Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 040153 AAB AFDGYX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAY ME 953 PM EDT SUN MAY 3 2015 .SYNOPSIS... HIGH PRESSURE OFFSHORE WILL BRING A SOUTHERLY FLOW OVER THE NORTHEAST AND TRANSPORT WARMER AIR INTO THE AREA. A WEAK COLD FRONT WILL CROSS THE AREA MONDAY NIGHT AND EARLY TUESDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS. A MOISTURE STARVED COLD FRONT WILL CROSS THE AREA WEDNESDAY. A RIDGE OF HIGH PRESSURE FOLLOWS FOR LATE WEDNESDAY AND THURSDAY. A DEVELOPING ONSHORE FLOW AND AN APPROACHING WARM FRONT WILL MAKE THE WEATHER INCREASINGLY UNSETTLED FOR FRIDAY. THE WARM FRONT SHOULD LIFT TO THE NORTH OF THE AREA BY SATURDAY FOLLOWED BY A TRAILING COLD FRONT LATE SATURDAY NIGHT AND SUNDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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.UPDATE... NO MAJOR CHANGES FOR THIS UPDATE. INGESTED CURRENT MESONET DATA TO ADJUST TEMPERATURE AND DEW POINT TRENDS.
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&& PREVIOUS DISCUSSION...ISSUED A FIRE WEATHER WATCH AFTER TALKING WITH NH FORESTRY SERVICE AND SURROUNDING OFFICES. THIS BRINGS US IN LINE WITH THE SURROUNDING OFFICES. WE ARE STILL SHORT OF CRITERIA BUT DEW POINTS MAY BE LOWER THAN FORECAST. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/... MONDAY WILL BE THE WARMEST DAY OF THE YEAR SO FAR WITH MANY AREAS CRACKING THE 80 DEGREE MARK. A LITTLE COOLER NEAR THE COAST WHERE A SEA BREEZE WILL BE PRONE TO DEVELOPING BUT EVEN PORTLAND SHOULD REACH 70 DEGREES. STRONG MIXING WITH THE DAYTIME HEATING WILL BRING REALLY DRY AIR TO THE SURFACE AGAIN MONDAY. MODEL DEW POINT FORECASTS CONTINUE TO BE PRETTY ATROCIOUS THIS TIME OF YEAR WITH THE DIFFICULTY IN ACCOUNTING FOR THE MIXING. HAVE UNDERCUT AFTERNOON DEW POINTS BY SEVERAL DEGREES TO ACCOUNT FOR THE MIXING AWAY FROM THE COAST BUT EVEN THIS MIGHT NOT BE LOW ENOUGH. THIS DRY AIR WILL SPELL FIRE WEATHER CONCERNS DETAILED IN THE FIRE WEATHER DISCUSSION BELOW. COLD FRONT BEGINS MOVING ACROSS THE FORECAST AREA OVERNIGHT. MOIST ADVECTION AHEAD OF THE FRONT WILL LIKELY LEAD TO CLOUDS AND WARMER OVERNIGHT TEMPERATURES. REMNANT CONVECTION FROM QUEBEC WILL LIKELY MOVE SOUTHEAST INTO THE BORDER REGIONS BEFORE DISSIPATING AS THE FRONT MOVES ACROSS THE FORECAST AREA OVERNIGHT. ANY SHOWERS WILL NOT ARRIVE UNTIL AFTER DARK AND THIS ALONG WITH THE LACK OF SUBSTANTIAL FORCING AND SIGNIFICANT MOISTURE WILL MAKE THE THREAT OF THUNDERSTORMS FAIRLY LOW. BY TUESDAY MORNING THE FRONT WILL BE NEARING THE COASTLINE AND SAGGING SLOWLY SOUTHWARD THROUGH SOUTHERN NEW HAMPSHIRE. COULD SEE SHOWERS TRYING TO DEVELOP ALONG THE FRONT IN THE LATE MORNING OR EARLY AFTERNOON OVER SOUTHERN NEW HAMPSHIRE BEFORE THE FRONT FINALLY PUSHES FULLY SOUTH INTO MASSACHUSETTS. OTHERWISE IT WILL BE A DRY AND WARM DAY AGAIN ACROSS THE REGION. OFFSHORE FLOW WILL PREVENT MUCH OF A SEA BREEZE SO TUESDAY COULD BE THE WARMEST DAY IN PORTLAND. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS ARE IN GENERAL AGREEMENT ON THE LONG WAVE PATTERN FOR THE ENTIRE FORECAST PERIOD. WE BEGIN THE PERIOD WITH WEST- NORTHWEST FLOW ALOFT IN ADVANCE OF AN UPPER RIDGE CENTERED ACROSS THE WESTERN GREAT LAKES. AN IMPULSE EMBEDDED IN THAT FLOW WILL DRIVE A WEAK MOISTURE STARVED COLD FRONT ACROSS THE AREA WEDNESDAY. HIGH PRESSURE THEN BUILDS BY TO OUR NORTH LATE WEDNESDAY THROUGH THURSDAY. THE FLOW TURNS ONSHORE BY THURSDAY NIGHT...AND WITH AN UPPER RIDGE BUILDING TO OUR WEST...A WARM FRONT DEVELOPS ACROSS THE REGION THURSDAY NIGHT AND FRIDAY. LIGHT OVERRUNNING PRECIPITATION AND SOME DRIZZLE AND FOG IS POSSIBLE FRIDAY MAINLY OVER NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA AS THE FRONT PRESSES NORTH. DURING THE PAST DAY...THE MODELS HAVE COME AROUND TO A SOLUTION THAT DRIVES THE WARM FRONT TO OUR NORTH BY SATURDAY FOLLOWED BY A TRAILING COLD FRONTAL PASSAGE SATURDAY NIGHT/EARLY SUNDAY. UNFORTUNATELY...THE FRONT THEN STALLS OUT AND PROVIDES THE PROSPECT OF CLOUDS AND UNSETTLED WEATHER FOR THE TAIL END OF THE WEEKEND AND EARLY NEXT WEEK. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... SHORT TERM...AFTERNOON SHOWERS DISSIPATE EARLY THIS EVENING. SHOULD SEE VFR CONDITIONS AND NEARLY CALM WINDS FOR MOST OF THE AREA. THE MARINE CLOUDS AND FOG ARE LESS LIKELY TO FORM TONIGHT THAN LAST NIGHT BUT CANNOT RULE IT OUT COMPLETELY. BEST CHANCE WOULD BE AT ROCKLAND. IF THIS DOES FORM IT WILL DISSIPATE AGAIN IN THE MORNING MONDAY LEADING TO VFR CONDITIONS AGAIN AREAWIDE. LONG TERM... FRIDAY...SCATTERED MVFR POSSIBLE IN SHOWERS. && .MARINE... SHORT TERM...LIGHT WINDS OVER THE WATERS TODAY BUT BECOMING MORE SOUTHWESTERLY AND STRENGTHENING MONDAY EVENING. COULD POTENTIALLY SEE GUSTS TO 25 KT MONDAY NIGHT OVER THE OUTER WATERS BEFORE A COLD FRONT MOVES THROUGH. LONG TERM... WEDNESDAY EVENING - THURSDAY MORNING...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. FRIDAY...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .FIRE WEATHER... AFTERNOON HEATING ON MONDAY WILL LEAD TO GOOD MIXING AND PULL DOWN SIGNIFICANTLY DRIER AIR FROM ALOFT. AFTERNOON HUMIDITY LEVELS FALL BELOW 25 PERCENT FOR MUCH OF THE AREA BUT WIND SPEEDS WILL ONLY REACH AROUND 10 OR 15 MPH. BOTH OF THESE CRITERIA ARE ONE CATEGORY BELOW RED FLAG WARNING CONDITIONS BUT THERE IS SOME CONCERN THAT DRY AIR COULD BE MORE INTENSE THAN FORECAST. THEREFORE A WATCH HAS BEEN ISSUED AND WE WILL CONTINUE TO MONITOR CONDITIONS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR MEZ007>009-012>014-018>021. NH...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR NHZ001>013-015. MARINE...NONE. && $$ UPDATE...HANES

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