Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 221347 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME ISSUED BY NATIONAL WEATHER SERVICE CARIBOU ME 947 AM EDT WED APR 22 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL SLOWLY CROSS THE REGION TONIGHT. LOW PRESSURE WILL MEANDER OVER SOUTHERN QUEBEC AND NORTHERN MAINE THIS WEEKEND AND INTO EARLY NEXT WEEK KEEPING SHOWERY WEATHER IN THE FORECAST. && .NEAR TERM /THROUGH TONIGHT/... 945 AM UPDATE... SLOWED DOWN THE ONSET OF SHOWERS AND INCREASED CLOUDCOVER, AS LATEST MODELS AND OBS HAVE THINGS MOVING IN A BIT SLOWER, WITH SHOWERS NOT ARRIVING IN NEW HAMPSHIRE UNTIL ABOUT MID AFTERNOON, AND WESTERN MAINE AROUND EARLY EVENING. OTHERWISE NO CHANGES. PREVIOUS DISCUSSION... AHEAD OF THE APPROACHING BROAD UPPER TROUGH FROM THE GREAT LAKES THERE WILL BE ANOTHER SHORT WAVE THAT WILL ROTATE THROUGH THE BASE OF THE TROUGH AND THEN NORTHEAST TOWARD NORTHERN NEW ENGLAND LATER TODAY. ASSOCIATED WITH THIS UPPER TROUGH WILL BE A SURFACE COLD FRONT. CLOUDS WILL BE ON THE INCREASE THIS MORNING AND SCATTERED SHOWERS WILL DEVELOP BY AFTERNOON FROM WEST TO EAST AHEAD OF THIS TROUGH. WINDS WILL INCREASE FROM THE SOUTH THIS AFTERNOON. OVERALL STAYED CLOSE TO THE PRIOR FORECASTERS GRIDS FOR CONTINUITY AS IT AGREES WITH CURRENT GUIDANCE AND TRENDS. ONLY MINOR ADJUSTMENTS WERE NEEDED. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... TONIGHT THE UPPER SHORT WAVE ROTATES NORTHEAST OUT OF THE BASE OF THE APPROACHING BROAD UPPER TROUGH AND THEN ACROSS NORTHERN NEW ENGLAND WITH SHOWERS. HIGHEST QPF AMOUNTS WILL BE ACROSS THE MOUNTAINS WHERE .50-1.0 INCHES OF PRECIPITATION CAN BE EXPECTED WHILE OVER SOUTHERN AREAS ONLY .25-50 INCHES ARE EXPECTED. IN AREAS ABOVE 2500 FEET IN THE MOUNTAINS SOME ACCUMULATIONS OF SNOW CAN BE EXPECTED. THE SYSTEM QUICKLY EXITS THE REGION BY THURSDAY MORNING ALTHOUGH THE BROAD UPPER TROUGH WILL BE SETTLING OVER THE REGION THURSDAY WITH A COLD POOL OF AIR ALOFT WITH THE CYCLONIC FLOW SO INSTABILITY SHOWERS CAN ONCE AGAIN PERK UP ESPECIALLY IN THE AFTERNOON WITH THE DIURNAL HEATING AND STEEPENING LAPSE RATES. WITH THE LOW FREEZING LEVEL CAN`T RULE OUT SOME PEA SIZE HAIL IN SOME OF THE SHOWERS. STAYED CLOSE TO A BLEND OF THE MODEL GUIDANCE FOR MAX TEMPERATURES THURSDAY. && .LONG TERM /FRIDAY THROUGH TUESDAY/... UPPER LOW GETS CUT OFF FROM THE FLOW AND STAYS STUCK OVER NORTHERN NEW ENGLAND AND SOUTHEAST CANADA FOR MOST OF THE NEXT SEVEN DAYS. THIS MAKES THE FORECAST A PERSISTENTLY SHOWERY ONE. WITH THE COLD UPPER LOW OVERHEAD... EXPECT DIURNAL INSTABILITY TO DRIVE SHOWERS DURING THE AFTERNOON EACH DAY WHILE SHOWER ACTIVITY DISSIPATES A BIT AT NIGHT. INITIALLY THE COLD AIR ALOFT WILL BE COLD ENOUGH TO PRODUCE SNOW SHOWERS DEPENDING ON LOCAL SURFACE TEMPERATURES PRIMARILY THURSDAY NIGHT AND FRIDAY. WITH TIME, THOUGH, THE LOW WILL GRADUALLY FILL AND WARM. GRAUPEL OR SMALL HAIL WILL BE POSSIBLE IN MANY OF THE SHOWERS EACH AFTERNOON AS WEAK INSTABILITY EXISTS ABOVE THE VERY LOW FREEZING LEVEL. TEMPERATURES WILL BE FAIRLY CONSTANT IN THE 50S DURING THE DAY AND IN THE 30S AT NIGHT. BUT AS THE LOW GRADUALLY WEAKENS AND WARMS... EXPECT TEMPERATURES TO ALSO GRADUALLY WARM THOUGH STILL REMAINING NEAR OR BELOW NORMAL FOR THIS TIME OF YEAR. BY NEXT WEDNESDAY MODELS ARE INDICATING THE UPPER LOW MAY FINALLY WEAKEN AND DRIFT EAST. BUT IT MAY ONLY BE REPLACED BY ANOTHER ONE FOR THE END OF NEXT WEEK. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...VFR CONDITIONS INTO THIS AFTERNOON WILL LOWER TO MVFR CONDITIONS LATER TODAY AND TONIGHT IN SCATTERED RAIN SHOWERS. VFR TO MVFR CONDITIONS ON THURSDAY AS RESIDUAL MOISTURE AND INSTABILITY LINGERS WITH SCATTERED SHOWERS. LONG TERM...GENERALLY VFR WITH LIGHT WINDS EXPECTED THROUGH THE WEEKEND. HOWEVER... PRIMARILY AFTERNOON SHOWERS COULD BRIEFLY BRING MVFR CONDITIONS AND EVEN SOME SMALL HAIL. && .MARINE... SHORT TERM...WILL CONTINUE THE SCA DUE TO HAZARDOUS SEAS THROUGH TONIGHT. IT WILL LIKELY NEED TO BE EXTENDED FURTHER INTO THURSDAY OVER THE OUTER WATERS. SEAS WILL BE VERY SLOW TO SUBSIDE. LONG TERM...WITH WEAK LOW PRESSURE LINGERING NEARBY EXPECT FAIRLY LIGHT WINDS THROUGH THE WEEKEND. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT THURSDAY FOR ANZ150>154. && $$ NEAR TERM...FOISY

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