076
FXUS61 KGYX 271015
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
615 AM EDT SUN JUL 27 2025
SYNOPSIS
CLOUDS AND SHOWER ACTIVITY ASSOCIATED WITH AN APPROACHING WARM
FRONT WILL KEEP DOWN TEMPERATURES ON SUNDAY 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 /UNTIL 6 PM THIS EVENING/
610AM UPDATE...BUMPED UP POPS AS BAND OF RAIN IS QUICKLY
ARRIVING THROUGH CENTRAL VT. PIVOT POINT SHOULD KEEP LONGER RAIN
CHANCES ACROSS THE SOUTHERN HALF OF NH, BUT WILL SEE SHOWERS
MAKE THEIR WAY ACROSS MUCH OF SOUTHERN ME THROUGH EARLY
AFTERNOON. ALSO ADJUSTED SKY FORECAST AS MUCH OF THE NORTHERN
HALF OF THE CWA HAS BEEN UNDER-PERFORMING IN THAT DEPARTMENT.
MUCH OF THE AREA WILL BEGIN THE EARLY DAY MOSTLY SUNNY OUTSIDE
OF SW NH.
PREVIOUS DISCUSSION...
KEY MESSAGES:
* SHOWERS WITH EMBEDDED THUNDERSTORMS MOVE ACROSS MAINLY THE
SOUTHERN HALF OF THE FORECAST AREA TODAY. SOME SHOWERS MAY
CONTAIN HEAVY DOWNPOURS, PARTICULARLY EARLY ALONG THE NH/VT
BORDER. WHILE THE THREAT OF FLASH FLOODING IS LOW, SOME
PONDING IN POOR DRAINAGE AREAS MAY RESULT WHERE REPETITIVE
RAINFALL OCCURS
* SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP ACROSS THE
MOUNTAINS THIS AFTERNOON. THE MAIN THREAT FROM THESE STORMS
WILL BE CLOUD TO GROUND LIGHTNING, WITH SOME GUSTY WINDS IN
TALLER STORMS.
A WARM FRONT APPROACHES FROM NEW YORK TODAY WITH SHOWERS AND
EMBEDDED THUNDERSTORMS AHEAD OF IT. WHILE THE ENVIRONMENT WILL
BE SOMEWHAT SUPPORTIVE OF INCREASED PRECIP EFFICIENCY, OVERALL
STORM MOTION INCREASES FROM DEVELOPMENT DURING THE OVERNIGHT
PERIOD. THIS REDUCES EXCESSIVE RAINFALL RISK AND THUS THE THREAT
OF FLOODING. DO EXPECT THESE SHOWERS TO BEGIN ACROSS THE
SOUTHERN HALF OF NH THIS MORNING, AND CONTINUE INTO THE EARLY
AFTERNOON HOURS. THIS EVENTUALLY SPREADS INTO FAR SOUTHERN ME.
GREATEST CONFIDENCE OF RAIN COVERAGE IS ASSOCIATED WITH THIS
INITIAL WAVE IN THE MORNING, BUT ENVIRONMENT WILL REMAIN
CONDUCIVE TO ISOLATED/SCATTERED SHOWER DEVELOPMENT THROUGH THE
AFTERNOON. THIS INCLUDES THE ARRIVAL OF ADDITIONAL LIFT PROVIDED
BY NORTHERN WAVE APPROACHING THE MOUNTAINS LATER THIS
AFTERNOON. SHEAR BUILDS LATE DAY, INTERSECTING WITH INSTABILITY
IN PLACE FROM DAYTIME HEATING. ONCE THIS LIFT NEARS, CAN'T RULE
OUT A ONE OR TWO STRONGER STORMS IN VICINITY TO THE ME/QUEBEC
BORDER. DRY AIR AND COVERAGE OF STEEPER LAPSE RATES WILL BE THE
ADDITIONAL LIMITING FACTORS WITH THE LATER TIMING.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/
COVERAGE OF SHOWERS DECREASES INTO THE EVENING HOURS, BUT WILL
STILL HOLD ON TO ELEVATED INSTABILITY THROUGH THE NIGHT. THE
MARGINAL AMOUNTS WON'T SUPPORT WIDESPREAD SHOWERS, BUT COMPLEXES
THAT CONTINUE FROM THE EARLY EVENING MAY CONTINUE TO MOVE SE
THROUGH THE NIGHT.
WINDS SHIFT W OVERNIGHT WITH WARMER LOWS THAN LATE LAST WEEK
THROUGH THE WEEKEND. THIS LEADS INTO HOT TEMPERATURES TO START
THE WEEK.
LITTLE CHANGE IN HIGH TEMPERATURE FORECAST FOR MONDAY AS 500MB
HEIGHT ANOMALY BUILDS IN THE EASTERN CONUS. 850MB TEMPS INCREASE
TOWARDS 16/17 DEG C, TRANSLATING TO SURFACE HIGHS IN THE MID 80S
TO LOWER 90S. CONTINUED DAY SHIFT'S TREND OF LOWER DEW POINT
TEMPS FOR THE DAY DUE TO MIXING AND NW SOURCE REGION. HOWEVER,
BL WINDS AREN'T OVERLY STRONG. THIS WILL HAVE IMPACTS ON
FORECAST HEAT INDEX VALUES NEARING THE MID 90S IN DAY 1 OF EARLY
WEEK HOT TEMPS. AT MINIMUM, HEAT HEADLINES MAY BE NEEDED FOR
PORTIONS OF ROCKINGHAM AND HILLSBOROUGH COUNTIES IN NH COME
MONDAY.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
KEY MESSAGES:
* HEAT PEAKS ON TUESDAY /ADVISORY HEAT INDICES LIKELY FOR PARTS OF
S NH AND SW ME/ BUT CONTINUES INTO WEDNESDAY.
* GREATEST THUNDERSTORM CHANCES COME WEDNESDAY AFTERNOON/EVENING
* TEMPERATURES COOL SIGNIFICANTLY THURSDAY - SATURDAY.
DETAILS:
A LOW PERCENTAGE OF THE ENSEMBLE SOLUTION SPACE FAVORS SOME RIDGE
ROLLING MCS REMNANTS MAKING A RUN AT NORTHERN NEW ENGLAND MONDAY
NIGHT...BUT IN A WEAKENING MODE AS IT ENCOUNTERS A DRY DOWNSTREAM
AIRMASS. AFTER THIS...THE FORECAST FOCUS REMAINS THE HEAT POTENTIAL
FOR TUESDAY /T8S +17-19C/ AND WEDNESDAY /T8S +15-+17C/. WHILE
TEMPERATURES THEMSELVES APPEAR SUFFICIENT TO SUPPORT THE POTENTIAL
FOR HEAT ADVISORIES OVER SOUTHERN NH AND SW ME...AN EARLY LOOK AT
MODEL SOUNDINGS SUGGESTS A DECENT AMOUNT OF DRIER AIR MIXING TO THE
SURFACE WHICH MAY KEEP DEWPOINTS MORE IN THE LOWER-MID 60S WHICH
WOULD LIMIT THE EXTENT OF 95F APPARENT TEMPERATURES. HIGHS ABOVE 90F
ARE AGAIN POSSIBLE ACROSS SOUTHERN NH WEDNESDAY AHEAD OF APPROACHING
COLD FRONT. THE GREATEST SIGNAL FOR POTENTIAL STRONG/SEVERE
THUNDERSTORMS IS WITH THIS FRONT WEDNESDAY AFTERNOON AND EVENING
WITH A MODEST SIGNAL FROM AI-BASED SEVERE WEATHER OUTLOOK GUIDANCE.
BEST FORCING CURRENTLY LOOKS TO BE MORE OVER THE NORTH
/ANOMALOUSLY STRONG MID LEVEL JET/...BUT UNCERTAINTIES ARE HIGH AT
THIS RANGE ESPECIALLY WITH FRONTAL TIMING WITH SOME ENSEMBLE MEMBERS
STALLING THE FRONT OVERHEAD OR NEARBY WITH AT LEAST SHOWER POTENTIAL
CONTINUING INTO THURSDAY. ALSO QUESTIONABLE ARE THERMODYNAMIC
PROFILES WITH WEAK MID LEVEL LAPSE RATES /<6C/KM/ FAVORED THROUGH
THE PERIOD. THIS QUESTIONABLE FRONTAL TIMING ALSO SUGGESTS SOME
BUST POTENTIAL FOR TEMPERATURES THURSDAY.
T8S MOVE BELOW SEASONAL NORMS AS LONGWAVE TROUGHING PULLS IN TO
END THE WEEK. THIS COOLER/DRIER AIRMASS LOOKS TO BRING
TEMPERATURES THAT ARE ONLY A TOUCH COOLER THAN NORMAL FOR THE
FIRST DAYS OF AUGUST WITH LOWS FALLING INTO THE 40S IN THE
MOUNTAINS AND 50S TO THE SOUTH.
AVIATION /10Z SUNDAY THROUGH THURSDAY/
SHORT TERM...BKN CIRRUS DECK CONTINUES INTO THE EARLY MORNING
HOURS AHEAD OF SHRA AND EMBEDDED TS. LOW DECK ARRIVES IN W NH
EARLY, WITH MVFR CEILINGS SLOWLY PUSHING EASTWARD. SCT IFR ALSO
ACCOMPANIES, BUT NOT EXPECTED TO LINGER. MVFR APPROACHES COASTAL
TERMINALS BY MID AFTERNOON WITH MUCH OF THE SHRA DECREASING IN
COVERAGE. ISOLATED SHOWERS DEVELOP ACROSS THE INTERIOR THROUGH
EVENING, WITH THINNING OF MVFR DECK EXPECTED. S WINDS BUILD
DURING THE DAY, BECOMING W AFTER MIDNIGHT. VFR THEN EXPECTED
MONDAY, WITH WINDS BECOMING NW.
LONG TERM...VFR CONDITIONS ARE LIKELY TO DOMINATE THE TUESDAY
THROUGH THURSDAY PERIOD. THERE WILL BE A THREAT OF
ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON
AND EVENING WITH UNCERTAINTY WHETHER SOME SHOWER ACTIVITY
PERSISTS INTO THURSDAY...ESPECIALLY ACROSS SOUTHERN NH AND SW
ME. IF THESE OCCUR...A PERIOD OF FOG WILL ALSO BE POSSIBLE
WEDNESDAY NIGHT. WINDS ARE EXPECTED TO GENERALLY REMAIN LIGHT
THROUGH THE PERIOD.
MARINE
SHORT TERM...SCA CONDITIONS ARE NOT FORECAST THROUGH MONDAY.
EXPECT PRIMARILY S/SE WINDS THROUGH SUNDAY NIGHT BEFORE FRONT
PASSES THE WATERS. THESE SHIFT NW FOR MONDAY.
LONG TERM...WINDS AND WAVES LOOK TO REMAIN BELOW SCA LEVELS
THROUGH THE WEEK. THE GREATEST POTENTIAL FOR THUNDERSTORMS OVER
THE WATERS WILL BE WEDNESDAY AFTERNOON AND EVENING THOUGH AT
THIS RANGE THE THREAT APPEARS LOW.
GYX WATCHES/WARNINGS/ADVISORIES
ME...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MEZ018>025-
033.
NH...NONE.
MARINE...NONE.
NEAR TERM...CORNWELL
SHORT TERM...CORNWELL
LONG TERM...ARNOTT
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