FXUS61 KBOX 251045
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
545 AM EST FRI DEC 25 2009

.SYNOPSIS...
MIDWEST LOW PRESSURE WILL REDEVELOP ALONG THE CAROLINAS AND MOVE UP
THE EASTERN SEABOARD THIS WEEKEND...BRINGING A PERIOD OF WINTRY
WEATHER INLAND WITH MAINLY RAIN ALONG THE COAST. THE LOW AND ITS
PRECIPITATION SHOULD DEPART SUNDAY AFTERNOON.  WEAK LOW PRESSURE WILL
BRING A CHANCE OF LIGHT SNOW TO SOUTHERN AREAS ON MONDAY. VERY COLD
AND BLUSTERY WEATHER WILL FOLLOW IN THE WAKE OF THIS LOW MONDAY NIGHT
INTO WEDNESDAY. A COASTAL STORM MAY BRING MORE WINTRY PRECIPITATION
TO THE REGION AROUND NEW YEARS EVE.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE CENTERED OVER QUEBEC EXTENDS INTO NEW ENGLAND. THIS
BRINGS A NORTHEAST MARINE FLOW INTO PARTS OF EASTERN MASS AND RI.
SATELLITE IMAGERY SHOWS MAINLY CLEAR SKIES OVER SOUTHERN NEW
ENGLAND...BUT WITH MARINE CLOUDS OVER CAPE COD AND THE SOUTH COAST
AND SOME STRATUS OVER PARTS OF CHESHIRE COUNTY NH AND THE BERKSHIRES.

THE UNCERTAINTY WITH TODAY/S FORECAST LIES WITH THE MARINE CLOUDS.
THEY EXPANDED NORTH QUICKLY LAST EVENING AND LOOKED PERSISTENT...
THEN SHIFTS SOUTH AGAIN AFTER 1 AM. CLOUDS OVER WESTERN GULF OF 
MAINE DO NOT SEEM TO BE SHIFTING BACK AS OF PRESS TIME...THEY ARE 
PROBABLY WAITING FOR THIS AFD TO BE ISSUED BEFORE MOVING.

WE WILL KEEP CLOUDS OVER THE CAPE AND ISLANDS THIS MORNING BUT GO
WITH MOSTLY CLEAR OVER THE INTERIOR...WITH PARTIAL CLEARING OF THE
STRATUS OVER THE NORTHWEST. INCREASING/THICKENING CIRRUS THIS
AFTERNOON AS THE MIDWEST STORM AND ITS COASTAL PARTNER FEED 
MOISTURE UP THE COAST.

MAX TEMPS ARE A BLEND OF GFS AND NAM MOS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
QUESTION ON TONIGHTS FORECAST IS THE POTENTIAL FOR DRIZZLE/FREEZING
DRIZZLE AS THE INCREASING EASTERLY LOW LEVEL FLOW RUNS INTO THE
CENTRAL HILLS AND BERKSHIRES. MOST OF THIS LIFT WILL OCCUR IN AREAS
THAT SHOULD BE AT OR BELOW FREEZING...BUT WITH DRY AIR ABOVE
CONFINING PRECIPITATION GROWTH TO A SHALLOW LAYER. WILL MENTION
CHANCE OF FREEZING DRIZZLE IN THE INTERIOR TONIGHT.

OTHERWISE THE QUESTION FOR TONIGHT AND SATURDAY IS THE TIMING OF
PRECIP ONSET. ENOUGH DRY AIR AND LACK OF ISENTROPIC LIFT TONIGHT TO
MAKE PRECIP GENERATION A TOUGH SELL. WE WILL BRING CHANCE POPS INTO
THE REGION BETWEEN MIDNIGHT AND 6 AM SATURDAY WITH THE BEST CHANCE
REMAINING WEST OF KEENE-PROVIDENCE. BETTER LIFT AND SATURATION
ARRIVES IN THE CT VALLEY SATURDAY MORNING AND IN EASTERN SECTIONS
DURING THE AFTERNOON AND EVENING. WE WILL TIME THE ARRIVAL OF LIKELY
POPS TO THIS SCHEDULE WITH CATEGORICAL POPS IN THE WEST SATURDAY
AFTERNOON.  

PRECIP TYPE WILL DEPEND ON THE ACTUAL TIME OF ONSET. TEMPERATURE
PROFILES LATER TONIGHT WOULD FAVOR SNOW OR ICE...WHILE PROFILES
SATURDAY AFTERNOON IN ALL BUT THE NORTHWEST WOULD FAVOR RAIN WITH A
LESSER CHANCE OF SNOW OR SLEET. WE USED THE NAM THERMAL PROFILES TO
GENERATE PRECIP TYPE. SURFACE TEMPERATURES COME FROM A BLEND OF MOS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SEEMS TO BE BETTER CONTINUITY WITH THE EARLY PORTION OF THE MEDIUM 
RANGE MODEL SUITE THIS MORNING. MODELS TEND TO FINALLY WEAKEN THE 
LOW AS IT MOVES OUT OF THE GREAT LAKES INTO NORTHERN NEW ENGLAND 
THIS WEEKEND. MODELS ALSO CONTINUE TO SIGNAL ANOTHER SHOT OF ARCTIC 
AIR MOVING INTO THE REGION EARLY NEXT WEEK...ALONG WITH ANOTHER SHOT 
OF SNOW SHOWERS. MODEL SOLUTIONS DIVERGE BEYOND TUESDAY...MAINLY DUE 
TO HOW THEY ARE HANDLING LOW PRESSURE THAT MAY PUSH INTO THE WEST 
COAST.

SATURDAY NIGHT...WILL SEE SOME LEFTOVER MIXED SLEET OR WET SNOW 
ACROSS THE HIGHER TERRAIN OF W AND N CENTRAL MA INTO S NH...BUT 
EXPECT TEMPS TO RISE OVERNIGHT AS E-SE WINDS INCREASE TO SCOUR OUT 
THE COLD AIR. ELSEWHERE...EXPECT A STEADY CHILLY RAIN. TEMPS WILL 
EITHER REMAIN STEADY OR SLOWLY RISE OVERNIGHT WITH MILDER AIR 
WORKING ASHORE MAINLY AFTER MIDNIGHT.

WITH GOOD SHOT OF LOW LEVEL MOISTURE CONVERGENCE MOVING INTO CENTRAL 
AND SOUTHERN AREAS...WILL SEE PERIODS OF HEAVY RAINFALL. ALL DEPENDS 
UPON HOW MUCH RAIN IS ABSORBED BY THE SNOWPACK...BUT WILL LIKELY SEE 
AREAS OF POOR DRAINAGE AND URBAN FLOODING MAINLY DUE TO CATCH BASINS 
BEING CLOGGED BY SNOW FROM THE STORM LAST WEEKEND. QPF COULD 
APPROACH AN INCH ON AVERAGE...WITH SOME LOCAL HIGHER AMOUNTS. 

SUNDAY...LOW PRES WILL MOVE ACROSS THE REGION DURING THE MORNING... 
WITH RAIN MOVING NE DURING THE DAY. WILL SEE DRY SLOT WORKING INTO 
THE REGION...WITH PRECIP ENDING ACROSS WESTERN AREAS BY MIDDAY...BUT 
LEFTOVER RAIN MAY LINGER INTO THE AFTERNOON ACROSS E MA/RI. MAY BE 
ENOUGH DRY AIR THAT WORKS IN TO ALLOW SOME SUN TO BREAK THROUGH 
ACROSS N CT/SW MA DURING THE AFTERNOON. NOT A LOT OF COLD AIR BEHIND 
THIS SYSTEM...SO TEMPS WILL BE MILD.

SUNDAY NIGHT...ANOTHER BATCH OF CLOUDS WORK ACROSS THE REGION AHEAD 
OF ANOTHER APPROACHING SHORT WAVE. WILL BE COOLER...THOUGH STILL 5 
TO 10 DEGREES ABOVE SEASONAL NORMS FOR LATE DECEMBER. TEMPS WILL 
FALL BELOW FREEZING ACROSS MOST AREAS...SO COULD SEE SOME LOCAL 
REFREEZING OF ANY STANDING WATER.

MONDAY-MONDAY NIGHT...ANOTHER SHORT WAVE WILL WORK ACROSS THE REGION 
AND MAY EVEN SPIN UP A WEAK LOW S OF NEW ENGLAND. AN AREA OF LOW 
LEVEL MOISTURE WILL ALSO MOVE E...SO HAVE CARRIED HIGH CHANCE POPS 
FOR SNOW SHOWERS. DEPENDING UPON AMOUNT OF MOISTURE...COULD SEE SOME 
LIGHT SNOW ACCUMULATIONS. AN ARCTIC FRONT WILL PUSH IN BEHIND THIS 
MONDAY NIGHT.

TUESDAY-WEDNESDAY...EXPECT SKIES TO BE MAINLY CLEAR AS HIGH PRES 
BUILDS W OF THE REGION...BUT WILL BE VERY WINDY AND COLD AS ANOTHER 
SHOT OF ARCTIC AIR MOVES IN. EXPECT DAYTIME HIGHS ON TUESDAY TO RUN 
10 TO 15 DEGREES BELOW NORMAL. COULD SEE OVERNIGHT LOWS NEAR OR 
BELOW ZERO WELL INLAND TUESDAY NIGHT.

THURSDAY...APPEARS THE HIGH WILL HOLD LONG ENOUGH TO KEEP DRY 
CONDITIONS WITH SLIGHTLY MODERATING TEMPERATURES. 

MODELS SHOWING SOME CONSISTENCY IN ADVERTISING A COASTAL STORM THAT 
MAY AFFECT THE REGION NEW YEARS EVE. WILL CONTINUE TO MONITOR THIS 
POTENTIAL. 

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
TODAY...
LINGERING MVFR CIGS IN NORTHEAST MARINE FLOW OVER THE CAPE AND
ISLANDS AND PARTS OF SOUTH COAST. ALSO SOME STRATUS OVER THE CT
VALLEY NORTH OF NORTHAMPTON MA. OTHER AREAS ARE VFR...AND EVEN THE
SOUTH COAST SHOULD LIFT TO VFR DURING THE MORNING. HIGH CONFIDENCE 
IN THE OVERALL TREND IN CIGS AT FMH-HYA-ACK BUT LOW CONFIDENCE ON 
EXACT TIMING. 

INCREASING CLOUDS AT 25K FEET IN THE AFTERNOON/EVENING.

TONIGHT...
MEDIUM CONFIDENCE THAT INCREASING EAST FLOW SHOULD SATURATE LOW
LEVELS AND BRING MVFR CIGS. LOW CONFIDENCE THAT UPSLOPE FLOW OF THE
MOIST AIR MAY BRING FREEZING DRIZZLE TO INLAND AREAS SUCH AS ORH-MHT-
BAF-BDL. LOW CHANCE THAT MIXED PRECIP MAY ARRIVE IN THE CT VALLEY AND
SOUTHERN RI AFTER 06Z.

SATURDAY...MVFR CIGS IN THE MORNING. PRECIP MOVING UP THE COAST
SHOULD MOVE INTO THE REGION...EARLIEST IN CT AND LATEST ALONG THE
MASS EAST COAST. FLIGHT CONDITIONS SHOULD LOWER TO IFR IN THE
AFTERNOON/EVENING AS PRECIP BEGINS. LOW CONFIDENCE IN THE EXACT
TIMING...IT COULD BE SLOWER.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT...IFR CONDITIONS EXPECTED IN MAINLY RAIN...ALTHOUGH A 
WINTRY MIX POSSIBLY AT KORH AND POSSIBLY KMHT EARLY.

SUNDAY...MVFR/IFR CONDITIONS IMPROVE TO VFR AROUND MIDDAY.

MONDAY...VFR. AREAS OF MVFR CIGS/VSBYS IN SNOW SHOWERS.

TUESDAY...VFR...GUSTY NW WINDS.

&&

.MARINE...
TODAY...
NORTHEAST WINDS GENERALLY 10 TO 15 KTS. SMALL CRAFT ADVISORY
CONTINUES ON THE OUTER WATERS FOR ROUGH SEAS.

TONIGHT...
EAST WINDS AND SEAS INCREASE DURING THE NIGHT WITH SMALL CRAFT
CONDITIONS EXPANDING CLOSER TO SHORE ESPECIALLY ON THE SOUTHERN
WATERS. 

SATURDAY...
EAST WINDS AND SEAS CONTINUE TO INCREASE. WINDS MAY APPROACH GALE
FORCE LATE IN THE DAY ON THE WATERS SURROUNDING BLOCK ISLAND. WILL
ISSUE A GALE WATCH FOR THE VINEYARD-TO-MONTAUK OUTER
WATERS...THIS MAY EXPAND TO OTHER WATERS AS WE GET CLOSER.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT-SUNDAY...EAST TO SOUTHEAST WINDS WILL LIKELY REACH 
GALE FORCE. SEAS COULD REACH 12-15 FEET ON THE OUTER WATERS.

MONDAY...SMALL CRAFT WINDS AND SEAS MAY REACH GALE FORCE AFTER 
MIDNIGHT ON THE OUTER WATERS.

MONDAY NIGHT AND TUESDAY...NW WINDS MAY CONTINUE AT GALE FORCE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 4 PM EST SATURDAY FOR 
     ANZ230>237.
     SMALL CRAFT ADVISORY UNTIL 4 PM EST SATURDAY FOR ANZ250-251-
     254>256.
     GALE WATCH FROM SATURDAY AFTERNOON THROUGH LATE SATURDAY 
     NIGHT FOR ANZ256.

&&

$$
SYNOPSIS...WTB
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...WTB/EVT
MARINE...WTB/EVT