Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 040004 AAA AFDGYX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAY ME 704 PM EST TUE MAR 3 2015 .SYNOPSIS... LOW PRESSURE WILL SWING THROUGH SOUTHERN CANADA TONIGHT TRYING TO PUSH A WARM FRONT NORTH ACROSS THE REGION. AS THE LOW SHIFTS TO OUR NORTH...IT WILL DRAG A COLD FRONT THROUGH THE REGION LATE WEDNESDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST THURSDAY AND CREST OVER THE REGION ON FRIDAY. A WEAK DISTURBANCE WILL DRAG TRAILING WARM AND COLD FRONTS ACROSS THE REGION THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... .UPDATE... WARM AIR ADVECTION OVERSPREADING THE REGION THIS EVENING IS ACCOMPANIED BY SPOTTY LIGHT SNOW SHOWERS. TIME OF ARRIVAL HAS SLOWED SOMEWHAT AND THIS HAS TO DO WITH ALL THE DRY AIR ALOFT AND TOP DOWN SATURATION TAKING ITS TIME. HAVE ADJUSTED POPS... QPF... AND HOURLY TEMPERATURE AND DEW POINT GRIDS. && PREVIOUS DISCUSSION... A STRONG SOUTHWEST FLOW ALOFT WITH AN EMBEDDED SHORT WAVE WITH BRING A BURST OF WARM AIR ADVECTION SNOW ACROSS THE REGION TONIGHT LASTING ABOUT 6 HOURS. MODELS AGREE ON TIMING. SNOW BEGINS IN SOUTHWEST NH BY EARLY THIS EVENING AND THEN QUICKLY SPREADS NORTH AND EAST AND OVERSPREADS THE REST OF NORTHERN NH AND ALL OF SOUTHWEST ME THIS EVENING. THE GFS IS THE WETTEST MODEL WITH CLOSE TO .50 QPF OVER MUCH OF THE AREA WHILE OTHER MODELS IN THE RANGE OF .25-.30. USED A COMPROMISE. OVERALL MOSTLY A 3-6 INCH SNOWFALL EXPECTED EXCEPT OVER SOUTHEAST NH AND MAYBE COASTAL SOUTHWEST MAINE WHERE AMOUNTS COULD BE IN THE 2-4 INCH RANGE DUE TO A BRIEF CHANGEOVER TO A MIXED BAG BEFORE ENDING. SNOW RATIOS OF 10-13:1 EXPECTED WITH THIS SYSTEM SO A WET SNOW IS EXPECTED. ALL MODELS QUICKLY SHUT OFF THE QPF AFTER 06Z BUT THERE COULD BE SOME LIGHT LINGERING PRECIPITATION FOR A FEW MORE HOURS LATER SO WILL KEEP THE WINTER WEATHER ADVISORIES IN PLACE ENDING AT 12Z. TEMPERATURES WILL BE SLOWLY ON THE RISE THROUGHOUT THE NIGHT SO DID NOT USE A DIURNAL TOOL. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... WE BREAK OUT INTO THE WARM SECTOR WEDNESDAY MORNING AND A LIGHT WEST TO SOUTHWEST FLOW WILL DEVELOP IN THE LOWER LEVELS. H85 TEMPERATURES A BALMY 0 TO -5C SHOULD ALLOW TEMPERATURES TO WARM INTO THE 40S AS SOME SUN IS ALSO EXPECTED TO DEVELOP AS THE DAY WEARS ON AND A DRY SLOT MOVES THROUGH BY LATE MORNING. A DRY WEST TO NORTHWEST FLOW CONTINUES FOR WEDNESDAY NIGHT BUT SOME CLOUDS WILL BE NOTED ACROSS THE SOUTHERN HALF OF THE FORECAST AREA AS A COLD FRONT STALLS SOUTH OF NEW ENGLAND AND WE REMAIN ON THE NORTHERN PERIPHERY. USED A BLEND OF THE THE MODELS FOR TEMPERATURES WED AND WED NIGHT. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AN EXTENDED PERIOD OF RELATIVELY QUIET WEATHER IS EXPECTED THROUGH THE PERIOD. A SOUTHERN STREAM SHORT WAVE TROUGH THAT WILL BRING SNOW TO THE SOUTH OF OUR AREA ON THURS WILL BE SHUNTED OUT TO SEA BEFORE IT CAN BRING US ACCUMULATING SNOWFALL. A FEW FLURRIES POSSIBLE ACROSS SOUTHERNMOST ZONES THEN...BUT THAT/S ABOUT IT. OTHERWISE...BELOW NORMAL TEMPERATURES ARE EXPECTED WITH MAINLY DRY WEATHER. A WARM UP IS QUITE POSSIBLE EARLY NEXT WEEK. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...CONDITIONS LOWERING TO IFR TONIGHT IN SNOW. THEN IMPROVING TO VFR BY WED MORNING AND CONTINUING INTO WED NIGHT. LONG TERM...VFR CONDITIONS THURSDAY THROUGH SUNDAY. && .MARINE... SHORT TERM...AN INCREASING SOUTH TO SOUTHWEST FLOW TONIGHT WILL REACH SCA CRITERIA BY LATER THIS EVENING SO A SCA HAS BEEN ISSUED AND WILL CONTINUE INTO WED OVER THE OUTER WATERS INTO THE AFTERNOON. LONG TERM...SCA CONDITIONS ARE EXPECTED MUCH OF THE TIME THU THROUGH SUN. THE STRONGEST OF WHICH ARE EXPECTED ON SAT WHEN GUSTS MAY APPROACH LOW-END GALE FORCE AT TIMES. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MEZ007>009-012>014-018>028. NH...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR NHZ001>015. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR ANZ151-153. SMALL CRAFT ADVISORY UNTIL 3 PM EST WEDNESDAY FOR ANZ150-152- 154. && $$ UPDATE...HANES

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