814
FXUS61 KBOX 021952
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
352 PM EDT FRI OCT 2 2026
WHAT HAS CHANGED
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE SOUTHERN
WATERS THROUGH THIS EVENING FOR GUSTY WINDS AND ELEVATED SEAS.
OTHERWISE, THE FORECAST REMAINS ON TRACK.
KEY MESSAGES
- SCATTERED SHOWERS THIS AFTERNOON AND TONIGHT. BRIEF GUSTY
WINDS OR A RUMBLE OF THUNDER POSSIBLE. MAINLY DRY AND COOLER
SATURDAY.
- A STRONG COLD FRONT BRINGS A CHANCE FOR SCATTERED SHOWERS
SUNDAY FOLLOWED BY MUCH COOLER TEMPERATURES FOR THE FIRST WEEK
OF OCTOBER.
DISCUSSION
KEY MESSAGE 1...SCATTERED SHOWERS THIS AFTERNOON AND TONIGHT.
BRIEF GUSTY WINDS OR A RUMBLE OF THUNDER POSSIBLE. MAINLY DRY
AND COOLER SATURDAY.
DAY CLOUD PHASE SATELLITE IMAGERY AND RADAR THIS AFTERNOON SHOW
SHOWER DEVELOPMENT INCREASING IN COVERAGE ACROSS PORTIONS OF
SOUTHERN NEW ENGLAND. THIS ACTIVITY WILL CONTINUE TO EXPAND AND
PUSH EASTWARD INTO THE EARLY EVENING ALONG AND AHEAD OF A
GRADUALLY ADVANCING COLD FRONT.
RECENT SPC MESOANALYSIS HIGHLIGHTS AN ENVIRONMENT CONDUCIVE TO
CONVECTIVE ELEMENTS WITH PWATS NEAR 1.6", MARGINAL INSTABILITY,
AND STEEP LOW LEVEL LAPSE RATES. THE WELL MIXED BOUNDARY LAYER
HAS CONTRIBUTED TO AN AXIS OF ELEVATED DCAPE VALUES AROUND 1000
J/KG EXTENDING FROM EAST CT TO A PORTION OF EAST MA. GIVEN THIS
SET-UP, EXPECT SCATTERED CONVECTIVE SHOWERS THIS EVENING. A FEW
SHOWERS MAY BE CAPABLE OF A RUMBLE OF THUNDER, BRIEF DOWNPOUR,
AND LOCALIZED GUSTY WINDS. ALTHOUGH NOT EXPECTING SEVERE
CRITERIA.
THE FRONT AND ASSOCIATED SHOWERS WILL SLOWLY PUSH THROUGH
TONIGHT. SHOWERS EXIT MOST AREAS BY MIDNIGHT, WITH THE EXCEPTION
OF SOUTHEAST MA AND THE CAPE/ISLANDS WHERE SHOWERS MAY LINGER
THROUGH AROUND 5 AM. SKIES CLEAR BEHIND THE DEPARTING SHOWERS
SATURDAY MORNING WITH POST-FRONTAL WINDS OUT OF THE NORTHWEST.
COLDER AIR ADVECTS IN POST-FRONT FOR SATURDAY WITH 850 MB
TEMPERATURES +4-6C. THIS WILL YIELD A MORE FALL-LIKE DAY WITH
TEMPERATURES IN THE MID TO UPPER 60S FOR MOST OF THE SOUTHERN
NEW ENGLAND. AS SURFACE HIGH PRESSURE SHIFTS EAST, FLOW WEAKENS
AND SHIFT TO THE EAST ACROSS THE EASTERN COASTAL AREAS. ONSHORE
MAY KEEP TEMPERATURES IN THOSE AREAS LOCKED IN THE LOW TO MID
60S.
RADIATIONAL COOLING SHOULD OPTIMIZE COOLING SATURDAY NIGHT GIVEN
THE CLEAR SKIES WITH LOWS DROPPING IN THE 40S FOR THE INTERIOR
AND LOW 50S NEAR THE COAST. THE TYPICAL RADIATOR SPOTS AND
HIGHER TERRAIN COULD DROP INTO THE UPPER 30S.
KEY MESSAGE 2...A STRONG COLD FRONT BRINGS A CHANCE FOR SCATTERED
SHOWERS SUNDAY FOLLOWED BY MUCH COOLER TEMPERATURES FOR THE FIRST
WEEK OF OCTOBER.
SHOWER CHANCES SUNDAY HAVE COME INTO BETTER FOCUS WITH THE LATEST
GUIDANCE SHOWING A BAND OF ANOMALOUSLY HIGH PWATS ADVECTING POLEWARD
ALONG AND AHEAD OF A STRONG COLD FRONT SUNDAY NIGHT INTO MONDAY
MORNING. WHILE MOST GUIDANCE HAS SHIFTED TOWARDS MORE WIDESPREAD
SHOWERS THE FLY IN THE OINTMENT FOR THIS FORECAST IS THE DEPTH AND
EXTENT OF A LAYER OF DRY AIR (RH <35%). MORE WIDESPREAD DRY AIR
ALOFT MAY SERVE TO HELP KEEP THE SHOWERS MORE SCATTERED IN NATURE AS
INSTEAD OF A BROAD SHIELD OF RAINFALL THAT SOME GLOBAL GUIDANCE IS
DEPICTING.
WILL SEE STRONG CAA BEHIND THE FRONT LATER MONDAY INTO TUESDAY AS
THE PARENT LOW DEEPENS OVER THE CANADIAN MARITIMES. ENSEMBLE
GUIDANCE SHOWS A 30-50% CHANCE OF THE LOW DEEPENING >980MB WHICH IS
AN INCREASE FROM PREVIOUS RUNS. A DEEPER LOW WOULD BRING STRONGER CAA
AND THUS COLDER 850 MB TEMPS. AT PRESENT, GUIDANCE SHOWS THE 0C
ISOTHERM MAKING IT AS FAR SOUTH AS COASTAL MA AND CT BY TUESDAY
MORNING. THESE COLD MID-LEVEL TEMPERATURES LIKELY TRANSLATE TO HIGHS
IN THE MID AND LOWER 50S TUESDAY AND WEDNESDAY. MORE NOTABLY, LOW
TEMPS LIKELY FALL INTO THE 30S MONDAY AND TUESDAY NIGHT. MONDAY
NIGHT SHOULD SEE THE <40 DEGREE READINGS LIMITED TO NORTHERN MA AND
THE HIGHER ELEVATIONS OF EASTERN CT AS THE BOUNDARY LAYER STAYS
BETTER MIXED. MORE WIDESPREAD 30-40 DEGREE READINGS ARRIVE TUESDAY
NIGHT AS THE CENTER OF CONTINENTAL HIGH PRESSURE CRESTS OVER THE
REGION RESULTING IN CALM WINDS AND CLEAR SKIES. THUS, THE BEST
CHANCE OF THE SEASON'S FIRST WIDESPREAD FROST/FREEZE SHOULD ARRIVE
TUESDAY NIGHT.
THE HIGH THEN PUSHES EAST BY THURSDAY, MARKING THE RETURN OF
PREDOMINANTLY SOUTHWEST FLOW AND SEASONABLE TEMPERATURE TO SOUTHERN
NEW ENGLAND FOR THE END OF THE WEEK.
AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE:
TODAY: HIGH CONFIDENCE IN TAF/TRENDS BUT MODERATE ON TIMING.
MAINLY VFR, WITH SW WINDS AROUND 8-12 KT WITH OCCASIONAL GUSTS
TO 20 KTS AND UP TO 25 KTS FOR EAST COAST AND CAPE TERMINALS.
- SHRA APPROACHES TAF SITES BETWEEN 19-03Z FROM WEST TO EAST WITH
BRIEF PERIOD OF MVFR VISBY/CIGS WITHIN ANY SHRA. WHILE NOT
ZERO, THE RISK FOR TS IS LOW (< 20%) AND PREDOMINANTLY SHOULD
BE SHRA. WINDS SHIFT BEHIND THE FRONT FROM SW TO W/WNW THIS
EVENING. COULD SEE A BRIEF GUST 20 KTS WITH THE FRONTAL
PASSAGE.
TONIGHT: HIGH CONFIDENCE.
VFR FOR MOST, WITH PATCHY MVFR POSSIBLE FOR CAPE COD AND ISLANDS
OVERNIGHT. ANOTHER "WAVE" OF -SHRA IS POSSIBLE FOR PORTIONS OF
EASTERN SOUTHERN NEW ENGLAND TONIGHT. THIS IS MORE LIKELY TO
IMPACT PVD AND CAPE/ISLAND TERMINALS, BUT COULD PUSH AS NORTH AS
BOS 00 TO APPROX 04Z. -SHRA MOVE OFFSHORE THE CAPE AND ISLANDS
BY 10Z SAT. NW TO N WINDS INCREASE TO AROUND 10 KT, ESPECIALLY
AROUND/AFTER MIDNIGHT. CEILINGS GRADUALLY INCREASE 06-12Z.
SATURDAY AND SATURDAY NIGHT: HIGH CONFIDENCE.
VFR. N WINDS AROUND 10 KT TO START SATURDAY, THOUGH DECREASE TO
AROUND 5-10 KT BY AFTERNOON, WITH ENE/E WINDS FOR THE EASTERN
MA COAST. SCT MID-LEVEL DECKS POSSIBLE. N/NNE WINDS CONTINUE
OVERNIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF/TRENDS BUT MODERATE ON
TIMING. THINKING SHRA BEGINS AROUND 20-22Z, WITH EMBEDDED
HEAVIER SHRA AND MVFR VISBY BETWEEN 21-23Z. ADDED IN A PROB30
FOR -SHRA 00-04Z AS SOME ADDITIONAL SHOWERS MAY PUSH NEAR BOS IN
THAT TIMEFRAME. WINDS SHIFT TO THE NW 22-00Z WITH THE FRONTAL
PASSAGE THIS EVENING.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. THINKING SHRA BEGINS
AROUND 19Z, WITH EMBEDDED HEAVIER SHRA AND MVFR VISBY BETWEEN
20-22Z.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUNDAY: VFR.
SUNDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. CHANCE
SHRA.
MONDAY THROUGH TUESDAY: VFR. BREEZY.
TUESDAY NIGHT THROUGH WEDNESDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH SUNDAY...HIGH CONFIDENCE.
A COLD FRONT APPROACHES THE SOUTHERN NEW ENGLAND COASTAL WATERS
THIS EVENING. AHEAD OF THE FRONT, SOUTHWEST FLOW WILL BRING
GUSTS OF 20-25 KNOTS ACROSS THE SOUTHERN NEARSHORE WATERS,
INCLUDING CAPE COD BAY, WITH MARGINAL SEAS OF 5-6 FEET ACROSS
THE SOUTHERN OUTER WATERS. A FEW SHOWERS AND AN ISOLATED
THUNDERSTORM ARE POSSIBLE WITH THE FRONTAL PASSAGE THIS EVENING.
WINDS SHIFT TO THE NW/N BEHIND THE FRONT THIS EVENING INTO
TONIGHT. HIGH PRESSURE BRIEFLY RETURNS SATURDAY WITH TRANQUIL
BOATING CONDITIONS.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUNDAY THROUGH SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF
SEAS APPROACHING 5 FT. CHANCE OF RAIN SHOWERS.
MONDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. SLIGHT CHANCE
OF RAIN SHOWERS.
MONDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. SEAS UP TO 5 FT.
TUESDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. LOCAL ROUGH SEAS.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY: WINDS LESS THAN 25 KT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ230>237-251.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR ANZ254>256.
DISCUSSION...MENSCH/FT
AVIATION...MENSCH
MARINE...MENSCH/FT
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