FXUS61 KBOX 222036
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
336 PM EST TUE DEC 22 2009
.SYNOPSIS...
MAINLY DRY AND COLD WEATHER TONIGHT AND WEDNESDAY WILL GRADUALLY
MODERATE BY THURSDAY AND FRIDAY ALONG WITH DIMINISHING WINDS...AS
HIGH PRESSURE CREST OVER NEW ENGLAND. LOW PRESSURE WILL APPROACH
FROM THE SOUTHWEST SATURDAY...WHICH WILL BRING A PERIOD OF WINTRY
WEATHER INLAND WITH MAINLY RAIN AND WIND ALONG THE COAST. THE LOW
AND ITS PRECIPITATION SHIELD MAY DEPART THE REGION LATER
SUNDAY...FOLLOWED BY COLDER AND BLUSTERY WEATHER EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
ANOTHER QUIET BUT CHILLY NIGHT AHEAD. POLAR VORTEX ACROSS NORTHERN
NY STATE DRIFTS EASTWARD INTO NORTHERN NEW ENGLAND. NOT MUCH
MOISTURE ASSOCIATED WITH THIS FEATURE. SO ONLY EXPECTING SOME MID
AND HIGH CLOUDS FROM TIME TO TIME. HOWEVER...AS VORTEX MOVES EAST
MODEST COLD AIR ADVECTION BEGINS ACROSS THE REGION.
REGARDING TEMPS...DID A 50/50 BLEND OF THE COLDER NAM MOS WITH THE
WARMER GFS MOS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
VORTEX BEGINS TO DESCEND SOUTHWARD INTO SOUTHERN NEW ENGLAND DURING
THE AFTERNOON. MID LEVEL LAPSE RATES BEGIN TO STEEPEN AS COLD POOL
ALOFT MOVES OVER THE AREA. ALSO MODELS SUGGEST SOME MODEST QG
FORCING ACROSS RI AND EASTERN MA DURING THE AFTERNOON AND EVENING.
HOWEVER DEEP LAYER MOISTURE IS LACKING SO ONLY EXPECTING SOME
SCATTERED FLURRIES OR A SNOW SHOWER ACROSS THIS REGION.
ELSEWHERE...DRY WEATHER SHOULD PREVAIL.
AS FOR TEMPS...COLDER THAN TODAY AS 850 AND 925 TEMPS COOL BY ABOUT
4C. SO DID A 50/50 BLEND OF THE COLDER NAM MOS AND THE WARMER GFS
MOS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MAIN FORECAST CONCERN REVOLVES AROUND THE TIMING OF PRECIP AND
PRECIP TYPE ASSOCIATED WITH OUR NEXT LOW PRESSURE SYSTEM OVER THE
WEEKEND.
RIDGING SHOULD BE IN CONTROL FOR THURSDAY AND FRIDAY...AND THIS
SHOULD RESULT IN FAIR WEATHER WITH TEMPERATURES NEAR NORMAL OR
SLIGHTLY BELOW. THE ONLY EXCEPTION MAY BE A PORTION OF THE CAPE AND
ISLAND WHERE SOME OCEAN EFFECT SNOW/RAIN SHOWERS COULD OCCUR.
BIG CUTOFF LOW MEANDERS FROM THE UPPER MIDWEST INTO THE LAKES OVER
THE WEEKEND. THIS WILL AID IN PUSHING SFC LOW PRESSURE CLOSER TO
SNE...AS WELL AID IN THE DEVELOPMENT OF A DECENT SELY INFLOW JET. THE
VARIOUS GLOBAL MODELS AGREE IN THE GENERALITIES...BUT DETAILS WITH
SPECIFICS /ESPECIALLY TIMING/ STILL NEED TO BE IRONED OUT. THE GFS IS
PRETTY FAST WITH THE PRECIP SHIELD...BASICALLY BRINGING IT THROUGH
ALL OF SNE BY LATE SATURDAY NIGHT OR EARLY SUNDAY MORNING. THE 12Z
ECMWF IS CONSIDERABLE SLOWER...WITH THE MAIN EVENT OCCURRING DURING
THE DAY SUNDAY. WILL TAKE A COMPROMISE AS FAR AS TIMING OF POPS
GO...BUT TEND TO PREFER THE SLOWER END OF THE GUIDANCE ENVELOPE AS
THE UPPER AIR PATTERN LOOKS TO BE QUITE AMPLIFIED.
AS FAR AS PRECIP TYPE GOES...THIS IS PROBABLY GOING TO BE A MIXED
PRECIP EVENT FOR MUCH OF THE INTERIOR AS COLD SFC AIR PROBABLY GETS
LOCKED IN. WE WILL LIKELY SEE SOME SNOW AT THE START ACROSS THE
INTERIOR...PERHAPS EVEN AT THE COAST...BUT WARMING TEMPS ALOFT WILL
TURN THE PRECIP OVER TO RAIN ON THE COASTAL PLAIN AND FREEZING RAIN
AND SLEET ACROSS THE INTERIOR. THE HEAVIEST PRECIP WILL PROBABLY
OCCUR SATURDAY NIGHT. IT REMAINS TO BE SEEN HOW BIG OF AN ICE EVENT
THIS MAY BE...BUT IT COULD GET PRETTY DICEY ACROSS PORTIONS OF THE
FAR NW INTERIOR AS CLIMATOLOGY SAYS A SFC LOW TRACK CLOSER TO SE MAS
IS MORE LIKELY THAN SOMETHING CUTTING ACROSS THE FAR INTERIOR.
AFTER SUNDAY...FAIRER WEATHER RETURNS BUT WE WILL LIKELY SEE ANOTHER
COLD SHOT ALONG WITH WIND FOR EARLY NEXT WEEK.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
TONIGHT...
VFR WITH DIMINISHING NORTHWEST WIND...EXCEPT GUSTS TO AROUND 25 KT AT
NANTUCKET.
WEDNESDAY...
HIGH CONFIDENCE OF VFR CONDITIONS WITH CIGS050. SCATTERED SNOW
SHOWERS OR FLURRIES LATER IN THE DAY WITH HIGHEST CONFIDENCE AT
MHT/BOS/HYA/FMH AND ACK IN THE AFTERNOON.
WED NIGHT...
VFR CONDITIONS WITH CIGS050. HOWEVER THERE IS A LOW PROBABILITY OF
CIGS020-025 FROM MHT/BOS/FMH/HYA/ACK. SCATTERED SNOW SHOWERS OR
FLURRIES AT THESE TERMINALS AS WELL WITH VSBYS GREATER THAN 6SM.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY THROUGH FRIDAY...VFR.
SATURDAY...VFR POSSIBLY BECOMING MVFR OR IFR LATE IN RAIN OR MIXED
PRECIPITATION.
SATURDAY NIGHT AND SUNDAY...IFR LIKELY SATURDAY NIGHT INTO EARLY
SUNDAY WITH RAIN OR MIXED PRECIP. IMPROVEMENT FORESEEN BY LATE
SUNDAY. CONFIDENCE LOW ON TIMING ATTM.
&&
.MARINE...
TONIGHT...
NORTHWEST WINDS AROUND 25 KNOTS ALONG WITH SOME FREEZING SPRAY
POSSIBLE.
WEDNESDAY...
NORTHWEST WINDS 20 TO 25 KNOTS CONTINUE. SCATTERED SNOW SHOWERS
ACROSS EASTERN MA WATERS MAY REDUCE VSBY.
WED NIGHT...
WINDS BECOME NORTHERLY LATE WITH SPEEDS UP TO 30 KT. FREEZING SPRAY
POSSIBLE.
OUTLOOK...THURSDAY THROUGH SUNDAY...
SMALL CRAFT CONDITIONS LIKELY OVER MUCH OF THE PERIOD WITH
SOUTHEASTERLY GALES POSSIBLE SATURDAY NIGHT AND SUNDAY IN ADVANCE OF
APPROACHING SURFACE LOW PRESSURE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR ANZ230>237-
250-251-254>256.
&&
$$
SYNOPSIS...NOCERA
NEAR TERM...NOCERA
SHORT TERM...NOCERA
LONG TERM...EKSTER
AVIATION...NOCERA/EKSTER
MARINE...NOCERA/EKSTER
