617
FXUS61 KBOX 070454
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
ISSUED BY NATIONAL WEATHER SERVICE GRAY ME
1254 AM EDT WED MAY 7 2025
SYNOPSIS
AN UPPER LEVEL LOW PRESSURE WILL BE PULLING INTO NORTHERN NEW
ENGLAND ON WEDNESDAY. MOSTLY CLOUDY WEATHER IS STILL EXPECTED
TONIGHT WITH AREAS OF PATCHY FOG. A FEW PEEKS OF SUN EARLY ON
WEDNESDAY THEN TRENDS TO PARTLY TO MOSTLY CLOUDY SKIES WITH
SCATTERED DIURNALLY DRIVEN SHOWERS OR A ROGUE THUNDERSTORM ON
WEDNESDAY. DRYING OUT THURSDAY, BEFORE ANOTHER WINDSWEPT RAIN
EVENT WITH BELOW NORMAL TEMPERATURES DEVELOPS FOR FRIDAY INTO
SATURDAY. CLEARING OUT AND TRENDING DRIER ON SUNDAY WITH A
STEADY WARMING TREND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TODAY/
KEY MESSAGES:
* BAND OF RAIN OVER INTERIOR SOUTHERN NEW ENGLAND TO MOVE ENE
INTO EASTERN MA/RI LATE THIS AFTN/EARLY TONIGHT. A RUMBLE OR
TWO OF THUNDER POSSIBLE BUT NOT LIKELY.
* TRENDING DRIER TONIGHT.
* PATCHY FOG, ESPECIALLY INTERIOR, IF WE CAN GET ANY BREAKS FROM
CLOUDINESS.
DETAILS:
UPDATE [715 PM]: FLOOD WATCH HAS BEEN CANCELLED. STILL A PRETTY
TRICKY FORECAST AS IT COMES DOWN TO TIMING THE FLIP TO
SOUTHEAST WINDS FOR CENTRAL, EASTERN AND NORTHEAST MA AS THE
WEDGE OF COLDER AIR STILL IS PRETTY STUBBORNLY ENTRENCHED, WITH
AREAS OF MIST/FOG AND NE WINDS ASSOCIATED WITH IT. GUIDANCE HAS
BEEN REALLY POOR WITH THIS ALL DAY; SIDED TOWARDS 03Z BUT IT MAY
END UP BEING LATER THAN THAT AS RAIN MOVES NE INTO NH/ME AND
REINFORCES THE COLDER AIR. PREV DISCUSSION FOLLOWS:
COMBO OF AN UPPER LEVEL LOW TO OUR WEST OVER THE NORTHERN GT
LAKES AND A RESIDUAL HIGH PRESSURE OVER THE CANADIAN MARITIMES
IS GOVERNING OUR WEATHER PATTERN TODAY, LEADING TO ANOTHER
RATHER DREARY DAY FOR MANY IN SOUTHERN NEW ENGLAND. A DIFFUSE
WARM FRONTAL BOUNDARY IS SNAKING ITS WAY ALONG THE MASS PIKE
THEN TRAILING DOWN THROUGH THE NORFOLK/BRISTOL/PLYMOUTH COUNTY
MA LINE, WITH COOL NE FLOW AND FOG/MISTY CONDITIONS NORTH OF
THAT BOUNDARY AND OVERCAST BUT NOTICEABLY MORE HUMID (DEWPOINTS
UPPER 50S TO LOW 60S) SOUTH OF THE BOUNDARY. THIS FEATURE IS
EXPECTED TO LIFT GRADUALLY NORTHWARD THRU THE REST OF THE
AFTERNOON AND TONIGHT. CURRENT RADAR SHOWS AN ARCING BAND OF
MODERATE SHOWERS WITH EMBEDDED RUMBLE OR TWO OF THUNDER ACROSS
WESTERN AND CENTRAL MA, CT INTO NW RI. THIS ACTIVITY IS EXPECTED
TO LIFT NORTHEAST INTO EARLY TONIGHT.
THEREAFTER CONDITIONS SHOULD START TO TURN GENERALLY DRY AND WE
COULD SEE SOME BREAKS IN THE CLOUD COVER WITH MODEST SOUTHERLY
WINDS. WE COULD HAVE SOME AREAS OF PATCHY FOG DEVELOP WITH ANY
CLEARING THOUGH AS MANY AREAS ARE SEEING VERY NARROW
TEMPERATURE-DEWPOINT SPREADS. LOWS MAINLY MID TO UPPER 50S
TONIGHT.
SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/
KEY MESSAGES:
* PARTLY TO MOSTLY CLOUDY, COUPLE LOW-TOPPED SHOWERS OR
THUNDERSTORMS, SOME WHICH MAY CONTAIN SMALL SUB-SEVERE
HAILSTONES DURING THE AFTERNOON. BEST CHANCE N/W OF THE MASS
PIKE, LESSER TO NIL CHANCES SOUTHEAST OF I-95.
* DRYING OUT WED NIGHT, POSSIBLE PATCHY FOG?
DETAILS:
WEDNESDAY:
UPPER LEVEL LOW CONTINUES TO DEAMPLIFY AND WILL BE CROSSING INTO
INTERIOR NEW ENGLAND WED. THERE IS OPTIMISM THAT WE'LL SEE A FEW
PEEKS OF SUNSHINE IN MOST AREAS BY THE MID TO LATE MORNING; BUT
IT IS REALLY MORE OF A "DESTRUCTIVE SUNSHINE" SCENARIO WHERE ANY
HEATING WILL GO TO BLOSSOM LOW-TOPPED CUMULUS CLOUDINESS OF
PRETTY GENEROUS COVERAGE. THIS OWES ITSELF TO THE UPPER LOW'S
COLD POCKET OF AIR ALOFT AND RATHER STEEP LAPSE RATES IN THE
850-500 MB LAYER AT AROUND 7C/KM. CONVECTIVE-PERMITTING GUIDANCE
SHOWS SOME DEVELOPMENT OF SCATTERED SHOWERS OR ROGUE LOW-TOPPED
THUNDERSTORMS IN AN ENVIRONMENTAL SETTING WITH LIMITED
INSTABILITY (MUCAPES 500 J/KG OR LESS) AND MODEST DEEP LAYER
SHEAR. AREA MOST FAVORED LOOKS TO BE THOSE LOCATIONS ALONG AND
NORTH OF THE MASS PIKE CLOSER TO THE TRACK OF THE UPPER LEVEL
FEATURE, WITH LESSER (IF ANY?) COVERAGE SOUTH AND EAST OF I-95.
THE COLD PROFILES ALOFT COULD FAVOR GRAUPEL OR SMALL SUB-SEVERE
HAILSTONES, BUT WE DO NOT EXPECT SEVERE WEATHER TO MATERIALIZE
FROM THIS ACTIVITY GIVEN THE SHEAR/INSTABILITY PARAMETER SPACE.
THIS ACTIVITY THEN LIFTS INTO NH BY LATE AFTERNOON WITH POPS
THEN DECREASING. HIGHS SHOULD BE MOSTLY IN THE 60S, THOUGH
WOULDN'T RULE OUT A FEW AREAS IN EASTERN/SOUTHEAST NEW ENGLAND
APPROACHING 70 DEGREES.
WEDNESDAY NIGHT:
CLEARING WITH FAIRLY GOOD RADIATIONAL COOLING WED EVENING WITH
WEAK HIGH PRESSURE BUILDING IN. COMING OUT OF AT LEAST TWO DAYS
OF SOGGY CONDITIONS WHERE SOILS ARE PRETTY DAMP, PARTICURLY
INTERIOR, THAT COULD MAKE US PRONE TO PATCHY FOG DEVELOPMENT.
SOMETHING TO MONITOR WITH LATER UPDATES. LOWS UPPER 40S TO MID
50S.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
KEY POINTS:
* BRIEF DRIER WEATHER AND SEASONABLE THURS.
* GROWING CONFIDENCE IN ONSHORE FLOW AND WINDSWEPT RAIN AND HIGH
TEMPS WELL BELOW NORMAL AS LOW PRESSURE MOVES THROUGH OR EAST
OF SOUTHERN NEW ENGLAND. NEED TO WATCH RIVERS FOR POSSIBLE
RISES AT OR ABOVE FLOOD STAGE.
* DRYING OUT SUNDAY AND CONTINUING INTO EARLY NEXT WEEK, WITH A
STEADY WARMING TREND.
DETAILS:
THURSDAY:
THURS STILL LOOKS TO BE THE ONLY RELATIVELY DRY DAY IN THE
WORKWEEK, WITH WEAK SFC RIDGING AND MOSTLY SUNNY TO PARTLY
CLOUDY CONDITIONS TO BEGIN THE DAY. HOWEVER LOOKS LIKE CLOUD
COVER STANDS TO INCREASE AGAIN AS WE MOVE INTO THURSDAY EVENING.
HIGHS IN THE 60S TO LOWER 70S.
FRIDAY AND SATURDAY:
IT IS LOOKING LIKE WE ARE UNFORTUNATELY HEADING INTO ANOTHER
SOGGY FRIDAY AND POSSIBLY INTO SATURDAY AS WELL, AS A UPPER
LEVEL TROUGH CLOSES OFF INTO AN UPPER LEVEL LOW OVER THE
NORTHERN MID-ATLANTIC. THIS WILL INDUCE A SUB-1000 MB LOW
PRESSURE TO TREK SOMEWHERE OVER OR JUST SOUTHEAST OF SOUTHERN
NEW ENGLAND. EXPECT THE LATTER PART OF THE WORKWEEK AND
POTENTIALLY INTO SATURDAY WITH ANOTHER COOL, WIND-SWEPT RAIN
EVENT. THIS COULD BE ENOUGH TO RAISE POSSIBLE RIVER FLOOD/HYDRO
CONCERNS FOR INTERIOR BASINS IN SOUTHERN NEW ENGLAND, WHICH
HAVE RECEIVED QUITE A BIT OF RAIN AND/OR ARE STILL EXPERIENCING
RISES. TEMPS TO TREND COOLER THAN NORMAL, PERHAPS SIGNIFICANTLY
BELOW NORMAL (HIGH TEMPS SOME 15-20 DEGS BELOW NORMAL).
SUNDAY INTO EARLY NEXT WEEK:
LOOKS LIKE SUNDAY IS TRENDING MORE OPTIMISTICALLY AS THE LATE-
WEEK/SAT SYSTEM PULLS AWAY. ALTHOUGH TEMPERATURE PROFILES ALOFT
STILL ARE ON THE COOLER SIDE, WE SHOULD SEE A SUSTAINED PERIOD
OF DRIER WEATHER AND A GRADUAL WARMING TREND TO TEMPS AS WE MOVE
INTO EARLY NEXT WEEK.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE:
REST OF TONIGHT: LOW CONFIDENCE
IFR WITH POCKETS OF LIFR SHOULD GRADUALLY LIFT TO MVFR, HOWEVER,
FOG MAY FILL IN BEHIND LOW CLOUD COVER, KEEPING LOW LYING
TERMINALS IN LIFR CONDITIONS UNTIL AFTER SUNRISE. RAIN HAS NOW
MOVED OFF SHORE, SO ANY REMAINING PRECIPITATION SHOULD BE LIGHT
MIST OR DRIZZLE
WEDNESDAY: MODERATE CONFIDENCE.
ANY FOG THAT FORMED OVERNIGHT SHOULD BURN OFF BY 15Z GIVING AWAY
TO VFR CONDITIONS WITH POCKETS OF MVFR POSSIBLE WITH DIURNAL
STRATO CU FORMING. LOW CHANCE FOR AN ISOLATED SHOWER MAINLY
NORTH OF RT-2. WINDS REMAIN SOUTHERLY AT 10-15 KNOTS
WEDNESDAY NIGHT: LOW CONFIDENCE
CLEAR SKIES MAY ALLOW FOR FOG FORMATION GIVEN THE LEFTOVER
MOISUTRE FROM THE RAINS THE LAST COUPLE DAYS. CONFIDENCE ON FOG
IS GENERALLY LOW RIGHT NOW AND MAY DEPEND ON HOW LIGHT THE WINDS
CAN BECOME OVERNIGHT.
THURSDAY: MODERATE CONFIDENCE
VFR WITH POCKETS OF MVFR DUE TO STRATO CUMULUS AGAIN. LOW CHANCE
FOR ISOLATED SHOWERS POSSIBLE ACROSS THE INTERIOR.
KBOS TAF...MODERATE CONFIDENCE.
IFR/MVFR TONIGHT TURNING VFR THIS MORNING. LOW CHANCE FOR AN
ISOLATED SHOWER THIS AFTERNOON.
KBDL TAF...MODERATE CONFIDENCE
IFR LIFTING TO MVFR/VFR THIS MORNING. SHOWERS ARE POSSIBLE IN
THE AFTERNOON.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT CHANCE
SHRA.
THURSDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. CHANCE
SHRA.
FRIDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. SHRA LIKELY,
SLIGHT CHANCE TSRA.
FRIDAY NIGHT: CHANCE SHRA.
SATURDAY: BREEZY. CHANCE SHRA.
SATURDAY NIGHT THROUGH SUNDAY:
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH WEDNESDAY NIGHT: HIGH CONFIDENCE.
SE TO S WINDS TO DEVELOP TONIGHT AROUND 10-15 KT WITH GUSTS TO
25 KT AT TIMES, WITH SEAS 3-6 FT. SCAS CONTINUE ON THE SOUTHERN
WATERS THROUGH TONIGHT. MAY STILL HAVE SOME LEFTOVER ELEVATED
SEAS ON WEDNESDAY ON SOUTHERN WATERS BUT SW WINDS WILL HAVE
DECREASED BELOW SCA THRESHOLDS.
FOGGY AREAS CONTINUE EARLY TONIGHT ON NORTHEAST WATERS. BAND OF
RAIN MOVES THROUGH EARLY TONIGHT TOO, THEN TRENDS TO DRY WEATHER
INTO WED. LOW CHANCE AT A TS OVER THE FAR NORTHEAST WATERS WED
AFTN BUT SHOULD BE DRY BY AND LARGE.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
THURSDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. CHANCE OF RAIN SHOWERS.
FRIDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. RAIN SHOWERS
LIKELY, ISOLATED THUNDERSTORMS.
FRIDAY NIGHT THROUGH SATURDAY: WINDS LESS THAN 25 KT. SEAS UP
TO 5 FT. CHANCE OF RAIN SHOWERS.
SATURDAY NIGHT: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS.
SUNDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS 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
ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ254>256.
SYNOPSIS...LOCONTO
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...LOCONTO
AVIATION...KP
MARINE...LOCONTO
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