Written by Sig Silber
NOAA issued their Seasonal Update on February 19 and discounts El Nino as a factor in their Seasonal Outlook. The RRR remains resilient. The PDO Index registers very high positive values. A Climate Shift is possible. The Southwest stays warmer than climatology indefinitely in this Seasonal Outlook and the Four Corners area is projected to be wet through July and Florida is projected to be dry next winter. In the short term, cold air intrusions are the main event.
This is my weekly Weather and Climate Update Report. A more complete report can be found here in what I call Page II of my Weekly Report.
Here are excepts from the NOAA Discussion issued on Thursday February 19 in conjunction with an updated seasonal outlook. I have reorganized the NOAA discussion a bit mostly to eliminate redundancy between the 30 day and long-lead discussions and to make it more readable.
“CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS
THE CONTINUED LACK OF ROBUST COUPLING BETWEEN THE OCEAN AND ATMOSPHERE IN THE TROPICAL PACIFIC HAS PROLONGED BORDERLINE CONDITIONS BETWEEN ENSO-NEUTRAL AND A WEAK EL NINO. OCEANIC PARAMETERS FAVOR A WEAK EL NINO, WHILE ATMOSPHERIC PARAMETERS FAVOR ENSO-NEUTRAL. SSTS IN THE WESTERN AND CENTRAL EQUATORIAL PACIFIC ARE ABOVE-AVERAGE, AND SSTS IN THE EASTERN PORTION OF THE BASIN ARE NEAR TO BELOW-AVERAGE. THE LATEST WEEKLY SST INDICES ARE +0.9C FOR THE NINO 4 REGION, +0.5C FOR NINO 3.4, +0.3C FOR NINO3, AND -0.8C FOR NINO 1+2. [Editor’s Note: this describes a Modoki and the warm water off the Northwest Coast and the NINO 4 reading suggest this is a Modoki Type II not a traditional El Nino which is why NOAA has had ongoing problems with their forecasts]
A NETWORK OF MOORED BUOYS ACROSS THE EQUATORIAL PACIFIC USED TO MONITOR THE STATE OF ENSO REVEALS WELL ABOVE-AVERAGE TEMPERATURES (AS MUCH AS 4-6 DEGREES C ABOVE-AVERAGE) DOWN TO A DEPTH OF 200 METERS NEAR AND EAST OF THE DATE LINE. BELOW-AVERAGE TEMPERATURES (AS MUCH AS 2-4 DEGREES C BELOW-AVERAGE) ARE OBSERVED ACROSS THE EASTERN EQUATORIAL PACIFIC BETWEEN ABOUT 110W-90W, DOWN TO A DEPTH OF 100 METERS. THE NEAR-EQUATORIAL UPPER-OCEAN HEAT CONTENT ANOMALIES (FROM THE DATE LINE TO 100W, UPPERMOST 300 METERS) HAD DECLINED TO NEAR ZERO IN EARLY JANUARY, BUT HAVE SINCE REBOUNDED IN EARLY FEBRUARY TO ABOUT +0.7C. THE OCEANIC COMPONENT OF THE GLOBAL CLIMATE SYSTEM IS CONSISTENT WITH A WEAK EL NINO. [Editor’s Note: Current Kelvin Wave and it is temporary]
ON THE OTHER HAND, THE ATMOSPHERIC CIRCULATION IS MORE CONSISTENT WITH THE NEUTRAL PHASE OF ENSO. OUTGOING LONGWAVE RADIATION (OLR) MEASUREMENTS INDICATE THAT CONVECTION IS ENHANCED OVER THE WESTERN EQUATORIAL PACIFIC, AND SUPPRESSED OVER INDONESIA, NORTHERN AUSTRALIA, AND EAST OF THE DATE LINE. LOW-LEVEL (850-HPA) TRADE WINDS FOR THE PAST MONTH HAVE BEEN AVERAGING CLOSE TO NORMAL ACROSS THE EQUATORIAL PACIFIC [Editor’s Note: wait until you see the La Nina type SOI values this week which I show later], WHILE THE UPPER-LEVEL (200-HPA) WIND PATTERN DEPICTS A LARGE ANTICYCLONIC CIRCULATION CENTERED NEAR HAWAII, AND ENHANCED EASTERLIES NEAR THE EQUATOR FROM ABOUT 140W TO THE DATE LINE.
POSITIVE SUBSURFACE TEMPERATURE ANOMALIES EXPANDED ACROSS MUCH OF THE CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC IN THE LAST MONTH ASSOCIATED WITH THE DOWNWELLING PHASE OF A KELVIN WAVE, WHILE NEGATIVE ANOMALIES REMAINED NEAR THE SURFACE IN THE EASTERN PACIFIC. ATMOSPHERIC CONDITIONS APPEARED TO INDICATE THE POSSIBILITY OF COUPLING OF POSITIVE SST ANOMALIES TO THE ATMOSPHERE, WITH NEGATIVE OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES POSITIONED JUST WEST OF THE DATELINE REPRESENTATIVE OF ENHANCED CONVECTIVE ACTIVITY AND POSITIVE OLR ANOMALIES TO THE EAST OF THE DATELINE. RECENT POSITIVE WESTERLY WIND ANOMALIES AT 850 HPA OVER THE EAST-CENTRAL AND WESTERN PACIFIC OCEAN HAVE NOW DIMINISHED. THE ENSO OUTLOOK OFFICIALLY CALLS FOR ABOUT A 50 TO 60 % PROBABILITY OF THE DEVELOPMENT OF COUPLED EL NINO CONDITIONS. CURRENTLY, THE OVERALL ATMOSPHERE AND OCEAN STATE CONTINUES TO BE CONSIDERED ENSO-NEUTRAL, AND ANY FURTHER DEVELOPMENT OF WEAK EL NINO CONDITIONS WILL HAVE LITTLE IMPACT ON THE SEASONAL CLIMATE OVER NORTH AMERICA. [Editor’s Note: I consider this to be the NOAA Capitulation I have been predicting for months]
ACCORDING TO THE JOINT INSTITUTE FOR THE STUDY OF THE ATMOSPHERE AND OCEAN (JISAO) IN SEATTLE, THE CALCULATED VALUE OF THE PACIFIC DECADAL OSCILLATION (PDO) INDEX FOR JANUARY 2015 IS +2.45. THE RECENT DECEMBER 2014 PDO INDEX VALUE OF +2.51 IS THE LARGEST DECEMBER VALUE ON RECORD (SINCE 1900) AND THE HIGHEST FOR ANY MONTH SINCE AUGUST 1997. [Editor’s Note: the topic last week was are we in the middle of a Pacific Climate Shift from PDO Negative to PDO Positive? It is still too soon to say]
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE IRI/CPC NINO 3.4 SST ANOMALY FORECAST PLUME OF VARIOUS DYNAMICAL AND STATISTICAL MODELS INDICATES MOST MODELS PREDICT A RANGE OF SST ANOMALIES FROM NEAR 0.0C TO +1.5C, WITH THE DYNAMICAL MODELS FAVORING THE HIGHER END OF THE RANGE, AND THE STATISTICAL MODELS FAVORING THE LOWER END OF THE RANGE. THE COLA CCSM3 IS THE HIGH-END OUTLIER, PEAKING NEAR +1.8C BY JAS AND ASO. THE CDC LIM IS THE LOW-END OUTLIER, BOTTOMING OUT AT -0.25C IN ASO. THE CFSV2 SST ANOMALY PREDICTIONS FOR NINO 3.4 RANGE FROM NEAR 0.0C TO +2.5C, WITH THE ENSEMBLE MEAN SLOWLY INCREASING FROM ABOUT +0.8C IN MAM TO +1.4C BY SON. [Editor’s Note: NOAA may be a year early in their call for an El Nino…it might happen next year but the analogs suggest La Nina is more likely. The Spring Prediction Barrier comes into play here i.e. it is too soon to draw any conclusions]
THE CPC CONSOLIDATION (CON) SST FORECAST STARTS OFF AT +0.4C IN MAM AND DECLINES VERY SLIGHTLY TO ABOUT +0.2C IN SON. THE BOX AND WHISKERS PLOT SHOWS RAPIDLY INCREASING UNCERTAINTY BY AUTUMN, WITH PREDICTED SST ANOMALY VALUES RANGING ANYWHERE FROM +2.5C TO -2.0C DURING OND AND NDJ. [Editor’s Note: with that wide range, NOAA is assured of being correct]
30-DAY OUTLOOK DISCUSSION FOR MARCH 2015
THE TEMPERATURE OUTLOOK FOR MARCH 2015 PREDICTS ENHANCED CHANCES OF ABOVE-NORMAL MONTHLY MEAN TEMPERATURES WEST OF THE ROCKY MOUNTAINS, WITH GREATER PROBABILITIES NEAR THE COAST, AS WELL AS FOR ALASKA WITH GREATEST PROBABILITIES IN THE SOUTHWEST PART OF THE STATE. THE OUTLOOK PREDICTS ENHANCED PROBABILITIES OF BELOW-NORMAL TEMPERATURES FROM THE GREAT LAKES REGION ACROSS THE NORTHEAST. DYNAMICAL MODEL GUIDANCE FOR MARCH INDICATES THE PERSISTENCE OF A RIDGE IN THE ATMOSPHERIC CIRCULATION OVER THE NORTH PACIFIC AND ALASKA WITH ABOVE-NORMAL HEIGHTS AT 200 HPA OVER MUCH OF WESTERN NORTH AMERICA. MODEL GUIDANCE PREDICTS THE MEAN LOCATION OF A TROUGH IN THE CIRCULATION DOWNSTREAM OVER THE EASTERN U.S AND CANADA. THIS OUTLOOK IS SUPPORTED BY THE FORECASTS OF THE DYNAMICAL MODELS FROM THE NMME AND IMME FOR MARCH AS WELL AS THE FORECASTS FOR THE FIRST WEEK OF THE MONTH FROM THE REFORECAST-CALIBRATED GEFS AND THE BIAS-CORRECTED NAEFS MODELS. RECENT WEEK 3 AND 4 FORECASTS FROM THE ECMWF MODEL SUPPORTED THE FORECAST FOR ABOVE-NORMAL TEMPERATURES IN THE WEST AND BELOW-NORMAL TEMPERATURES IN THE EAST AS OF LAST WEEK. FORECASTS FROM THE CFS AND THIS WEEKS ECMWF MODEL FORECASTS INDICATE SUBSEASONAL VARIABILITY BRINGING BELOW NORMAL TEMPERATURES INTO THE PACIFIC NORTHWEST AND ABOVE-NORMAL TEMPERATURES INTO THE SOUTHEAST. AN INDICATION OF ENHANCED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES IN THE NMME MODELS FOR THE SOUTHEAST WAS REMOVED AND PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES IN THE PACIFIC NORTHWEST WERE REDUCED CONSIDERING UNCERTAINTY IN THIS REGION ASSOCIATED WITH THIS MOST LIKELY PREDICTED SUBSEASONAL VARIABILITY. OVERALL, MONTHLY FORECASTS OF LONGER-TIMESCALE MONTHLY AND SEASONAL VARIABILITY WAS MORE CLOSELY FOLLOWED THAN SUBSEASONAL FORECASTS.
THE PRECIPITATION OUTLOOK FOR MARCH 2015 PREDICTS ENHANCED CHANCES OF ABOVE-MEDIAN PRECIPITATION FOR MUCH OF SOUTHEASTERN ALASKA WITH MEAN STORM TRACKS EXPECTED OVER THE TOP OF THE PREDICTED RIDGE. AN ENHANCED PROBABILITY FOR BELOW-MEDIAN PRECIPITATION IS INDICATED FOR THE PACIFIC COASTAL REGION IN THE PACIFIC NORTHWEST, ASSOCIATED WITH THE PREDICTED RIDGE. AN ENHANCED PROBABILITY OF ABOVE-MEDIAN PRECIPITATION IS PREDICTED FOR THE U.S. SOUTHWEST AS WELL AS FOR THE SOUTHEAST. THE PRECIPITATION OUTLOOK IS GENERALLY SUPPORTED BY THE MODEL FORECASTS OF THE NMME AND IMME MODELS. ENHANCED PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION OVER THE SOUTHEAST WERE EXPANDED TO THE NORTH USING GUIDANCE FROM RECENT MONTHLY AND WEEK 3 AND 4 FORECASTS OF THE CFS.
March-April-May Outlook
TEMPERATURE
FOR LEAD 1 (MAM 2015) [Editor’s Note: the terminology here is the first three-month period is called Lead 1, the next next three month period which covers the second and third month from LEAD 1 plus the next month is called LEAD 2 etc], ENHANCED PROBABILITIES FOR BELOW-NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. THIS SIGNAL IS EVIDENT IN THE NMME, CFS, GFDL AND NASA MODELS, AS WELL AS THE CA-SST TOOL. PROBABILITIES ARE ENHANCED FOR ABOVE-NORMAL TEMPERATURES IN ALASKA AND THE WESTERN CONUS, WITH PROBABILITIES NEAR 60 PERCENT ALONG THE SOUTHERN COAST OF ALASKA, AND THE COASTS OF WASHINGTON AND OREGON. THIS LARGE EXTENT OF PREDICTED ABOVE-NORMAL SEASONAL MEAN TEMPERATURES IS FAVORED BY NEARLY ALL OF THE VARIOUS TOOLS. THE NMME, IMME, CFS, AND OTHER SOLUTIONS EXTEND THIS RELATIVE WARMTH EASTWARD ACROSS THE NORTH-CENTRAL CONUS, BUT THIS IS DEEMED TOO UNCERTAIN, ESPECIALLY IN LIGHT OF HIGHER FREQUENCY CLIMATE SIGNALS (INTRA-SEASONAL VARIABILITY) THAT SUGGEST THIS AREA MAY BE OPEN TO LONGER PERIODS OF COLD AIR INTRUSIONS. IN WESTERN NORTH AMERICA, HOWEVER, THE LOW-FREQUENCY SEASONAL SIGNAL APPEARS STABLE ENOUGH TO WARRANT THE HIGHER PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES.
PRECIPITATION
FOR MAM 2015, THERE ARE ELEVATED ODDS OF ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHWEST, THE CENTRAL AND SOUTHERN ROCKIES, THE SOUTHERN HIGH PLAINS AND SOUTHERN TEXAS, THE SOUTHERN ATLANTIC COAST INCLUDING FLORIDA, AND MUCH OF THE SOUTHERN COAST OF ALASKA. ODDS FOR BELOW-MEDIAN PRECIPITATION ARE ELEVATED ALONG THE PACIFIC NORTHWEST COAST. THIS OUTLOOK IS PRIMARILY BASED ON THE NMME, IMME, CFS, AND TO SOME DEGREE THE GFDL, CANCM4 AND NASA MODELS. IT IS ALSO CONSISTENT WITH THE EXPECTATION OF A VERY STABLE, LOW-FREQUENCY SIGNAL IN THE VICINITY OF WESTERN NORTH AMERICA, FAVORING A RIDGE.
DISCUSSION OF OUTLOOKS – MAM 2015 TO MAM 2015
TEMPERATURE
FOR LEADS 2-6, THE PREVIOUS SET OF OUTLOOKS WAS MODIFIED ACCORDING TO THE LATEST DYNAMICAL MODEL OUTPUT. THE MOST RELIABLE SIGNALS ARE FOR ABOVE-NORMAL TEMPERATURES ACROSS ALASKA AND THE WESTERN CONUS, ASSOCIATED WITH THE LOWER FREQUENCY SIGNAL OF LONG-TERM RIDGING OVER WESTERN NORTH AMERICA. IN GENERAL, THE DYNAMICAL SOLUTIONS FAVOR ENHANCED ODDS OF ABOVE-NORMAL TEMPERATURES ACROSS THE GREAT LAKES REGION AND NORTHEAST DURING AMJ AND MJJ, AND MUCH OF THE ATLANTIC AND GULF COAST REGIONS DURING JJA, JAS AND ASO. THE ELEVATED ODDS OF ABOVE-NORMAL MEAN TEMPERATURES CONTINUES IN THE NORTHEAST DURING SON AND OND 2015, BASED LARGELY ON HISTORICAL TEMPERATURE TRENDS. THE SPATIAL COVERAGE OF EXPECTED ABOVE-NORMAL MEAN TEMPERATURES IN THE WESTERN CONUS GRADUALLY DIMINISHES IN SIZE DURING THE AUTUMN AND WINTER, TO INCLUDE ONLY THE SOUTHWEST DURING THE LAST 4 SEASONS.
FROM SON 2015 TO MAM 2016, THERE ARE ENHANCED ODDS OF ABOVE-NORMAL TEMPERATURES ACROSS NORTHERN ALASKA, PRIMARILY DUE TO STRONG TRENDS IN SURFACE TEMPERATURE AND SEA ICE COVER.
PRECIPITATION
[Editor’s Note: It is unfortunate that NOAA does not extend their maps into Mexico because it is a little difficult to imagine how this Southwest Precipitation will get to the Southwest. It does not appear to be coming from the North or West. Perhaps it is Gulf of Mexico origin or is coming up from Mexico more or less like an early Monsoon. The 6 – 14 Day Outlooks may shed some light on this question. Also the repeated reference in the discussion to low-frequency influences is not explained. Usually “low frequency refers to PDO or AMO cycles. So I am curious as to what they have in mind here especially given the recent high values of the PDO index. But PDO Positive is not usually associated with this RRR so I am perplexed.]
THROUGH THE SPRING AND EARLY PORTIONS OF THE SUMMER, THE STRONGEST SIGNAL IN THE MODELS IS FOR ENHANCED ODDS OF ABOVE-MEDIAN PRECIPITATION OVER THE SOUTHWEST. THE OUTLOOK THERE IS HIGHLY UNCERTAIN, ESPECIALLY DURING AMJ, A CLIMATOLOGICALLY DRY TIME OF YEAR ACROSS THAT REGION. FROM JAS TO NDJ, PRECIPITATION SIGNALS ACROSS THE U.S. ARE TOO WEAK TO JUSTIFY ANY ONE OF THE THREE CATEGORIES (BELOW, NEAR, OR ABOVE-MEDIAN), SO EQUAL CHANCES (EC) IS INDICATED. FROM DJF 2015-16 TO FMA 2016, HISTORICAL TRENDS SLIGHTLY FAVOR BELOW-MEDIAN PRECIPITATION IN THE SOUTHEAST, DUE IN PART TO THE DOMINANCE OF LA NINA EVENTS DURING THE PAST 15 YEARS. FOR MAM 2016, THIS HISTORICAL TREND IS NOT AS CLEAR, [Editor’s Note: Although Neutral or La Nina is suggested by the Analogs] SO EC IS FAVORED.
Now lets us shift gears and discuss the:
Short-term Outlook
Let us take a look at the 8 – 14 day outlook that was issued today February 23, 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.
Generally I only show 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 updated March Temperature Outlook Issued Thursday February 19, 2015 and previously shown earlier in this report.
And here is the 8 – 14 Day Temperature Outlook.
The Temperature Outlook for the first week of March is not consistent with the Monthly Outlook but combined with the similar 6 – 10 Day Outlook only covers the first nine days of the month.
Here is the updated February Precipitation Outlook Issued on February 19, 2015 and previously shown earlier in this report.
And here is the 8 – 14 Day Precipitation Outlook issued today February 23, 2015.
The Precipitation Outlook for the first week of March does appear to be developing somewhat in line with the February Outlook. The RRR is supposed to go away during an El Nino but has not.
Here are excerpts from the NOAA release today February 23, 2015.
“6-10 DAY OUTLOOK FOR MAR 01 – 05 2015
TODAY’S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON A FAIRLY HIGH-AMPLITUDE 500-HPA PATTERN FORECAST FOR THE 6-10 DAY PERIOD. ALL MODELS ARE FORECASTING A RIDGE OVER THE GULF OF ALASKA, A BROAD TROUGH OVER CENTRAL NORTH AMERICA. NEGATIVE 500-HPA HEIGHT ANOMALIES ARE OVER CENTRAL AND NORTHEASTERN CONUS WITH POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE WEST COAST AND THE SOUTHEASTERN CONUS. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE FORECAST DOMAIN.
THERE ARE ENHANCED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE CONUS EXCEPT FOR THE SOUTHEAST, IN ASSOCIATION WITH AN EXPECTED TROUGH, CONSISTENT WITH NAEFS GUIDANCE AND BIAS CORRECTED TEMPERATURES FROM THE 0Z ECMWF ENSEMBLES. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR ALASKA INCLUDING THE ALEUTIANS AND THE PANHANDLE.
ABOVE-MEDIAN PRECIPITATION IS FAVORED FOR THE EASTERN CONUS, THE CENTRAL AND SOUTHERN PLAINS AND SOUTHWEST IN ASSOCIATION WITH THE FORECAST TROUGH IN CENTRAL NORTH AMERICA. NEAR- TO BELOW-MEDIAN PRECIPITATION PROBABILITIES ARE ENHANCED FOR THE WESTERN CONUS AND THE NORTHERN PLAINS CONSISTENT WITH NAEFS AND GEFS REFORECAST GUIDANCE. THERE ARE ENHANCED PROBABILITIES OF NEAR-TO ABOVE-MEDIAN PRECIPITATION FOR ALASKA, EXCEPT THE ALEUTIANS.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, REASONABLY GOOD AGREEMENT AMONG THE TEMPERATURE/PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR MAR 03 – 09 2015
THE ENSEMBLE MEAN PREDICTIONS ON THE 500-HPA HEIGHT PATTERN FOR THE WEEK-2 PERIOD ARE IN FAIR AGREEMENT OVER NORTH AMERICA. A RIDGE IS PREDICTED OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE CENTRAL CONUS, ASSOCIATED WITH NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST OVER THE CENTRAL CONUS. IN THE SOUTHEASTERN CONUS, MODEL ENSEMBLE MEAN SOLUTIONS ALSO FORECAST A RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES. OVER THE ALASKA SECTOR, A CONSENSUS OF THE ENSEMBLE MEAN SOLUTIONS FORECAST A RIDGE OVER THE GULF OF ALASKA WITH POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE STATE.
ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE ENHANCED FOR ALASKA, THE ALEUTIANS AND THE PANHANDLES EXCEPT THE SOUTHERN INTERIOR, IN ASSOCIATION WITH THE POSITIVE 500-HPA HEIGHT ANOMALIES. ALL FORECAST TOOLS ARE IN REASONABLY GOOD AGREEMENT ON THE FORECAST TEMPERATURE PATTERN ACROSS THE MOST CONUS WITH BELOW-NORMAL TEMPERATURE PROBABILITIES FAVORED FOR THE AREAS NEAR THE FORECAST TROUGH. WITH A MEAN RIDGE POSITION FORECAST NEAR THE WEST COAST AND GULF OF MEXICO, ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER THE WEST COAST AND FLORIDA.
ABOVE-MEDIAN PRECIPITATION CHANCES ARE ENHANCED FOR ALASKA AND THE PANHANDLES EXCEPT THE ALEUTIANS RELATED TO THE PREDICTED RIDGE IN THE AREA. BELOW-MEDIAN PRECIPITATION CHANCES ARE ENHANCED FOR THE WESTERN CONUS, THE NORTHERN AND CENTRAL GREAT PLAINS AND THE UPPER AND MIDDLE MISSISSIPPI VALLEY, CONSISTENT WITH NAEFS AND GEFS REFORECAST GUIDANCE. WITH NEGATIVE HEIGHT ANOMALIES CENTERED OVER THE CENTRAL CONUS, ABOVE-MEDIAN PRECIPITATION IS FAVORED ALONG AND EAST OF THE ANOMALOUS TROUGH AXIS ACROSS THE EASTERN CONUS ASSOCIATED WITH AN ACTIVE STORM TRACK.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT AMONG THE 0Z/6Z GFS AND 0Z ECMWF ENSEMBLE MEANS OFFSET BY CONTINUED LARGE SPREAD AMONG 0Z GFS AND 0Z ECMWF ENSEMBLE MEMBERS WITH THE POSITION AND AMPLITUDE OF THE NORTH PACIFIC (WESTERN NORTH AMERICA) RIDGE TROUGH).”
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 forecasted 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.
Analog Centered Day | ENSO Phase | PDO | AMO | Other Comments |
1976 February 2 | La Nina | – | – | Just before Pacific Climate Shift |
1976 February 3 | La Nina | – | – | Just before Pacific Climate Shift |
1981 February 3 | Neutral | + | – | |
1995 February 8 | El Nino | + | Neutral | Tail end Mokoki, Atlantic Climate Shift |
1995 February 9 | El Nino | + | Neutral | Tail end Modoki, Atlantic Climate Shift |
2003 February 5 | El Nino | + | + | Tail end Modoki Type I |
2003 February 6 | El Nino | + | + | Tail end Modoki Type I |
2007 February 2 | El Nino | Neutral | + | Tail end Traditional El Nino |
2007 February 3 | El Nino | Neutral | + | Tail end Traditional El Nino |
All six of the El Nino analogs are dates that are at the tail end of an El Nino. Four of the six are Modokis. Mid 1976 is when the Pacific changed phase and 1995 is the year the Atlantic changed phase. So those were transition periods. All of the analogs are about two weeks earlier than one would expect suggesting mid-February rather than early March weather over the next 14 days. The analogs are suggesting that we may be in a transition phase of some sort. There were many references to a low-frequency factor in the NOAA Seasonal Outlook Discussion but I could not tell which low-frequency phenomenon they were referring to. My guess is the Pacific. But that is just a guess.
Back to the Current Situation:
Sometimes it is useful to take a look at the location of the Jet Stream or Jet Streams.
And sometimes the forecast is revealing. Below is the forecast out five days. Both the current view and 5 day forecast show the RRR and the enormous trough created allowing cold air to enter the Midwest and Northeast.
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 below is another view which highlights the surface highs and the lows re air pressure on Day 3. You can see how the counter-clockwise Aleutian Low is funneling warm wet air towards the Alaskan Panhandle and the Lower 48 Northwest. The RRR is clearly evident and robust and contributing to the steering of weather patterns into Canada and then down into the Midwest. But notice the low pressure off of British Columbia. By the time you see this it may no longer be there but it has the potential to influence the weather in the short term.
And here is Day 6
There has been talk of the possibility that the Aleutian Low would weaken and move west and allow the Ridge to slide north. The Aleutian Low appears to be cooperating but so far the RRR remains in place having moved somewhat to the north but not weakened. Perhaps that is why it is called the Ridiculously Resilient Ridge.
El Niño Discussion
Because NOAA has finally acknowledged that the “ImagiNiño” has no impact on their Outlooks (even though it should as it is a Modoki) I am truncating my ENSO Report.
It is useful to understand where ENSO is measured.
Of most interest to NOAA is 120 W to 170 W labeled Nino 3.4 as that is where the ONI Index is measured. More information can be found here.
And now the low-level wind anomalies.
This shows considerable change from last week. Notice the blue area between 150E and 170W. That indicates stronger than usual Easterlies. The Southern Oscillation Index (SOI) this week it is clearly consistent with ENSO Neutral or possibly even La Nina conditions. You can find the daily and 30 and 90 day averages here. The 30 day average of -0.93 is certainly not consistent with 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 of -9.30 is consistent with El Nino but only 3 out of 27 of the most recent days have been. The SOI fluctuates based on local weather conditions in Tahiti and Darwin Australia which is why the 30 and 90 day average are more significant than the daily values. The 90 day average is currently -5.87 which is not sufficiently negative to be considered consistent with El Nino conditions.
17 Feb 2015 +9.6
18 Feb 2015 +17.3
19 Feb 2015 +16.3
20 Feb 2015 +24.1
21 Feb 2015 +25.0
22 Feb 2015 +10.9
23 Feb 2015 -9.3
And finally the latest model results released by NOAA on February 23, 2015.
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. I probably could do a better job with triangles but just by eyeballing this chart it looks like it is showing an ONI reading of about 0.6 forecast through the Spring. I believe that NOAA just reported a weekly ONI of 0.5.
“THE LATEST WEEKLY SST INDICES ARE +0.9C FOR THE NINO 4 REGION, +0.5C FOR NINO 3.4, +0.3C FOR NINO3, AND -0.8C FOR NINO 1+2.”
If the SSTA in NINO 3.4 was your only criteria, this would be considered a marginal El Nino but the other factors have not fallen into place. And this model does not attempt to classify the type of El Nino which is very important in terms of weather impacts. Notice the model is forecasting higher ONI levels as we move into the summer. It is difficult to read the maps to the right but the upper left map is the forecast for March/April/May and it looks more like a Modoki Type II than a traditional El Nino to me. The further-out maps do look like an El Nino. Are we going to have a traditional El Nino next year?
Below is another graphic that confirms that we are not in a traditional El Nino but perhaps a borderline El Nino Modoki. The top graphic shows surface temperatures and wind direction and speed conditions 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 bottom graphic shows anomalies.The bottom graphic shows the deviation from average conditions. You can see many things in this 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. West of 170W in the Nino 4 area you have warm water on the Equator which is consistent with a Modoki Type II. Looking between 170W and 120W on the Equator, you see a large area where the anomaly is under 0.5C. And you also see an area above 0.5C which has decreased in size. In the Nino 1+2 Area over by Ecuador, one can see a positive anomaly i.e.colder water. This area of colder water has expanded both above and below the equator. That does not figure in to the ONI calculation but determines the type of El Nino that we have and the impact it has on weather. Also the anomaly analysis of the wind anomalies in the Eastern Pacific generally point to the west which is the opposite of what you would expect with a traditional El Nino. Not shown here but the warm water off the Northwest Coast of the U.S. is also consistent with a Modoki Type II.
Pulling it All Together. .
So this continues to look to me like a warm event that is not a full-fledged El Nino and is not a traditional El Nino. So the expected impacts are different than the expected impacts from a traditional El Nino. Whatever this pattern is, it is not very different from ENSO Neutral. 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 (or possibly rotated) than would be the case for a traditional El Nino which is why the weather where I live is more typical of a La Nina than an El Nino which is characteristic of a Modoki. This has been the case since the PDO went into its Negative Phase in 1998/1999 which is why a possible change to PDO Positive is so very important. Where I live it would end the drought but of course it would initiate drought elsewhere. An extensive discussion of the PDO is found here in Part II of this report.
I do not see a traditional El Nino of any significant strength likely to happen this winter although a “near” El Nino appeared in January to be making its presence known to a limited extent but mainly outside of the U.S. That no longer appears to be the case for March. It remains 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 in the Warm Pool but usually it takes a few years for that to built up sufficiently for another warm event to get under way. ENSO Neutral is where some of the models are headed and I suspect that they have it correct for next winter. But if the PDO has indeed switched to its Positive Phase we should expect a powerful El Nino soon. It could be next winter.
Click Here for the Econointersect Weather and Climate Page II where you will find:
- A more complete set of NOAA and other agency graphics (including international agencies) that auto update. So this includes both short term- and seasonal “updates”. Most of the graphics 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.
- 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.
Click Here for Page III which deals with Global Warming.
- 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 as it is very deficient.