FXUS61 KBOX 101535
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1035 AM EST THU DEC 10 2009
.SYNOPSIS...
LARGE LOW PRESSURE OVER SOUTHEAST CANADA WILL CIRCULATE BLUSTERY AND
UNSEASONABLY COLD WEATHER INTO SOUTHERN NEW ENGLAND LATER TODAY AND
CONTINUING INTO THIS WEEKEND. A WARM FRONT MAY APPROACH FROM THE
SOUTH BY MONDAY. A PERIOD OF RAIN AND OR SNOW SHOWERS MAY OCCUR
TUESDAY IN ASSOCIATION WITH LOW PRESSURE AND AN APPROACHING COLD
FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SUPPRESSED JET STREAM RESULTS IN BELOW NORMAL COLD THIS PERIOD.
MUCH COLDER AND BLUSTERY WEATHER BEHIND THE FRONT WITH HIGH TEMPS
TODAY PROBABLY OCCURRING LATE THIS MORNING...THEN HOLDING STEADY
EARLY THIS AFTERNOON AND THEN FALLING QUICKLY LATE TODAY.
DRY WEATHER TODAY ALTHOUGH CAN/T RULE OUT A STRAY SNOW SHOWER
SPILLING OVER THE BERKS AS THE LAKE-EFFECT SNOW MACHINE GETS
CRANKING. COULD ALSO HAVE SOME OCEAN-EFFECT CLOUDS AND SHOWERS NEAR
NANTUCKET AS COLD AIR ADVECTION IS DELIVERED ON SOUTHWEST WINDS
VEERING TO WEST. LOW LEVEL TRAJECTORY BECOMES WESTERLY SO CLOUDS AND
PRECIP SHOULD STAY JUST SOUTH OF NANTUCKET...ALTHOUGH IT COULD BE
CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...
COLDEST AIR OF THIS EARLY WINTER/AUTUMN SEASON ARRIVES TONIGHT WITH
850 TEMPS FALLING TO -16C/-17C! GUSTY WEST WINDS WILL PROVIDE WIND
CHILLS AROUND ZERO ACROSS THE INTERIOR WITH SINGLE DIGITS ELSEWHERE.
PREFERRED THE COLDER METNAM GUIDANCE GIVEN MAGNITUDE OF COLD AIR
ALONG WITH SNOW COVER ACROSS MUCH OF THE AREA ALONG AND NORTHWEST OF
I95.
SHOULD BE A DRY NIGHT FOR MOST IF NOT THE ENTIRE REGION. AS MENTIONED
ABOVE GIVEN THIS COLD WESTERLY FLOW REGIME CAN/T RULE OUR A STRAY
SNOW SHOWER SPILLING OVER THE BERKS INTO THE AREA.
WIND GUSTS WILL BE NEAR 45 MPH SO LATER SHIFTS WILL HAVE TO EVALUATE
POTENTIAL FOR A WIND ADVISORY TONIGHT AND FRI.
FRIDAY...
MORE OF THE SAME - DRY BUT BITTERLY COLD WITH GUSTY WEST WINDS
YIELDING WIND CHILLS IN THE TEENS TO NEAR 20. MOST LOCATIONS WILL
STRUGGLE TO HIT THE FREEZING MARK WITH INLAND LOCATIONS ONLY CLIMBING
INTO THE 20S! AGAIN...LEANED TOWARD THE COLDER METNAM GIVEN VERY COLD
TEMPS ALOFT SNOW COVER ACROSS MUCH OF THE AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRIDAY NIGHT...BRISK WNW FLOW PREVAILS. OPERATIONAL 00Z GFS FEATURES
A MORE ROBUST RH FIELD AT H85 IN RESPONSE TO LAKE MOISTURE ADVECTING
ESE ACROSS THE BERKSHIRES AND PORTIONS OF SOUTHERN NEW ENGLAND. THIS
WILL DEPEND ON THE TIMING OF SHORT WAVE DISTURBANCES TRACKING ACROSS
THE AREA. WIND TRAJECTORY AND TIMING FOR SHSN APPEARS MORE OPTIMAL
ON THE 00Z GFS COMPARED TO THE NAM. OVERALL HAVE INCLUDED SLIGHT TO
LOW CHANCE POPS AT THIS TIME.
SATURDAY...SCT LAKE EFFECT MORNING SHSN POSSIBLE. OTHERWISE HIGH
PRESSURE BUILDS ACROSS THE AREA WITH INCREASING SUBSIDENCE. A DRY
DAY EXPECTED BUT TEMPERATURES REMAIN COLDER THAN NORMAL. MOSGUIDE
NUMBERS LOOK TOO WARM. USED A 70/30 BLEND OF RAW 2M TEMPS AND
MOSGUIDE FOR HIGHS.
SUNDAY...TIMING ISSUES WITH RESPECT TO THE ARRIVAL OF AN INVERTED
TROUGH. NAM/ECMWF/UKMET ARE LESS PROGRESSIVE WHILE THE GFS/CANADIAN
GLOBAL ARE FASTER WITH SOUTHERN STREAM SHORT WAVE ENERGY QUICKLY
EJECTING FROM THE PLAINS STATES WITH A WARM FRONT APPROACHING FROM
THE SOUTH. HAVE DECIDED TO HOLD TIMING OF PRECIPITATION THREAT UNTIL
SUNDAY NIGHT AT THIS TIME...REFLECTIVE OF THE MORE AMPLIFIED
NAM/ECMWF/UKMET. ALSO PLENTY OF DRY AIR WILL REMAIN IN PLACE
ESPECIALLY TO START THE DAY EVEN WITH THE MORE PROGRESSIVE SOLUTIONS.
OTHERWISE SHOULD SEE SOME MODERATION IN TEMPERATURES SUNDAY WITH THE
LOSS OF COLD AIR ADVECTION AND ALSO AS THE WIND SHIFTS TO THE SOUTH
SOUTHWEST.
MONDAY THROUGH WEDNESDAY...SIGNIFICANT DIFFERENCES EXIST BETWEEN
THE LONG RANGE MODELS AND ENSEMBLES REGARDING THE TIMING OF THE
FOLLOWING STRONG COLD FRONT AND PRECIPITATION THREAT. GENERALLY
FAVORED THE MORE AMPLIFIED 00Z ECMWF...BUT ALSO DID SOME BLENDING
WITH THE 00Z GFS AND 18Z HPC GUIDANCE. OVERALL PRECIPITATION CHANCES
INCREASE EARLY NEXT WEEK WITH SOME MODERATION IN TEMPERATURES WHICH
SHOULD BE FOLLOWED BY THE RETURN OF MUCH COLDER AND DRIER AIR EITHER
WEDNESDAY OR SHORTLY THEREAFTER.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
TODAY...
WIND GUSTS TO 30 KT WILL BE COMMON AT ALL TERMINALS BEHIND A COLD FRONT.
ANY CIGS THAT DEVELOP THIS AFTERNOON WILL FORM AROUND 040.
TONIGHT...
STRONG WEST WINDS CONTINUE WITH GUSTS 30 TO 40 KT ALL TERMINALS. VFR
CONDITIONS WITH PATCHY CIGS 040.
FRIDAY...
MORE OF THE SAME WITH STRONG WEST WINDS GUSTING TO 30-35 KT. VFR WITH
PATCHY CIGS 040.
OUTLOOK /FRI NIGHT THROUGH MONDAY/...
FRIDAY NIGHT AND SATURDAY...VFR CONDITIONS. W WINDS GUSTING UP TO
30 KT AT TIMES. COULD SEE LOCALIZED MVFR OR IFR FRIDAY NIGHT AND
SATURDAY MORNING WITH SCT SHSN.
SATURDAY NIGHT...VFR. WINDS DIMINISHING.
SUNDAY...VFR.
SUNDAY NIGHT AND MONDAY...MVFR CONDITIONS POSSIBLE IN -SHRA/-SHSN AS
A COLD FRONT ADVANCES ACROSS THE AREA.
&&
.MARINE...
TODAY...
WIDESPREAD WEST GALES CONTINUE BEHIND A COLD FRONT. LARGE LEFTOVER
SE SWELLS WILL COMBINE WITH BUILDING WESTERLY WIND WAVES TO CREATE
HAZARDOUS SEAS /STEEP AND CHOPPY/.
TONIGHT AND FRI...
WEST GALES CONTINUE WITH GUSTS TO 40 KT.
OUTLOOK /THURSDAY NIGHT THROUGH MONDAY/...
FRIDAY NIGHT AND SATURDAY...GALE WARNINGS WILL LIKELY CONTINUE FOR
WNW WIND GUSTS TO 35 TO 40 KT AS COLD AIR ADVECTION CREATES
FAVORABLE WIND MOMENTUM TRANSFER ACROSS THE WATERS.
SATURDAY NIGHT AND SUNDAY...LEFTOVER GALE SATURDAY EVENING THEN
REPLACED BY SMALL CRAFT ADVISORIES AS WINDS DIMINISH. LEFTOVER
HAZARDOUS SEAS ACROSS THE WATERS SUNDAY.
MONDAY...SOME UNCERTAINTY EXISTS DEPENDING ON THE DEVELOPMENT OF
COASTAL LOW PRESSURE OFF THE MID ATLANTIC COAST. SHIFTING WINDS
EXPECTED. COULD BE MARGINAL WIND GUSTS TO 20 TO 25 KT WITH SEAS NEAR
5 FT ACROSS THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ230>237-250-251-
254>256.
&&
$$
SYNOPSIS...NOCERA/STRAUSS
NEAR TERM...BELK
SHORT TERM...NOCERA
LONG TERM...STRAUSS
AVIATION...NOCERA/BELK/STRAUSS
MARINE...NOCERA/STRAUSS
