758
FXUS61 KBOX 210430
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1130 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/
IR SATELLITE SHOWING A THIN VEIL OF HIGH CIRRUS CLOUDS CROSSING THE
REGION IN THE UPPER LEVEL W FLOW AT 04Z. NOTING MORE CIRRUS CLOUDS
WORKING OUT OF PA/OHIO VALLEY THAT WILL WORK E OVERNIGHT. HIGH PRES
WILL WORK OUT OF WV/MD/VA REGION INTO NY STATE BY SAT MORNING.
WINDS HAVE DIMINISH ACROSS MANY LOWLAND AREAS...WITH SOME WIND STILL
ACROSS THE HIGHER TERRAIN. DEWPTS DOWN TO THE 30S TO AROUND 40 AS
TEMPS HAVE FALLEN TO THE 40S AT 04Z...EXCEPT AROUND 50 ON THE
ISLANDS.
HAVE KEPT MINS IN THE MID 30S TO MID 40S TOWARD SUNRISE...BUT WILL
DEPEND UPON IF HIGH CLOUDS BREAK UP ENOUGH TO ALLOW TEMPS TO DROP.
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 /04Z SATURDAY THROUGH WEDNESDAY/
OVERNIGHT...VFR.
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
OVERNIGHT...HAVE TAKEN DOWN THE SMALL CRAFT ON BOTH BLOCK ISLAND AND
RHODE ISLAND SOUNDS. NOTED SEAS HAVE SUBSIDED TO 3-4 FEET WELL
OFFSHORE. CONTINUE THE SMALL CRAFT THROUGH THE OVERNIGHT ACROSS THE
FAR OUTER WATERS AS SEAS REMAIN AT 5-6 FEET. SOME GUSTS UP TO 25 KT
WILL ALSO CONTINUE UNTIL AROUND 06Z-07Z ACROSS THE WATERS EAST OF
THE MASSACHUSETTS COAST.
SATURDAY...W-NW WINDS UP TO 20 KT. SEAS MAY LINGER AT AROUND 5 FEET
ON THE OUTER WATERS THROUGH MID TO LATE MORNING. 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 5 AM EST SATURDAY FOR ANZ250-256.
SMALL CRAFT ADVISORY UNTIL 9 AM EST SATURDAY FOR ANZ254-255.
SYNOPSIS...KJC/RLG
NEAR TERM...EVT
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...KJC/NOCERA/EVT
MARINE...KJC/EVT/RLG
EQUIPMENT...
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