FXUS61 KBOX 251608
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1108 AM EST FRI DEC 25 2009
.SYNOPSIS...
LOW PRESSURE DEVELOPING OVER SOUTH CAROLINA LATE THIS MORNING WILL
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/...
WHATEVER BREAKS IN THE CLOUDINESS REMAINED OVER THE INTERIOR PART OF
SOUTHERN NEW ENGLAND SHOULD FILL IN THIS AFTERNOON...EITHER FROM LOW
CLOUD DEVELOPMENT OR MID AND HIGH CLOUDS SPREADING IN FROM THE
SOUTHWEST. NORTHEAST WINDS HAVE INCREASED TO 14 KT AT THE BOSTON BUOY
AS THE MOIST FLOW AHEAD OF THE NEXT SYSTEM BEGINS TO GET ESTABLISHED.
TEMPERATURE FORECAST ON TRACK IN EASTERN AREAS BUT WILL LOWER MAXES
FOR THIS AFTERNOON A FEW DEGREES IN THE WEST SINCE LOW CLOUDS IN THE
CT RIVER VALLEY HAVE LOCKED IN THE COOLER TEMPERATURES AND NOW THE
HIGH CLOUDS ARE INCREASING FROM THE SOUTHWEST.
LOOKS LIKE THE POTENTIAL FOR FREEZING DRIZZLE DEVELOPMENT TONIGHT IS
HIGH. MAY NEED TO ISSUE AN ADVISORY LATER THIS AFTERNOON.
&&
.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 /16Z FRIDAY THROUGH TUESDAY/...
THIS AFTERNOON...
AREAS OF IFR MAINLY MHT-ORH-BAF-BDL DUE TO LOW CLOUDINESS AND A FEW
FOG PATCHES. OTHERWISE MVFR CIG AT ALL OTHER TERMINALS THROUGH THE
AFTERNOON AS CLOUDS IN THE 1500-2500 FT RANGE CONTINUE TO EXPAND
WESTWARD FROM THE OCEAN AND ALSO DEVELOP OVER THE LAND.
TONIGHT...
MEDIUM CONFIDENCE THAT INCREASING EAST FLOW SHOULD SATURATE LOW
LEVELS AND BRING MVFR OR IFR CIGS. INCREASING 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 AROUND 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/EVT/GAF
NEAR TERM...GAF
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...GAF/WTB/EVT
MARINE...WTB/EVT/GAF
