272
FXUS61 KBOX 251724
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
124 PM EDT MON AUG 25 2025
SYNOPSIS
ISOLATED SHOWER/THUNDERSTORM ACTIVITY IS POSSIBLE INTO THIS EVENING
WITH A COLD FRONTAL PASSAGE...BUT AREAL COVERAGE/DURATION OF ANY
ACTIVITY WILL BE LIMITED. OTHERWISE...DRY AND VERY PLEASANT WEATHER
IS IN STORE FOR THE NEXT FEW DAYS OUTSIDE THE RISK FOR A BRIEF SPOT
SHOWER WEDNESDAY. THE NEXT MAIN RISK FOR SOME SHOWERS IS NOT UNTIL
SOMETIME FRIDAY INTO EARLY SATURDAY IN ASSOCIATION WITH THE NEXT
COLD FRONT.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES...
* ISOLATED SHOWER/T-STORM RISK INTO THIS EVENING...BUT NOT WIDESPREAD
* OTHERWISE...DRY/COOLER TONIGHT WITH LOWS IN THE 50S TO LOWER 60S
DETAILS...
THROUGH TONIGHT...
AN APPROACHING COLD FRONT ALONG WITH SOUTHWEST FLOW HAS ALLOWED FOR
750 TO 1500 J/KG OF CAPE TO DEVELOP THIS AFTERNOON. EFFECTIVE SHEAR
WILL ALSO INCREASE TO OVER 40 KNOTS IN THE NEXT FEW HOURS.
HOWEVER...THE BETTER UPPER LEVEL DYNAMICS ARE PASSING WELL TO OUR
NORTH AND THERE IS SOME MID-LEVEL DRY AIR WORKING IN FROM THE WEST.
CAMS ARE ALSO NOT THAT IMPRESSIVE WITH THEIR SIMULATIONS...SO WHILE
THERE WILL BE AN ISOLATED SHOWER/T-STORM RISK INTO THE FIRST HALF OF
THIS EVENING NOT EXPECTING ANYTHING SIGNIFICANT OR WIDESPREAD.
OTHERWISE...THE DRY AND COOLER TONIGHT BEHIND THE COLD FRONTAL
PASSAGE. OVERNIGHT LOWS SHOULD BOTTOM OUT IN THE 50S TO THE LOWER
60S.
SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/
KEY MESSAGES...
* PLENTY OF SUNSHINE WITH LOW HUMIDITY TUE...HIGHS MIDDLE-UPPER 70S
* DRY AND COOL TUE NIGHT WITH LOWS IN THE UPPER 40S TO THE MIDDLE 50S
DETAILS...
TUESDAY...
POST-FRONTAL AIRMASS WILL RESULT IN BEAUTIFUL WEATHER ON TUESDAY.
PLENTY OF SUNSHINE WITH JUST A BIT OF FAIR WEATHER DIURNAL CU WILL
RESULT IN HIGHS MAINLY IN THE MIDDLE TO UPPER 70S. DEWPOINTS WILL BE
DROPPING INTO THE UPPER 40S TO THE LOWER 50S RESULTING IN LOW
HUMIDITY. WESTERLY WINDS WILL GUST TO 15-20 MPH AT TIMES WITH A FEW
BRIEF GUSTS NEAR 25 MPH. REGARDLESS...A BEAUTIFUL AND COMFORTABLE
DAY IS IN STORE FOR THE REGION ON TUESDAY.
TUESDAY NIGHT...
LARGE SPRAWLING HIGH PRESSURE WILL NOSE EASTWARD FROM THE MIDWEST.
THIS WILL RESULT IN DIMINISHING WINDS AND DRY/PLEASANTLY COOL
TEMPERATURES TUESDAY NIGHT. AN APPROACHING MOISTURE STARVED UPPER
LEVEL TROUGH MAY BRING A BIT OF MID LEVEL CLOUDINESS...BUT STILL
THINKING LOW TEMPS WILL BOTTOM OUT MAINLY IN THE UPPER 40S TO THE
MIDDLE 50S. THE URBAN HEAT ISLAND OF BOSTON SHOULD BE THE MILD SPOT
WITH LOW TEMPS NEAR 60.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
KEY MESSAGES:
* COOLER AND MAINLY DRY THROUGH LATE WEEK.
* NEXT CHANCE FOR SHOWERS/PRECIPITATION LATE THURSDAY-FRIDAY.
THIS WILL BRING A PERIOD OF COOLER TEMPERATURES THROUGH THE END
OF THE WEEK. HIGH TEMPERATURES WILL STAY MAINLY IN THE MID 70S.
HIGH PRESSURE WILL BRING DRY CONDITIONS AND MAINLY CLEAR
CONDITIONS THROUGH THURSDAY. COOL NIGHTS WILL RESULT FROM THE
OPTIMAL RADIATIONAL COOLING WITH POTENTIAL FOR SOME PATCHY FOG
IN THE VALLEYS. OVERNIGHT LOWS WILL LIKELY RANGE IN THE UPPER
40S TO 50S WITH THE COOLER TEMPERATURES ACROSS THE INTERIOR.
CAN'T RULE OUT EVEN COOLER TEMPERATURES FOR THE HIGHER TERRAIN
SPOTS.
ENSEMBLE GUIDANCE SHOWS A GENERAL CONSENSUS WITH A SHORTWAVE MOVING
THROUGH LATE WEEK. SOLUTIONS BECOME A LITTLE LESS AGREEABLE ON THE
DETAILS OF TIMING, BUT MOST GENERALLY HAVE A COLD FRONT DROPPING
ACROSS THE REGION SOMETIME LATER THURSDAY-FRIDAY. THIS WILL BRING
OUR NEXT CHANCE FOR PRECIPITATION. DETAILS SUCH AS AMOUNTS, EXACT
TIMING, COVERAGE ARE LESS CERTAIN, BUT SHOULD BECOME MORE CLEAR
FURTHER ALONG IN THE WEEK.
AVIATION /18Z MONDAY THROUGH FRIDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE...
THROUGH TONIGHT...HIGH CONFIDENCE.
ANY LEFTOVER MVFR CEILINGS WILL BE IMPROVING TO MAINLY VFR
CONDITIONS INTO EARLY THIS EVENING. ONLY ISSUE WILL BE THE RISK FOR
ISOLATED SHOWER/T-STORM ACTIVITY INTO THE FIRST HALF OF THE
EVENING...BUT NOT EXPECTING ANYTHING WIDESPREAD. OTHERWISE...VFR
CONDITIONS TONIGHT. WINDS BECOMING W GENERALLY 10 KNOTS OR LESS.
TUESDAY...HIGH CONFIDENCE.
VFR. W WIND GUSTS OF 15-20 KNOTS DEVELOPING WITH PERHAPS A FEW BRIEF
GUSTS APPROACHING 25 KNOTS BY AFTERNOON.
TUESDAY NIGHT...HIGH CONFIDENCE.
VFR. CALM/LIGHT WNW WINDS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. STILL NEED TO WATCH FOR A
SPOT SHOWER/T-STORM IN THE VICINITY OF THE TERMINAL THROUGH
00Z...BUT AREAL COVERAGE/DURATION OF ANY ACTIVITY WILL BE QUITE
LIMITED. SEA BREEZE SHOULD KICKOUT BY 22Z.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. ISOLATED SHOWERS WITH THE
LOW RISK FOR A T-STORM POSSIBLE IN THE VICINITY OF THE TERMINAL
THROUGH 22Z/23Z...BUT AREAL COVERAGE/DURATION OF ANY ACTIVITY WILL
BE LIMITED.
OUTLOOK /WEDNESDAY THROUGH FRIDAY/...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT: VFR.
THURSDAY: VFR. BREEZY.
THURSDAY NIGHT: VFR.
FRIDAY: VFR. BREEZY. CHANCE SHRA, SLIGHT CHANCE TSRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TONIGHT THROUGH TUESDAY NIGHT...HIGH CONFIDENCE.
A COLD FRONT CROSSES THE WATERS THIS EVENING. LONG SOUTHWEST FETCH
AHEAD OF THIS FRONT WILL RESULT IN 3 TO 6 FOOT SWELL ACROSS OUR
OUTER-WATERS AS WELL AS OUR SOUTHERN OPEN WATERS INTO TONIGHT. THIS
SWELL WILL DIMINISH EARLY TUE MORNING AND WITH LARGE HIGH PRESSURE
NOSING IN FROM THE WEST. NO ADDITIONAL MARINE HEADLINES WILL BE
NEEDED THROUGH TUESDAY NIGHT. THAT BEING SAID SOME W WIND GUSTS OF
20+ KNOTS WILL BE POSSIBLE AT TIMES LATE TONIGHT INTO TUE BEHIND THE
COLD FRONT.
OUTLOOK /WEDNESDAY THROUGH FRIDAY/...
WEDNESDAY THROUGH THURSDAY NIGHT: WINDS LESS THAN 25 KT.
FRIDAY: WINDS LESS THAN 25 KT. SLIGHT CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EDT
TUESDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ254>256.
SYNOPSIS...FRANK
NEAR TERM...FRANK
SHORT TERM...FRANK
LONG TERM...MENSCH
AVIATION...FRANK/MENSCH
MARINE...FRANK/MENSCH
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