306
FXUS61 KBOX 270717
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
317 AM EDT MON OCT 27 2025
SYNOPSIS
CANADIAN HIGH PRESSURE WILL RESULT IN COOL TEMPERATURES TODAY
THROUGH WEDNESDAY. IN ADDITION...NORTHEAST WINDS WILL BRING SOME
SCATTERED SHOWERS TO AREAS MAINLY NEAR AND SOUTHEAST OF I-95 TUESDAY
INTO WEDNESDAY. STRONG LOW PRESSURE FOLLOWS WITH A PERIOD OF
HEAVY WINDSWEPT RAIN TO SOUTHERN NEW ENGLAND SOMETIME THURSDAY
INTO THURSDAY NIGHT. A FEW SHOWERS MAY LINGER INTO FRIDAY BUT
DRIER WEATHER IS LIKELY BY SATURDAY.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES...
* EARLY SUN GIVES WAY TO MORE CLOUDS FROM THE NORTH LATER TODAY
* HIGHS TODAY 50-55 WITH UPPER 40S PARTS OF THE HIGH TERRAIN
* CHILLY AGAIN TONIGHT WITH LOWS IN THE UPPER 20S AND 30S
* DRY OUTSIDE A BRIEF SPOT SPRINKLE/LIGHT SHOWER ACROSS CAPE/ACK
DETAILS...
TODAY AND TONIGHT...
A LARGE 1035 MB HIGH PRESSURE SYSTEM ACROSS QUEBEC WILL REMAIN IN
CONTROL OF OUR WEATHER TODAY AND TONIGHT. THIS WILL GENERATE A COOL
NORTHERLY FLOW OF AIR INTO SOUTHERN NEW ENGLAND WITH SLIGHTLY BELOW
NORMAL TEMPS. PLENTY OF SUNSHINE EARLY...BUT SHOULD SEE MORE IN THE
WAY OF CLOUDS THIS AFTERNOON ESPECIALLY IN NORTHERN MA AS MID LEVEL
CLOUDS DROP DOWN FROM THE NORTH. THIS IS SUPPORTED BY MODEL CROSS
SECTIONS WHICH SHOW SATURATION LATER TODAY AROUND 850 MB.
DRY WEATHER IS EXPECTED TODAY AND TONIGHT...BUT COOL NORTHERLY FLOW
WITH NEARLY A 20C TEMP DIFFERENTIAL FROM THE TOP OF THE MIXED LAYER
TO THE SST. THIS MAY RESULT IN BRIEF SPOT SPRINKLE/LIGHT SHOWER OR
TWO...BUT NOTHING MORE THAN THAT. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 50 TO 55 DEGREE RANGE WITH UPPER 40S IN PARTS OF
THE HIGH TERRAIN. WINDS WILL NOT BE TOO BAD THOUGH FROM THE NORTH AT
5 TO 15 MPH.
WHILE CLOUDS WILL LIKELY HANG TOUGH ALONG PARTS OF THE COAST
TONIGHT...WE SHOULD SEE A LOT OF THEM SCOUR OUT ACROSS THE INTERIOR.
THIS SHOULD ALLOW LOW TEMPS TO BOTTOM OUT IN THE UPPER 20S AND 30S
IN MOST LOCALES.
SHORT TERM /TUESDAY THROUGH WEDNESDAY/
KEY MESSAGES...
* COOL TUE/WED...HIGHS LOWER-MIDDLE 50S AND UPPER 40S HIGHEST TERRAIN
* NE WIND GUSTS OF 20-30 MPH TOWARDS CAPE/ISLANDS TUE INTO WED
* SCATTERED SHOWERS TUE-WED MAINLY NEAR AND SOUTHEAST OF I-95
DETAILS...
TUESDAY AND WEDNESDAY...
A LARGE HIGH PRESSURE SYSTEM WILL REMAIN ENTRENCHED ACROSS QUEBEC AS
WEAK WAVES OF LOW PRESSURE PASSES WELL SOUTHEAST OF THE BENCHMARK.
THIS WILL RESULT IN NE LOW LEVEL FLOW AND IT WILL BE A BIT BREEZY
TOWARDS THE CAPE AND ISLANDS WITH 20-30 MPH WIND GUSTS AT TIMES.
HIGH TEMPS WILL BE MAINLY IN THE LOWER TO MIDDLE 50S WITH SOME UPPER
40S ACROSS PARTS OF THE HIGHEST TERRAIN.
ALTHOUGH THE WEAK WAVES OF LOW PRESSURE WILL PASS WELL SOUTHEAST OF
THE BENCHMARK...THE MOIST COOL LOW LEVEL NE FLOW WILL RESULT IN SOME
OCEAN ENHANCED SCATTERED SHOWERS AT TIMES MAINLY NEAR AND SOUTHEAST
OF I-95 TUE INTO WED. WHILE RAINFALL TOTALS WILL BE LIGHT TUE INTO
WED...EXPECT COOL, RAW AND OCCASIONALLY WET CONDITIONS NEAR AND
SOUTHEAST OF I-95.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
KEY MESSAGES...
* A WINDSWEPT HEAVY RAIN EXPECTED SOMETIME THU INTO THU NIGHT
* 1-3" OF RAIN APPEARS REASONABLE THU INTO THU NIGHT
* NUISANCE STREET FLOODING AND 30-50 MPH GUSTS ON THE COAST
* A FEW SHOWERS MAY LINGER INTO FRI WITH DRIER WEATHER SAT
DETAILS...
THURSDAY AND THURSDAY NIGHT...
DEEP ANOMALOUS CLOSED UPPER LEVEL LOW OVER THE SOUTHEAST WILL LIFT
NORTHEASTWARD INTO THE MID-ATLANTIC AND NEAR THE EASTERN GREAT LAKES
BY THE END OF THE WEEK. THIS WILL INDUCE FAIRLY STRONG CYCLOGENESIS
WITH AN INITIAL MAIN LOW PRESSURE SYSTEM LIKELY PASSING WEST OF OUR
REGION...WHICH LOOKS TO BE SUB 990 MB. WE MAY SEE SECONDARY
DEVELOPMENT NEAR THE COAST AS WELL. MAKING THIS FORECAST EVEN MORE
COMPLEX IS MAJOR HURRICANE MELISSA CURRENTLY IN THE CARIBBEAN WILL
BE MOVING NORTHEAST...PASSING WELL TO OUR EAST LATER IN THE WEEK.
WHILE THIS WILL NOT IMPACT OUR REGION DIRECTLY...SOME OF ITS
MOISTURE PLUME MAY BE PULLED NORTHWEST WITH PWATS APPROACHING 1.5
INCHES. THIS COMBINED WITH A 50 TO 60+ KNOT ESE LLJ WILL RESULT IN A
SIGNIFICANT PERIOD OF FORCING FOR A PERIOD OF HEAVY WINDSWEPT RAIN.
SO IN AN NUTSHELL...WHILE UNCERTAINTY REMAINS CONFIDENCE HAS
INCREASED IN A PERIOD OF HEAVY WINDSWEPT RAIN SOMETIME THU INTO
THU NIGHT. THIS SYSTEM DOES LOOK TO BE FAIRLY PROGRESSIVE AND
WITH THE UPPER LEVEL CENTERS PASSING TO OUR WEST...THE DURATION
OF HEAVY RAIN MAY BE SOMEWHAT LIMITED. NONETHELESS...GIVEN THE
STRONG FORCING AND HIGH PWAT PLUME...RAINFALL AMOUNTS OF 1 TO 3
INCHES ARE REASONABLE WHICH MAY RESULT IN SOME NUISANCE STREET
FLOODING. WE MAY ALSO SEE A PERIOD OF 30-50 MPH EAST SOUTHEAST
WIND GUSTS WITH THE STRONGEST NEAR THE COAST. WE SHOULD NOTE
THAT DESI IS INDICATING SOME LOW PROBABILITIES OF 4+ INCHES OF
RAIN WITH THIS SYSTEM. IF WE CAN GET STRONGER SECONDARY
DEVELOPMENT...THAT MAY INCREASE THAT POTENTIAL. SO THERE IS A
LOW PROBABILITY OF MORE SIGNIFICANT FLOODING...BUT CURRENTLY
THINKING THIS WILL BE MORE OF THE TYPICAL URBAN STREET FLOODING.
CERTAINLY SOMETHING TO MONITOR OVER THE NEXT FEW DAYS.
FRIDAY INTO SATURDAY...
EXACT TIMING OF THIS SYSTEM REMAINS UNCERTAIN...BUT WE MAY SEE RAIN
DIMINISH TO A FEW SHOWERS FRIDAY AS THE MID LEVEL DRY SLOT WORKS
ACROSS THE REGION. MUCH OF SATURDAY MAY END UP BREEZY BUT MAINLY DRY
OUTSIDE A SPOT SHOWER WITH SEASONABLE TEMPERATURES.
AVIATION /07Z MONDAY THROUGH FRIDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE...
TODAY AND TONIGHT...HIGH CONFIDENCE.
VFR. THE EXCEPTION MIGHT BE SOME BRIEF MARGINAL MVFR CEILINGS NEAR
THE CAPE/NANTUCKET FROM OCEAN EFFECT CLOUDS AND PERHAPS A BRIEF
PASSING SPRINKLE/LIGHT SHOWER. N WINDS 5 TO 10 KNOTS EXCEPT 10-15
KNOTS ACROSS THE CAPE/NANTUCKET.
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE.
CONSIDERABLE CLOUDINESS WITH LOW END VFR-MVFR CEILINGS. LOWEST OF THE
CONDITIONS WILL BE MORE DOMINANT NEAR AND SOUTHEAST OF I- 95.
THIS IS ALSO WHERE WE EXPECT THE BULK OF THE SCATTERED OCEAN
ENHANCED SHOWERS. NE WINDS OF 5 TO 15 KNOTS STRONGEST OF WHICH
TOWARDS THE CAPE AND ISLANDS WHERE GUSTS OF 20-30 KNOTS ARE
EXPECTED.
KBOS TERMINAL... HIGH CONFIDENCE IN TAF.
KBDL TERMINAL... HIGH CONFIDENCE IN TAF.
OUTLOOK /WEDNESDAY NIGHT THROUGH FRIDAY/...
WEDNESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
CHANCE SHRA.
THURSDAY: MAINLY VFR, WITH AREAS MVFR POSSIBLE. WINDY WITH
GUSTS UP TO 35 KT. RA.
THURSDAY NIGHT: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. WINDY
WITH GUSTS UP TO 35 KT. RA.
FRIDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. WINDY WITH GUSTS
UP TO 35 KT. CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY...HIGH CONFIDENCE.
HIGH PRESSURE ACROSS QUEBEC WILL RESULT IN N WINDS OF 10 TO 15 KNOTS
TODAY. SOME GUSTS OF 20 KNOTS ARE POSSIBLE...BUT EXPECT WINDS/SEAS
TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT THROUGH WEDNESDAY...HIGH CONFIDENCE.
LARGE HIGH PRESSURE ANCHORED OVER QUEBEC WILL COMBINED WITH A FEW
WEAK WAVES OF LOW PRESSURE PASSING WELL SOUTHEAST OF THE BENCHMARK.
THIS RESULT IN STRONG ENOUGH PRESSURE GRADIENT TO RESULT IN NE WIND
GUSTS OF 25 TO 30 KNOTS WITH A FEW GUSTS UP TO 35 KNOTS POSSIBLE
LATE TONIGHT RIGHT THROUGH WEDNESDAY. THEREFORE...WE OPTED TO HOIST
SMALL CRAFT HEADLINES FOR ALL OPEN WATERS. WE MAY BRIEFLY TOUCH
GALES...BUT THINKING SMALL CRAFT HEADLINES ARE MORE
REPRESENTATIVE. THE LONG NE FETCH WILL RESULT IN ROUGH SEAS AS
WELL.
OUTLOOK /WEDNESDAY NIGHT THROUGH FRIDAY/...
WEDNESDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS
WITH LOCAL GUSTS UP TO 30 KT. ROUGH SEAS UP TO 8 FT. CHANCE OF
RAIN SHOWERS.
THURSDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 40 KT.
ROUGH SEAS UP TO 8 FT. RAIN.
THURSDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 40 KT. ROUGH SEAS
UP TO 12 FT. RAIN.
FRIDAY: MODERATE RISK FOR GALE FORCE WINDS WITH GUSTS UP TO
40 KT. ROUGH SEAS UP TO 12 FT. RAIN LIKELY, CHANCE OF RAIN
SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT
THURSDAY FOR ANZ231>235-237-250-251-254>256.
SYNOPSIS...FRANK
NEAR TERM...FRANK
SHORT TERM...FRANK
LONG TERM...FRANK
AVIATION...FRANK
MARINE...FRANK
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