Written by Sig Silber
Fall is coming at least for the eastern half of the Lower 48. La Nina conditions persist. The Southern Oscillation (SOI) is not cooperating in the development of the
well advertized El Nino. I think John Steinbeck has written about this. Others might conclude that when the pieces are not falling into place, perhaps the assumed outcome was misconstrued.
A. Housekeeping: In last week’s report there appeared the following sentence in the beginning of the report.
There are no signs yet of the negative AO or NAO required for El Nino, but that has not been predicted to occur until later in the winter.
The “required for El Nino” was artifact and I don’t know how it got there. I was not trying to suggest that AO or NAO controls the development of an El Nino but my attention to the AO or NAO has been related to the mention of a possible negative phase of these two indices occuring later this winter and the prior week I began addressing the potential impacts.
But given the inadvertent relating of the AO and NAO to El Nino in last week’s report, it seems appropriate to discuss that subject. Is El Nino correlated to the AO or NAO to any significant extent?
So here goes.
Beginning with this article. From the Abstract
“We have applied a multiresolution cross-spectral analysis technique to resolve the temporal relationship between the NAO and ENSO. The study shows significant coherence between NAO and Nino3 SST in about 70% of the warm ENSO events from 1900 to 1995, of which 33% and 37% are associated with a 5-to 6-year period (El) and a 2-to 4-year period (E2) oscillation terms in the spectral decomposition, respectively. The dominant teleconnection pattern associated with changes in the mean atmospheric circulation during the initial winter of a typical E1 and E2 events is the positive phase of the Pacific/North American (PNA) pattern. Non-coherence Between the NAO and ENSO occurs during relatively weak Nino3 SST anomaly, with a teleconnection pattern which shows a strong negative phase of the NAO and a pattern which resembles a weak eastward shifted negative phase of the PNA pattern.”
And from an article in the American Meteorological Society:
The dynamical mechanism for the late-winter teleconnection between El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) is examined using the output from a 2000-yr integration of a coupled general circulation model (GCM). The coupled model captures many salient features of the observed behavior of both ENSO and NAO, as well as their impact on the surface climate in late winter. Both the observational and model data indicate more occurrences of negative phase of NAO in late winter during El Niño events, and positive NAO in La Niña episodes.
The potential role of high-frequency transient eddies in the above teleconnection is diagnosed. During El Niño winters, the intensified transient disturbances along the equatorward-shifted North Pacific storm track extend their influences farther downstream. The eddy-induced negative height tendencies are found to be more coherent and stronger over North Atlantic than that over North Pacific. These negative height tendencies over the North Atlantic are coincident with the southern lobe of NAO, and thus favor more occurrences of negative NAO events.
During those El Niño winters with relatively strong SST warming in eastern equatorial Pacific, the eastward extension of eddy activity is reinforced by the enhanced near-surface baroclinicity over the subtropical eastern Pacific. This flow environment supports a stronger linkage between the Pacific and Atlantic storm tracks, and is more conducive to a negative NAO phase.
These model results are supported by a parallel analysis of various observational datasets. It is further demonstrated that these transient eddy effects can be reproduced in atmospheric GCM integrations subjected to ENSO-related SST forcing in the tropical Pacific.
So it would appear that there may be some correlation of an El Nino and negative NAO with the direction of causality being from the ENSO process to the occurrence of a negative NAO. So although it was not my intention to draw the inference that the lack of appearance of a negative NAO was suggestive that El Nino was less likely, it does seem that the development of the El Nino and its intensity and location will impact the intensity and duration of a possible negative NAO (but later this winter, not now). That may be important for the U.S. East Coast and Northern Europe (see table on the impacts of the NAO and AO which can be found in Part II of this Report).
But remember that each process has an impact but when you combine them you can not rely on the impact that has been identified to occur on average. That is what makes forecasting so difficult as there are many interactions to consider.
B. November Update.
At the end of the month, the Early Outlook for the next month is updated.
Here is the prior Early Outlook for November Temperatures.
And here is the updated Temperature Outlook for November:
As you can see there had not been a major change except for removing the Mid-Atlantic States as having higher than climatology temperatures.
Here is the discussion of the updated Temperature Outlook.
“THE COLD START TO THE MONTH IN THE PARTS OF THE EASTERN CONUS DIMINISHES THE CONFIDENCE IN THE OUTLOOK FOR ABOVE-NORMAL TEMPERATURES, AND RESULTS IN SOME DIMINISHED COVERAGE. THERE CONTINUES TO BE A BROAD CONSENSUS FOR ABOVE-NORMAL TEMPERATURE AMONG TOOLS IN THE MUCH OF THE NORTHERN AND WESTERN CONUS, RESULTING IN LITTLE CHANGE FROM THE NOVEMBER OUTLOOK ISSUED AT MID-MONTH OUTSIDE OF THE EASTERN CONUS.”
And this also is interesting.
“THE UPDATED MONTHLY OUTLOOK FOR NOVEMBER, 2014 REFLECTS BOTH THE INFLUENCE EXPECTED WEATHER SYSTEMS IN THE FIRST HALF OF THE MONTH TOGETHER WITH THE CLIMATIC SIGNALS. THE ATMOSPHERIC AND OCEANIC CONDITIONS THAT INFLUENCE THE CLIMATE REMAINED QUITE SIMILAR TO CONDITIONS IN MID-MONTH FOR MOST ELEMENTS. ONE EXCEPTION IS THE SEA SURFACE TEMPERATURE ANOMALIES OFF WESTERN ALASKA THAT HAVE DECREASED SIGNIFICANTLY IN THE TWO WEEKS SINCE THE MID-MONTH OUTLOOK WAS ISSUED. THIS RESULTS IN LOWER CONFIDENCE FOR ABOVE-NORMAL MONTHLY MEAN AIR TEMPERATURES FOR WESTERN PARTS OF THE STATE. HOWEVER, PREDICTIONS FROM BOTH THE GFS AND CFS MODELS CONTINUE TO GENERALLY FAVOR ABOVE-NORMAL TEMPERATURES FOR MOST OF ALASKA, INCLUDING COASTAL REGIONS”
To me, the sentence in bold type is actually favorable for the development of a traditional El Nino rather than a Modoki Type II.
Moving to Precipitation, here is the prior Early Outlook for November Precipitation.
And here is the updated November Precipitation Outlook:
This is a little different with more intense precipitation for Texas and a now shown wet area in the Northwest and the removal of the drier than climatology area in the Great Lakes area.
Here is the NOAA discussion related to the revised November Precipitation Outlook.
“THE PRECIPITATION OUTLOOK FOR NOVEMBER REMAINS QUITE SIMILAR TO THE OUTLOOK ISSUED IN MID-OCTOBER. THE AREA OF ANTICIPATED ABOVE-MEDIAN MONTHLY PRECIPITATION TOTALS IN THE SOUTH-CENTRAL CONUS HAS BEEN ADJUSTED SLIGHTLY ON THE BASIS OF EXPECTED PRECIPITATION IN THE FIRST TWO WEEKS. CONFIDENCE IS QUITE HIGH FOR TEXAS DUE TO WET CONDITIONS EXPECTED EARLY IN THE MONTH. THE ATMOSPHERIC CIRCULATION CONTINUES TO SUPPORT ENHANCED PRECIPITATION FOR PARTS OF THE WEST COAST IN THE FIRST WEEK OF NOVEMBER, BUT THEN PRECIPITATION CHANCES DIMINISH IN THE WEEK-TWO PERIOD IN CALIFORNIA. THUS, AN AREA OF ENHANCED CHANCES FOR MONTHLY PRECIPITATION TOTALS EXCEEDING THE CLIMATOLOGICAL MEDIAN HAS BEEN ADDED TO PARTS OF THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THERE HAS BEEN CONSIDERABLE RUN-TO-RUN VARIABILITY IN RECENT DAYS AMONG THE EXTENDED RANGE GFS MODEL ENSEMBLES, AS WELL AT CFSV2 ENSEMBLES IN THE PREDICTED PRECIPITATION AMOUNT FALLING OVER THE UPPER GREAT LAKES. A NEAR EVEN SPLIT AMONG ENSEMBLES PREDICTING WET AND DRY CONDITIONS SUGGESTS EQUAL CHANCES FOR ABOVE- NEAR- OR BELOW-MEDIAN MONTHLY PRECIPITATION AMOUNTS NEAR THE GREAT LAKES, REVISED FROM THE EARLIER SIGNALS FOR DRY CONDITIONS ISSUED IN MID-OCTOBER.”
C. 6 – 14 Day Outlook
Now let us take a look at the 6 – 14 day outlook that was issued today November 3, 2014.
I am only showing the “second week” map namely the day 8 -14 outlook. The first week map can be found in Part II of my report but 8 – 14 days covers most of the 6 – 14 day period and does not vary much from the first part of the outlook issued today.
As you can see, there is no resemblance between this map (and also the 6 – 10 day map not shown here but available in Part II of this report) and the updated monthly Temperature Outlook issued just a few days ago. Although it was not stated as such, it seems the monthly outlook placed a lot of weight on El Nino arriving in November but at this point in time the mid-month outlooks reflect pre-El Nino conditions.
And here is the 8 – 14 Day Precipitation Outlook issued today.
The mid-month Precipitation Outlook is totally inconsistent with the November Precipitation Outlook issued a few days ago. Again it seems that the November Outlook placed substantial weight on the arrival of an El Nino in November. That could still happen but we now have shorter-term outlooks for more half of the month so it will be difficult for the month to average out to the recently issued November Outlook.
Key points from the NOAA Discussion:
- Ridge (high pressure) over the West will tend to keep the West warmer than climatology
- Trough (Low pressure) over the East will tend to keep the East cooler than climatology
- For a variety of reasons most of the Lower 48 will be drier than climatology. The exceptions are the Mid-West and Northeast which will be wetter
- The phasing of the progression of the west to east movement of air masses and highs and lows is inconsistent among the forecasting models leading to less confidence in the later part of the outlook.
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.
What are they telling us today?
|1952 November 13||Neutral||–||+||Right before an El Nino not recognized using Asian Criteria|
|1955 October 17||La Nina||–||+|
|1963 October 31||El Nino||–||–||Modoki Type I|
|1963 November 4||El Nino||–||–||Modoki Type I|
|1969 November 6||El Nino||–||–||Considered already ended using Asian Criteria|
|1992 October 28||Neutral||+||–||Right after an El Nino Modoki Type II|
|2005 October 26||La Nina||–||+|
|2007 October 13||La Nina||–||+|
|2007 October 14||La Nina||–||+|
The analogs are providing a consistent picture of La Nina conditions. They also reflect PDO negative conditions even though the PDO is positive. So I do not know what the analogs are telling us about the future but they are consistent with the 6 – 14 day outlook. They may simply be telling us that El Nino conditions will not arrive until later this month. We shall see how this evolves.
D. El Nino Discussion
“From JAMSTEC (Japan)
October 22, 2014
ENSO forecast: The SINTEX-F model predictions indicate that the present weak El Niño will continue until early next year. The SST anomalies extended all the way along the equator will then gradually turn to an El Niño Modoki.
Indian Ocean forecast: The negative IOD in the Indian Ocean is now changing to a basin-wide warm mode and that condition is expected to continue in boreal winter as the Indian Ocean capacitor effect in response to Pacific El Niño/El Niño Modoki.
Regional forecast: In boreal winter, as a seasonally averaged view, most parts of Europe, Africa, Middle East, central Russia, India, Southeast Asia, South American Continent, Canada, and the Far East including Japan will experience a warmer-than-normal condition. On the other hand, U.K., western/eastern Russia, southern parts of Australia, and central-eastern U.S. will be in a colder-than-normal condition.
The seasonal averaged rainfall in Dec.2014-Feb. 2015 suggests that most parts of Southeast Asia, northern Australia, and East Africa will experience a drier-than-normal condition. All those may be somehow related to the course of El Niño. A wetter-than-normal condition is predicted for U.S, in particular, western U.S., partly because of the warmer-than-normal SST associated with the continuation of the newly identified regional phenomenon “California Niño”.
I have come across that term California Nino before but I can not locate the reference. I will have to search for it but I think it referred to special impacts related to the Baja area.
Now let us look at the latest NOAA Hovmollers.
First Sea Surface Temperatures
Over to the left side of the graphic at 160E at the bottom you can see where there had been some warming surface water. It is now there again and does appear to be moving east. Also you can see what was just hinted at last week which is some warmer water in the Eastern part of the Equator which is significant for an El Nino. But it is still not enough.
And now the low-level wind anomalies.
We had a westerly anomaly two weeks ago that could do something and apparently it did. Is that enough to actually have an El Nino with enough strength to have an impact?
The Southern Oscillation Index (SOI) has definitely NOT been cooperating although it decided to today. You can find the daily and 30 and 90 day averages here. With the SOI there is always a cause and effect issue. Is the SOI a cause of or a result of warm water being to the east? The SOI is an imperfect index as the two reference points are not on the Equator but I will not go into that today. The 30 day average is now marginal for El Nino conditions. Today’s reading is -9.74 which is an El Nino reading after six days of anything but El Nino readings. You can not deduce anything from one day but it reminds us that situations can change rapidly. Also notice the small blue area way to right at the bottom of this Hovmoller. That is not what we would be looking for to confirm an El Nino.
And then the third part of the equation (there are more than three but I focus on three): Kelvin Waves.
And here we do have a signal of warm water moving east but:
- the prior Kelvin wave has played out and is no longer shown on the Equator. Thus it is no longer contributing to the creation of an El Nino.
- although there was no upwelling wave we currently are in a situation with warm water from this sort of activity but it is below the level required for an El Nino.
- and then there is the newest Kelvin wave. It appears to be about the same intensity as the prior wave but curiously might be proceeding a bit more slowly (visual analysis of the slope of the lines drawn by NOAA. It is not that this Kelvin Wave could not trigger an El Nino, but it does seem to me that we are not talking about November for this to have an effect.
I believe that this Kelvin Wave and the tendency to have repeated Kelvin waves is the only reason for continued optimism that we will have an El Nino this year but it will be very late arriving if it arrives at all.
I still do not see a traditional El Nino of any significant strength likely to happen this winter, especially the first half of the winter. It appears to be a very complicated situation. There are many possibilities on the table in my opinion:
- A short weak traditional El Nino which arrives late.
- A weak traditional El Nino arriving late but being reinforced and turning into a long lasting stronger traditional El Nino. (Not forecast by NOAA but not inconsistent either) This would be somewhat like the 1982/1983 Super El Nino.
- A weak traditional El Nino that turns into a Modoki next year (The Japanese Forecast)
- Nothing much at all at least until next summer (seems to be where the Australia model is headed)
- Other variations of the above all related to warmer water further east than usual in the ENSO cycle but not necessarily translating into the usual El Nino that would normally be here now if it fit the usual mold.
Last week I presented two papers that discussed the relationship between the PDO and the AMO. Next week I will present a third paper that brings the East Asian Surface Air Temperatures (EATs) into the equation. It is not just about the U.S. All weather and climate is interconnected.
Click Here for the Econointersect Weather and Climate Page where you will find:
- NOAA and other agency graphics (including international agencies) that auto update. So this includes both short term- and seasonal “updates”. It will ALWAYS be up to date even if my commentary on the graphics is not. I update my commentary when it seems necessary and certainly every Monday but some of these graphics auto update every six hours. This section of the report has been reorganized to make it easier to follow.
- Economic and other Impacts of major weather events. Not sure there is any other place to obtain this information consistently other than very specialized subscription services.
- Information on Climate Cycles both those which are fairly short term i.e. less than a decade in duration and multi-decadal cycles.
- Economic and other Impacts of those Climate Cycles which are referred to by the IPCC as Internal Variability as opposed to secular Climate Change which is always in the same direction. Again I am not sure if there is another source for this information where it is pulled together in one place as I have.
- Information on Anthropogenic Global Warming science i.e. the secular change in our climate that overlays both short term weather and historical climate cycles as well as black swan events like volcanic eruptions. I prefer to call this Global Warming as it is the warming that triggers the other changes.
- Economic and other Impacts of Global Warming. The IPCC AR5 WG2 attempts to describe and quantify these and I have some excerpts from their report. Over time I will go beyond their report.
For now this is all in one article which may be a little difficult to navigate but that will soon change and the information will be accessed easily by topic.