Another significant one Thursday

[wxwatcher91]

000
FXUS61 KBOX 102133
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
358 PM EST SAT DEC 10 2005

LONG TERM (MONDAY THROUGH SATURDAY)...
...GENERALLY DRY AND UNSEASONABLY COLD WITH A SIGNIFICANT WINTRY
WEATHER EVENT POSSIBLE THURSDAY INTO FRIDAY...
A LONG WAVE TROUGH WILL BE PROGRESSING THROUGH THE FORECAST AREA
MONDAY. A SHORT WAVE DISTURBANCE ASSOCIATED WITH THE LONG WAVE
TROUGH WILL BE PIVOTING THROUGH THE FORECAST AREA MONDAY EVENING.
700 MILLIBAR TEMPERATURES DROP TO MINUS 20 CELCIUS CAUSING LAPSE
RATES TO STEEPEN. SNOW SHOWERS WILL THEREFORE BE POSSIBLE MONDAY
AFTERNOON AND EVENING. IN ADDITION...WINDS BEGIN TO SHIFT TO NORTH
AS HIGH PRESSURE GRADUALLY BUILDS FROM THE WEST. THE WIND TRAJECTORY
APPEARS FAVORABLE FOR OCEAN EFFECT SNOW SHOWERS ACROSS OUTER CAPE
COD AND NANTUCKET MAINLY TUESDAY AFTERNOON AND NIGHT. GFS BUFKIT
INDICATES OMEGA WITHIN THE FAVORABLE SNOW GROWTH REGION BETWEEN THE
SURFACE AND 850 MILLIBARS. WIND SHEAR AND WIND VELOCITIES ARE
EXPECTED TO DECREASE WITH TIME WITHIN THE BOUNDARY LAYER. LATER
SHIFTS WILL NEED TO MONITOR THIS FOR POTENTIAL SNOW ACCUMULATIONS.
HIGH PRESSURE BUILDS OVER THE FORECAST AREA WEDNESDAY WITH
INCREASING SUBSIDENCE AND UNSEASONABLY COLD TEMPERATURES. LONG RANGE
GUIDANCE CONTINUES TO DIVERGE SIGNIFICANTLY REGARDING THE THE IMPACT
OF THE NEXT POTENTIAL SIGNIFICANT WINTRY WEATHER EVENT. THE GFS
APPEARS TOO AGGRESSIVE AND PROGRESSIVE SENDING PUSHING A 1030MB
HIGH EASTWARD OUT TO SEA BY THURSDAY. THE ECMWF IS LESS PROGRESSIVE
AND INDICATES A DEEPER LONG WAVE TROUGH FORMING ACROSS THE MIDWEST
WITH A 1033 MB HIGH ACROSS THE CANADIAN MARITIMES. THE UKMET IS THE
DEEPEST AND LEAST PROGRESSIVE MODEL WITH THE DEEPEST MIDWESTERN LONG
WAVE TROUGH AND A 1047MB HIGH CENTERED OVER THE CANADIAN MARITIMES.
THUS THERE REMAINS SIGNIFICANT UNCERTAINTY REGARDING THE TIMING OF
PRECIPITATION...PRECIPITATION TYPE...PRECIPITATION AMOUNTS AND
TEMPERATURES IN THE EXTENDED RANGE. THEREFORE DID NOT MAKE MANY
CHANGES TO THE PREVIOUS FORECAST. GENERALLY DISCARDED THE 12Z GFS
RUN AND RELIED MORE HEAVILY ON THE ECMWF/UKMET SOLUTIONS. THE
+PNA/-NAO PATTERN WOULD BETTER VERIFY THESE SOLUTIONS. IN ADDITION
THE GFS DOES NOT APPEAR TO PICK UP ON ANY LOW LEVEL COLD AIR DAMMING
DURING THIS UPCOMING EVENT. GENERALLY RELIED ON CLIMATOLOGICAL
NORMALS FRIDAY AND BEYOND.


precip is more in question this time even inland.

[WindRunner]

Yeah, it looks to be mostly a rain event for Mid-Atlantic.