FXUS61 KBOX 231750
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1250 PM EST WED DEC 23 2009

.SYNOPSIS...
DRY AND COLD WEATHER WILL GRADUALLY MODERATE THURSDAY AND FRIDAY
ALONG WITH DIMINISHING WINDS...AS HIGH PRESSURE CRESTS OVER NEW
ENGLAND. LOW PRESSURE WILL APPROACH FROM THE SOUTHWEST
SATURDAY...WHICH WILL BRING A PERIOD OF WINTRY WEATHER INLAND AND
MAINLY RAIN AND WIND ALONG THE COAST. THE LOW AND ITS PRECIPITATION
MAY DEPART THE REGION LATER SUNDAY...FOLLOWED BY COLDER AND BLUSTERY
WEATHER EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT MUCH CHANGE FROM PREVIOUS FORECAST AS NEW 12Z SOUNDINGS FROM
CHATHAM AND ALBANY INDICATE FULL SUN TEMPS OF ONLY 20-25 FOR THIS
AFTERNOON. PREVIOUS FORECAST REFLECTS THIS WELL. COLD AIRMASS ON
NORTHWEST WINDS GENERATING LOTS OF STRATO-CU OVER THE OUTER CAPE FROM
EASTHAM NORTHWARD TO PROVINCETOWN MA. COULD SEE SOME FLURRIES WITH
THIS ACTIVITY THIS AFTERNOON. ALSO SOME SNOW SHOWERS OVER THE
BERKSHIRES MAY SPILL INTO THE UPPER CT RIVER VALLEY THIS AFTERNOON. 

POLAR VORTEX OVER NORTHERN NEW ENGLAND AS SEEN ON LATEST WATER VAPOR
IMAGERY WILL CONTINUE TO DRIFT SOUTHWARD THIS AFTERNOON. VERY COLD
AIR ALOFT ASSOCIATED WITH THIS FEATURE WILL STEEPEN MID LEVEL LAPSE
RATES ESPECIALLY ACROSS EASTERN MA. ALSO SOME MID AND UPPER LEVEL QG
FORCING ASSOCIATED WITH DESCENDING VORTEX. HOWEVER MOISTURE IS
LIMITED WITH COLUMN REMAINING FAIRLY DRY. THEREFORE NOT EXPECTING
MUCH MORE THAN SCATTERED FLURRIES OR SNOW SHOWERS ACROSS EASTERN MA
LATE TODAY AND THIS EVENING.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
THE UPPER LOW MOVES EAST OUT TO SEA TONIGHT WHILE A GREAT LAKES UPPER
RIDGE BUILDS EAST. EXPECT CLEARING SKIES IN THE CT VALLEY AND OTHER
WESTERN SECTIONS. THERE MAY BE A CLEARING TREND LATER IN THE NIGHT
IN THE EAST...BUT WITH SURFACE WINDS SHIFTING FROM NORTHWEST TO
NORTHEAST BY MORNING THIS MAY RETARD THE DEPARTURE OF CLOUD COVER.

RIDGE BUILDS IN SURFACE AND ALOFT FOR THURSDAY AND FOR CHRISTMAS DAY
WITH THE SURFACE RIDGE PASSING NORTH OF NEW ENGLAND. THIS WILL BRING
OUR WINDS AROUND TO NORTHEAST OFF THE GULF OF MAINE. SO EVEN THOUGH
THE COLDEST AIR MOVES OFF WITH THE DEPARTING LOW...A COOL SURFACE
LAYER OF AIR SHOULD REMAIN. THIS AND THE EXISTING SNOWPACK WILL BE A
RESISTING INFLUENCE ON ANY LATE WEEK WARMING TREND. SKY COVER
FORECAST GRIDS LINGER IN THE 25-50 PERCENT RANGE ESPECIALLY FRIDAY IN
ANTICIPATION OF INCREASING CIRRUS. TEMPERATURES ARE AGAIN A BLEND OF
MOS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE MODELS STILL STRUGGLING IN HANDLING THE MOVEMENT OF 
STRONG LOW PRES AND ITS ASSOCIATED CUTOFF UPPER LOW ACROSS THE 
CENTRAL U.S. INTO THE GREAT LAKES...THEN ANOTHER WEAKER LOW AND 
ASSOCIATED FRONT INTO NORTHEASTERN U.S. WITH THE HIGH AMPLITUDE 
BLOCKING PATTERN IN PLACE...MODELS HAVE SHOWN SOME CONSISTENCY IN 
SLOWING THE ARRIVAL OF THE SECOND LOW AND FRONT INTO THE REGION 
UNTIL SATURDAY...THOUGH WHEN IT WILL EXIT IS STILL IN QUESTION. 
NOTED THAT THE ECMWF...WHICH HAD BEEN ON THE SLOWER SIDE OF THE 
SOLUTION ENVELOPE...HAS COME IN A BIT FASTER ON ITS 00Z OP RUN. 
LEANED TOWARD A BLEND OF THE EC AND GFS ENSEMBLES FOR THIS PORTION 
OF THE FORECAST. TOUGH TO CALL HOW THE SENSIBLE WEATHER WILL RESOLVE 
BEYOND MONDAY...AS ALL IS DEPENDENT UPON THE EXIT OF THE LOW AND 
FRONT.

FRIDAY NIGHT...LOOKS LIKE IT WILL REMAIN DRY ON CHRISTMAS 
NIGHT...THOUGH CLOUDS CURRENTLY FORECAST TO INCREASE. HAVE LOWERED 
TEMPS A BIT FROM PREVIOUS FORECAST CONSIDERING THAT PRECIP WILL HOLD 
OFF...ESPECIALLY WELL INLAND. 

SATURDAY-SUNDAY...HAVE BROUGHT PRECIP INTO THE REGION FROM W-E 
DURING THE DAY SATURDAY. BIG QUESTION BEYOND THE MOVEMENT OF THE LOW 
AND FRONT WILL BE HOW QUICKLY THE COLD TEMPS SCOUR OUT WELL INLAND. 
PRECIP MAY START OFF AS A WINTRY MIXTURE ACROSS THE COLDER VALLEYS 
OF S NH/N CENTRAL MA...BUT SHOULD CHANGE OVER. 

HEAVIEST PRECIP DUE TO PUSH IN SATURDAY NIGHT...WITH RAIN FALLING 
HEAVILY AT TIMES ACROSS E MA INTO RI/NE CT. THIS COULD PRODUCE URBAN 
AND POOR DRAINAGE FLOODING...ESPECIALLY SINCE THIS WILL FALL IN 
THOSE AREAS THAT RECEIVED THE HEAVIEST SNOWFALL SEVERAL DAYS AGO. 
HOWEVER...THE BIGGER PROBLEM WOULD BE WELL INLAND /S NH AND N 
CENTRAL AND W MA/ WHERE TEMPS WILL BE CRITICAL...WHICH COULD MEAN A 
MIX BACK TO FREEZING RAIN AND/OR SLEET. DO NOTE THAT WINDS WILL 
SHIFT TO E-SE AND WILL INCREASE...WHICH MAY HELP IN MIXING THE LOW 
LEVELS AND HOLDING TEMPS UP. WILL NEED TO BE MONITORED VERY 
CLOSELY...ESPECIALLY IF THE WINDS DO NOT MIX AND TEMPS DROP. HAVE 
CONTINUED WITH CATEGORICAL POPS.

HAVE CONTINUED WITH LIKELY POPS FOR MOST AREAS INTO SUNDAY MORNING. 
CURRENT TIMING SUGGESTS THAT THE PRECIP WILL TAPER OFF FROM SW-NE BY 
MIDDAY ACROSS N CT/SW MA...BUT MAY LINGER ACROSS S NH/E MA THROUGH 
THE DAY. AGAIN...COULD STILL SEE MIXED PRECIP ACROSS INLAND AREAS 
THAT SHOULD CHANGE BACK TO RAIN BEFORE ENDING. HAVE ENDED ALL PRECIP 
EARLY SUNDAY NIGHT FOR NOW.

MONDAY-TUESDAY...WILL CONTINUE WITH A DRY BUT COLD FORECAST FOR 
NOW...BUT ALL DEPENDS UPON HOW FAST THE WEEKEND SYSTEM MOVES OUT DUE 
TO BLOCKING UPPER LEVEL PATTERN. HAVE LOW CONFIDENCE WITH THIS 
PORTION OF THE FORECAST.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...

REMAINDER OF THIS AFTERNOON...
SNOW SHOWERS OVER NY STATE WILL SPILL OVER THE BERKSHIRES INTO
SOUTHERN NEW ENGLAND LATER THIS AFTERNOON. HOWEVER MOST OF THE PRECIP
WILL DRY UP WITH HIGH CONFIDENCE OF CIGS030-040. WEST WINDS WILL
CONTINUE TO GUST TO AROUND 20 KT.

TONIGHT...
HIGH CONFIDENCE ON VFR CIGS LOWERING TO MVFR AFTER 06Z. CONFIDENCE IS
LOW ON WESTWARD EXTENT OF MVFR CIGS. THINK HIGHEST PROBABILITY OF
MVFR CIGS LATE TONIGHT ARE FROM MHT/BOS/HYA/FMH AND ACK. ALTHOUGH LOW
PROB OF MVFR CIGS EXTENTING WEST TO PVD-ORH. VFR VSBYS EXPECTED.
NORTHWEST WINDS DIMINISH.

THURSDAY...
HIGH CONFIDENCE ON MVFR CIGS BUT LOW CONFIDENCE ON WESTWARD EXTENT.
FOR NOW EXPECT MVFR CIGS FROM MHT/BOS/HYA/FHM AND ACK...WITH LOWER
CONFIDENCE WESTWARD. NORTHWEST WINDS BECOMING NORTH DURING THE
AFTERNOON. GUSTS 25-30 KT ACROSS HYA AND ACK. WINDS MUCH LESS
ELSEWHERE. 

THU NIGHT...
MODERATE TO HIGH CONFIDENCE OF MVFR CIGS CONTINUING AT
MHT/BOS/HYA/FMH AND ACK. VFR ELSEWHERE. NORTH TO NORTHEAST WINDS
BEGIN TO DIMINISH AT HYA AND ACK. 

OUTLOOK...FRIDAY THROUGH SUNDAY...

CHRISTMAS DAY...VFR WITH INCREASING CIRRUS AT 25K FEET.

FRIDAY NIGHT...VFR CIGS.

SATURDAY...VFR TO START...LOWERING TO MVFR OR IFR FROM W-E AS RAIN 
OR MIXED PRECIPITATION PUSHES E. LOW CONFIDENCE ON TIMING.

SATURDAY NIGHT AND SUNDAY...IFR CIGS AND MVFR-IFR VSBYS LIKELY WITH 
RAIN OR MIXED PRECIPITATION. LOW CONFIDENCE ON TIMING.

&&

.MARINE...
TODAY...
NORTHWEST WINDS 20 TO 25 KNOTS SLOWLY DIMINISHING. SMALL CRAFT
ADVISORY WILL CONTINUE TO MOST OF OUR WATERS.  BOSTON HARBOR AND
NARRAGANSETT BAY WILL GUST NEAR 20 KNOTS BUT SHOULD REMAIN BELOW
SMALL CRAFT LEVELS.

TONIGHT...
HIGH PRESSURE BUILDS NORTH OF NEW ENGLAND. THIS WILL BRING WINDS
AROUND TO NORTH OVERNIGHT. FREEZING SPRAY POSSIBLE.

THURSDAY...WINDS INCREASE TO 20-30 KNOTS OVER MOST OF THE WATERS
ESPECIALLY THURSDAY MORNING. THIS BRINGS SEAS UP TO 5-10 FEET
ESPECIALLY EAST OF CAPE COD. WINDS AND SEAS DIMINISH BY THURSDAY
NIGHT. 

CHRISTMAS DAY...LIGHT NORTHEAST TO EAST WINDS. SEAS ON MASSACHUSETTS
BAY AND THE OUTER WATERS WILL REMAIN AT 5 FEET OR HIGHER SO SMALL
CRAFT ADVISORIES WILL LINGER OVER THOSE WATERS.

OUTLOOK...FRIDAY NIGHT THROUGH SUNDAY...

FRIDAY NIGHT...SMALL CRAFT WINDS AND SEAS CONTINUE.

SATURDAY-SUNDAY...E-SE WINDS INCREASE TO GALE FORCE MAINLY OVER THE 
OUTER WATERS WITH GUSTS UP TO 40 KT POSSIBLE. SEAS MAY BUILD UP TO 
10-12 FT...HIGHEST ON THE SOUTHERN OUTER WATERS. WINDS SHIFT TO W 
AND DIMINISH TO SMALL CRAFT LATER SUNDAY.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR 
     ANZ231>235-251.
     SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR ANZ237-250-
     254>256.

&&

$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB/NOCERA
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...NOCERA/EVT - UPDATED 1250 PM
MARINE...WTB/EVT