns normally associated with El Nino Conditions. So we may have what is advertised as an El Nino, but because it is not Fall or Winter it is not showing up in our weather to any significant extent.
Progress of the Warm Event
Because of the long discussion at the beginning of my report this week, I decided to cover the Warm Event in a concise (for me) fashion. This graphic shows the current situation quite well. You can see the warm anomaly along the Equator. The anomalies are quantified and are not extreme. You see three sections of warm anomalies. The middle one is in the Nino 3.4 area and is above 0.5 which makes this El Nino Conditions. The one on the right which extends along the coast of South America down to Peru makes it a Traditional El Nino. The warm water off of Mexico entending up to the Northwest Coast of North America and the warm water near and west of the Date Line makes this an El Nino Modoki Type II. We have a mixed bag. It is summer, so none of this means very much. The real question is what will the Fall and Winter be like?
For my own amusement, I thought I would recalculate the ONI again as I have been doing recently. The little tick marks on the chart can be used instead of a ruler. When I print out this graphic one tick is about one centimeter. So you can use a ruler or just estimate the number (including fractions) of tick marks.
So as of Monday April 27 in the afternoon working from the April 26 TAO/TRITON report, this is what I calculated.
My estimate of the Nino 3.4 ONI is now 1.15 which is a very respectable value but less than last week. Overall it looks to me like this warm event may be petering out. The asymmetry around the Equator has increased a bit. I think the NOAA reading is a bit too low and will be reported as higher next week. Remember that NOAA is providing a weekly average and I am estimating a daily value. So if the ONI is rising, the average will lag a daily reading and that is the case right now as this Kelvin Wave moves through the area where Nino 3.4 is measured. The NOAA estimate is impacted to some extent by some cooler water near 5S Latitude but I do not think that is a major factor.
Now this week's weekly SST Departures and the trend graphs on the right.
The view of El Nino as a 2014/2015 event appears to be morphing into a view that it is a 2015/2016 event. But all predictions about El Nino for next winter must be tempered by what is called the Spring Prediction Barrier (SPB). Nevertheless, an El Nino this coming winter is a possibility. It is due and many factors are in place that suggest it will happen. But it needs another Kelvin Wave to make it happen. At this point I am leaning towards thinking it is not going to happen. The reason I am less positive than most computer models is that both warm and cold ENSO events are processes that have negative feedback loops i.e. they tend not to reinforce themselves but dissipate. Greater than one-winter warm events are fairly rare. I am looking at the NOAA list of El Ninos declared since 1950 and there are 19 of them and one lasted through two winters years starting when this warm event first reached a ONI 0.5 level and one lasted two winters but started later in the season. Both were during a period later recognized as PDO+. So I am just wondering if there is a reason to assume that this particular Warm Event has the staying power of the former champions. The PDO is currently positive and what has occurred so far has been minimal so the dissipating impacting may have been sufficiently minimal to allow this event to make it through this winter. I will be surprised.
The Southern Oscillation Index (SOI) reporting by Queensland, Australia has been off the air for a while but is now back in service so I am showing two weeks of daily readings. The first column is the tentative daily reading, the second is the 30 day running average and the third is the 90 day average.
The SOI has been quite unfavorable for the development of an El Nino. Usually -8 is considered El Nino Conditions. Sometimes -6 is used for local forecasting in Australia. The 30 average which is now reported as being -2.73 is the most widely used measure and if it is being calculated correcly (and I have some doubts about that) it is further from -8 than it has been in a long time.
The Kelvin Wave graphic to me is the key to the situation at this point. It is really the Upper Ocean Heat Anomaly.
We need to pay attention to the western side of the wave and there it does appear that we see a potential upwelling phase beginning in the far Western Pacific that intense blue patch. So far NOAA continues to turn a blind eye to this but eventually they will be forced to recognize it. You can measure with a ruler (or by looking at the latitude designations) the length of the Equator impacted by this Kelvin Wave and it is again less this week than last week especially with regards to the more intense part of the anomaly. The future value of the Nino 3.4 Index which is measured between 120W and 170W will soon start to decline. Remember it is calculated between 170 W and 120 W and even a High School Student would be able to figure out that the darker red area is about to move east of that sector of the Pacific and the ONI will decline in two months (July) and be neutral in four months (September) unless there is another strong Kelvin Wave. It appears to me that in Japan they can figure this out (see their model results below) but in Virginia or wherever this graphic is produced, they are not able to figure this out. Go figure!
There is some warm water further west at depth. Will it enter the equation? That remains to be seen. The SOI is not cooperating. I think most of the models have it wrong. Time will tell.
I decided that the NOAA model provided no additional useful information this week so I am going with the Japanese Model. I presented it last week but since then it has been updated.
I provided the discussion that goes with this graphic at the beginning of this report. Notice JAMSTEC is showing El Nino ONI readings peaking in about June and then declining but extending through the Winter as a relatively weak El Nino.
Australia has today released their updated model run but they do not release the discussion until about 3 a.m. my time. If released later tonight, I will add it late tonight or early tomorrow morning as I have a 24 hour window to update my article.
Here is the discussion that was released with the graphic:
Notice they have not declared that El Nino Conditions were in effect at this point in time.
Pulling it All Together.
We may or may not have an El Nino this Winter. We may or may not have a Pacific Climate Shift as the PDO+ may be simply related to the Warm Event. But for now we do have PDO+. The AMO being an overturning may be more predictable so the Neutral status moving towards AMO- is probably fairly reliable. So none of this is very difficult to figure out actually. 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 the first part of this weekly report. For various reasons, more people know about Global Warming than about Ocean Cycles which the IPCC refers to as "Internal Variability". It is quite likely that more attention will be paid to Ocean Cycles given the likelihood that the changes in the phase of three ocean cycles will be having a significant impact on weather patterns and agriculture production and prices and other economic impacts in many parts of the World.
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