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Area Forecast Discussion
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000
FXUS61 KGYX 131348
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
948 AM EDT FRI MAR 13 2015

.SYNOPSIS...
HIGH PRESSURE CENTERED SOUTH OF NEW ENGLAND THIS MORNING SHIFTS
OFFSHORE LATER TODAY. LOW PRESSURE WILL MOVE IN FROM THE SOUTHWEST
ON SATURDAY....BRINGING A MIX OF WINTRY PRECIPITATION TO MUCH OF
THE AREA INTO SATURDAY NIGHT. AS THE LOW SHIFTS TO THE NORTHEAST
SATURDAY AND SUNDAY...PRECIPITATION WILL CHANGE TO SNOW BEFORE
ENDING SUNDAY AFTERNOON. HIGH PRESSURE RETURNS BRIEFLY ON MONDAY.
A COLD FRONT WILL CROSS THE AREA ON TUESDAY...WITH ANOTHER SHOT OF
UNSEASONABLY COLD AIR FOR THE MID-LATE PART OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...

930 AM...1038 MILLIBAR HIGH OVER WESTERN NEW ENGLAND WILL CREST
ACROSS THE FORECAST AREA THIS AFTERNOON BEFORE SLIDING OFFSHORE.
ONLY MINOR 1ST PERIOD GRID ADJUSTMENTS FOR THIS ESTF TO INGEST
LATEST MESONET.

PREV DISC...
630 AM UPDATE...FORECAST REMAINS ON TRACK AND JUST HAD TO MAKE
MINOR CHANGES TO TEMPS BASED ON CURRENT OBS AND TRENDS.

PREVIOUS DISCUSSION...HIGH PRESSURE SLIDES OFFSHORE THIS MORNING
PROVIDING WEAK RETURN FLOW...HOWEVER TEMPERATURES STILL LOOK TO
REMAIN BELOW NORMAL. CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON
AS WARM ADVECTION BEGINS ALOFT.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH SUNDAY/...
WARM AIR ADVECTION CLOUDINESS WILL THICKEN TONIGHT AS LOW
PRESSURE MOVES ACROSS THE GREAT LAKES...HOWEVER PRECIP SHOULD
LIKELY HOLD OFF UNTIL TOMORROW MORNING FOR MOST AREAS. COULD SEE
SOME OVERRUNNING SNOWFALL TO START ON SATURDAY MORNING AND MODEL
SOUNDINGS HAVE A DECENT WARM LAYER FROM APPROXIMATELY 1 TO 5
THOUSAND FEET FOR SOUTHERN NEW HAMPSHIRE SATURDAY MORNING. THIS
COULD BRING A PERIOD OF FREEZING RAIN BEFORE NOON AND THEN CHANGE
TO ALL RAIN LATER IN THE DAY. MIXING WILL HOLD OFF LONGER ACROSS
NORTHERN LOCATIONS WITH THE BEST CHANCE OF PRECIP STAYING ALL SNOW
BEING IN NORTHWEST MAINE. STILL SOME UNCERTAINTY ON PRECIP TYPES
AND THE AMOUNT OF WARM AIR THAT WILL WORK INTO THE AREA...HOWEVER
WITH LIGHT WINDS THE THOUGHT IS THAT THE COLD AIR AT THE SURFACE
IS GOING TO HOLD ON LONGER THAN THE MODELS CURRENTLY SUGGEST SO
HELD ON TO FREEZING RAIN UNTIL ALMOST NOON ON SATURDAY ACROSS
SOUTHERN NEW HAMPSHIRE.

A SECONDARY LOW PRESSURE WILL DEVELOP SOMEWHERE NEAR CAPE COD AND
STRENGTHEN AS IT ABSORBS ENERGY FROM NORTHERN STREAM WAVE THAT
DIVES SOUTHEAST OUT OF QUEBEC SATURDAY NIGHT. DEPENDING ON WHERE
THIS LOW TRACKS IT COULD THROW BACK MOISTURE INTO MAINE WITH THE
MIDCOAST ON NORTHWARD LIKELY SEEING THE BRUNT OF THE PRECIP.
ALTHOUGH SNOW ACCUMULATIONS WILL BE FAIRLY LIGHT DURING THE DAY ON
SATURDAY WITH WARM AIR ADVECTION...THIS SECONDARY LOW COULD
PROVIDE HEAVY SNOWFALL FROM INTERIOR WESTERN MAINE ON EASTWARD.
STILL QUITE A BIT OF UNCERTAINTY THOUGH ON WHERE EXACTLY THIS
SECONDARY LOW DEVELOPS AND QPF AMOUNTS STILL VARY QUITE A BIT
BETWEEN MODELS MAKING IT DIFFICULT TO DETERMINE THE PLACEMENT OF
THE HEAVIEST SNOWFALL. BECAUSE OF THIS AND AFTER COORDINATING WITH
SURROUNDING OFFICES WE DECIDED TO HOLD OFF ON WATCHES AND
ADVISORIES FOR NOW AND SEE IF MODELS BECOME A BIT MORE CONSISTENT
WITH THE 12Z RUNS.

THE LOW PULLS OUT SUNDAY...HOWEVER SNOW SHOWERS WILL CONTINUE
INTO THE AFTERNOON HOURS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE 500 MB PATTERN...WHILE NOT QUITE A CLASSIC +PNA...STILL
FEATURING BLOCKING BOTH DOWNSTREAM AND UPSTREAM...ALTHOUGH THE
DOWNSTREAM BLOCKING OVER THE ERN ATLANTIC AND EUROPE IS MUCH
STRONGER THAN THE UPSTREAM BLOCKING. THIS DOES NOT CHANGE THE FACT
THAT TEMPS WILL CONTINUE TO RUN BELOW NORMAL WELL INTO NEXT
WEEK...BUT WOULD PUSH THE CORE COLD AIR FURTHER EAST...AND ALLOW A
FASTER MORE ZONAL FLOW OVER THE NERN CONUS...LEADING TO FAST
MOVING FRONTS AND NO STRONG SYSTEMS. 

STARTING SUNDAY NIGHT...SHOULD SEE CLEARING AS DRIER AIR MOVES IN
BEHIND THE SYSTEM. MONDAY LOOKS MAINLY DRY WITH TEMPS MAKING A RUN
TO NEAR NORMAL HIGHS...AND INCREASING CLOUDS LATE IN THE DAY. THE
NEXT CHC FOR ANY PRECIP WILL BE MON NIGHT INTO TUE AS COMPACT 500
MB TROUGH DIVES SE INTO NEW ENGLAND AND CLOSED THE OFF 500 MB TO
OUR NE OVER THE MARITIMES...BRINGING A ROUND OF SHSN OR A PERIOD
OF LIGHT SN MON NIGHT INTO TUE. THIS SYSTEM WILL USHER IN ANOTHER
ROUND OF UNSEASONABLY COLD AIR /TEMPS ABOUT 10 F BLO NORMAL/ BY
THE MIDDLE OF NEXT WEEK.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...VFR EXPECTED THROUGH TONIGHT AND THEN MVFR TO IFR
CONDITIONS EXPECTED BY MORNING WITH THE ONSET OF WINTER
PRECIPITATION. CONDITIONS WILL LIKELY REMAIN MOSTLY MVFR TO IFR
IN MOST AREAS UNTIL LOW PRESSURE PUSHES EAST ON SUNDAY.

LONG TERM...VFR EXPECTED SUN EVE INTO MON EVE...WITH POTENTIAL
MVFR...AND PERIODS OF IFR IN SN MON NIGHT INTO EARLY TUE.

&&

.MARINE...
SHORT TERM...WINDS WILL CONTINUE TO DROP OFF THIS MORNING AND
DECIDED TO LET SCA EXPIRE AT 6AM. TODAY WILL BE QUIET AS SURFACE
HIGH PRESSURE TRAVERSES THE WATERS. FREEZING SPRAY LOOKS TO BE
LIMITED TO LIGHT ACCUMULATIONS THIS AFTERNOON. A COASTAL LOW
DEVELOPS ON SATURDAY NIGHT AND MARGINAL GALES MAY BE POSSIBLE
THROUGH SUNDAY MORNING.  

LONG TERM...WINDS/SEAS DIMINISH SUN NIGHT. MAY NEED SCA LATE TUE
INTO TUE NIGHT.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$
ES



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