Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 262255 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 655 PM EDT THU MAR 26 2015 .SYNOPSIS... LOW PRESSURE WILL MOVE ACROSS SOUTHERN NEW ENGLAND THIS EVENING. HIGH PRESSURE WILL THEN GRADUALLY BUILD INTO THE REGION FRIDAY THROUGH SUNDAY. LOW PRESSURE WILL MOVE EASTWARD ACROSS QUEBEC ON MONDAY AND WILL DRAG A COLD FRONT ACROSS OUR REGION MONDAY NIGHT. QUICK MOVING LOW PRESSURE CROSSES THE AREA TUESDAY NIGHT INTO WEDNESDAY AND AGAIN ON THURSDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... UPDATE... DENSE FOG HAS BECOME WIDESPREAD ACROSS MUCH OF SOUTHERN MAINE AND SOUTHERN NEW HAMPSHIRE. HAVE ISSUED A DENSE FOG ADVISORY UNTIL 11 PM. NORTHERLY WINDS SHOULD ADVECT SLIGHTLY DRIER AIR INTO THE REGION AND MIX OUT SOME OF THE FOG AT THAT TIME. AREAS OF RAIN AND RAIN SHOWERS CONTINUE TO MOVE RAPIDLY TO THE NORTHEAST IN A STRONG GRADIENT FLOW ALOFT. THE CHANGEOVER TO SNOW WILL CONTINUE THIS EVENING ACROSS THE HIGHER TERRAIN OF THE NORTHERN MOUNTAINS. SNOW WILL MIX IN OVER CENTRAL AREAS AS WELL BY AROUND 08Z...BUT THIS IS MAINLY AN ELEVATION BASED SNOW EVENT. PREV DISC...A POSITIVE TILTED AND PROGRESSIVE LONG WAVE TROUGH WILL MOVE ACROSS NEW ENGLAND TONIGHT. AHEAD OF IT WARM AIR AT ALL LEVELS SPREAD ACROSS THE REGION DURING THE AFTERNOON. A WEAK WAVE WILL DEVELOP ALONG THE BASE OF THIS TROUGH AND MOVE ACROSS SOUTHERN NEW ENGLAND TONIGHT. TO THE NORTH OF THIS WAVE OVERUNNING RAIN IS EXPECTED ACROSS THE REGION WITH SNOW OVER THE HIGHER ELEVATIONS. QPF AMOUNTS WILL RANGE FROM .50-.75 INCHES WHICH SHOULD NOT POSE ANY FLOODING PROBLEMS. OVERNIGHT COLD AIR ADVECTION GRADUALLY SPREADS SOUTH ALLOWING THE RAIN TO CHANGE TO SNOW IN THE LOWER ELEVATIONS IN THE MOUNTAINS AND FOOTHILLS WITH SOME LIGHT ACCUMULATIONS EXPECTED BY MORNING. OVER SOUTHERN AREAS THE PRECIPITATION WILL PROBABLY END BEFORE ENOUGH COLD AIR SPREADS SOUTH TO CAUSE ANY CHANGEOVER. USED A BLEND OF THE MODELS FOR QPF AND OVERNIGHT LOWS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY AND FRIDAY NIGHT THE BASE OF THE UPPER TROUGH SLOWLY PROGRESSES EAST BUT WILL HAVE PLENTY OF CLOUD COVER LINGERING ACROSS THE AREA. SOME PARTIAL CLEARING MAY OCCUR OVER NORTHERN AREAS WHILE SOUTHERN AREAS REMAIN MOSTLY CLOUDY. TEMPERATURES WILL BE NEAR SEASONAL ON FRIDAY AND FRIDAY NIGHT AS A BLEND OF THE MODEL GUIDANCE SUGGESTS. && .LONG TERM /SATURDAY THROUGH THURSDAY/... THE BULK OF THE PRECIPITATION ASSOCIATED WITH A DEEPENING LOW PRESSURE WAVE ALONG THE OFFSHORE FRONT WILL REMAIN IN THE GULF OF MAINE ON SATURDAY... HOWEVER COASTAL SECTIONS OF NH AND MAINE WILL HAVE A SLIGHT CHANCE OF SHOWERS THROUGH THE DAY. SKIES WILL BE CLOUDY CONTRIBUTING TO A SMALL DIURNAL RISE INTO THE MID 30S OVER THE COASTAL PLAIN. FARTHER NORTH MID TO UPPER 20S FOR HIGHS IS MORE LIKELY. SKIES BEGIN TO CLEAR OUT NORTH TO SOUTH OVERNIGHT AND COLDER AIR FILTERS IN MAKING FOR A CHILLY NIGHT. SPRAWLING HIGH PRESSURE COVERING MOST OF THE NATION MOVES INTO THE SOUTHEASTERN STATES BRINGING A NORTHERLY AND THEN EVENTUALLY WESTERLY WIND GRADIENT TO NEW ENGLAND. SURFACE TEMPERATURES FOR MUCH OF THE AREA RESPOND TO THIS DOWNSLOPING COMPONENT AS WELL AS SYNOPTIC SCALE WARMING RESULT IN A WARMING TREND SUNDAY. THE NEXT CHANCE OF PRECIPITATION ARRIVES MONDAY AS WARM AIR ADVECTION RAMPS UP AHEAD OF A DEEPENING SURFACE CYCLONE WELL TO OUR NORTH. THE LITTLE BIT OF COLD AIR ASSOCIATED WITH THIS SYSTEM SHOULD MOSTLY DAM NORTH OF THE MOUNTAINS AND MODERATE WITHIN 12-18 HOURS. OVER THE COASTAL PLAIN WE WILL CONTINUE TO SEE READINGS REACH THE 40S IN THE AFTERNOON WITH THE OCCASIONAL 50 DEGREE READING TUESDAY AND WEDNESDAY. A WEAK WAVE TRANSPORTS QUICK MOVING LOW PRESSURE ACROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY BEFORE MOVING IT OUT TO SEA. THIS WILL BRING CHANCE PRECIPITATION TO THE REGION... AT THIS TIME IT LOOKS LIKE IT WOULD BRING MIXED PTYPE. LASTLY MODELS FOLLOW THIS WITH A STRONGER SYSTEM FOR EASTER WEEKEND WHICH MAY CAUSE HAVE TRAVEL IMPLICATIONS. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... SHORT TERM...IFR CONDITIONS ARE EXPECTED LATER THIS AFTERNOON AND TONIGHT IN RAIN...WITH SNOW AT HIGHER ELEVATIONS ACROSS NORTHERN NH AND THE WESTERN ME MOUNTAINS. VFR CONDITIONS WILL GRADUALLY RETURN ON FRIDAY AND CONTINUE FRIDAY NIGHT. LONG TERM...SCATTERED MVFR CONDITIONS POSSIBLE IN MOUNTAIN AND COASTAL SNOW SHOWERS SATURDAY. SCATTERED MVFR CONDITIONS POSSIBLE MONDAY IN RAIN AND SNOW SHOWERS AS A COLD FRONT CROSSES FROM NORTH TO SOUTH. && .MARINE... SHORT TERM... A SCA WILL BE REQUIRED OVER THE OUTER WATERS DUE TO EXPECTED BUILDING SEAS LATER THIS EVENING AND CONTINUING THROUGH FRIDAY. WINDS WILL REMAIN WELL BELOW SCA CRITERIA THROUGH FRIDAY NIGHT. LONG TERM...WAVES REMAIN HIGH ON SATURDAY BEFORE DROPPING BY SUNDAY MORNING. SEAS AND WINDS INCREASE BRIEFLY MONDAY MORNING TO SCA CRITERIA AHEAD OF A COLD FRONTAL PASSAGE. && .HYDROLOGY... WARMER WEATHER AND ONE HALF TO THREE QUARTERS OF AN INCH OF RAIN WILL INDUCE SOME RUNOFF THIS EVENING. WE WILL LIKELY SEE SOME RISES ON SOUTHERN RIVERS. AT THE CURRENT TIME WE DO NOT EXPECT ANY BIG ISSUES. PERHAPS SOME MINOR POOR DRAINAGE FLOODING THIS EVENING. HOWEVER...WILL HAVE TO MONITOR FOR ICE MOVEMENT ON RIVERS AND STREAMS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...DENSE FOG ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MEZ018>028. NH...DENSE FOG ADVISORY UNTIL 11 PM EDT THIS EVENING FOR NHZ005- 007>015. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ150-152-154. && $$

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