Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 302254 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 550 PM EST FRI JAN 30 2015 .SYNOPSIS... LOW PRESSURE WILL 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...POTENTIALLY BRINGING SOME SNOW TO THE REGION. HIGH PRESSURE WILL FOLLOW MIDWEEK. LOW PRESSURE WILL PASS BY TO OUR SOUTH ON THURSDAY. && .NEAR TERM /TONIGHT/... 6 PM UPDATE...HAVE UPDATED THE FORECAST TO ADJUST POPS AND SNOWFALL FOR THE EVENING HOURS BASED ON LATEST HI-RES MODELS AND RADAR IMAGERY. THE HEAVIEST SNOW WILL CONTINUE TO BE ACROSS CENTRAL AND MID COAST MAINE. FURTHER SOUTH...ONLY LIGHT ADDITIONAL ACCUMULATIONS ARE EXPECTED. WINDS WILL PICK UP AND BECOME GUSTY THIS EVENING...POSSIBLY ALLOWING FOR LOCALIZED WHITEOUT CONDITIONS IN BLOWING SNOW. PREVIOUSLY... VERY INTERESTING NIGHT UNFOLDING AS LOWER PRESSURE DEVELOPS JUST SOUTHEAST OUTSIDE THE GULF OF MAINE BEFORE RAPIDLY INTENSIFYING AND BRIEFLY STALLING WEST SOUTHWEST OF YARMOUTH NOVA SCOTIA. INITIAL WARM AIR ADVECTION SNOWS OUT AHEAD OF A TROUGH WILL COME TO AN END THIS EVENING. THIS WILL BE FOLLOWED BY A STRENGTHENING NORTHEAST FLOW AND SNOW WRAPPING AROUND THE PERIPHERY OF THE INTENSIFYING SYSTEM. 12Z MESOSCALE MODEL SUITE HAS BACKED OFF ON PRECIPITATION SOMEWHAT FOR THIS SYSTEM. HOWEVER...WITH ACCUMULATING SNOWS CONTINUING THIS AFTERNOON ACROSS THE FORECAST AREA...HAVE LEFT WARNINGS AND ADVISORIES INTACT FOR ALL AREAS. HAVE NUDGED SNOWFALL FORECAST DOWNWARDS SLIGHTLY HOWEVER...MAINLY FOR WESTERN PORTIONS OF THE FORECAST AREA IN NEW HAMPSHIRE AND ADJACENT WESTERN MAINE. THE SURFACE LOW WILL CONTINUE TO TAKE OFF AND INTENSIFY THIS EVENING. AS OF LATE THIS AFTERNOON...A DEEPENING SYSTEM WAS LOCATED NEAR BUOY 44008...MOVING EAST. SNOW WILL INCREASE IN INTENSITY...ESPECIALLY OVER EASTERN PORTIONS OF OUR FORECAST AREA. COLD AIR WILL BEGIN TO RUSH INTO THE REGION FROM CANADA...DROPPING WIND CHILLS VALUES AS WELL. ACROSS NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA...WIND CHILL ADVISORIES HAVE BEEN HOISTED. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... SYSTEM EVOLVES INTO A FULL STORM STATUS TO OUR EAST ON SATURDAY...WRAPPING PRECIPITATION BACK INTO EASTERN PORTIONS OF OUR FORECAST AREA DURING THE MORNING HOURS. EXPECT ACCUMULATING SNOW TO CONTINUE IN AND NEAR THE PENOBSCOT RIVER VALLEY. SYSTEM DEPARTS SATURDAY AFTERNOON AND SATURDAY NIGHT. THIS WILL LEAVE THE REGION UNDER CLEARING SKIES AND VERY LOW WIND CHILL TEMPERATURES. WIND CHILL WARNINGS MAY BE REQUIRED FOR SATURDAY NIGHT FOR A GOOD PORTION OF OUR REGION WITH ADVISORIES ELSEWHERE. HIGH CLOUDS WILL ALREADY BE POURING INTO THE REGION LATE SATURDAY NIGHT WITH THE APPROACH OF YET ANOTHER SYSTEM THAT WILL PASS BY TO OUR SOUTH IN THE LONG RANGE PORTION OF THE FORECAST. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... 500 MB HEMISPHERIC PATTERN GENERALLY UNCHANGED WITH PERSISTENT RIDGE ON THE W COAST ITO ALASKA AND BROAD TROUGHING OVER ERN NOAM. THE ONE ITEM OF INTEREST IN THE EXTENDED IS THE "SUPER" BLOCK THAT DEVELOPS UPSTREAM OF THE RIDGE OVER THE PACIFIC AND BASICALLY ALLOWS NOAM CONNECTION WITH SIBERIAN AIR...AND THUS WAVES OF COLDER AND COLDER AIR SPILL INTO THE TROUGH OVER THE NE CONUS THRU THE MID-LATE NEXT WEEK...WITH...PERHAPS SOME MODERATION BY NEXT WEEKEND AS THE UPSTREAM BLOCKING BREAKS DOWN. AS FOR PRECIPITATION...IT WILL ALL BE SNOW. WE ARE WATCHING A 500 MB WAVE ROTATING AROUND THE BASE OF THE LARGE SCALE TROUGH OVER ERN NOAM...WHICH WILL TILT SLIGHTLY NEGATIVE AND DIG...BUT MOVE FAMILY QUICKLY. MOST MODELS IN AGREEMENT THAT THE STORM STAYS FAR ENOUGH S TO ONLY GRAZE THE SRN CWA WITH SOME LIGHT SNOW ON MONDAY...ALTHOUGH NAM12...WHICH HITS THIS SYSTEM AT THE END OF ITS 12Z RUN IS MORE AGGRESSIVE DEVELOPING THE SYSTEM AND COULD PUSH SNOW INTO THE AREA. LEANING TOWARD THE SRN SOLNS...BUT CONFIDENCE IS NOT HIGH AT THIS TIME. ALSO GIVEN COLD AIR MAS TO OUR N IF THE SYSTEM STAYS WELL S...WILL IT TAP INTO VERY COLD FROM OUR N AND HIGHS WILL BE LIMITED TO SINGLE NUMBERS INLAND AND 10-15F ON THE COAST. BEHIND THIS SYSTEM THE STEADY FLOW OF COLD AIR INTO THE LARGE SCALE TROUGH CONTINUES ON TUE...WITH PERHAPS A BIT OF A WARM UP ON WED. A CLIPPER COMES THROUGH ON THUS WITH A CHANCE OF SNOW...FOLLOWED BY ANOTHER SURGE OF VERY COLD AIR AT THE END OF THE WEEK. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... SHORT TERM... IFR OR LOWER AT TIMES IN SN AND LOW CIGS...PERSISTING INTO EARLY SATURDAY MORNING. SOME IMPROVEMENT MAY BE POSSIBLE LATE FRI NIGHT IN KLEB...KBML AND KHIE...BUT WILL HAVE TO WAIT UNTIL SAT MOST EVERYWHERE ELSE. NW WINDS TONIGHT AND SAT WILL GUST UP TO 35 KT. LONG TERM...HIGH CHANCE OF FLIGHT RESTRICTIONS AT COASTAL TERMINALS LATE SUNDAY INTO MONDAY IN LIGHT SNOW. && .MARINE... SHORT TERM...GALES WILL DEVELOP TONIGHT THROUGH SATURDAY BEHIND THE DEEPENING OCEAN LOW. A FEW GUSTS TO NEAR STORM ARE POSSIBLE EARLY SATURDAY OVER OUR EASTERN WATERS. FREEZING SPRAY WILL BECOME AN ISSUE SATURDAY...LASTING INTO SUNDAY. HAVE ISSUED FREEZING SPRAY ADVISORIES FOR THIS PERIOD. LONG TERM...SCA WILL LKLY BE NEEDED MONDAY AFTERNOON INTO TUESDAY...WITH THE POTENTIAL FOR GALES. && .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. WIND CHILL ADVISORY FROM 2 AM TO 9 AM EST SATURDAY FOR MEZ007>009. NH...WINTER STORM WARNING UNTIL 6 AM EST SATURDAY FOR NHZ001-002- 004-006-009-010-013-014. WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR NHZ003-005-007-008. WIND CHILL ADVISORY FROM 2 AM TO 9 AM EST SATURDAY FOR NHZ001>003-005-007-011. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NHZ011- 012-015. MARINE...FREEZING SPRAY ADVISORY FROM 6 AM SATURDAY TO 5 PM EST SUNDAY FOR ANZ150>154. GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST SUNDAY FOR ANZ150>154. && $$ NEAR TERM UPDATE...MLE

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