114
FXUS61 KGYX 010655
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
255 AM EDT TUE SEP 1 2026
WHAT HAS CHANGED
SOME OF THE SHORT TERM GUIDANCE HAS SLOWED THE PROGRESSION OF
RAIN THIS MORNING AND CONTINUED A MORE SOUTHERLY TREND.
KEY MESSAGES
1. LOW PRESSURE TRACKING ALONG A STATIONARY FRONT WILL PROVIDE A
FOCUS FOR CLOUDS AND RAIN TODAY, MAINLY ACROSS SOUTH-CENTRAL NH
AND SW MAINE.
2. AN UNSETTLED PATTERN BRINGS THE BEST CHANCE FOR WIDESPREAD
RAINFALL LATE WEDNESDAY AND THURSDAY.
3. A GRADUAL DRYING TREND FOLLOWS FOR FRIDAY AND LABOR DAY WEEKEND.
DISCUSSION
KEY MESSAGE 1 DESCRIPTION...
EXPECT A CRISP MORNING WITH LOWS MAINLY IN THE MID 40S NORTH TO
THE MID 50S ELSEWHERE. THE ONE EXCEPTION WILL BE SOUTHERN NEW
HAMPSHIRE AND THE FAR SOUTHERN TIP OF MAINE WHERE WE MAY ONLY
DIP INTO THE LOWER 60S. VALLEY FOG WILL BE POSSIBLE NORTH AS
LIGHT WINDS AND CLEAR SKIES PROMOTE EFFICIENT RADIATIONAL
COOLING.
A MODEST UPPER-LEVEL RIDGE AXIS WILL MOVE SLOWLY TOWARDS THE
REGION TODAY WITH STRANDS OF VORTICITY FORECAST TO RIPPLE
THROUGH NORTHWEST FLOW ALOFT. AT THE SURFACE, A STATIONARY FRONT
REMAINS IN PLACE, EXTENDING FROM AROUND LAKE ONTARIO TO LONG
ISLAND, NY. A LOW IS FORECAST TO RIDE EAST SOUTHEAST ALONG THIS
BOUNDARY, WHICH WILL LEAD TO SOME RAIN ACROSS SOUTHERN NEW
HAMPSHIRE AND PORTIONS OF WESTERN MAINE. THE NORTHERN EXTENT OF
THE RAIN REMAINS A BIT UNCERTAIN AS MOISTURE WILL BE FIGHTING
AGAINST DRY HIGH PRESSURE TO THE NORTH. SOME OF THE LATEST SHORT
TERM GUIDANCE HAS TRENDED A TOUCH LATER WITH THE PRECIPITATION
ONSET AND THERE HAS BEEN A SLIGHT NUDGE SOUTH THE PAST FEW RUNS
OF THE HRRR. THESE TRENDS COULD SUGGEST HIGH PRESSURE WINNING
OUT VERSUS MORE WIDESPREAD PRECIPITATION OVER THE FORECAST AREA.
ALL OF THAT SAID, CONFIDENCE REMAINS HIGH THAT WE SHOULD SEE
SOME STEADY RAINFALL OVER MUCH OF SOUTHERN NEW HAMPSHIRE AND
PORTIONS OF THE WESTERN MAINE, MOST LIKELY THE SOUTHWEST. 24-HOUR
NBM QPF PROBABILITIES SUGGEST THAT THE HIGHEST TOTALS WILL BE
MAXIMIZED OVER SOUTHWEST NEW HAMPSHIRE WITH AMOUNTS MOST LIKELY
IN THE HALF INCH TO ONE INCH RANGE. TOTALS WILL DIMINISH RATHER
QUICKLY MOVING NORTHEAST.
WE SHOULD SEE PLENTY OF CLOUD COVER TODAY WHICH WILL KEEP
TEMPERATURES ON THE COOLER SIDE. AFTERNOON HIGHS ARE FORECAST TO
RANGE FROM THE UPPER 60S TO MID 70S. THE COOLEST TEMPERATURES
WILL LIKELY BE ACROSS SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE
WHERE WE WILL SEE THE MOST RAINY/CLOUDY CONDITIONS.
KEY MESSAGE 2 DESCRIPTION...
WE FIND OURSELVES BETWEEN SHORTWAVES ON WEDNESDAY, WHICH SHOULD LEAD
TO RAIN-FREE CONDITIONS DURING THE DAY. LIKELY WILL STILL HAVE TO
CONTEND WITH MOSTLY CLOUDY SKIES AND ONSHORE FLOW, WHICH SUGGESTS
ANOTHER DAY OF COOLER HIGHS, PRIMARILY IN THE 60S-NEAR 70, BUT A BIT
OF A MUGGY FEEL PERSISTING, WHICH WILL ALSO LEAD TO ANOTHER MILD
NIGHT OF LOWS IN THE MID 50S-LOW 60S.
THE SECOND WAVE MOVES IN FOR THURSDAY. RAIN CHANCES START AS EARLY
AS WEDNESDAY NIGHT, BUT HIGHER POPS, AND THE CHANCE FOR HEAVIER
RAIN, WILL LIKELY BE ON THURSDAY WHEN THE BEST UPPER-LEVEL SUPPORT
AND FORCING ARRIVES LOCALLY. TIMING OF PRECIPITATION REMAINS TO BE
IRONED OUT, WITH OUTCOMES RANGING FROM A SOAKING RAIN ALL DAY, TO A
FEW ROUNDS OF MORE CONVECTIVE PRECIPITATION WITH SOME DRY PERIODS.
STORM MOTIONS ON THE SLOWER SIDE, COMBINED WITH A RATHER SOUPY
AIRMASS, SUGGESTS LOCALLY HEAVY RAIN MAY BE THE PRIMARY THREAT. DEW
POINTS REACH THE 60S-NEAR 70, AND PWATS APPROACHING 1.7-1.8" IN OUR
SOUTHERN ZONES. AROUND 30 KTS OF DEEP-LAYER SHEAR SUGGEST STORMS
COULD ORGANIZE A BIT, BUT GUIDANCE VARIES SIGNIFICANTLY AT THIS TIME
ON IF INSTABILITY WILL BE ABLE TO BUILD OR NOT.
KEY MESSAGE 3 DESCRIPTION...
THURSDAY'S WAVE CLOSES OFF AND DEEPENS OVER NOVA SCOTIA FRIDAY INTO
EARLY WEEKEND, AND IS SLOW TO DEPART. DRYING NORTHERLY FLOW OUT OF
CANADA SHOULD FLUSH OUT WITH HUMIDITY WITH AN OVERALL COOLER
AIRMASS. THIS WILL LEAD TO A TASTE OF EARLY FALL ESPECIALLY AT
NIGHT, BUT WINDS OUT OF THE NORTH SHOULD ALSO SERVE TO DOWNSLOPE/ACT
AS AN OFFSHORE WIND, WHICH WILL KEEP AFTERNOONS MILD WITH 70S IN THE
LOWER ELEVATIONS.
WITH US STILL ON THE EDGE OF THE TROUGH AND COLD CORE ALOFT, COULD
SEE SOME DIURNAL CLOUDS AND SHOWERS EACH AFTERNOON, MOSTLY FOCUSED
IN THE MOUNTAINS/INTERIOR, BUT NOT EXPECTING ANYTHING HIGH-IMPACT OR
WIDESPREAD. FINALLY, IT WILL BE BREEZY NEAR THE COAST WITH A RATHER
TIGHT PRESSURE GRADIENT SETTING UP.
AVIATION /06Z TUESDAY THROUGH SUNDAY/
THROUGH WEDNESDAY MORNING...VALLEY FOG LIKELY BRINGS IFR/LIFR
TO LEB AND HIE EARLY THIS MORNING. MVFR CIGS AND -RA MOVE INTO
SOUTHERN NH BY 12Z AND EXPAND NORTH AND EAST TO LEB, CON, AND
PWM THROUGH THE MORNING. CIGS MAY LOWER TO IFR THRESHOLDS AT
TIMES INTO THIS AFTERNOON. HIE, AUG, AND RKD LIKELY STAY VFR
THROUGH THE DAY. ONSHORE FLOW MAY ALLOW FOR A PERIOD OF IFR
CIGS ACROSS MUCH OF THE AREA THIS EVENING INTO THE FIRST HALF
OF TONIGHT WITH SOME IMPROVEMENT TO MVFR/VFR TOWARDS WEDNESDAY
MORNING.
OUTLOOK...
WEDNESDAY-THURSDAY: MVFR OR LOWER POSSIBLE BY LATE WEDNESDAY AT
MOST TERMINALS WITH SHOWERS.
THURSDAY NIGHT-FRIDAY: IMPROVING CONDITIONS, WITH MVFR STILL
POSSIBLE IN BRIEF SHOWERS. VALLEY FOG IS POSSIBLE AT LEB AND
HIE.
FRIDAY NIGHT - SUNDAY: MAINLY VFR DURING THE DAYTIME, BUT BRIEF
MVFR CEILINGS REMAIN POSSIBLE IN AFTERNOON SHOWERS. NIGHTTIME
VALLEY FOG IS LIKELY AT HIE, LEB, AND CON, AND STILL POSSIBLE AT
ALL OTHER TERMINALS.
MARINE
WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS THROUGH TONIGHT. LOW
PRESSURE WILL TRACK ALONG A FRONT SOUTH OF THE WATERS TODAY
BRINGING STEADY SE TO E FLOW AND PERIODS OF RAIN. CHANCES FOR
RAIN DIMINISH TONIGHT AS THE LOW TRACKS SOUTHEAST OF CAPE COD.
A BROAD DEVELOPING LOW PRESSURE SYSTEM APPROACHES FROM THE WEST
WEDNESDAY NIGHT, CROSSING THE WATERS ON THURSDAY. A PERIOD OF
SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF THIS
SYSTEM ON THURSDAY. NORTHERLY FLOW BRINGS A RETURN TO FAIR
CONDITIONS THURSDAY NIGHT AND FRIDAY. MARGINAL SCA CONDITIONS
ARE THEN POSSIBLE ACROSS THE OUTER WATERS THIS WEEKEND IN
NORTHERLY FLOW AS LOW PRESSURE DEEPENS ACROSS ATLANTIC CANADA.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
DISCUSSION...HARGROVE/BARKER
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