storms for Christmas and New Years

[wxwatcher91]

http://www.eastcoastwx.net/forums/showthread.php?t=4

[wxwatcher91]

000
FXUS61 KBOX 201058
AFDBOX

AREA FORECAST DISCUSSION..UPDATED LT AS FINAL..
NATIONAL WEATHER SERVICE TAUNTON MA
557 AM EST TUE DEC 20 2005

...COLDER THAN NORMAL UNTIL THE WEEKEND WHEN FIRST OF TWO MIXED
COMPLEX EVENTS DEVELOP WITHIN THE PERIOD 12/25-1/1...

.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
TEMP FCST IN THIS SECTION IS A MIX OF ECMWF GFS OP RUNS AND THE
18Z/19 GFS ENS 850 TT AND 18Z-00Z GFS ENS 2M TEMP FCST. THINK THERE
IS SOME USEFUL CONFIDENCE-GUIDANCE IN THE RESEARCH IN PROGRESS FOR 2M
TEMP SPAGHETTI ENSEMBLES AS POSTED HTTP://MOE.FSU.EDU/CONFIDENCE/

WED NIGHT-THU...SORT OF A WINDEX TYPE EVENT DURING THU MORNING AS
ANOTHER COLD FRONT CROSSES THE REGION WITH A REINFORCING COLD SURGE
THURSDAY. GENERAL NW BL-850 MB WIND FLOW MAY PREVENT WIDESPREAD
ACCUMULATIVE SNOW EVENT FOR THE OUTER CAPE OR ACK THU MORNING BUT
NEEDS REEVALUATION. BUMPED THE POPS UP IN THE OUTER WATERS
ESPECIALLY.

FRI..BEGINS WARMING TREND. CLOUD COVER MAY LIMIT THE POTENTIAL
WARMING BELOW WHAT IS NOW FORECAST. COULD BE FLURRIES OR MINOR MEAS
SNOW NW PTN OPF THE FCST AREA. FOR NOW CONTINUITY ON POPS.

SAT...CONTS THE WARMING TREND.

SUNDAY INTO MON...THE 00Z/20 GFS ENS HAVE TRENDED CONSIDERABLY DEEPER
WITH THE TROF AS IT CROSSES 80W AT 00Z/26 WITH -2SD 500 FLOW CROSSING
GEORGIA...A NICE CONFLUENCE ZONE IN QUEBEC AND MAKINGS FOR A NICE NE
COAST STORM.

MULTIMODEL SUGGESTION OF ANYWHERE FM 2 TO 22 HOURS OF
PRECIPITATION...TENDENCY FOR RAIN COAST AND MIXED PCPN WELL INLAND.
WHILE A SUBSTANTIAL TROF WILL MOVE FROM THE PLAINS TO THE E COAST
OVER THE WEEKEND...THE LA/LO OF THE SFC LOW PRES REDEVELOPMENT IS
HIGHLY UNCERTAIN. FOR NOW KBOX GRIDS RAISED POPS TO 50-60 PCT IN THE
12 HR PERIODS INCLUSIVE OF 12/25...REALIZING WHILE TIMING
UNCERTAIN...AN EVENT IS CERTAIN! WHAT KIND OF EVENT IT IS...IS
UNCERTAIN. GFS ENS 24 HR POPS FOR .60 ARE DRAMATICALLY HIGHER THAN
PREV RUNS...WHETHER THIS TREND HOLDS WE ARENT SURE...ESP SINCE UKMET
AND NOGAPS DONT WANT MUCH TO DO WITH THE GFS/GGEM/ECMWF E COASTER.
THOSE 00Z/20 GFS ENS POPS BTW ARE NOW 60+ PCT FOR THE I95 CORRIDOR
EWD. THIS EVEN HAS A 15 PCT POP 2" AT 44013. SO...WE'RE LOOKING AT A
SYSTEM OF POTENTIAL SUBSTANCE HERE (TALKING DAY 5-6 INDICATIONS).


TUE AND BEYOND...ANOTHER 5H TROF TO THE E COAST. TIMING AND IMPACT
UNCERTAIN. FOR NOW ITS DPROG/DT TREND IS A BIT WEAKER AND FURTHER S
THAN THE FIRST EVENT OF THE 25-26TH. ITS PRIMARY DAYS OF IMPACT
SEEMINGLY ARD THE 30TH-31ST THO WE SAW A GLIMPSE OF THE ECMWF 180 HR
WHICH WAS MUCH MUCH SOONER. HPC PREEPD THINKING IS TO NOT PUT A LOT
OF STOCK INTO THIS RUN OF THE EC OPERATIONAL. ANYWAY...THERE IS LESS
CERTAINTY ON THIS SECOND EVENT TRANSLATING THIS FAR N...BUT THE DOOR
IS OPEN...EVEN POP WISE.

ON THE ABOVE: THE 06Z OP GFS RUN HAS SWAPPED PRIMARY SUBSTANTIAL
IMPORTANCE FROM EVENT ONE TO EVENT TWO. SUFFICE TO SAY...THOSE WITH
WINTER INTERESTS INCLUDING TRAVEL WILL PROBABLY WANT TO START A
CLOSER MONITORING OF FCST TRENDS-CONFIDENCE FOR THE PERIOD 12/25-
1/1/06. WE JUST DONT KNOW WHAT WILL TRANSPIRE YET BUT THE POTENTIAL
EXISTS FOR A SIGNIFICANT WINTER EVENT.

[Steve Carpenter]

Just to add fuel to the fire, from the NWS for the WNC Mountains:

LONG TERM (THURSDAY NIGHT THROUGH MONDAY)...
DRY HIGH PRESSURE REMAINS PARKED ACROSS THE AREA THROUGH LATE-WEEK.
BY LATE SATURDAY...HEIGHTS WILL BEGIN TO FALL IN RESPONSE TO
DEVELOPING PLAINS STORM. FOR CHRISTMAS DAY...THE LATEST RUNS OF THE
GFS AND THE CANADIAN MODEL REPRESENT A RADICAL DEPARTURE FROM
EARLIER MODEL RUNS...AS BOTH NOW DEPICT A SIGNIFICANT SNOW EVENT
DEVELOPING ACROSS THE MNTNS...WITH MEASURABLE SNOWFALL A POSSIBILITY
IN THE FOOTHILLS AND PORTIONS OF THE PIEDMONT. FOR OBVIOUS
REASONS...WILL DEFER TO THE DAY SHIFT AND EXTENDED RANGE
COLLABORATION BEFORE MAKING ANY RADICAL CHANGES TO THE FORECAST.