Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 220417 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1217 AM EDT TUE JUL 22 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD TO OUR SOUTH THROUGH TUESDAY. WE`LL BECOME PROGRESSIVELY WARMER AND MORE HUMID THROUGH WEDNESDAY AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL APPROACH LATE WEDNESDAY AND BRING SHOWERS AND THUNDERSTORMS. THE FRONT MOVES ACROSS THE REGION WEDNESDAY NIGHT AND EXITS OFFSHORE THURSDAY MORNING. HIGH PRESSURE BUILDS IN FROM THE WEST FRIDAY AND SATURDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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1210 AM...UPDATED T/TD OVERNIGHT....MINS COME OUT SLIGHTLY HIGHER...BASED ON CURRENT OBS AND MESOSCALE MODEL DATA. ALSO UPDATED SKY A BIT...MAINLY TO REFLECT THE OFFSHORE FOG/STRATUS BANK...AND HOW IT MAY BRUSH THE COAST BY DAYBREAK. PREV DISC: A QUIET DAY WITH SURFACE HIGH PRESSURE DRAPED ACROSS THE AREA. IT WAS NEAR 80F INLAND BUT COOLER ALONG THE COAST WITH THE ONSHORE FLOW. THERE WERE SOME BUILD UPS ACROSS THE HIGHER TERRAIN ON GOES IMAGERY AND THERE COULD BE AN ISOLATED LIGHT SHOWER THERE THROUGH EARLY EVENING. OTHERWISE...MOSTLY SUNNY AND PLEASANT ACROSS THE AREA THROUGH EVENING. THERE WAS SOME MARINE STRATUS SOUTH OF CASCO BAY ON GOES IMAGERY. THAT MAY WORK ONSHORE OVERNIGHT AS THE FLOW BECOMES MORE EASTERLY. EXPECT WE`LL SEE SOME AREAS OF LATE NIGHT FOG AND STRATUS...ESPECIALLY ACROSS THE INTERIOR VALLEYS. A BLEND OF MET/MAV WAS USED FOR MINIMUM TEMPERATURES.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM WEDNESDAY/... SOUTHERLY FLOW BEHIND THE OFFSHORE HIGH WILL TRANSPORT WARMER AND MORE HUMID AIR INTO THE AREA ON TUESDAY. SHOULD BE A PARTLY SUNNY DAY WITH HIGHS WELL INTO THE 80S AND DEWPOINTS IN THE 60S. PARTLY CLOUDY AND HUMID TUESDAY NIGHT WITH AREAS OF HAZE AND FOG. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... THE MAIN FORECAST CONCERN DURING THE EXTENDED PERIOD WILL BE THE CHANCE OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. STRONG SFC COLD FRONT WILL APPROACH FROM THE NW WEDNESDAY AFTERNOON AND WILL PASS ACROSS THE REGION DURING THE LATE EVENING OR NIGHT. THETA-E RICH AIR IN THE BOUNDARY LAYER WILL FLOW NORTHEASTWARD ACROSS NORTHERN NEW ENGLAND ON WEDNESDAY IN ADVANCE OF THE COLD FRONT. IN ADDITION...AS THE SHORT WAVE TROUGH APPROACHES...DEEP LAYER SHEAR LOOKS TO INCREASE TO AROUND 40 KT BY LATE IN THE DAY. THEREFORE THE COMBINATION OF INSTABILITY AND SHEAR WILL BE SUFFICIENT FOR SEVERE THUNDERSTORMS WITH THE MAIN THREAT BEING DAMAGING WINDS. A MODEL BLEND YIELDS SO-SO MID LEVEL LAPSE RATES...BUT A FEW MODELS CONTINUE TO TRY AND TAP SOME REMNANT EML AIR AND FUNNEL IT AHEAD OF THE TROUGH. IF THIS OCCURS...THE SEVERE WEATHER THREAT COULD BE PRETTY SUBSTANTIAL. THE MAIN THREAT WILL EXIST ACROSS WESTERN ZONES LATE AFTERNOON AND EARLY EVENING BUT THE THREAT MAY MOVE TO THE COAST IN A SLIGHTLY WEAKER FASHION DURING THE EVENING. PWATS LOOK TO RISE CLOSE TO 2 INCHES BY LATE AFTERNOON. WHILE THE STORMS ARE EXPECTED TO BE MOVING ALONG QUITE WELL...ANY TRAINING COULD POSE A LOCALIZED FLASH FLOOD THREAT. THE FRONT WILL SLIDE OFFSHORE DURING THE NIGHT WEDNESDAY NIGHT AND MAY DEVELOP SOME ANAFRONTAL CHARACTERISTICS. THEREFORE...A CHANCE OF SHOWERS MAY STILL EXIST INTO THURSDAY MORNING...ESPECIALLY ACROSS SOUTHEASTERN ZONES. HIGH PRESSURE LOOKS TO BUILD IN THROUGH THE WEEKEND...WITH WET WEATHER POTENTIALLY RETURNING EARLY NEXT WEEK. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... SHORT TERM /THROUGH TUESDAY NIGHT/...AREAS OF MVFR TONIGHT AND AGAIN TUESDAY NIGHT IN FOG AND STRATUS WITH BRIEF LCL IFR POSSIBLE. OTHERWISE...VFR DURING THE DAY TUESDAY. LONG TERM...SHOWERS AND THUNDERSTORMS WED AFTN AND NIGHT WILL BRING CONDITIONS DOWN TO IFR LOCALLY AT TIMES. OTHERWISE...IMPROVING CONDITIONS ARE FORESEEN FOR THU THRU SAT. && .MARINE... SHORT TERM /THROUGH TUESDAY NIGHT/...QUIET ON THE WATERS THROUGH TOMORROW. THERE WILL BE SOME VSBY RESTRICTIONS AT TIMES IN FOG AND HAZE. SOUTHERLY WINDS INCREASE TUESDAY NIGHT ALONG WITH SEAS BUT SHOULD REMAIN BELOW SMALL CRAFT THRESHOLD. LONG TERM...SCA CONDITIONS POSSIBLE WED INTO THU IN ASSOCIATION WITH COLD FRONT. OTHERWISE...SUB-SCA CONDITIONS ARE LIKELY OVER THE WEEKEND. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...

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