631
FXUS61 KBOX 170508
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1208 AM EST SUN NOV 17 2024
SYNOPSIS
DRY WEATHER AND ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO
WEDNESDAY. A DEVELOPING LOW PRESSURE SYSTEM TO OUR WEST MAY
FINALLY BRING MUCH NEEDED WIDESPREAD RAINFALL LATE WEDNESDAY
NIGHT AND THURSDAY. UNSETTLED WEATHER PATTERN WILL PREVAIL
FRIDAY AND SATURDAY WITH THE CHANCE OF SHOWERS AT TIMES BUT NOT
A WASHOUT.
NEAR TERM /UNTIL 6 AM THIS MORNING/
815 PM UPDATE...
PATCHY STRATO-CU ACROSS THE CAPE/ISLANDS WILL BE MOVING
OFFSHORE THIS EVENING AS LOW LEVEL MOISTURE PUSHES EAST,
OTHERWISE CLEAR SKIES TONIGHT. MODEST LOW LEVEL JET TONIGHT
WILL REMAIN ABOVE THE INVERSION BUT ENOUGH FOR A MODEST N-NW
BREEZE WHICH WILL LIMIT RADIATIONAL COOLING. LOWS WILL BE
MOSTLY IN THE 30S WITH LOWER 40S OUTER CAPE/ISLANDS, BUT SOME
UPPER 20S POSSIBLE IN THE UPPER CT VALLEY IF WINDS DECOUPLE.
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/
SUNDAY HEIGHTS WILL BE ON THE RISE AS MID LEVEL RIDGING MOVES
OVERHEAD AND THE GREAT LAKES HIGH PRESSURE SHIFTS EAST. THIS MEANS A
WEAKER PRESSURE GRADIENT AND LIGHTER WINDS FOR SUNDAY WHILE SUNNY
SKIES STICK AROUND. CONDITIONS WILL CONTINUE TO BE VERY DRY, DESPITE
THE WEAKER WIND, WITH RH VALUES IN THE 20S SO A SPECIAL WEATHER
STATEMENT FOR ELEVATED FIRE DANGER WILL LIKELY BE NEEDED. SUNDAY
LATE EVENING INTO THE OVERNIGHT HOURS THAT RIDGE IS SUPPRESSED BY A
SHORTWAVE DISTURBANCE WHICH WILL BRING INCREASED CLOUDCOVER BUT
LIKELY LITTLE TO NO RAIN GIVEN VERY LIMITED MOISTURE.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
MONDAY THROUGH WEDNESDAY
A COLD FRONT ASSOCIATED WITH NORTHERN STREAM ENERGY DIGGING DOWN
FROM CANADA SWEEPS OVER SOUTHERN NEW ENGLAND DURING THE DAY ON
MONDAY. CAN'T RULE OUT SOME SPOTTY PRECIP FOR A FEW LOCATIONS ACROSS
THE INTERIOR, BUT THE COLUMNS LOOKS TO BE VERY DRY SO NOT EXPECTING
MUCH IN THE WAY OF PRECIPITATION. AHEAD OF THE FRONT 925 HPA TEMPS
ARE FORECAST TO BE RATHER MILD FOR MID-LATE NOVEMBER IN THE 5 TO 10
CELSIUS RANGE. IT MAY TAKE SOME TIME FOR THE COOLER AIR TO SETTLE
OVER THE REGION, THUS THE MILD AIR AHEAD OF THE FRONT IS EXPECTED TO
SUPPORT A MILD AFTERNOON WITH TEMPS IN THE UPPER 50S TO LOW 60S F AT
THE SURFACE. COOLER AIR ALOFT WILL SUPPORT STEEP LAPSE RATES WHICH
WILL ALLOW FOR SOME 20+ MPH WIND GUSTS AT THE SURFACE. CURRENT
FORECAST KEEPS RH AT A MINIMUM OF 50% ACROSS THE REGION WHICH SHOULD
HELP SUPPRESS FIRE WEATHER ACTIVITY, BUT GIVEN HOW DRY IT'S BEEN
LATELY, THE GUSTY WINDS ARE A CAUSE FOR CONCERN. WE'LL BE MONITORING
THE HUMIDITY PORTION OF THE FORECAST CLOSELY TO DETERMINE IF FIRE
WEATHER HEADLINES MAY BE NEEDED EARLY NEXT WEEK.
NORTHWEST FLOW BEHIND THE COLD FRONT ADVECTS A MUCH COOLER AIR MASS
OVER SOUTHERN NEW ENGLAND FOR TUESDAY AND WEDNESDAY, THUS WE CAN
EXPECT A DOWNWARD TREND IN TEMPERATURES THROUGH MID-WEEK. A MID-
LEVEL RIDGE SLOWLY BUILDS EAST THROUGH MID-WEEK AS WELL, THUS WE
SHOULD BE LOOKING AT A QUIET TUESDAY/WEDNESDAY WITH A GOOD AMOUNT OF
SUNSHINE. SURFACE TEMPS WILL BE CLOSE TO NORMAL FOR THIS TIME OF
YEAR WITH HIGHS/LOWS IN THE MID TO UPPER 50S AND MID 30S
RESPECTIVELY.
WEDNESDAY NIGHT THROUGH SATURDAY
A PATTERN CHANGE IS IN STORE FOR THE EASTERN US LATE WEEK AS A
ROBUST UPPER-LEVEL LOW DIGS AND DEEPENS OVER THE OHIO RIVER VALLEY
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SUPPORT THE DEVELOPMENT OF
A POTENTIALLY STRONG LOW-PRESSURE SYSTEM OVER THE MIDWEST WITH A LOW-
PRESSURE CENTER WELL BELOW 1000 HPA. THIS SYSTEM MAY GIVE SOUTHERN
NEW ENGLAND THE SUBSTANTIAL RAINFALL IT'S BEEN WAITING FOR. THERE IS
STRONG AGREEMENT AMONG GLOBAL ENSEMBLES FOR A SUBSTANTIAL RAIN EVENT
WITH ENSEMBLE MEAN 24 HOUR PRECIPITATION ACCUMULATIONS NEAR A HALF
AN INCH FOR MOST LOCATIONS IN SOUTHERN NEW ENGLAND. WHILE THIS
WOULDN'T BE ENOUGH TO MAKE UP RECENT DEFICITS IT WOULD CERTAINLY BE
WELCOME GIVEN THE RECENT DRYNESS. LATEST GUIDANCE SUPPORTS PRECIP
FOR MUCH OF THE DAY THURSDAY, FOLLOWED BY A PERIOD OF
COOLER/UNSETTLED WEATHER FRIDAY AND SATURDAY AS THE ASSOCIATED UPPER-
LOW MEANDERS OVER THE NORTHEAST. IN THE 5 TO 7 DAY TIME RANGE, THE
SPECIFICS REGARDING THIS SYSTEM ARE VAGUE, BUT WE'LL HAVE MORE
INFORMATION AS WE PROGRESS INTO NEXT WEEK. STAY TUNED FOR FURTHER
DETAILS.
AVIATION /05Z SUNDAY THROUGH THURSDAY/
FORECAST CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE...
HIGH CONFIDENCE THROUGH MONDAY...
VFR THROUGH THE PERIOD. INCREASING HIGH CLOUDS LATE TODAY AND
TONIGHT, THEN SOME LOW-MID LEVEL CLOUD CIGS MONDAY MORNING. NW
GUSTS TO 15-20 KT TODAY, LIGHT NW TO CALM WIND TONIGHT, THEN NW
WIND INCREASING TO 10-20 KT MON AFTERNOON WITH A FEW HIGHER
GUSTS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
SUNDAY NIGHT: VFR.
MONDAY THROUGH TUESDAY: VFR. BREEZY.
TUESDAY NIGHT THROUGH WEDNESDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
815 PM UPDATE...
WINDS NOT QUITE AS STRONG AS PRECIOUSLY FORECAST SO HAVE
DROPPED SCA OVER NEARSHORE WATERS. GUSTS TO 25 KT STILL
EXPECTED OVER THE OUTER WATERS BEFORE DIMINISHING LATE TONIGHT
AND SUNDAY.
THROUGH SUNDAY NIGHT...HIGH CONFIDENCE.
NW GUSTS TO 20-25 KT EXPECTED TODAY AND TONIGHT, BEFORE
DIMINISHING SLIGHTLY ON SUNDAY. SMALL CRAFT ADVISORIES CONTINUE
ON ALL WATERS INTO THIS EVENING.
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
MONDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
MONDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. SEAS UP TO 5 FT.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY: WINDS LESS THAN 25 KT.
FIRE WEATHER
RED FLAG WARNING IN EFFECT UNTIL 6 PM TODAY FOR ALL OF SNE.
HIGH FIRE DANGER TODAY AS GUSTY NW WINDS DEVELOP WITH GUSTS TO 20-30
MPH COMBINED WITH VERY DRY CONDITIONS. MINIMUM RH VALUES WILL BE 15
TO 25 PERCENT THIS AFTERNOON, EXCEPT 30 TO 40 PERCENT OVER THE
CAPE/ISLANDS.
CONDITIONS REMAIN VERY DRY ON SUNDAY WITH RH VALUES LOWERING TO
20 TO 30 PERCENT IN THE AFTERNOON AWAY FROM CAPE COD. LESS WIND
IS EXPECTED WITH GUSTS TO 15-20 MPH. AFTER COORDINATING WITH
OUR STATE FIRE WEATHER PARTNERS, A SPECIAL WEATHER STATEMENT TO
HIGHLIGHT THE FIRE DANGER IS MOST LIKELY.
TIDES/COASTAL FLOODING
ASTRONOMICAL TIDES PEAK DURING THE LATE MORNING ON SUNDAY, A BIT
LOWER THAN SATURDAY WITH HIGH TIDE REACHING JUST UNDER 12 FT
MLLW AT BOSTON. LATEST SURGE GUIDANCE JUST UNDER 1 FT WOULD BE
CLOSE ENOUGH TO MINOR FLOOD LEVEL TO CAUSE SPORADIC NUISANCE
COASTAL FLOODING AT HIGH TIDE, ESPECIALLY ALONG N AND NE FACING
BEACHES. A COASTAL FLOOD STATEMENT IS IN EFFECT FOR EAST
COASTAL MA FOR THE LATE MORNING HIGH TIDE.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ250-
254-255.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ256.
SYNOPSIS...KJC/BW
NEAR TERM...KJC/BW
SHORT TERM...BW
LONG TERM...KJC
AVIATION...KJC/RM
MARINE...KJC/BW
FIRE WEATHER...KJC/BW
TIDES/COASTAL FLOODING...BW
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