Winter '09 / '10 - Larry Cosgrove

Preeminent synoptic meteorologist Larry Cosgrove discusses current flow regimes... patterns...trends and their potential impact on the coming winter in his latest newsletter.

"Since we have not yet settled into calendar autumn, it is unwise to make an absolute prediction for the upcoming winter season. But the character of the El Niño Southern Oscillation, which will dominate the course of weather in upcoming months, seems to be visible.



"Unlike a "typical El Niño" (if indeed there is such a thing), there have been NO signs of a true split flow in the polar westerlies. The northern branch has been dominant, even showing signs of buckling with Rex and Omega formations in Alaska, Canada, and Greenland (although the recent development of a North American theater +AO signature is a major break from the summer pattern). The fledgling lower latitude stream arises from the very warm waters adjacent to Mexico, running well south of California. This is one of the reasons that I think the Golden State will have its driest +ENSO since 1976-77, and Dixie and the East Coast are in line to get a very active "Miller A" type storm track."

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Arctic Sea Ice - SEP '09

The extent of arctic sea ice at the end of meteorological summer remains abnormally low (> 2 STD below 1979 - 2000 mean); however...not as dire as the two previous years.

Image courtesy National Snow and Ice Data Center

Winter '09 / '10 - Expecting el Niño

NOAA/s Climate Prediction Center (CPC) expects a moderate to strong el Niño during the upcoming winter (3-month Niño-3.4 SST index of +1.0°C or greater)...which suggests a good chance for above-average precipitation along most of the East Coast.

"Warm Event Winter" image courtesy COAPS

The 3-month moving average SST anomalies in region 3.4 are currently 0.9°C.

CPC/s 3.5-month long-lead forecast for temperature and precipitation...issued AUG 20...reflect elements of an el Niño event.

Complicating the impact of el Niño on the winter's forecast will be the PDO...which is 23 months and four 'years' (OCT - MAR) into a negative phase. -PDO correlates to above normal heights over the SE CONUS...which could keep the primary storm track away from the coast.

Winter '09 / '10 - Weather Trends International

"For a year now, WTI has been projecting a more typical El Nino Winter pattern with the active jet stream split along the Southern tier of the U.S. bringing a lot of rain to the parched Southwest and Texas with the other jet stream well up in Canada with only occasional very cold snaps for the later half of Winter.

"This also suggests an active threat for the East Coast for a few Nor’easters with snowfall up 30% to 100% over last year for the major cities from Washington D.C. to Boston, less well inland. In this case we agree with the Almanac forecast along with the potential for a brutal February and March in terms of late Winter cold and bigger snow events."

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Winter '09 / '10 - Old Farmer's Almanac

"Winter will be colder than normal, on average, especially north of the Chesapeake Bay. The coldest periods will occur in early to mid- and late January and mid-February.

"While precipitation will be below normal, slightly above-normal snowfall will occur in many parts of the region. Watch for snow around Thanksgiving, with other snowy periods in mid-January and mid- and late February."

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Beginning to hear a little chatter about NOV snows. Last time there was a contest-worthy snow-storm was November 27, 2002.

Moscow Mayor Seeks to Banish Snow from City Limits

"Yuri Luzhkov has said that snow should be banished from Moscow in winter to save money and improve life in the city. He claimed that farmers outside the capital would enjoy more abundant harvests if his cloud-seeding programme was adopted.

"A programme to manage the weather would cost only a third of the amount spent on snowploughs and round-the-clock clearance operations. City authorities send 2,500 snowploughs into action to clear snow, and employ an army of 50,000 workers to clear Moscow’s streets and pavements.

"There are other risks: a 25kg (55lb) bag of cement crashed through the roof of a Moscow home last year as an air force cargo aircraft carried out a cloud-seeding operation. Officials said that the bag had “failed to pulverise completely at high altitude”."

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Apparently...the Chinese are doing the same thing. Cash-strapped municipalities in New England might want to look into this...as well.

Winter '09 / '10 - NAO Forecast - MET Office

The UKMET Office...the British version of the US NWS...produces a statistical NAO forecast (reg. reqd.) for the upcoming winter.

The forecast for 500 mb heights is based on an analysis of observed and the 'predictor pattern' of SST anomalies in the northern Atlantic Ocean during the month of May.

"By taking the observed SST anomaly for May (figure at left) and calculating how it projects onto the predictor pattern we can make a prediction for the winter NAO. If the projection is positive (i.e. the anomaly pattern looks similar to the predictor pattern shown below) then the prediction is for a positive winter NAO. Conversely, if the observed May SST anomaly projects negatively onto the predictor pattern (i.e. it looks like the reverse of the predictor pattern) then we would predict a negative NAO."



There's a weakly negative statistical correlation between season-total snowfall in New England and the Mid-Atlantic regions and the NAO. This association is often mis-applied to individual storm systems -- if we could just get the NAO to turn negative...then we're more likely to get snow.

NAO forecast was quite good last year. Snow crows hope it's not as advertised this winter.

Now Playing: 2009 Tour of the Cryosphere

Press START to play.

Courtesy NASA.

Winter '09 / '10 - Farmer's Almanac

First out of the gate for the upcoming winter is the Farmer's Almanac...

"For the Middle Atlantic and Northeast States, for instance, we are predicting a major snowfall in mid-February; possibly even blizzard conditions for New England indeed, even shovelry is not dead)."

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Final Results - 10th Annual Regular Season Snowfall Forecast Contest

8 Storms
683” Total Snowfall
2,353 Station Forecasts

25 Forecasters
6 Rookies
3 Interns
4 Journeymen
12 Seniors

Don Sutherland has successfully defended his 'Chief Forecaster' title for the second year in a row by winning handily the 10th Annual NE.Wx Snowfall Forecast Contest.

Don/s final scores:
AVG SUMSQ Z-score: -1.025
AVG Total Absolute Error Z-score: -1.171
AVG Error: 1.37"

The award for placing first is a copy of the two-volume set Northeast Snowstorms by Kocin / Uccellini and three (3) months of free access to StormVista GOLD

Second place goes to Shanabe...
Shanabe/s final scores:
AVG SUMSQ Z-score: -0.743
AVG Total Absolute Error Z-score: -0.765
AVG Error: 1.62"
Shanabe/s prize is two (2) months of free access to StormVista GOLD

Donald Rosenfeld finished in third place...
Donald Rosenfeld final scores:
AVG SUMSQ Z-score: -0.737
AVG Total Absolute Error Z-score: -0.660
AVG Error: 1.56"
Donald Rosenfeld/s prize is one (1) month of free access to StormVista GOLD

Honorable Mention: Raven
Raven/s final scores:
AVG SUMSQ Z-score: -0.564
AVG Total Absolute Error Z-score: -0.438
AVG Error: 1.83"

Complete results and season summary @ the web site.

Many thanks to Jack @ StormVista for his generous contribution of prizes to the top forecaster after each storm and again at season/s end.

Thanks also...to everyone who entered a forecast. Hope you enjoyed the many challenges and we look forward to seeing y'all again next winter.