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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