089
FXUS61 KGYX 271756
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
156 PM EDT SUN JUL 27 2025
SYNOPSIS
CLOUDS AND SHOWER ACTIVITY ASSOCIATED WITH AN APPROACHING WARM
FRONT WILL KEEP DOWN TEMPERATURES TODAY BEFORE THE HEAT AND
HUMIDITY BUILDS FOR THE FIRST HALF OF THE WORK WEEK. A STRONG
COLD FRONT IS EXPECTED TO APPROACH THE REGION WEDNESDAY...BRINGING
THE THREAT FOR SHOWERS AND THUNDERSTORMS. THIS WILL USHER IN
COOLER AND DRIER AIR TO END THE WEEK.
NEAR TERM /THROUGH TONIGHT/
LATEST RAP ANALYSIS SHOWS THE PRIMARY SHORTWAVE WILL SHIFT OFFSHORE
HERE WITHIN THE NEXT HOUR OR TWO WITH PRECIP CHANCES LOWERING BEHIND
THIS WAVE THE REMAINDER OF THE AFTERNOON. STILL, MODELS SHOW
WEAK TROUGHING REMAINING OVERHEAD WITH A WEAK FRONTAL BOUNDARY
AND LOW PRESSURE MOVING SLOWLY EASTWARD, WHICH LEADS TO THE
POTENTIAL FOR ADDITIONAL ISOLATED TO SCATTERED SHOWERS AND A FEW
STORMS TO DEVELOP THROUGH EARLY THIS EVENING, ESPECIALLY TOWARD
THE MOUNTAINS AS ANOTHER SHORTWAVE/VORTMAX RACES ACROSS
SOUTHERN QUEBEC. THERE IS A BRIEF WINDOW OF MORE INSTABILITY AND
INCREASING SHEAR TO WHERE THERE COULD BE A STRONG STORM IN THE
MOUNTAINS WITH GUSTY WINDS AS THE MAIN CONCERN BEFORE DAYTIME
INSTABILITY WANES TOWARD SUNSET. THE HRRR IS ALSO SUGGESTING SW
NH AS AN AREA TO KEEP AN EYE ON, BUT THERE HAS NOT BEEN MUCH RUN
TO RUN CONSISTENCY.
A FEW SHOWERS LINGER INTO THIS EVENING AND THEN INTO THE EARLY
OVERNIGHT IN THE MOUNTAINS WITH UPSLOPE FLOW BEHIND THE WEAK
BOUNDARY. BOUNDARY LAYER MOISTURE REMAINS SUFFICIENT AND FLOW
REMAINS VERY LIGHT OVERNIGHT, SO I HAVE ADDED PATCHY FOG FOR
MOST AREAS TONIGHT. GUIDANCE IS PARTICULARLY FAVORING PORTIONS
OF COASTAL AND INTERIOR MAINE SO I HAVE ADDED PATCHY DENSE
WORDING IN THESE REGIONS. COOLER SPOTS COULD SEE LOWS IN THE
UPPER 50S, BUT FOR THE MOST PART LOWS WILL BE IN THE 60S.
SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
TODAY'S WEAK FRONT AND LOW PRESSURE WILL FURTHER DEPART TO THE EAST
ON MONDAY ALLOWING HIGH PRESSURE AND DRIER AIR TO MOVE IN.
SUBSIDENCE FROM THE HIGH AND THE DRIER AIR WILL BRING A MOSTLY SUNNY
DAY TO THE AREA, BUT IT WILL BE HOT, EVEN TOWARD TOWARD THE COAST A
LIGHT NORTH TO NORTHWEST FLOW WILL DELAY THE SEABREEZE. 850 MB
TEMPERATURES SUPPORT WIDESPREAD HIGHS IN THE UPPER 80S SOUTH OF THE
MOUNTAINS WITH LOW 90S IN PORTIONS OF SOUTHERN NH AND INTO SW ME.
WHILE IT WILL BE HOT, MIXING DOWN THE DRY AIR ALOFT SHOULD BE
SUFFICIENT TO LOWER AFTERNOON DEWPOINTS INTO THE LOW 60S, WHICH
SHOULD KEEP HEAT INDICES PRETTY CLOSE TO THE AIR TEMPERATURES. FOR
THIS REASON, I HAVE OPTED TO NOT PUT OUT ANY HEAT HEADLINES FOR
MONDAY ALTHOUGH IT'S POSSIBLE THAT HEAT INDICES MAY REACH THE 95F
THRESHOLD FOR A BRIEF PERIOD BUT NOT THE DURATION OF 3 HOURS FOR A
HEAT ADVISORY.
A 500MB SHORTWAVE APPROACHES FROM SOUTHERN QUEBEC LATE THE DAY AND
MAY BRING SHOWERS TO THE MOUNTAIN IN THE EVENING AND INTO THE EARLY
PART OF MONDAY NIGHT. OTHERWISE, MOSTLY CLEAR SKIES AND LIGHT WINDS
SHOULD ALLOW PATCHY VALLEY FOG IN SOME AREAS. LOWS WILL BE
MAINLY IN THE 60S.
LONG TERM /TUESDAY THROUGH SUNDAY/
OVERVIEW: WARM AND HUMID CONDITIONS WILL CONTINUE THROUGH WEDNESDAY
WITH SCATTERED SHOWERS AND THUNDERSTORMS, ESPECIALLY DURING THE
AFTERNOON HOURS. COOLER WEATHER WILL THEN ARRIVE THURSDAY AND LINGER
THROUGH SATURDAY BEFORE SLOWLY MODERATING AGAIN.
IMPACTS: AFTERNOON HEAT INDEX VALUES ARE EXPECTED TO REACH THE
MIDDLE TO UPPER 90S ACROSS PORTIONS OF SOUTHERN NH ON TUESDAY AND
PERHAPS WEDNESDAY. VALUES COULD REACH THE LOWER TO PERHAPS MIDDLE
90S IN PORTIONS OF CENTRAL NH AND SOUTHWESTERN ME ON TUESDAY
AFTERNOON BUT CONFIDENCE IS A LITTLE LOWER IN THESE LOCATIONS. IN
ADDITION, STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY
AND ESPECIALLY WEDNESDAY AFTERNOON.
FORECAST DETAILS: HOT AND HUMID CONDITIONS WILL PERSIST ON TUESDAY
AS THE H5 S/WV RIDGE AXIS MOVES OVERHEAD WITH T8 TEMPERATURES
HOVERING AROUND +20C. MIXING PROFILES SUGGEST DEEP AFTERNOON MIXING
UP TO AROUND H850, WHICH PUTS HIGH TEMPERATURES INTO THE LOWER TO
MIDDLE 90S. THIS MIXING WILL LIKELY HELP TO LOWER DEW POINTS SOME
BUT REGARDLESS IT WILL BE A HOT DAY WITH HEAT INDEX VALUES INTO THE
MIDDLE TO UPPER 90S ACROSS PORTIONS OF SOUTHERN NH. HEAT INDEX
VALUES INTO THE LOWER TO PERHAPS MIDDLE 90S ARE POSSIBLE IN CENTRAL
NH AND PORTIONS OF SOUTHWESTERN ME BUT CONFIDENCE IS A LITTLE LOWER
GIVEN THE EXPECTED LOWERING DEW POINTS. DID GO AHEAD AND ISSUED A
HEAT ADVISORY FOR PARTS OF SOUTHERN NH WHERE CONFIDENCE FOR IMPACTS
IS GREATEST. A FEW WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE DURING THE AFTERNOON/EARLY EVENING AND THEY COULD CONTAIN
GUSTY WINDS.
A WEAK COLD FRONT WILL CROSS TUESDAY NIGHT BUT WILL BRING LITTLE IN
THE WAY OF SENSIBLE WEATHER IMPACTS OTHER THAN SOME ADDED CLOUD
COVER AND A FEW SHOWERS, MAINLY OVER THE NORTH AND MOUNTAINS. LOWS
WILL BE WARM WITH READINGS RANGING FROM AROUND 60 NORTH TO NEAR 70
SOUTH. THE MAIN COLD FRONT WILL THEN SLOWLY CROSS THE AREA ON
WEDNESDAY WITH A LARGE TEMPERATURE GRADIENT FROM NORTH TO SOUTH.
ACROSS THE NORTH HIGHS WILL ONLY BE INTO THE 70S WHILE SOUTH-CENTRAL
NH AND PERHAPS EXTREME SOUTHWESTERN ME ONCE AGAIN WARMS INTO THE
LOWER TO MIDDLE 90S. CURRENT GUIDANCE INDICATES A GREATER THREAT FOR
A FEW STRONG TO SEVERE STORMS DURING THE AFTERNOON/EARLY EVENING AS
AN UNSEASONABLY STRONG MID-LEVEL JET MOVES OVERHEAD. UNCERTAINTY
REMAINS HIGH THOUGH REGARDING THE AREAL EXTENT/SEVERITY OF ANY
POTENTIAL STORMS THOUGH AT THIS TIME RANGE. THE PRIMARY THREAT
WOULD LIKELY BE LOCALLY DAMAGING WINDS. WEDNESDAY NIGHT WILL
REMAIN MILD WITH LOWS PRIMARILY INTO THE 60S AND A FEW SCATTERED
SHOWERS WILL REMAIN POSSIBLE AS A WEAK WAVE MOVES ALONG THE
FRONTAL BOUNDARY.
MUCH COOLER TEMPERATURES WILL THEN ARRIVE ON THURSDAY AS A LONG WAVE
H5 TROF AXIS ARRIVES AND FLOW TURNS TO THE NORTHWEST AT THE SURFACE.
T8S WILL FALL TO AROUND +10C, WHICH PLACES HIGH TEMPERATURES MOSTLY
INTO THE MIDDLE TO UPPER 70S WITH GRADUALLY CLEARING SKIES AS
SCATTERED SHOWERS SINK SOUTH OF THE REGION. THURSDAY NIGHT WILL BE
NOTICEABLY COOLER WITH LOWS INTO THE 40S ACROSS THE NORTH WITH 50S
ELSEWHERE. COOL AND MAINLY DRY CONDITIONS WILL THEN PERSIST THROUGH
SATURDAY BEFORE A MODERATING TREND BEGINS ON SUNDAY.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
SHORT TERM...COULD SEE MVFR TO POSSIBLY IFR CEILINGS AS WELL AS
ISOLATED TO SCATTERED SHRA AND A FEW STORMS INTO EARLY THIS
EVENING, MAINLY OVER SOUTHERN NH, BUT PRECIP CHANCES WILL
STEADILY DECLINE GOING INTO THIS EVENING. FOR TONIGHT, PATCHY
FOG IS LOOKING MORE LIKELY THAT COULD BRING IFR TO LIFR
RESTRICTIONS INTO EARLY MONDAY. OTHERWISE, VFR MONDAY, BUT
VALLEY FOG IS POSSIBLE MONDAY NIGHT, MAINLY AT HIE AND LEB.
LONG TERM...MAINLY VFR CONDITIONS ARE EXPECTED THROUGH THE
PERIOD OUTSIDE OF ANY SHRA/TSRA ON TUESDAY AND WEDNESDAY
AFTERNOON. SOME VALLEY NIGHTTIME/EARLY MORNING FG IS ALSO
POSSIBLE LATE WEEK BUT CONFIDENCE IS LOW AT THIS TIME RANGE.
FLOW WILL BE S-SW THROUGH WEDNESDAY BEFORE VEERING TO THE NW ON
THURSDAY BEHIND A COLD FRONT.
MARINE
SHORT TERM...COULD SEE MVFR TO POSSIBLY IFR CEILINGS AS WELL AS
ISOLATED TO SCATTERED SHRA AND A FEW STORMS INTO EARLY THIS
EVENING, MAINLY OVER SOUTHERN NH AND INTO PWM, BUT PRECIP
CHANCES WILL STEADILY DECLINE GOING INTO THIS EVENING. FOR
TONIGHT, PATCHY FOG IS LOOKING MORE LIKELY THAT COULD BRING IFR
TO LIFR RESTRICTIONS INTO EARLY MONDAY. OTHERWISE, VFR MONDAY,
BUT VALLEY FOG IS POSSIBLE MONDAY NIGHT, MAINLY AT HIE AND LEB.
LONG TERM...WIND AND SEAS TO REMAIN BELOW SCA CRITERIA THROUGH
THE PERIOD. WINDS WILL BE S-SW THROUGH WEDNESDAY BEFORE BECOMING
NW ON THURSDAY BEHIND A COLD FRONT. A FEW STORMS ARE POSSIBLE
WEDNESDAY AFTERNOON, WHICH COULD CONTAIN LOCALLY STRONGER WINDS.
GYX WATCHES/WARNINGS/ADVISORIES
ME...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MEZ007>009-
012>014-018>028-033.
NH...HEAT ADVISORY FROM 11 AM TO 8 PM EDT TUESDAY FOR NHZ008-010-
012>015.
MARINE...NONE.
NEAR TERM...COMBS
SHORT TERM...COMBS
LONG TERM...TUBBS
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