Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 241751
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1251 PM EST SAT JAN 24 2015

.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE NORTHEAST COAST TODAY AND EXIT INTO
THE CANADIAN MARITIMES TONIGHT. AFTER A BRIEF BREAK SUNDAY
ANOTHER LOW PRESSURE SYSTEM MOVES OUT OF THE OHIO VALLEY AND
QUICKLY DEVELOPS WELL SOUTH OF NEW ENGLAND AND COULD END UP MOVING
FAR ENOUGH NORTH TO AFFECT OUR AREA EARLY NEXT WEEK.
THEREAFTER...COLD AND DRY WEATHER WILL MOVE ON IN.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230PM UPDATE... DUAL POL RADAR AND REPORTS INDICATE SOME SLEET
MIXING IN IN FAR SOUTHEASTERN NH. WHILE THE BACK END OF THE
PRECIPITATION IS MOVING INTO WESTERN NH, THE LOW ITSELF CONTINUES
TO DEEPEN AND TRACK TOWARDS THE BENCHMARK. IN MAINE HEAVIER SNOW
BANDS ARE BEGINNING TO DEVELOP AND WILL MOVE ONSHORE THIS
AFTERNOON. UPDATED TEMPS AND ADDED SLEET TO SE NH. HAVE INCREASED
SNOW TOTALS SLIGHTLY FOR THE MIDCOAST WHERE HEAVIEST SNOW IS MOST
LIKELY.

9AM UPDATE... SNOW HAS JUST
MOVED INTO GRAY AND FORECAST REMAINS ON TRACK. UPDATED TEMPS AND
DEW POINTS, WHICH ARE RUNNING A BIT COLDER. HAVE NOT CHANGED SNOW
TOTALS SIGNIFICANTLY. THE SNOW RATIO AND POTENTIAL FOR HEAVIER
SNOW BANDS TO DEVELOP THIS AFTERNOON REMAIN THE STICKING POINT FOR
THE FORECAST.

7 AM UPDATE...HAVE UPDATED THE FORECAST TO ACCOUNT FOR RELATIVELY
MINOR CHANGES IN POP...QPF...AND SNOW FOR THE MORNING HOURS BASED
ON LATEST TRENDS IN OBSERVATIONAL DATA. SNOW HAS REACHED SOUTHERN
NEW HAMPSHIRE AND WILL CONTINUE PROGRESSING NORTHWARD THIS MORNING.
NO CHANGES IN WARNINGS AND ADVISORIES AT THIS TIME.

PREVIOUSLY...

LOW PRESSURE CONTINUES OFF OF THE DELAWARE COAST AS OF 4 AM. A
PRETTY EXPANSIVE SNOW SHIELD IS GRADUALLY WORKING ITS WAY
NORTHWARD ACROSS CONNECTICUT. THIS WILL CONTINUE TO PUSH NORTHWARD
AND LIKELY ARRIVE ACROSS SOUTHERN ZONES AROUND SUNRISE IF NOT AN
HOUR OR TWO AFTERWARD.

OVERALL...WE HAVE NOT MADE SIGNIFICANT CHANGES TO THE FORECAST
SNOW AMOUNTS. ON AVERAGE...THE 00Z DETERMINISTIC AND ENSEMBLE
GUIDANCE HAS SHIFTED THE HEAVIEST SNOWFALL EASTWARD A BIT...AND
THE FORECAST REFLECTS THIS SLIGHT CHANGE. ONE THING IS FAIRLY
CERTAIN...AND THAT IS THERE WILL BE A VERY TIGHT SNOWFALL
GRADIENT ON THE WESTERN EDGE OF THE PRECIP SHIELD. ONE TOWN MAY
HAVE 5 OR 6 INCHES OF SNOW AND ANOTHER TOWN 10 MILES TO THE WEST
MAY END UP WITH NEXT TO NOTHING. HAVE TRIED TO ACCOUNT FOR THIS IN
THE FORECAST GRIDS BY INCORPORATING THE LATEST HRRR POPS FOR THE
FIRST 12-15 HOURS OF THE FORECAST. HOWEVER...THIS BACK EDGE WILL
LIKELY HAVE TO BE ADJUSTED TODAY BASED ON LATEST TRENDS. TODAY
WILL MOST CERTAINLY BE A CASE OF THE HAVES AND HAVE NOTS. RIGHT
NOW...IT APPEARS THAT OUR MOUNTAINS ZONES WILL REMAIN DRY OR
MOSTLY DRY.

THE HEAVIEST SNOWFALL IS EXPECTED TO OCCUR IN SOUTHEASTERN NH AND
COASTAL MAINE...WITH THE HEAVIEST SNOW FALLING THIS AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE SNOW WILL QUICKLY WIND DOWN THIS EVENING...AND MUCH OF THE
AREA WILL BE SNOW-FREE AFTER 00Z. A COLD FRONT WILL FOLLOW IN THE
WAKE OF THE LOW PRESSURE SYSTEM LATE TONIGHT AND SUNDAY MORNING
WITH A CHANCE OF SNOW SHOWERS AND A FEW SQUALLS IN THE MOUNTAINS.
COLD AND WINDY WEATHER IS EXPECTED DURING THE DAY ON SUNDAY AFTER
THE FRONTAL PASSAGE.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
ANY CURRENT WEAKNESS IN THE 500MB +PNA PATTERN WILL DISAPPEAR AS
THE FLOW BECOMES INCREASINGLY MORE AMPLIFIED AND BOTH UPSTREAM AND
DOWNSTREAM BLOCKING STRENGTHEN. THIS WILL PRODUCE PERSISTENT AND
FAIRLY DEEP TROUGHING OVER ERN NO AMERICA AND ALLOW COLD CORE OF
AIR TO DROP EQUATORWARD ACROSS HUDSON BAY DURING THE LATTER PART
OF WEEK. SO...COLD TO START THE EXTENDED...MAYBE A LITTLE WARM UP
TO AROUND NORMAL LATE WEEK...AND POTENTIALLY EVEN COLDER NEXT
WEEKEND.

SUNDAY NIGHT WITH BE COLD WITH ENOUGH WIND SUNDAY EVE TO PUSH
APPARENT TEMPS TO NEAR -20 IN THE N...AND BLO ZERO EVERYWHERE
ELSE...BUT SHOULD SEE WINDS DIMINISH OVERNIGHT. MONDAY WILL COLD
AS HIGH PRES PASSES TO THE N...WITH HIGHS MOSTLY IN THE 10-20 F
RANGE AND INCREASING CLOUDS LATE AS 500 MB TROUGH BEGINS TO CLOSE
OFF OVER THE MID-ATLANTIC OR CAROLINA COAST....DEPENDING ON
WHETHER YOU FOLLOW THE EURO OR GFS. THE EURO IS MUCH MORE
AGGRESSIVE WITH CLOSING OFF THE 500 MB LOW AND INTENSIFYING THE
SFC LOW IN VICINITY OF THE 40/70 BENCHMARK...ENOUGH TO SPREAD
SOME ACCUMULATING SNOW INTO THE CWA. THE GFS KEEPS THE SFC FLOW
FURTHER E AND INTENSIFIES LATER...WHICH WOULD MEAN LESS SNOW AND
THE BETTER CHANCE FOR ACCUMULATIONS WOULD BE IN THE ERN ZONES.
GIVEN THE SOLID PERFORMANCE OF THE EURO LEANING IN THAT DIRECTION
AND HAVE SPREAD CHC POPS ACROSS ENTIRE CWA ON TUE. STILL IT LOOKS
COLD...WITH TEMPS IN THE SINGLE DIGITS TO TEENS...SO ANY SNOW WILL
HAVE A HIGH SNOW TO LIQUID WATER RATIO.

SHOULD SEE NW WINDS PICK UP BEHIND THIS SYSTEM WITH A REINFORCING
SHOT OF COLD AIR AND HIGHS ON WED LIMITED TO THE TEENS TO AROUND
20 AGAIN. AS THAT INTENSE LOW HEADS NE THROUGH THE NEWFOUNDLAND AND
LABRADOR THUS...WILL SEE SOME RIDGING DEVELOPING UPSTREAM OVER
NH/ME...AND A BIT OF WARM UP IS EXPECTED ON THU INTO FRI...BEFORE
ANOTHER DEEPENING TROUGH APPROACHES AND BRINGS THE COLD BACK BY
NEXT WEEKEND.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
SHORT TERM...VFR CONDITIONS ACROSS THE FAR INTERIOR TODAY...WITH
SOUTHERN NH AND COASTAL MAINE BECOMING IFR OR LOWER IN SNOW BY
AFTERNOON. VFR CONDITIONS RETURN TONIGHT AND LAST THROUGH SUNDAY.

LONG TERM...VFR EXPECTED SUN NIGHT INTO MON EVE. POSSIBLE FLIGHT
RESTRICTIONS IN SNOW LATE MON INTO TUE EVENING...WITH A RETURN TO
VFR BY WED...ALTHOUGH GUSTY NW WINDS ARE POSSIBLE.

&&

.MARINE...
SHORT TERM...GALES REMAIN UP FOR MOST WATERS AS COASTAL STORM
MAKES ITS CLOSEST APPROACH LATE THIS AFTERNOON AND TONIGHT. STRONG
SCA LIKELY ON SUNDAY IN THE WAKE OF THE LOW AND ANOTHER COLD
FRONTAL PASSAGE.

LONG TERM...WINDS DIMINISH SUN NIGHT...ALTHOUGH LIGHT FREEZING
SPRAY IS A GOOD BET SUN NIGHT INTO MON NIGHT...AND PERHAPS RIGHT
THROUGH TUE NIGHT. SCA POSSIBLE LATE MON NIGHT...WITH A CHANCE OF
GALES TUE INTO TUE NIGHT AS COASTAL LOW TRACKS JUST TO THE S AND
E.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
     MEZ018>021.
     WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MEZ022>028.
NH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
     NHZ008-009-011-015.
     WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR NHZ010-
     012>014.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EST
     SUNDAY FOR ANZ153.
     GALE WARNING FROM 5 PM THIS AFTERNOON TO 3 AM EST SUNDAY FOR
     ANZ150>152-154.

&&

$$
SYNOPSIS...
NEAR TERM...CURTIS
SHORT TERM...EKSTER
LONG TERM...CEMPA
AVIATION...
MARINE...



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