831
FXUS61 KBOX 180524
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
124 AM EDT THU SEP 18 2025
SYNOPSIS
SCATTERED SHOWERS AND A FEW EMBEDDED THUNDERSTORMS WILL LIFT
NORTHWARD ACROSS THE REGION TONIGHT INTO EARLY THURSDAY AS LOW
PRESSURE TRACKS TO THE SOUTH. DRYING OUT THURSDAY AFTERNOON
WITH WARM AND DRY CONDITIONS FRIDAY, THEN A COLD FRONT WILL BE
FOLLOWED BY MORE AUTUMN-LIKE TEMPERATURES THIS WEEKEND. DRY
WEATHER PATTERN CONTINUES INTO NEXT WEEK WITH A NOTABLE WARMING
TREND.
NEAR TERM /THROUGH TODAY/
TONIGHT
A WAVE OF LOW-PRESSURE LIFTS NORTHEAST WITH SCATTERED SHOWERS
OVERNIGHT. A FEW EMBEDDED THUNDERSTORMS WILL BE POSSIBLE AS WELL.
DEEP LAYER SHEAR IS LACKING, BUT THERE WILL BE A FEW HUNDRED J/KG OF
CAPE AVAILABLE ALONG WITH SUFFICIENT MID-LEVEL LAPSE RATES TO
SUPPORT A STRONGER STORM OR TWO OVER THE COASTAL WATERS OFF THE
SOUTH COAST. WEST OF I-95/I-495 EXPECTED MAINLY DRY/MILD CONDITIONS
WITH A SPOT SHOWER OR TWO. CLOUDS AND INCREASED HUMIDITY KEEP
TEMPERATURES MILD OVERNIGHT IN THE MID TO UPPER 50S.
SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/
KEY MESSAGES:
* SHOWERS OVER THE EAST COAST TAPER OFF THURSDAY AFTERNOON
* WARM/DRY CONDITIONS PERSIST THURSDAY NIGHT INTO FRIDAY
THURSDAY
AREA OF LOW-PRESSURE OFF THE SOUTH COAST WILL SHIFT EAST TOMORROW
MORNING, BRINGING AN END TO ANY SHOWERS OVER EASTERN MA, CAPE, AND
ISLANDS. WINDS GRADUALLY SHIFT TO THE WEST/SOUTHWEST BY TOMORROW
AFTERNOON RESULTING IN A SURGE OF TEMPERATURES AND DEWPOINTS INTO
THE MID 70S/MID 60S TOMORROW, THUS EXPECT A RATHER MUGGY AFTERNOON
FOR MID-SEPTEMBER. SUBSTANTIALLY WARMER CONDITIONS ACROSS THE
INTERIOR WITH LOW 80S LIKELY IN THE CT RIVER VALLEY. SHOULD BE A
GOOD AMOUNT OF SUNSHINE BY EARLY AFTERNOON AS SKIES CLEAR FROM WEST
TO EAST.
THURSDAY NIGHT
SKIES COMPLETELY CLEARING OVER NIGHT WITH WINDS SHIFTING TO
WEST/NORTHWEST AND BECOMING MORE STEADY AROUND 10 MPH. EXPECT MILD-
LOW TEMPERATURES AGAIN IN THE MID TO UPPER 50S. SOME PATCHY FOG
POSSIBLE, BUT STEADY NORTHWEST WINDS SHOULD LIMIT ANY WIDESPREAD FOG
DEVELOPMENT.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
KEY MESSAGES:
* WARM AND DRY FRIDAY
* DRY AND COOLER FRIDAY NIGHT THROUGH THE WEEKEND BEFORE WARMING
TREND NEXT WEEK
COLD FRONT WILL BE DROPPING SOUTH ACROSS SNE FRI AFTERNOON, REACHING
THE SOUTH COAST BY EARLY EVENING. LIMITED MOISTURE AND LOW LEVEL
CONVERGENCE WILL RESULT IN A DRY FROPA. COOLER AIR LAGS WELL TO THE
NORTH WHICH WILL ALLOW TEMPS TO REACH WELL INTO THE 70S WITH A FEW
LOCATIONS ACROSS CT/RI AND SE MA POSSIBLY GETTING TO 80F. COOLER AIR
WITH BELOW NORMAL TEMPS SETTLES SOUTH INTO SNE FRI NIGHT THROUGH THE
WEEKEND WITH MAINLY CLEAR SKIES AS HIGH PRES BUILDS IN FROM THE
NORTH. HIGHS SAT WILL RANGE FROM MID 60S TO AROUND 70 WITH SLIGHT
WARMING SUNDAY. COOLEST NIGHT WILL BE SAT NIGHT WITH GOOD
RADIATIONAL COOLING ALLOWING WIDESPREAD 40S FOR LOWS WITH SOME UPPER
30S IN THE COLDER RADIATORS.
LOOKING AHEAD TO NEXT WEEK, DRY PATTERN CONTINUES WITH A WARMING
TREND AS RIDGING ALOFT DEVELOPS WITH WARMING MID LEVEL TEMPS.
CONFIDENCE IN DRY WEATHER THROUGH TUE IS ABOVE NORMAL THEN
DECREASING CONFIDENCE WED AS THERE IS UNCERTAINTY WITH TIMING AND
LOCATION OF A SHORTWAVE APPROACHING NEW ENG. EPS AND GEFS TO A
LESSER EXTENT SHOW INCREASING PROBS OF 0.10" QPF ON WED SO CHANCE OF
SHOWERS MAY RETURN BY NEXT WED. 850 MB TEMPS WARM TO 15C TUE AND WED
WHICH SHOULD ALLOW TEMPS TO REACH INTO THE 80S AWAY FROM THE SOUTH
COAST. IN FACT, GEFS AND EPS ENSEMBLES HAVE 50-80 PERCENT PROBS OF
80+ TUE WED WHICH IS A PRETTY STRONG SIGNAL AT DAY 6. THEN PROBS OF
80 DECREASE WED BUT STILL IN THE 20-50 PERCENT RANGE.
AVIATION /06Z THURSDAY THROUGH MONDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE:
THROUGH 12Z...HIGH CONFIDENCE.
MVFR WITH IFR (AND SOME POCKETS OF LIFR) POSSIBLE IN SHRA.
SCATTERED SHOWERS ARE ONGOING OVER MUCH OF SE MA, CAPE COD, AND
AROUND THE ISLANDS, PLUS SOME MOVING OVER BOS. THIS TREND IS
EXPECTED TO CONTINUE FOR THE NEXT FEW HOURS. CONVERTED PROB30S
TO TEMPOS WITH THESE SHOWERS MOVING NORTH. INSTABILITY HAS
DROPPED OFF CONSIDERABLY AND THESE SHOWERS HAVE NOT PRODUCED ANY
THUNDER FOR A FEW HOURS NOW, SO CONFIDENCE IN TS IS VERY LOW.
ANY THAT MAY OCCUR WILL LIKELY BE RESTRICTED OUT TOWARDS CAPE
COD AND WATERS NORTH.
THURSDAY...HIGH CONFIDENCE IN TRENDS.
MVFR/IFR CEILINGS AND -SHRA EARLY WILL STEADILY IMPROVE TO VFR
BETWEEN 15-17Z, EXCEPT OVER CAPE COD AND THE ISLANDS WHERE
IMPROVEMENT MAY BE SLOWER. LIGHT NORTHEAST GRADUALLY SHIFTING
TO WEST/NORTHWEST TOMORROW AFTERNOON.
THURSDAY NIGHT...HIGH CONFIDENCE.
VFR. LIGHT WEST/SOUTHWEST WINDS FOR THE FIRST HALF OF THE NIGHT
BECOME NORTHEAST BY 12Z FRIDAY.
FRIDAY...HIGH CONFIDENCE.
VFR. BREEZY NW WINDS AROUND 10 KTS, OCCASIONALLY GUSTING TO 15
KTS.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. SHRA ONGOING AND MAY
LAST THROUGH 10Z. CHANCE FOR IFR REMAINS, THOUGH CONFIDENCE
IN LIFR HAS LOWERED. REMOVED FROM TAF AT THIS TIME.
BDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...
FRIDAY NIGHT: VFR. BREEZY.
SATURDAY THROUGH SATURDAY NIGHT: VFR.
SUNDAY THROUGH SUNDAY NIGHT: VFR. BREEZY.
MONDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH THURSDAY NIGHT
AN AREA OF LOW-PRESSURE MOVES OVER THE COASTAL WATERS THIS EVENING
AND OVERNIGHT. A FEW STRONG THUNDERSTORMS MAY DEVELOP OVER THE
COASTAL WATERS NEAR THE ISLANDS. OTHERWISE, EXPECT RELATIVELY QUIET
CONDITIONS FOR MID-SEPTEMBER WITH SUSTAINED WINDS 10 KNOTS OR LESS
AND GUSTS LESS THAN 20 KNOTS. SEAS GRADUALLY BECOMING 3 FEET OR LESS
BY THURSDAY AFTERNOON. SCY CONDITIONS/ 5 FOOT SEAS CONTINUES THROUGH
06Z THIS EVENING FOR ANZ256 SOUTH OF BLOCK ISLAND.
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...
FRIDAY: WINDS LESS THAN 25 KT.
FRIDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
SATURDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
SATURDAY NIGHT THROUGH SUNDAY: WINDS LESS THAN 25 KT.
SUNDAY NIGHT THROUGH MONDAY: WINDS LESS THAN 25 KT. SEAS
LOCALLY APPROACHING 5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT EARLY THIS MORNING FOR
ANZ256.
SYNOPSIS...KJC/RM
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...KJC
AVIATION...KJC/HRENCECIN/RM
MARINE...KJC/RM
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