FXUS61 KGYX 051012
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
512 AM EST SAT DEC 5 2009
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE WILL MOVE EAST OF THE AREA TODAY. LOW
PRESSURE FORMING OFF THE SOUTHEAST COAST THIS MORNING WILL
INTENSIFY AND MOVE TO THE NORTHEAST THIS AFTERNOON AND TONIGHT.
HIGH PRESSURE WILL BUILD TO THE SOUTH OF THE AREA SUNDAY AND
MONDAY. A WEAK DISTURBANCE WILL CROSS THE AREA LATE MONDAY AND
MONDAY NIGHT. AN AREA OF HIGH PRESSURE FOLLOWS FOR TUESDAY AND
EARLY WEDNESDAY. LOW PRESSURE WILL APPROACH FROM THE GREAT LAKES
ON WEDNESDAY, THEN REDEVELOP ALONG THE MID ATLANTIC COAST AND
TRACK NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT AND
EARLY THURSDAY. THIS SYSTEM WILL GRADUALLY EXIT INTO THE MARITIMES
LATE THURSDAY INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE TO INPUT LATEST OBSERVED DATA. NO REAL CHANGES AT THIS TIME
OTHER THAN A FEW MINOR TWEAKS.
WEAK AREA OF HIGH PRES SLIDES ACROSS THE REGION TDA. LOW PRES
FORMS OFF THE SE COAST THIS MORNING THE TRACKS TO THE NE AND
INTENSIFIES. THIS SPREADS SN N INTO THE FCST AREA LATE TDA.
DEPENDING ON BOUNDARY LAYER TEMPS THE PRCP MAY START AS A MIX OF RN
AND SN...BUT WITH EVAPORATIONAL COOLING SHOULD QUICKLY CHANGE TO
ALL SN. WINDS PICK UP FROM THE N AS THE LOW APPROACHES. THIS WILL
BRING IN SOME DRIER AIR FROM THE N WHICH MAY SLOW DOWN ONSET OF
PRCP BUT ALSO HELP CHANGE OVER TO SN. GENERALLY USED THE GFS40
WITH A BLEND OF MAV AND MET MOS FOR TEMPS AND DEW POINTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE LOW CONTINUES TO INTENSIFY AND TRACK TO THE NE. AT THIS TIME
MODELS CONT TO SHOW THE LOW TRACKING OUTSIDE THE 40N 70W LAT/LON
BENCHMARK FOR A SIGNIFICANT SNOW EVENT FOR THE FCST AREA. MODELS
STILL VARYING IN HOW THEY HANDLE THIS EVENT BUT MOST LIKELY
SCENARIO AT THIS TIME SUGGESTS LIGHT ACCUMULATIONS OF SNOW WITH
HIGHEST AMOUNTS NEAR THE COAST AND LOWEST AMOUNTS WELL INLAND.
ACCUMULATIONS EXPECTED TO BE LESS THAN 4 INCHES AS SUPPORTED BY
HPC SNOW FCST. THUS NO HEADLINES (IN PARTICULAR A WINTER WX
ADVISORY) WILL BE ISSUED AT THIS TIME. SE NEW HAMPSHIRE IS THE
AREA THAT HAS THE BEST CHC OF REACHING WINTER WX CRITERIA OF 4 OR
5 INCHES OF SNOW. GENERALLY USED THE GFS40 WITH A BLEND OF MAV
AND MET MOS FOR TEMPS AND DEW POINTS.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LATEST AVAILABLE ECMWF AND GFS WERE IN DECENT AGREEMENT THROUGH
NEXT THURSDAY. EVOLVING PATTERN RESULTS IN A DEEP TROUGH VICINITY
OF THE FOUR CORNERS REGION WITH A CLOSED LOW SITUATED JUST WEST OF
HUDSON BAY. THE RESULTING WEST-SOUTHWEST FLOW ALOFT WILL ALLOW
ARCTIC AIR TO SEEP SOUTHWARD INTO THE NORTHEAST AND PLAINS AND
GIVE RISE TO A MAJOR DISTURBANCE IN THE FOUR CORNERS REGION BY
EARLY NEXT WEEK. EARLY INDICATIONS ARE THAT THIS SYSTEM WILL
APPROACH THE AREA BY MID WEEK WITH A TRACK AND SUBSEQUENT COASTAL
DEVELOPMENT THAT FAVORS A WINTRY MIX...CHANGING TO RAIN ALONG THE
IMMEDIATE COAST.
OTHERWISE...COLD AND RATHER QUIET THIS PERIOD WITH ONLY OTHER
SYSTEM OF NOTE A WEAK DISTURBANCE THAT MAY TOUCH OFF A FEW SNOW
SHOWERS LATE MONDAY AND MONDAY NIGHT AS IT CROSSES THE AREA.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH TONIGHT/...VFR CONDITIONS LWR TO IFR AS SNOW
DEVELOPS LATE TDA AND CONTINUES THRU THE NGT. THE EXACT TRACK OF
THE OCEAN LOW WILL DETERMINE HOW MUCH SNOW FALLS AND AS A RESULT
IF CONDITIONS ONLY LWR TO MVFR (IN PARTICULAR FOR AREAS AWAY FROM
THE COAST) IF THE TRACK IS FURTHER OUT TO SEA OR IF THEY LWR TO
LIFR WITH A TRACK CLOSER TO THE COAST. N WINDS PICK UP AND BECOME
GUSTY AS WELL.
LONG TERM...MVFR POSSIBLE LATE MON AND MON NIGHT IN SNOW
SHOWERS. IFR POSSIBLE WEDNESDAY IN SNOW.
&&
.MARINE...
SHORT TERM /TODAY THROUGH TONIGHT/...UPDATE TO INPUT LATEST
OBSERVED DATA. NO REAL CHANGES AT THIS TIME OTHER THAN A FEW MINOR
TWEAKS. WINDS INCREASE AS OCEAN LOW INTENSIFIES AND MOVES TO THE
NE TDA AND TNGT. NORTHERLY WINDS AND GUSTS INCREASE THRU THE SHORT
TERM...REACHING SMALL CRAFT ADVISORY OVER THE BAYS AND GALE FORCE
OVER THE REST OF THE WATERS BY MIDNIGHT TNGT...THEN CONTINUING
THRU THE NGT. SEAS WILL BUILD QUICKLY IN RESPONSE TO THE
INCREASING WINDS AND APPROACHING LOW.
LONG TERM...GALE MAY LINGER SUNDAY MORNING...WITH SMALL CRAFT
WINDS AND SEAS LIKELY FOR THE BALANCE OF SUNDAY. GALE FORCE WINDS
ARE POSSIBLE WEDNESDAY.
&&
.TIDES/COASTAL FLOODING...
NOT EXPECTING ANY PROBLEMS WITH THE UPCOMING OCEAN STORM DESPITE
HIGH ASTRONOMICAL TIDES. THE PWM PREDICTED TIDE IS 11.0 FT AT 1247
PM TODAY. GENERALLY LGT WINDS WILL BE FROM THE N WITH NOT MUCH
WAVE ACTION. DURING THE HEIGHT OF THE EVENT THE 133 AM SUNDAY
PREDICTED TIDE FOR PWM IS ONLY 9.5 FT AND WINDS WILL BLOW
OFFSHORE. THEN ON SUNDAY AS OFFSHORE WINDS BACK TO NW AND SEAS
BEGIN TO SUBSIDE THE PREDICTED TIDE IS 10.7 FT AT 143 PM. SO
LIMITED IF ANY STORM SURGE AS INDICATED BY GFS STORM SURGE FCSTS
AND HIGHEST WAVES OCCUR WITH THE LWR TIDE OVERNIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR ANZ151-153.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST SUNDAY FOR
ANZ150-152-154.
&&
$$
