Winter '09 / '10 - Pattern Change - Part Deux

ECMWF 100-mb forecast advertising a split and dramatic shift in the polar vortex (PV) over the next 10 days...with a minor stratospheric warming thrown in for good measure.

PV is forecast to move from its present position in the eastern HEMI north of Siberia...

...to extreme NW Canada in the western HEMI.

Winter '09 / '10 - Coastal Teaser CANCEL

FORECAST


OBSERVED

Winter '09 / '10 - NHEMI Snowcover - November

Could be better.  Much better.  Not only is much of Canada still below normal but so is a fair chunk of the Upper Plains and mid-West.

Orange (blue) areas are below normal (above).  White areas are normal.

Late OCT rally lasted through early NOV before fading rapidly.

State of the cryosphere at month/s end and the start of meteorological winter shows there/s a lot of ground to be made up.  Good hi-latitude snow pack is an important element for creating polar and arctic air masses.

9th Annual 'Season-total' Snowfall Forecast Contest - The Forecasts

Welcome rookie forecasters and welcome back veterans to the start of another NE.Wx snowfall forecasting season.  19 entries this year.  Only three expecting below-normal snowfall.

Forecasts in the table below are ranked in ascending order by sum-total snowfall for all stations.

Sum-total period-of-record normal (PORN) snowfall for all stations during D-J-F-M is 916.9".
The percentage displayed next each forecaster/s 'season total' snowfall forecast is its PORN percentage.

Forecasts colored in BLUE (RED) indicate the 25th (75th) percentile.

Minimum sum-total forecast is 576.6" (63% of PORN).

Maximum sum-total forecast is 1,298" (42% above PORN)

Forecaster average is 1,042" (14% above PORN)
Average of all 25-station forecasts is 16% above PORN.

Consensus station forecasts for snowfall at least 25% above PORN:
BGR - 139%
BDR - 135%
SBY - 133%
PHL - 132%
ACY - 128%

® = rookie
© = defending champion

Detailed forecasts here.

9th Annual 'Season-total' Snowfall Forecast Contest - UPDATE

Deadline for entries has passed.  Thanks to all who submitted a forecast.

 

Expected to have the forecasts posted this evening but that will have to wait until tomorrow.

Winter '09 / '10 - 9th Annual 'Season-total' Snowfall Forecast Contest - Last Call!

Deadline:  Monday...November 30 2009 @11:59 PM EST

Full details here.

Hope to have forecaster summary posted Tuesday evening...01 December.

Winter '09 / '10 - WSI - November Update

"WSI expects the upcoming period (December-February) to average cooler than normal in the eastern and south-central US, with above-normal temperatures common across the western and north-central US. The WSI seasonal outlooks reference a standard 30-year normal (1971-2000).

"The combination of the current El Nino event, abundant Eurasian snow cover, and a favorable pattern of ocean temperatures in the Atlantic Ocean suggest that this winter will be a cold one in the eastern US, especially after the New Year" said WSI seasonal forecaster Dr. Todd Crawford.

"There are even indications that a significant pattern change will occur in late November and that December may be colder than we are currently forecasting.

"In December, WSI predicts...
Northeast - Warmer than normal

"In January...
Northeast - Colder than normal

"In February...
Northeast - Colder than normal"

More...

NOAA Stays Put in World Wx Building

"The National Oceanic and Atmospheric Administration has extended its lease at its World Weather Building in Suitland, providing an alternative for space as its legal dispute over a new College Park location drags on with the bankrupt Opus East, according to Grubb & Ellis Co., which represents the current landlord.

"The agency will remain for an unspecified time at its longtime home of the National Centers for Environmental Prediction and the National Weather Service. NOAA occupies the 137,004-square-foot facility at 5200 Auth Road.

"Opus East stopped work this summer and sued the General Services Administration for back payments on the College Park project, which was nearly completed. Opus said it put more than $36 million into the complex but that the GSA held up payments over disputed add-on work. The resulting liquidity crunch contributed to Opus Corp. of Minneapolis declaring bankruptcy for Opus East of Rockville."

Source...

Winter '09 / '10 - C-C-C-O-L-D December

Takes ~3 weeks for 10 mb signatures to reach the troposphere

Unless your winter outlook is all-in for a mild DEC in the eastern CONUS...what's not to like about HIGH pressure parked in PNA-land as the winter solstice approaches?

Winter '09 / '10 - Pattern Change

NWP has been hinting at a change in the flow regime for some time.  As early DEC draws near...more and more evidence points toward the arrival of winter wx.

ECMWF height-latitude cross-section forecast for 01-DEC depicts deep layer easterlies near the North Pole...supporting the -AO forecast from the GFS shown above.   Note the long period (into week2) where AO remains well-below zero.

Cold pool aloft shown over central Canada in the 100-mb height-field.  Warm stratosphere ==> cold troposphere.

Excellent antecedent conditions for the season/s 1st coastal teaser.  500 mb heights are a little high but with the 'event' still a week away...taking it one step at a time.  Never want the progs looking too good this far out.