26 forecasters...including 10 rookies...issued 550 stations forecasts for this season/s inaugural snow storm. Forecasts are ranked by storm total precipitation (STP) in ascending order. Blue (red) values are in the 25th (75th) percentile.
Consensus heavy snowfall axis from IAD - DCA - BWI - PHL - EWR - JFK - ISP -ACY - IAD.
Amplifying flow regime evidenced by rising PNA and cold air source indicated by strongly negative values for NAO and AO. Oscillations come on the heels of a minor stratospheric warming event that slowed and split the PV. Arctic region surface pressure rose as the one piece of the PV moved from eHEMI to wHEMI...where opposing flow between the two circulations created weak ridging near the pole.
986 surface LOW over HSE SAT 19-DEC-09 at 12z crawls to a position abeam the southern end of Delmarva peninsula 12 hours later laying down a wide swath of heavy snow from VA to MD on its way to SNE.
Verification period ends 11:59 PM EST...SUN 20-DEC-09. Preliminary storm-total snowfall totals will be posted the evening of MON 21-DEC-09.