Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KGYX 041425 AAA
AFDGYX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GRAY ME
925 AM EST THU FEB 4 2016

.SYNOPSIS...
A COLD FRONT WILL EXIT THE COAST THIS MORNING BEFORE STALLING TO
OUR EAST. COLDER AIR WILL GRADUALLY FILTER INTO THE REGION BEHIND
THIS FRONTAL SYSTEM LATER TODAY AND TONIGHT. LOW PRESSURE WILL
TRACK NORTHEAST ALONG THIS STALLED FRONTAL BOUNDARY EARLY FRIDAY.
THE WESTERN EDGE OF THE SNOW SHIELD WITH THIS SYSTEM COULD BRUSH
COASTAL SECTIONS WITH SOME LIGHT SNOW ACCUMULATION. A RIDGE OF
HIGH PRESSURE FOLLOWS FOR FRIDAY NIGHT INTO SATURDAY. A COLD
FRONT WILL CROSS THE REGION SUNDAY. THERE IS A CHANCE THAT A
COASTAL STORM AFFECTS THE REGION EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
UPDATE...A FEW ADJUSTMENTS TO THE FORECAST AS A WEAK S/WV TROF
RIDES ALONG THE BACKSIDE OF STALLING FRONTAL BOUNDARY OFFSHORE.
THIS IS PRODUCING AN AREA OF SHOWERS THAT IS MOVING NEWD ALONG THE
COAST OF WRN ME. HAVE UPPED POP NEAR THE COAST THRU MID
MORNING...WHEN FRONT WILL GRADUALLY SHIFT E AND DRY THINGS OUT.

PREV DISC...
AT 07Z...A 997 MILLIBAR LOW WAS OVER QUEBEC WITH A TRAILING COLD
FRONT THROUGH WESTERN NEW ENGLAND AND A SECONDARY COLD FRONT
THROUGH THE UPPER GREAT LAKES. FOR TODAY...THE FRONT WILL RACE
EAST AND EXIT THE COAST ALONG WITH ANY LINGERING SHOWER ACTIVITY
BY MID MORNING. WE`LL SEE QUICK CHANGES IN SURFACE TEMPERATURES
AHEAD OF THIS BOUNDARY AS WE MIX OUT NEAR THE SURFACE. WE`LL SEE
SOME SUNNY BREAKS BEHIND THE COLD FRONT TODAY AND WITH THE COLD
AIR TAKING ITS TIME FILTERING IN THE RECORD HIGH AT PORTLAND / 50F
SET IN 1991/ AND CONCORD 61F SET IN 1991/ COULD BE TIED OR BROKEN.
IN EITHER EVENT...IT`LL BE ANOTHER DAY WITH HIGH TEMPERATURES
A GOOD 20 TO 25 DEGREES ABOVE AVERAGE. THE FRONT WILL HANG UP JUST
OFFSHORE LATER TODAY AS IT BECOMES NEARLY PARALLEL TO THE UPPER
FLOW.

&&

.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM FRIDAY/...
AN IMPULSE WILL RACE NORTHEAST FROM THE GULF STATES AND EXIT THE
MID ATLANTIC TO OUR SOUTH ON FRIDAY. THIS SHORTWAVE WILL DEVELOP
A SURFACE LOW ON THE STALLED OFFSHORE FRONT WHICH WILL TRACK
NORTHEAST TONIGHT AND FRIDAY. THE WESTERN PERIPHERY OF THE
PRECIPITATION SHIELD MAY BRUSH COASTAL SECTIONS WITH SOME LIGHT
SNOW LATE TONIGHT INTO FRIDAY MORNING AS IT RACES EAST-NORTHEAST.
CLOUDS...AND COLDER AIR BEING DRAWN INTO THE AREA BY THE OFFSHORE
LOW...WILL RESULT IN TEMPERATURES ONLY A FEW DEGREES ABOVE AVERAGE
FOR FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE MAIN FORECAST CONCERNS REVOLVE AROUND THE POTENTIAL FOR A
COASTAL STORM TO AFFECT THE REGION EARLY NEXT WEEK...MAINLY LATER
MONDAY THROUGH TUESDAY. BEFORE THEN...RATHER BENIGN WEATHER IS
EXPECTED. THE ONLY WEATHER MAKER THROUGH THE WEEKEND MAY BE A COLD
FRONT WITH THE POTENTIAL TO BRING SNOW SQUALLS LATER SATURDAY
NIGHT INTO SUNDAY MORNING. THE BTV SNOW SQUALL PARAMETER SHOWS
POTENTIAL FOR THIS ON SEVERAL DETERMINISTIC MODELS.

TURNING OUR ATTENTION TO EARLY NEXT WEEK...UNCERTAINTY IN
EVOLUTION IN SHORT WAVE TROFS CONTINUES TO ALLOW FOR LOW
CONFIDENCE IN TIMING OF A POTENTIAL SNOWFALL AS WELL AS ANY SORT
OF AMOUNTS. THE DETERMINISTIC RUNS OF THE GFS AND ECMWF CONTINUE
TO SHOW DIFFERENT SCENARIOS WITH THE MAIN PLAYERS ON THE
TABLE...IE...A SOUTHERN STREAM SHORT WAVE TROUGH MOVING OFF THE
SOUTHEAST COAST AND A LARGER MORE POTENT TROUGH OR CLOSED LOW
MOVING SOUTHEASTWARD INTO THE GREAT LAKES AND OHIO VALLEY REGIONS.

THE 00Z DETERMINISTIC ECMWF RUN CONTINUES TO SHOW THE SOUTHERN
STREAM ENERGY BEING MORE OF A PLAYER HERE AS IT ALLOWS THIS TROUGH
AND RESULTANT SFC LOW TO TRACK CLOSER TO THE COAST AND INTERACT
WITH THE APPROACHING NORTHERN STREAM LOW. ONE OF THE CAUSES FOR
THIS IS THE AMPLIFICATION OF UPSTREAM RIDGING OVER THE MARITIMES
AS A NORTHERN STREAM SHORT WAVE TROUGH EXISTS THAT AREA RATHER
QUICKLY. THE RESULT IS A MAINLY LIGHT TO POTENTIALLY MODERATE
SNOWFALL FOR THE REGION STARTING BY EARLY MONDAY AFTERNOON AND
LASTING THROUGH A GOOD PORTION OF TUESDAY.

THE 00Z GFS ON THE OTHER HAND KEEPS THE SOUTHERN STREAM SHORT WAVE
TROUGH AND SFC LOW WELL OFFSHORE AND NOT MUCH OF A PLAYER HERE. AS
THAT SYSTEM SPEEDS OUT TO SEA...THE LARGE CLOSED LOW AMPLIFYING AS
IT MOVES ACROSS THE GREAT LAKES AND OHIO VALLEY TRANSFERS SOME
ENERGY TO THE COAST AND ALLOWS A SECONDARY TO FORM NEARBY. THIS
SOLUTION WOULD ALSO BRING US A BOUT OF SNOW...PERHAPS HEAVY...AND
PERHAPS ALSO WITH SOME MIXED PRECIP INVOLVED. THIS WOULD START
MONDAY NIGHT AND CONCLUDE LATE TUESDAY.

SO IN A NUTSHELL...WHILE THE ECMWF AND GFS SOLUTIONS ARE
DIFFERENT IN HANDLING OF THE SYSTEMS...THE NET RESULT WOULD BE
SOMEWHAT SIMILAR IN THAT ACCUMULATING SNOW WOULD PROBABLY OCCUR
CENTERED ON MONDAY NIGHT AND AT LEAST THE FIRST PART OF TUESDAY.
HOWEVER...DUE TO THE HIGH UNCERTAINTY IN SYSTEM EVOLUTION...LOW
CONFIDENCE EXISTS IN ANY DETAILS SINCE A MYRIAD OF OUTCOMES ARE
STILL POSSIBLE.

IT IS WORTH NOTING THAT MOST OF THE GFS ENSEMBLE MEMBERS SUPPORT
THE DETERMINISTIC GFS RUN AND KEEP THE SOUTHERN STREAM LOW AWAY
FROM THE AREA. MUCH OF THE ECMWF ENSEMBLE MEMBERS SEEM TO AGREE
WITH THAT SOLUTION ALSO BUT THE MEAN IS FURTHER NORTH. HOPEFULLY
THERE WILL BE BETTER AGREEMENT ON THE HANDLING OF THE TWO STREAMS
SOON.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...GRADUAL IMPROVEMENT TO VFR BY MID MORNING. AREAS OF
MVFR PSBL BTW 09Z AND 15Z FRI VCNTY OF THE COAST IN SNOW WITH LCL
IFR CONDS PSBL NR KPSM.

LONG TERM...LOCAL IFR IN SNOW SHOWERS POSSIBLE LATE SATURDAY NIGHT
INTO SUNDAY MORNING. THEREAFTER...IFR CONDITIONS POSSIBLY TO
DEVELOP LATE MONDAY IN SNOW.

&&

.MARINE...
SHORT TERM...WINDS HAVE DIMINISHED AND GALE HAS BEEN REPLACED WITH
A SMALL CRAFT MAINLY FOR SEAS THROUGH EARLY EVENING. WE`LL SEE A
BRIEF LULL TONIGHT BEFORE SMALL CRAFT CONDITIONS RETURN ON FRIDAY
AS LOW PRESSURE PASSES BY OFFSHORE.

LONG TERM...SCA CONDITIONS ARE LIKELY SATURDAY NIGHT AND SUNDAY IN
ASSOCIATION WITH A COLD FRONT. A COASTAL STORM COULD AFFECT THE
WATERS EARLY NEXT WEEK WITH SCA OR GALE CONDITIONS BUT UNCERTAINTY
REMAINS HIGH AT THIS TIME.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
     ANZ150>154.

&&

$$

NEAR TERM...LEGRO



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.