181
FXUS61 KBOX 202100
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
400 PM EST FRI NOV 20 2009
SYNOPSIS
DRY AND PLEASANT WEATHER WILL RETURN OVER THE WEEKEND WITH HIGH
PRESSURE IN PLACE. COASTAL LOW PRESSURE MAY STAY FAR ENOUGH TO THE
SOUTH TO JUST CLIP THE REGION MONDAY INTO TUESDAY. A FRONTAL SYSTEM
AND LOW PRESSURE MAY AFFECT SOUTHERN NEW ENGLAND TOWARD THE END OF
NEXT WEEK.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES ACROSS THE
MAJORITY OF SOUTHERN NEW ENGLAND. A FEW LOCATIONS HAVE PARTLY CLOUDY
SKIES WITH THE OUTER CAPE AND NANTUCKET REMAINING UNDER OVERCAST
SKIES. DOWNSLOPING WESTERLY WINDS ARE DRYING OUT THE LOWER LEVELS AS
EVIDENCED IN DEWPOINTS DROPPING INTO THE 30S TO AROUND 40 ACROSS THE
INTERIOR. SOUTHWEST WINDS ACROSS SOUTHEAST MASSACHUSETTS HAVE
PREVENTED DEWPOINTS FROM FALLING BELOW THE MID 50S THERE.
19Z MSAS ANALYSIS SHOWS THE FRONT HAVING CLEARED ALL OF SOUTHERN NEW
ENGLAND WITH THE EXCEPTION OF THE CAPE AND ISLANDS. ONCE THE FRONT
MOVES THROUGH...THE SOUTHWESTERLY WINDS WILL SHIFT MORE TO THE WEST
OR NORTHWEST ALLOWING FOR DRYING OUT OF THE LOWER LEVELS.
HIGH PRESSURE OVER THE MIDWEST WILL START BUILDING INTO THE AREA
TONIGHT. THERE MAY BE A THIN LAYER OF HIGH CLOUDS THAT MOVES IN
OVERNIGHT. OTHERWISE MOSTLY CLEAR SKIES EXPECTED. BEING ON THE
PERIPHERY OF THE HIGH...EXPECT LIGHT WESTERLY WINDS AROUND 10 KTS TO
PERSIST THROUGH THE NIGHT. LOW TEMPERATURES WILL DROP TO AROUND 40
DEGREES...STILL ABOVE NORMAL FOR THIS TIME OF YEAR BUT A GOOD 15 TO
20 DEGREES BELOW THIS MORNINGS LOWS. MAY SEE AN HOUR OR TWO OF
PATCHY FOG TOWARDS SUNRISE.
SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/
HIGH PRESSURE CONTINUES TO BUILD INTO SOUTHERN NEW ENGLAND THROUGH
SATURDAY...MOVING OVER NORTHERN NEW ENGLAND SATURDAY NIGHT. CLEAR
SKIES...LIGHT WINDS...AND ABOVE NORMAL TEMPERATURES WILL BE THE RULE.
SATURDAY NIGHT...TEMPERATURES WILL DROP INTO THE 30S /RIGHT AROUND
NORMAL/. USED A BLEND OF AVAILABLE GUIDANCE FOR THE GRIDS.
LONG TERM /SUNDAY THROUGH FRIDAY/
HIGH PRESSURE WILL GRADUALLY SHIFT TO THE NE SUN INTO SUN
NIGHT...BUT SFC RIDGING WILL REMAIN IN CONTROL ACROSS SNE. THIS
WILL KEEP ANY MOISTURE TO THE SOUTH THROUGH SUN NIGHT...SO DRY
FORECAST.
MOSUNNY SKIES EXPECTED SUNDAY ACROSS MUCH OF THE REGION...BUT
SHALLOW LOW LEVEL MOISTURE IN DEVELOPING NE FLOW MAY BRING MORE
CLOUDINESS NEAR THE COAST. USED A MAV/MET BLEND FOR TEMPS.
NOT MUCH CHANGE IN CLOUD COVER EXPECTED SUN NIGHT WITH MOST CLOUDS
NEAR THE COAST. WE LEANED TOWARD COOLER MET GUIDANCE FOR TEMPS AS
GFS IS TOO FAST BRINGING IN MOISTURE.
MODELS STILL SHOW CONSIDERABLE SPREAD IN THEIR HANDLING OF COASTAL
LOW PRESSURE SYSTEM MON AND TUE SO FORECAST CONFIDENCE REMAINS BELOW
NORMAL. GFS/GGEM ARE FURTHEST NW AND BRING RAIN TO SNE MON/MON
NIGHT. GGEM REALLY HITS THE QPF HARD MON NIGHT. NAM/EC/UK ALL KEEP
RAIN TO THE SOUTH WITH COASTAL LOW REMAINING WELL OFFSHORE.
MAJORITY OF GEFS ENSEMBLES ALSO SOUTH WITH COASTAL LOW AND SUPPORT
DRIER SOLUTION SO WE WILL TREND IN THIS DIRECTION AND SCALE BACK THE
POPS WITH BEST CHC OF RAIN/SHOWERS NEAR THE COAST MON/MON NIGHT.
TUE...HELD ON TO CHC POPS SE COAST BASED ON EC SOLUTION WHICH
CONTINUED MOIST NE FLOW WITH OFFSHORE COASTAL LOW.
FORECAST CONFIDENCE REMAINS LOW FOR THE MIDDLE AND END OF THE WEEK
GIVEN THE CONSIDERABLE MODEL SPREAD IN HANDLING THE TIMING/EVOLUTION
OF SHORTWAVE ENERGY EJECTING FROM THE MIDWEST. WE GENERALLY
FOLLOWED ECMWF SOLUTION WHICH SHOWS AMPLIFYING MID LEVEL TROF
APPROACHING THE NE BY THE END OF THE WEEK...SO CHC SHOWERS THU INTO
FRI. BOTH GFS/ECMWF INDICATE THIS WILL BE A DYNAMIC SYSTEM BUT
DIFFER ON TIMING AND THE EXTENT OF PHASING. POTENTIAL IS THERE FOR
HEAVY PRECIP.
AVIATION /20Z FRIDAY THROUGH WEDNESDAY/
THIS AFTERNOON...
AT 1230 PM COLD FRONT/WIND SHIFT JUST WEST OF BOS-PVD LINE. AHEAD OF
THE FRONT WIDESPREAD MVFR CIGS WITH PATCHY IFR. HOWEVER FRONT WILL
CONTINUE MOVING STEADILY EASTWARD WITH VFR /CIGS 035-050/ BEHIND THE
FRONT. ALSO WITH THE FRONTAL PASSAGE EXPECT WEST-NORTHWEST WINDS TO
GUSTS TO 25 KT. THESE WINDS WILL DIMINISH AROUND 21Z-22Z.
TONIGHT...
VFR. LOW PROB OF MVFR CIGS FROM 06Z-12Z SLIPPING OVER THE
BERKSHIRES INTO MHT AND NEARBY TERMINALS.
SAT AND SAT NIGHT...
VFR WITH LIGHT W-NW WINDS.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUN...VFR...WITH LOW PROB OF MVFR CIGS DEVELOPING NEAR THE COAST.
MON...MVFR POSSIBLE NEAR THE COAST WITH CHC RAIN. VFR NORTH OF THE
PIKE.
TUE...MVFR CIGS POSSIBLE...ESPECIALLY NEAR THE COAST.
WED...VFR.
MARINE
TONIGHT...HAVE OPTED TO KEEP THE SMALL CRAFT THROUGH TONIGHT ACROSS
THE OUTER WATERS. W WINDS MAY GUST UP TO 25 KT EARLY WITH BRIEF COLD
AIR ADVECTION...THEN LINGERING 5 FOOT SEAS WILL CONTINUE.
SATURDAY...W-NW WINDS UP TO 20 KT. SEAS MAY LINGER AT AROUND 5 FEET
ON THE OUTER WATERS. WAVE GUIDANCE HAS INITIALIZED HIGH SO AM NOT
CONFIDENT THAT SEAS WON/T DROP A BIT FASTER THAN FORECAST. SO HAVE
OPTED TO NOT EXTEND THE SMALL CRAFT YET.
SATURDAY NIGHT...HIGH PRESSURE BUILDS OVERHEAD WITH WINDS AND SEAS
DIMINISHING.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUN-SUN NIGHT...DEVELOPING NE FLOW SLOWLY INCREASES THROUGH SUN
NIGHT BUT CONDITIONS EXPECTED TO REMAIN BELOW SCA.
MON-TUE...A PERIOD OF SCA E/NE WINDS LIKELY...ESPECIALLY ACROSS
SOUTH COASTAL WATERS AS COASTAL LOW PASSES OFFSHORE. LOWERED
WNAWAVE GUIDANCE DUE TO ITS RELIANCE ON THE GFS...BUT STILL HAVE
SEAS BUILDING TO 5-7 FT.
WED...DIMINISHING WINDS AND SEAS WED AS GRADIENT RELAXES.
EQUIPMENT
THE FAA TERMINAL DOPPLER WEATHER RADAR /TDWR/ S OF BOSTON IS OUT OF
SERVICE UNTIL FURTHER NOTICE.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST SATURDAY FOR ANZ235-237-
250-254>256.
SYNOPSIS...KJC/RLG
NEAR TERM...RLG
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...KJC/NOCERA
MARINE...KJC/RLG
EQUIPMENT...
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