Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 241638 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1238 PM EDT SUN MAY 24 2015 .SYNOPSIS... HIGH PRESSURE SHIFTS TO OUR SOUTH TODAY AND WILL WILL PROVIDE FAIR AND WARMER WEATHER INTO MEMORIAL DAY. A WARM FRONT WILL CROSS THE AREAS MONDAY NIGHT AND TUESDAY....PROVIDING A CHANCE FOR SHOWERS AND STORMS. WARM AND MORE HUMID CONDITIONS ARE EXPECTED MID TO LATE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE... ***RED FLAG WARNING HAS BEEN ISSUED FOR WESTERNMOST MAINE AND SOUTHERN NEW HAMPSHIRE*** HAVE UPDATED FORECAST BASED ON CURRENT CONDITIONS AND LATEST SET OF MESOSCALE MODELS. FRONTAL BOUNDRY FORMING OVER NORTHERN NEW HAMPSHIRE AND WEST- CENTRAL MAINE THIS MORNING. A WEAK IMPULSE WILL ENTER THE REGION IN A NORTHWEST FLOW AS INSTABILITY SLOWLY INCREASES THIS AFTERNOON. CAPE VALUES CLIMB TO AROUND 500 J/KG IN THE AREA OF FRONTOGENESIS. BASED ON ABOVE...HAVE INCREASED THE CLOUD COVERAGE FOR TODAY AND INCREASED POPS TO CHANCE OR SLIGHT CHANCE OVER THE NORTHEASTERN HALF OF OUR FORECAST AREA. THE SHOWERS AND ISOLD RUMBLES OF THUNDER WILL LIKELY DRY UP WHEN ATTEMPTING TO REACH SOUTHWESTERN PORTIONS OF THE FORECAST AREA. TEMPERATURES CLIMBING FASTER THAN ANTICIPATED...BUT CLOUDS WILL INHIBIT READINGS SOMEWHAT THIS AFTERNOON. NEVERTHELESS...SOME AREAS TO PEAK OUT AT 80 DEGREES TODAY OVER SOUTHERNMOST AREAS. PREV DISC... UPDATE...A FEW MINOR CHANGES BASED ON CURRENT OBSERVATIONAL TRENDS. COULD BE A SPRINKLE IN NRN ZONES THIS MORNING...AS S/WV TROF CROSSES JUST N OF THE INTERNATIONAL BORDER. PREVIOUS DISCUSSION...AS HIGH PRES SETTLES S OF NEW ENGLAND...WLY RETURN FLOW WILL HELP TO WARM UP THE FORECAST AREA NICELY TODAY. WIDESPREAD 70S ARE EXPECTED...WITH POCKETS OF 80S FROM KASH TO KCON AND EWD TO KSFM. DESPITE THE ADVECTION OF HIGHER DEWPOINTS THAN YESTERDAY...THE WARM TEMPS WILL OFFSET THAT AND KEEP RH VALUES BELOW 30 PERCENT. CONTINUED GUSTY WLY WINDS WILL MEAN FIRE DANGER WILL STAY ELEVATED FOR AT LEAST ANOTHER DAY. A NRN STREAM S/WV TROF WILL BRUSH THE FORECAST AREA LATER TODAY...AND MAY HELP TRIGGER A FEW SHOWERS ACROSS THE NRN ZONES. MESOSCALE MODEL FORECASTS FAVOR ENOUGH GRAUPEL DEVELOPMENT FOR SOME ISOLD THUNDER...SO HAVE ALSO ADDED THIS TO THE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... RETURN FLOW CONTINUING OVERNIGHT WILL KEEP TEMPS MUCH MILDER THAN THE PAST COUPLE OF NIGHTS. BY MON A WARM FRONT WILL TRY AND LIFT THRU THE FORECAST AREA. INCREASING DEWPOINTS FROM THE SW ADVECTING OVER THE COLD GULF OF ME WILL LIKELY SUPPORT LOW STRATUS DEVELOPMENT. AT THIS TIME WIND DIRECTION LOOKS TO KEEP THAT MOSTLY OFFSHORE...BUT WILL HAVE TO MONITOR TOWARDS THE END OF THE PERIOD. ANOTHER FEATURE TO WATCH WILL ALSO BE LATE DAY CONVECTION ACROSS THE UPPER MIDWEST TODAY. MODEL FORECASTS SHOW AN AREA DEVELOPING AND MOVING NEWD INTO THE GREAT LAKES OVERNIGHT. SOME OF THE MORE AGGRESSIVE FORECASTS...LIKE THE GFS...BRING THIS OVER THE RIDGE AND INTO PARTS OF NEW ENGLAND FOR MON. FOR NOW HAVE INCREASED POP IN THE MTNS DURING THE DAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... LARGE 500MB RIDGE BUILDS IN EARLY IN THE WEEK AND OVERRUNS CLOSED LOW TO THE SOUTH SETTING UP REX BLOCK THRU THE END OF THE WEEK...LEADING TOP A WARM AND HUMID CONDITIONS INTO EARLY NEXT WEEKEND. INITIALLY ON MON NIGHT A WEAK WAVE RIDES OVER THE TOP OF THE RIDGE AND PUSHES LOW-MID LVL WARM FRONT SW-NE THRU THE AREA. AS IS OFTEN THE CASE AS THE WAVE ENCOUNTERS THE RIDGE IT FLATTENS OUT AND DYNAMICS WEAKEN AS THE WAA MOVES THRU. SO BEST CHC OF OF ANY SHRA/TSRA WILL BE IN THE NRN AND WRN ZONES...WITH COASTAL AREAS ONLY SEE A SLIGHT CHC OF RAIN FROM THIS FRONT. THE FRONT LINGERS INTO TUE MORNING...BUT RIDGING BUILDS QUICKLY BEHIND THIS FRONT AND EXPECT PARTIAL CLEARING AT LEAST AND WARMING TEMPS TUE AFTERNOON WITH HIGHS 80-85 INLAND AND 70S ON THE COAST. WITH TDS RISING INTO THE LOW-MID 60S. AFTER A MUGGY TUE NIGHT WITH LOWS MAINLY IN THE UPPER 50S TO MID 60S...WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK AS HIGHS CLIMB SECURELY IN THE 80S...WITH A FEW SPOTS IN SRN NH MAKING A RUN AT 90. A WEAK FRONT MOVES IN FROM THE NW WED AFTERNOON...BUT THE TREND IS FOR IT TO STALL OR WASH OUT BEFORE IT REACHES THE CWA...AT LEAST ACCORDING TO THE 00Z EURO. STILL COULD SET OFF SOME SOME CONVECTION IN THE MOUNTAINS WED AFTERNOON. FOR THU-SAT WE WILL BE SITTING ON THE ANTICYCLONIC SIDE OF THE 500 MB JET...AND WILL HAVE TO WATCH FRO SOME WAVES MOVING THRU THE FLOW. WHICH COULD SET OFF SHRA/TSRA AT LEAST ONE DAY DURING THAT TIMEFRAME...BUT MODELS ARE NOT CONSISTENT ENOUGH WITH ANY FEATURE TO NAIL DOWN THESE WAVES AT THIS TIME. IT WILL STAY WARM AND HUMID THRU THIS PERIOD WITH HIGHS LOW-MID 80S INLAND AND IN THE 70S ON THE COAST. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SHORT TERM...VFR CONDITIONS TO PREVAIL THRU MON. GUSTY WLY WINDS EXPECTED TODAY...WITH GUSTS AROUND 25 KTS AT TIMES AT ALL TERMINALS. THERE IS THE POSSIBLY THAT INCREASING MOISTURE ADVECTION OVER THE WATERS WILL SUPPORT SOME LOW STRATUS DEVELOPMENT LATER MON. THIS IS A LOW CONFIDENCE FORECAST AT THIS TIME HOWEVER. LONG TERM...MVFR OR IFR IN SHOWERS IS POSSIBLE MONDAY NIGHT...OTHERWISE MAINLY VFR TUE-THU. SCT TSRA ARE POSSIBLE WED AND THU AFTERNOON..E.SPECIALLY AWAY FROM THE COAST. && .MARINE... SHORT TERM...OVERLAND TEMPS ARE EXPECTED TO WARM NICELY TODAY...ALLOWING FOR DEEPER MIXING NEAR-SHORE. OCCASIONAL GUSTS OF 25 KTS ARE POSSIBLE FOR THE BAYS AS A RESULT. ON THE OUTER WATERS THE CONTINUED WLY FLOW WILL KEEP SEAS NEAR 5 FT WITH GUSTS AROUND 20 KTS AT TIMES. GIVEN THE HOLIDAY WEEKEND AND INCREASED RECREATION ON THE WATERS A SCA HAS BEEN ISSUED THRU THIS EVENING. LONG TERM...HIGH PRESSURE BUILDS SOUTH OF THE WATERS THIS WEEK...BUT WEAK WAVES OF LOW PRESSURE WILL PASS N OF NEW ENGLAND AND COULD ENHANCE SW FLOW AT TIMES THAT WINDS/SEAS APPROACH SCA LEVELS. && .FIRE WEATHER... RED FLAG CONDITIONS ARE CURRENTLY BEING MET OVER SOUTHERN NEW HAMPSHIRE AND WESTERNMOST MAINE. AFTER COORDITION WITH ADJACENT OFFICES AND THE STATE OF ME/NH...HAVE OPTED FOR A RED FLAG WARNING IN THESE AREAS. ADJACENT AREAS WILL CONTINUE TO HAVE AN ELEVATED THREAT AS WELL THROUGH 8 PM. WILL CONTINUE TO HANDLE WITH THE HWO PRODUCT WHICH WE HAVE ALL SEASON. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MEZ012-018- 019. NH...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NHZ004>015. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ151- 153. SMALL CRAFT ADVISORY UNTIL 2 AM EDT MONDAY FOR ANZ150-152-154. && $$ JC

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