FXUS61 KBOX 250907
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
407 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 SATUDAY 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/...
WENT WITH CATEGORICAL POPS FOR SATURDAY NIGHT AS MAIN SLUG OF
RAINFALL MOVES ON IN WITH THE SELY LLJ. AS OF RIGHT NOW...IT LOOKS AS
THOUGH ENOUGH RELATIVELY WARM AIR WILL FLOOD NORTHWARD TO PRECLUDE A
MAJOR ICE EVENT. HOWEVER...WITH THAT SAID...WE WILL HAVE TO WATCH
SOME ESPECIALLY PRONE LOCATIONS SUCH AS THE BERKS...MONADS...AND THE
WORCESTER HILLS FOR SOME POCKETS OF ENHANCED ICING. MOST OTHER AREAS
WILL BE A PLAIN COLD RAIN. THIS COULD SPELL SOME URBAN AND POOR
DRAINAGE FLOODING AS A LOT OF STORM DRAINS ARE LIKELY STUFFED WITH
SNOW FROM THE PREVIOUS STORM. WE AREN/T EXPECTING ANY SIGNIFICANT
FLOODING ISSUES AT THIS TIME AS THE CURRENT SNOWPACK SHOULD BE ABLE
TO ABSORB MUCH OF THE RAINFALL...WHICH IS EXPECTED TO BE AROUND AN
INCH OR SO.
DRY SLOT QUICKLY MOVES IN ON SUNDAY...ENDING THE PRECIP FROM WEST TO
EAST IN THE MORNING...POSSIBLY EARLY AFTERNOON EAST COAST OF MASS.
SUNDAY AFTERNOON COULD ACTUALLY BE HALFWAY DECENT...WITH WARMING
TEMPS AND SUN IN THE DRY SLOT. IF ALL BREAKS RIGHT...WOULDN/T BE
SURPRISED TO SEE SUNSHINE WITH TEMPS AROUND 50F ON THE COASTAL PLAIN
SUNDAY AFTERNOON.
NEXT SHORT WAVE MOVES ACROSS THE REGION ON MONDAY. FOR NOW...WE HAVE
A CHANCE OF LIGHT SNOW GOING...MAINLY FOR SOUTHERN ZONES. THERE IS A
LOW PROB THAT WE COULD HAVE A 1-3 INCH SNOW EVENT OUT OF THIS...BUT
IT MAY STAY JUST SOUTH OF US. VERY COLD AND WINDY FOR MONDAY NIGHT
THROUGH EARLY WED IN WAKE OF ARCTIC FRONT. WIND ADVISORY EVENT
POSSIBLE TUE...ALONG WITH NASTY WIND CHILLS.
THE MODELS HAVE CONTINUED TO ADVERTISE A SIGNIFICANT COASTAL SYSTEM
AFFECTING MUCH OF SOUTHERN NEW ENGLAND FOR NEW YEARS EVE...AND THIS
CONTINUES TO BEAR WATCH.
&&
.AVIATION /09Z 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 ORH AND MAYBE MHT.
SUNDAY...MVFR/IFR CONDITIONS IMPROVE TO VFR AROUND MIDDAY.
MONDAY...VFR...BUT POSSIBLE MVFR 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...
SUNDAY...EAST TO SOUTHEAST WINDS MAY REACH GALE FORCE SATURDAY NIGHT
AND CONTINUE INTO SUNDAY.
MONDAY...SMALL CRAFT WINDS AND SEAS.
MONDAY NIGHT AND TUE...NW GALES PROBABLE.
&&
.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...EKSTER
AVIATION...WTB/EKSTER
MARINE...WTB/EKSTER
