Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 301623 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1123 AM EST FRI JAN 30 2015 .SYNOPSIS... INITIALLY WEAK LOW PRESSURE WILL TRACK EASTWARD FROM THE GREAT LAKES AND REACH THE NEW ENGLAND COAST TODAY. THIS LOW WILL THEN INTENSIFY RAPIDLY AS IT MOVES NORTHEAST TO THE CANADIAN MARITIMES. HIGH PRESSURE FOLLOWS OVER THE WEEKEND...WITH ANOTHER SYSTEM TRACKING SOUTH OF NEW ENGLAND ON MONDAY. HIGH PRESSURE WILL FOLLOW MIDWEEK. LOW PRESSURE WILL PASS BY TO OUR SOUTH ON THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE... HAVE UPDATED GRIDS. MIXED SNOW...SLEET AND FREEZING RAIN HAS DEVELOPED OVER SOUTHERN PORTIONS OF THE FORECAST AREA. EXPECT THIS TREND TO CONTINUE WHILE THE PRECIPITATION IS RELATIVELY LIGHT. DURING THE MID AFTERNOON HOURS...EXPECT THE DEVELOPING LOW AND DYNAMICS TO KICK IN. THIS SHOULD TRANSITION MIXED PRECIPITATION BACK TO SNOW IN MOST AREAS. AREAS ALONG THE MIDCOAST SUCH AS ROCKLAND MAY TAKE A LITTLE LONGER TO CHANGEOVER. MAY NEED TO ADJUST SNOWFALL ACCUMULATIONS DOWNWARDS OVER SOUTHERN AREAS DUE TO THE MIX. PREV DISC... 630 AM...ONLY MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS FOR THIS ESTF UPDATE TO REFLECT THE CURRENT MESONET. OTHERWISE...MONITORING THE PRESSURE FALLS JUST OFFSHORE AND AWAITING SECONDARY LOW DEVELOPMENT...AND ULTIMATELY THE LOCATION OF THE SURFACE TROUGH AND AXIS OF HEAVIER SNOWS. PREV DISC... AT 07Z...A 1007 MILLIBAR LOW WAS VICINITY OF MONTREAL /CYUL/ WITH A TRAILING FRONT THROUGH THE MID ATLANTIC REGION. GOES WATER VAPOR IMAGERY SHOWED THE ASSOCIATED SHORTWAVE OVER THE UPPER GREAT LAKES. THE IMPULSE WILL DIG SOUTHEAST AND GO NEGATIVE TILT BY LATE TODAY. BANDS OF LIGHT SNOW WERE BREAKING OUT ACROSS THE REGION ON NATIONAL WEATHER SERVICE DOPPLER RADAR MOSAIC IN RESPONSE TO THE APPROACHING SYSTEM. THREE HOUR SURFACE PRESSURE FALLS ON THE ORDER OF 3 MILLIBARS WERE OBSERVED OVER SOUTHEAST NEW ENGLAND AND EXPECT THE SECONDARY LOW TO DEVELOP SOUTHEAST OF CAPE COD LATE TODAY WITH SURFACE TROUGH EXTENDING NORTHWARD INTO THE FORECAST AREA. THE SNOW WILL BECOME HEAVY AT TIMES LATER TODAY ALONG AND TO THE EAST OF THIS BOUNDARY. NO SIGNIFICANT CHANGE TO MODEL QPF FORECASTS...AND THE CURRENT WINTER WEATHER HEADLINES REMAIN IN PLACE WITH THE NEW FORECAST PACKAGE THIS MORNING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... THE LOW WILL QUICKLY DEEPEN OFFSHORE TONIGHT AS THE UPPER SYSTEM CLOSES OFF...WITH SNOW CONTINUING HEAVY AT TIMES MAINLY ACROSS MAINE AND EXTREME EASTERN NEW HAMPSHIRE. GUSTY NORTHWEST WINDS WILL DEVELOP ACROSS THE AREA TONIGHT...DRAGGING COLDER AIR BACK INTO THE AREA AND PRODUCING BLOWING AND DRIFTING SNOW. THE SNOW WILL TAPER FROM SOUTHWEST TO NORTHEAST ACROSS THE AREA OVERNIGHT AND SATURDAY MORNING AS THE SYSTEM PULLS FURTHER OFFSHORE. WE`LL SEE SOME CLEARING OVER MUCH OF NEW HAMPSHIRE AND SOUTHWEST MAINE BY AFTERNOON...WHILE CLOUDS LINGER OVER FAR EASTERN SECTIONS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... CANADIAN HIGH PRESSURE BUILDS INTO THE AREA FOR SATURDAY NIGHT AND SUNDAY WITH A RETURN TO FAIR WEATHER BUT VERY COLD TEMPERATURES. MODELS ARE IN AGREEMENT THAT A PROGRESSIVE UPPER SHORT WAVE WILL MOVE OFF THE MID ATLANTIC COAST MONDAY THAT WILL DEVELOP A COASTAL SURFACE LOW THAT WILL PASS WELL SOUTH OF NEW ENGLAND. SOUTHERN AREAS OF MAINE AND NEW HAMPSHIRE WILL BE ON THE NORTHERN FRINGE OF THE SYSTEM AND SOME LIGHT SNOW IS POSSIBLE MONDAY. THE SYSTEM QUICKLY MOVES WELL OUT TO SEA TO THE EAST MONDAY NIGHT. ANOTHER ARCTIC HIGH WILL BUILD ACROSS THE AREA FOR MIDWEEK WITH TEMPERATURES BELOW NORMAL. ON THURSDAY A WARMER SOUTHWEST FLOW WILL DEVELOP AS ANOTHER TROUGH APPROACHED FROM THE WEST. OVERALL STAYED VERY CLOSE TO THE SUPERBLEND MODEL FOR THE OUTLOOK PERIOD FOR BOTH POPS AND TEMPERATURES. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... SHORT TERM...IFR OR LOWER AT TIMES IN SN AND LOW CIGS...PERSISTING INTO TONIGHT. SOME IMPROVEMENT MAY BE POSSIBLE LATE FRI NIGHT IN KLEB/KHIE/KHIE...BUT WILL HAVE TO WAIT UNTIL SAT MOST EVERYWHERE ELSE. NW WINDS TONIGHT AND SAT WILL GUST UP TO 30 KT. LONG TERM...VFR SATURDAY NIGHT AND SUNDAY. A STORM PASSING TO THE PASSING TO THE SOUTH MONDAY MAY PRODUCE SOME MVFR OR EVEN IFR CONDITIONS OVER SOUTHERN AREAS ON MONDAY. && .MARINE... SHORT TERM...WINDS AND SEAS GRADUALLY INCREASE LATER TODAY...WITH GALES DEVELOPING TONIGHT THROUGH SATURDAY BEHIND THE DEEPENING OCEAN LOW. A FEW GUSTS TO NEAR STORM ARE POSSIBLE EARLY SATURDAY OVER OUR EASTERN WATERS. LONG TERM...GALES WILL LIKELY CONTINUE INTO SATURDAY NIGHT. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER STORM WARNING UNTIL 6 AM EST SATURDAY FOR MEZ007-008- 012-013-018>020-023-024. WINTER STORM WARNING UNTIL 10 AM EST SATURDAY FOR MEZ009-014- 021-022-025>028. NH...WINTER STORM WARNING UNTIL 6 AM EST SATURDAY FOR NHZ001-002- 004-006-009-010-013-014. WINTER WEATHER ADVISORY UNTIL 6 AM EST SATURDAY FOR NHZ003-005- 007-008-011-012-015. MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST SUNDAY FOR ANZ150>154. && $$

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