Monday, November 23, 2009

"Adopt the pace of nature;
her secret is patience."
- Ralph Waldo Emerson

6:00 AM TUESDAY, 11-24-09 Synopsis of 10-day forecast trend for the Mid-Atlantic region, including metro areas of Washington, Baltimore, Philadelphia, New York:

Wed 11/25 - Thu 11/26 For the I-95 corridor...chilly with occasional showers. By Thursday, possible evening rain/snow mixed for elevations 500' and above. Interior Mid-Atlantic sees a mix of rain and snow, changing to snow and increasing toward nightfall.

Fri 11/27 - Sat 11/28 A coastal "MIX"storm brings noticeably cooler temperatures, with accumulating snowfall possible for western Maryland, West Virginia, central Pennsylvania, interior New York, northern New England. Some computer models continue to show potential for snow to be "falling" in the I-95 corridor by Friday morning.

Sun 11/29 - Mon 11/30 A significant pattern shift follows the storm, with chilly and dry conditions in it's wake. Portions of a -20 to -40 F air mass in central Alaska* will move southeast to central Canada, supporting snowpack recovery. This may lead to initial stages of a 2-week cross-polar flow from Siberia, increasing potential for colder conditions downstream across the Eastern U.S.**

Tue 12/1- Sat 12/5 Increasing probability of the Mid-Atlantic's first significant snowfall (4" or greater) for this season.*** This period should feature below-normal temperatures, positive PNA and neutral to negative NAO (per HPC 11-21) coupled with active subtropical jet.

* Links and data provided by colleague and reader Mr. B at Penn State Univ.
** Analysis by meteorologists on the Eastern US Weather Board;
*** Original forecast from 10/19 & 10/28, refined 11/1 & 11/10-11

NWS Forecast discussions (examine their "long-term" comments):
Baltimore-Washington  | Mount Holly, NJ  | State College, PA 

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