923
FXUS61 KBOX 072007
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
ISSUED BY NATIONAL WEATHER SERVICE GRAY ME
407 PM EDT WED MAY 7 2025
SYNOPSIS
AN UPPER LEVEL LOW MOVES EASTWARD THROUGH INTERIOR NORTHERN NEW
ENGLAND TONIGHT. DRIER WEATHER THEN BRIEFLY DEVELOPS ON
THURSDAY. ANOTHER WINDSWEPT RAIN EVENT WITH BELOW-NORMAL
TEMPERATURES DEVELOPS FOR THURSDAY NIGHT INTO FRIDAY NIGHT, WITH
MORE HIT OR MISS SHOWERS POSSIBLE INTO SATURDAY. RISES TO AT OR
OVER BANKFULL AND POCKETS OF URBAN AND POOR DRAINAGE STREET
FLOODING COULD AGAIN DEVELOP FOR THE INTERIOR. CLEARING OUT AND
TRENDING DRIER ON SUNDAY WITH A STEADY WARMING TREND INTO EARLY
NEXT WEEK.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
KEY MESSAGES:
* WIDELY SCATTERED SHOWERS IN NORTHEAST MA END BY SUNDOWN.
* CLEARING TONIGHT. OUTSIDE CHANCE AT PATCHY FOG.
UPPER LEVEL LOW IN INTERIOR NORTHERN NEW ENGLAND IS PRODUCING
WIDELY SCATTERED SHOWERS INTO THE NORTH SHORE/GREATER BOSTON
AREA AND INTO FAR NORTHERN WORCESTER COUNTY; SPC MESOANALYSIS
CAPE VALUES ARE SLIGHTLY HIGHER IN NH AND ME AT AROUND 500
J/KG, SO ALREADY PRETTY WEAK INSTABILITY ACROSS SOUTHERN NEW
ENGLAND. ALTHOUGH A FEW LIGHTNING STRIKES ARE BEING OBSERVED IN
NH/ME, ACTIVITY LOOKS TOO SHALLOW AND CONVECTIVE INSTABILITY TOO
WEAK TO PRODUCE ANY THUNDERSTORMS WITH MAINLY SCATTERED HIT OR
MISS SHOWERS ACROSS EASTERN/NORTHEAST MA THROUGH SUNDOWN.
WEAK SHORTWAVE RIDGING ALOFT THEN BUILDS INTO SOUTHERN NEW
ENGLAND FOR TONIGHT, WITH A WEAK SURFACE TROUGH LEFT BEHIND BY
THE UPPER LOW DRAPED NEAR OR JUST WEST OF THE CAPE COD CANAL.
WEAK NORTHWEST FLOW SHOULD BE PREVALENT FOR MOST AREAS TO I-95
AS WE MOVE INTO THE EVENING AND OVERNIGHT. WE HAD QUITE A BIT OF
PATCHY FOG LAST NIGHT, AND THAT STILL SEEMS POSSIBLE GIVEN THE
DAMP GROUND FROM THE LAST COUPLE DAYS, BUT WITH THE NORTHERLY
FLOW AND SOME HEATING THAT TOOK PLACE TODAY, IT ADDS MORE
UNCERTAINTY IF WE CAN SEE RE-DEVELOPMENT OF PATCHY FOG. LEFT OUT
OF THE GRIDS FOR NOW. A BETTER CHANCE AT STRATUS AND FOG/MIST
TONIGHT IS FOR THE CAPE AND ISLANDS GIVEN LEFTOVER MARITIME SW
FLOW. LOWS TONIGHT SHOULD BE A LITTLE BIT COOLER THAN PRIOR
NIGHTS, WITH READINGS IN THE MID 40S TO LOW 50S.
SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/
KEY MESSAGES:
* DRY MOST OF THURSDAY, THOUGH RAIN INCREASES THURSDAY
AFTERNOON AND ESPECIALLY THURSDAY NIGHT INTO WESTERN NEW
ENGLAND.
* MORE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE
THURSDAY
THURSDAY:
WE GET INTO WEAK SURFACE RIDGING DURING THE FIRST PART OF
THURSDAY, OFFERING PARTLY TO MOSTLY SUNNY CONDITIONS AND WEAK
NORTHERLY WINDS. MOVING INTO THE AFTERNOON, A UPPER TROUGH WITH
POSITIVE TILT FROM ONTARIO CONTINUES TO DIG INTO SOUTHERN NY
BEFORE CLOSING OFF. THIS WILL INDUCE AN ORGANIZING AREA OF LOW
PRESSURE NEAR OR SOUTH OF THE LOWER HUDSON VALLEY IN NY, AND
LEAD TO AN ENHANCED ENE FLOW WITH A INVERTED TROUGH FROM SFC TO
700 MB WHICH EXTENDS INTO WESTERN CT AND THE BERKSHIRES.
INCREASED MOISTURE BRINGS ANOTHER ROUND OF INITIALLY LIGHT RAIN
FOR THE LATTER PORTION OF THIS PERIOD FOR WESTERN MA AND CT,
BUT THIS WILL HERALD THE BEGINNING OF ANOTHER RATHER WET WEATHER
PATTERN AS WE MOVE INTO THURSDAY NIGHT. SHOULD SEE HIGHS IN THE
INTERIOR IN THE LOWER 70S, BUT COOLER READINGS IN THE MID 60S
BY EARLY AFTERNOON ONCE ONSHORE FLOW STARTS TO DEVELOP.
THURSDAY NIGHT:
CARRYING OVER FROM THE AFTERNOON, THE START OF ANOTHER WET
WEATHER PATTERN THEN CONTINUES IN EARNEST WITH STEADY LIGHT TO
MODERATE RAIN BREAKING OUT INTO WESTERN AND PERHAPS INTO CENTRAL
MA AND INTO MUCH OF CT. THIS WILL BE ENHANCED BY PRETTY STOUT
UPSLOPE FLOW AND FOCUSED ALONG THE 925-700 MB INVERTED TROUGH
AXIS. THESE AREAS HAVE SEEN QUITE A BIT OF RAIN IN RECENT DAYS,
LOCALLY UP TO 4 INCHES IN SOME LOCATIONS, AND HYDRO CONCERNS
INCLUDING CONTINUED OR EXACERBATED RISES ON RIVERS AND STREAMS
AND MINOR STREET FLOODING COULD ENSUE STARTING THURSDAY NIGHT.
SEE THE ADDED HYDROLOGY SECTION FOR MORE DETAILS. FORECAST
RAINFALL FOR THURSDAY NIGHT RANGES FROM A HALF TO THREE QUARTERS
OF AN INCH (WITH LOCALLY HIGHER AMTS POSSIBLE) IN WESTERN MA/CT.
ALTHOUGH IT WILL BE OVERCAST AND BREEZY FOR THE VAST MAJORITY OF
EASTERN MA AND RI, LOOKS GENERALLY DRY. LOWS IN THE 40S TO NEAR
50.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
KEY POINTS:
* SOAKING, WINDSWEPT RAINS FRIDAY INTO FRIDAY NIGHT WITH BELOW
NORMAL TEMPERATURES.
* MORE HIT OR MISS TYPE SHOWERS FOR SATURDAY, BUT TRENDING DRIER
LATE IN THE DAY.
* POSSIBLE HYDRO CONCERNS FOR FRIDAY INTO SATURDAY.
* DRYING WITH A WARMING TREND SUNDAY INTO MIDWEEK.
DETAILS:
FRIDAY INTO SATURDAY:
ANOTHER DREARY, COOL AND OVERCAST FRIDAY INTO FRIDAY NIGHT,
WITH RAINS OVER THE INTERIOR HIGHER TERRAIN EXPANDING EASTWARD.
ALTHOUGH TEMPERATURES LOOK TO BE QUITE A BIT BELOW NORMAL, RATHER
MOIST AIRMASS WITH ELEVATED PRECIPITABLE WATER VALUES AROUND
1.3 TO 1.5 INCHES WILL CONTINUE TO BE FORCED UPSLOPE IN EASTERLY
FLOW, WITH HIGHEST RAIN TOTALS FOCUSED INTO WESTERN NEW ENGLAND.
EASTERN NEW ENGLAND SEES THE PERIOD OF WETTEST CONDITIONS
FOCUSED INTO FRIDAY AFTERNOON TO THE EVENING AS LOW PRESSURE
SLOWLY TRUDGES NORTHEASTWARD INTO NORTHEAST MA AND THE GULF OF
MAINE. HYDROLOGIC CONCERNS SHOULD CONTINUE TO LINGER INTO FRIDAY.
STILL GENERALLY UNSETTLED INTO SATURDAY, ALTHOUGH THE RAIN
COVERAGE SHOULD TURN MORE SHOWERY AS THE POTENT UPPER LOW TREKS
THROUGH SOUTHERN NEW ENGLAND. WHILE SATURDAY MIGHT NOT PROVE TO
BE A TRUE WASHOUT, THERE STILL SHOULD BE SOME SHOWERS TO DODGE.
SUNDAY INTO MIDWEEK:
ENSEMBLES CONTINUE TO POINT TO AT LEAST AN EXTENDED SPELL OF
DRIER WEATHER WITH A GRADUAL WARMING TREND AS WE MOVE INTO
MIDWEEK.
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE:
THROUGH 00Z THURSDAY: HIGH CONFIDENCE.
VFR FOR MOST, THOUGH HYA/ACK SHOULD STILL DEAL WITH LIFR
CEILINGS. LOW CHANCE AT A SHOWER AT ORH AND BED THRU 23Z BUT
BETTER CHANCES AT SHRA IN NH. SW WINDS AROUND 10-12 KT.
TONIGHT: HIGH CONFIDENCE OVERALL, THOUGH MODERATE ON INTERIOR
FOG.
VFR FOR THE INTERIOR AND COASTAL PLAIN, ALTHOUGH THERE'S A
CHANCE AT SOME PATCHY FOG (INDICATED BY TEMPO 2-5 SM VIS BR). IT
IS NOT CERTAIN IF FOG CAN DEVELOP AS DRIER NW WINDS DEVELOP.
BETTER CHANCE AT SUB-VFR OVER THE CAPE AND ISLANDS WITH LIFR
STRATUS AND MIST/FOG.
THURSDAY: HIGH CONFIDENCE.
ANY PATCHY FOG AND STRATUS WHICH DEVELOPED OVERNIGHT TO
DISSIPATE BY EARLY THURS MORNING TO VFR. CEILINGS START TO LOWER
AGAIN INTO BORDERLINE VFR RANGE LATE IN THE DAY IN
INTERIOR/WESTERN AIRPORTS. NW WINDS 5 KT THEN SHIFT TO NE/E BY
AFTERNOON.
THURSDAY NIGHT: MODERATE CONFIDENCE.
DETERIORATING CONDITIONS THURS NIGHT WITH SUB-VFR CEILINGS AND
STEADY RAIN MAINLY W OF ORH. NE/E WINDS AROUND 10-15 KT.
KBOS TAF...HIGH CONFIDENCE. VFR, OUTSIDE CHANCE AT A SHOWER
19-23Z BUT BETTER CHANCES CLOSER TO THE NH/MA BORDER. SE WINDS
AROUND 8 KT CURRENTLY TO SHIFT TO SW AROUND 10-12 KT BY 17-18Z.
KBDL TAF...HIGH CONFIDENCE. VFR. THINKING MOSTLY DRY TODAY,
ALTHOUGH MAY HAVE TO WATCH FOR PATCHY FOG AGAIN TONIGHT.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY THROUGH FRIDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE.
BREEZY. RA.
SATURDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY. CHANCE
RA.
SATURDAY NIGHT THROUGH MONDAY:
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH THURSDAY: HIGH CONFIDENCE.
WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERION THROUGH THIS
PERIOD.
SW WINDS AROUND 15 KT THRU TONIGHT, THEN WILL BECOME LIGHTER NW
INTO OVERNIGHT AND THURSDAY. WINDS THEN INCREASE FROM THE E/ENE
THURS AFTN AND EVENING TO AROUND 20 KT, WITH AN OUTSIDE CHANCE
AT SCA LEVEL GUSTS ON NORTHEAST WATERS.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF RAIN.
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. RAIN.
SATURDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF
RAIN.
SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT.
SUNDAY THROUGH MONDAY: WINDS LESS THAN 25 KT.
HYDROLOGY
355 PM UPDATE:
RIVER FLOOD WARNINGS CONTINUE FOR THE CONNECTICUT RIVER AT
HARTFORD AND AT MIDDLE HADDAM (OKX CWA) AS RUNOFF FROM RAINS
EARLY IN THE WEEK CONTINUE TO FLOW DOWNRIVER. RECESSION LIKELY
TO BE SLOW.
HOWEVER WE ARE EXPECTING ANOTHER ROUND OF RAIN THURSDAY NIGHT
THROUGH FRIDAY NIGHT, WITH EMBEDDED DOWNPOURS POSSIBLE.
REASONABLY HIGH CONFIDENCE THAT WESTERN NEW ENGLAND WILL AGAIN
SEE THE GREATEST RAINFALL AMOUNTS WITH LESSER RAINFALL TOTALS IN
EASTERN MA AND RI. ENSEMBLES SUGGEST LOW PROBS FOR 2" IN 24
HOURS TIME CENTERED AROUND THURSDAY NIGHT INTO FRIDAY IN WESTERN
NEW ENGLAND, WITH AN INCH OR LESS MORE LIKELY INTO EASTERN
MA/RI. GIVEN THE SATURATED SOIL CONDITIONS AND THAT SOME RIVERS
ARE STILL SWOLLEN OR IN SOME CASES ARE STILL IN FLOOD STAGE IN
WESTERN MA/CT, ADDITIONAL OR WORSENED RISES ON AREA RIVERS AND
STREAMS SEEM LIKELY. FLASH FLOOD GUIDANCE HAS LOWERED SOMEWHAT
TOO AND THOUGH WE'RE PROBABLY NOT LOOKING AT TRUE FLASH
FLOODING, POCKETS OF URBAN OR STREET FLOODING COULD DEVELOP AS
WELL LATE THIS WEEK INTO EARLY IN THE WEEKEND. WILL WAIT ANOTHER
MODEL CYCLE TO ASSESS QPF TRENDS BUT A FLOOD WATCH MAY NEED TO
BE CONSIDERED.
MOST OF EASTERN MA AND RI REALLY MISSED OUT ON SIGNIFICANT
RAINFALL EARLY IN THE WEEK. THESE LOCATIONS ALSO SEEM REMOVED
FROM THE HIGHEST QPF PER 24 HRS WORTH OF ENSEMBLE QPF TRENDS.
SO CURRENT EXPECTATIONS THERE IS FOR LITTLE TO NO SIGNIFICANT
HYDRO CONCERNS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
SYNOPSIS...LOCONTO
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...LOCONTO
AVIATION...LOCONTO
MARINE...LOCONTO
HYDROLOGY...LOCONTO
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