995
FXUS61 KGYX 241833
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
233 PM EDT MON AUG 24 2026
WHAT HAS CHANGED
NO MAJOR CHANGES WERE NEEDED FOR THIS FORECAST PACKAGE. SHOWERS
HAVE STARTED DEVELOPING OVER THE MOUNTAINS A LITTLE BIT EARLIER
THAN INITIALLY EXPECTED WITH ONLY A COUPLE OF LIGHTNING STRIKES
THUS FAR.
KEY MESSAGES
1. A SLOW MOVING UPPER LOW WILL BRING ISOLATED TO SCATTERED
SHOWERS AND STORMS TO THE REGION THIS AFTERNOON AND TUESDAY
AFTERNOON. A FEW STRONG STORMS ARE POSSIBLE THIS AFTERNOON.
2. DRY WEATHER MIDWEEK WILL GIVE WAY TO A WEAK SYSTEM LATE
THURSDAY INTO FRIDAY. FOLLOWING THIS SYSTEM, MOSTLY DRY WEATHER
RETURNS FOR THE WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1 DESCRIPTION...
A CLOSED UPPER LOW CONTINUES TO SLOWLY DRIFT NORTH NORTHEAST
OVER QUEBEC THIS AFTERNOON WITH A SURFACE TROUGH EXTENDING SOUTH
INTO NEW HAMPSHIRE. THIS BOUNDARY WILL BE FOCUS FOR SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON. INSTABILITY
WILL BE LIMITED THIS AFTERNOON WITH SPC MESOANALYSIS TRENDS
SUGGESTING 100 TO 250 J/KG OF MLCAPE OF MOST OF THE AREA, BUT A
POCKET OF 500 J/KG WILL BE POSSIBLE OVER PORTIONS OF THE
WESTERN MAINE MOUNTAINS BY MID TO LATE AFTERNOON. EFFECTIVE
SHEAR IS CURRENTLY IN THE 40 TO 50 KNOT RANGE OVER MUCH OF THE
FORECAST AREA, BUT SHOULD START TO GRADUALLY DECREASE THROUGH
THE AFTERNOON AS THE SURFACE TROUGH PUSHES EAST. THAT BEING
SAID, IT WILL NOT TAKE MUCH INSTABILITY FOR STORMS TO PRODUCE
SOME HAIL WITH THE COLD MID-LEVEL TEMPERATURES IN PLACE
OVERHEAD. THE LATEST RAP ANALYSIS SUGGESTS DONOVAN HEIGHTS ARE
ANYWHERE FROM 20 KFT TO 23 KFT ACROSS THE NORTH WHERE THE BEST
ENVIRONMENT IS FORECAST (FREEZING LEVELS ARE ALSO RELATIVELY
LOW) SO A MARGINALLY SEVERE HAIL REPORT IS NOT OUT OF THE
QUESTION UNDER THE STRONGEST STORMS. GUSTY WINDS WILL ALSO BE
POSSIBLE GIVEN STEEP LOW-LEVEL LAPSE RATES.
SHOWERS AND STORMS SHOULD DISSIPATE RATHER QUICKLY THIS EVENING
AS WE LOSE DAYTIME HEATING. ANOTHER FOGGY NIGHT IS THEN
POSSIBLE, ESPECIALLY IN THE VALLEYS AND OVER THE MIDCOAST OF
MAINE.
THE UPPER LOW DRIFTS FURTHER NORTHEAST TOWARDS THE GULF OF SAINT
LAWRENCE BUT ANOTHER SURFACE TROUGH WILL ROTATE DOWN INTO THE
REGION TUESDAY AFTERNOON, LEADING TO SOME MORE
ISOLATED/SCATTERED SHOWERS AND STORMS. INSTABILITY WILL REMAIN
MARGINAL AND SHEAR WILL BE WEAKER SO THE CONCERN FOR STRONGER
STORMS IS A BIT LOWER THAN TODAY. ONCE AGAIN, SHOWERS AND STORMS
WILL DIMINISH WITH THE LOSS OF DIURNAL HEATING.
KEY MESSAGE 2 DESCRIPTION...
THE TROUGH AXIS SHIFTS OFFSHORE WEDNESDAY MORNING WITH
NORTHWESTERLY FLOW ADVECTING DRIER AIR INTO THE REGION. HIGH
PRESSURE BUILDS IN AT THE SURFACE SO HIGH TEMPERATURES SHOULD BE
ABLE TO CLIMB INTO THE LOW 80S SOUTH OF THE MOUNTAINS UNDER
MOSTLY CLEAR SKIES AND DOWNSLOPE FLOW. NORTH OF THE MOUNTAINS IT
MAY TAKE A LITTLE LONGER TO CLEAR OUT SO WOULD EXPECT THE
CEILING FOR TEMPERATURES TO BE MORE IN THE WAY OF MID TO UPPER
70S. SURFACE RETURN FLOW BEGINS TO ADVECT MOISTURE BACK INTO THE
REGION WEDNESDAY NIGHT MAKING FOR A CLOUDIER AND WARMER NIGHT
WITH LOW TEMPERATURES IN THE MID TO UPPER 50S SOUTH OF THE
MOUNTAINS, AND IN THE LOW 60S RIGHT ALONG THE COAST. NORTH OF
THE MOUNTAINS TEMPERATURES FALL INTO THE LOW 50S. HIGH PRESSURE
DEPARTS TO THE EAST THURSDAY AS A TROUGH BEGINS TO APPROACH FROM
THE GREAT LAKES REGION. MOST OF THE DAY LOOKS TO REMAIN DRY
WITH PARTLY CLOUDY SKIES AS SOUTHWESTERLY FLOW CONTINUES.
TEMPERTURE-WISE THURSDAY LOOKS A FEW DEGREES WARMER THAN
WEDNESDAY, BUT THE DIFFERENCE WILL BE FELT AS DEWPOINTS CLIMB
INTO THE MID-60S SOUTH OF THE MOUNTAINS.
LOOKING AT THE TAIL END OF THE 24.12Z NAM AND RRFS, THE BULK OF
THE PRECIPITATION LOOKS TO HOLD OFF UNTIL THE EVENING HOURS
THURSDAY WITH A CHANCE FOR SOME EARLIER AFTERNOON SHOWERS IN NEW
HAMPSHIRE AS THE WARM FRONT APPROACHES. THE MAIN SHOW LOOKS TO
COME AHEAD OF THE COLD FRONT THURSDAY NIGHT INTO FRIDAY. NBM
PROBABILITIES OF GREATER THAN A HALF INCH RAINFALL HAVE ALREADY
TRENDED DOWN SINCE YESTERDAY WITH MOST OF THE AREA BEING GIVEN A
20 TO 40 PERCENT CHANCE. HOWEVER, THIS MAY BE OWING TO THE HI-
RES MODELS STARTING TO BE INGESTED AND DEPICTING THE MORE
CONVECTIVE NATURE WHERE HIGHER RAINFALL TOTALS WILL BE ISOLATED.
SPEAKING OF CONVECTION CSU'S MACHINE LEARNING MODEL DOES HAVE
SOME LOW PROBABILITIES OF SEVERE WEATHER FOR THIS PERIOD, BUT
AROUND HERE IF THE COLD FRONT IS COMING THROUGH TOO LATE OR TOO
EARLY IT DOES SO WITHOUT MUCH FANFARE. TRENDS WILL CONTINUE TO
BE MONITORED AND WE SHOULD BE ABLE TO START FLESHING OUT THESE
DETAILS BETTER WITH CONSECUTIVE RUNS OF THE CAMS.
THE AFOREMENTIONED SERIES OF FRONTS IS PROGGED TO BE THROUGH
THE AREA BY SATURDAY MORNING, AND WITH BROAD TROUGHING
REMAINING OVER THE REGION TEMPERATURES REMAIN SEASONABLE. HIGH
PRESSURE SLIDES EASTWARD FROM THE GREAT LAKES REGION THROUGH THE
WEEKEND KEEPING US DRY DESPITE AN UPPER LEVEL TROUGH. GLOBAL
MODELS SUGGEST FORCING FROM AN UPPER LEVEL LOW SINKING SOUTHWARD
OUT OF QUEBEC MAY REACH OUR REGION SUNDAY NIGHT INTO NEXT
MONDAY, BUT AT THIS TIME RANGE THERE IS STILL MUCH UNCERTAINTY.
I AM FINE WITH THE NBM THROWING LOW CHANCE POPS INTO THAT TIME
WINDOW FOR NOW, BUT I WOULD NOT BE SURPRISED IF THIS EVENTUALLY
CHANGES.
AVIATION /18Z MONDAY THROUGH SATURDAY/
VFR CONDITIONS ARE MAINLY EXPECTED THE REST OF THE AFTERNOON AND
INTO THE EVENING BUT SOME ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS MAY LEAD TO BRIEF MVFR OR LOWER RESTRICTIONS. HIGH
UNCERTAINTY REGARDING STORM COVERAGE AND TIMING PRECLUDE MENTION
AT ANY SPECIFIC TAF SITE. MORE FOG IS POSSIBLE TONIGHT WHICH
WILL LEAD TO MVFR VISIBILITIES OR LOWER UNTIL FOG LIFTS BY MID
MORNING TUESDAY.
OUTLOOK:
TUESDAY: GENERALLY VFR CONDITIONS EXPECTED WITH LOCAL MVFR OR
LOWER RESTRICTIONS UNDER ISOLATED SHOWERS AND THUNDERSTORMS.
TUESDAY NIGHT: GENERALLY VFR OUTSIDE OF ANY VALLEY FOG.
WEDNESDAY-THURSDAY: GENERALLY VFR CONDITIONS EXPECTED
THURSDAY NIGHT-FRIDAY: GENERALLY MVFR CONDITIONS EXPECTED WITH
WIDESPREAD SHOWERS. IFR CONDITIONS POSSIBLE IN FOG AT NIGHT.
SATURDAY: ANY EARLY MVFR/IFR CONDITIONS SHOULD QUICKLY IMPROVE
TO VFR FOR THE REMAINDER OF THE DAY.
MARINE
CONDITIONS REMAIN BELOW SCA LEVELS FOR AT LEAST THE NEXT FEW
DAYS, WITH A COLD FRONT PASSING THROUGH THE WATERS THIS
AFTERNOON.
GENERALLY SUB-SCA CONDITIONS EXPECTED THROUGH THE WEEKEND AS
THE GULF OF MAINE REMAINS ON THE PERIPHERY OF ATLANTIC HIGH
PRESSURE.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
DISCUSSION...HARGROVE/BARON
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