FXUS61 KGYX 030220
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
920 PM EST WED DEC 2 2009
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY THIS EVENING WILL CONTINUE TO
DEEPEN AS IT RACES NORTHEAST TONIGHT. IT WILL CROSS INTERIOR
NORTHERN NEW ENGLAND THURSDAY. WEAK HIGH PRESSURE TO FOLLOW. LOW
PRESSURE WILL THEN PASS WELL EAST OF THE REGION ON SATURDAY. MORE
COLD...HIGH PRESSURE TO FOLLOW THEREAFTER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE DIGITAL AND TEXT FORECASTS WERE UPDATED EARLIER THIS EVENING
TO FOLLOW TRENDS IN CLOUD COVER AND TEMPERATURES.
THE RAIN SHIELD ASSOCIATED WITH LOW PRESSURE OVER THE OHIO VALLEY
IS ADVANCING NORTHEAST THIS EVENING...AND HAS REACHED SOUTHWEST
NEW HAMPSHIRE AS OF 900 PM. THE HIGH THIN CLOUDS EARLIER ALLOWED
PORTIONS OF NORTHERN NEW HAMPSHIRE AND THE MOUNTAINS OF WESTERN
MAINE TO FALL BELOW THE FREEZING MARK. WHILE WARMING SHOULD OCCUR
THERE IN THE NEXT COUPLE OF HOURS WITH THICKENING CLOUD COVER AND
A SOUTHEAST WIND...INCLUDED A CHANCE OF FREEZING RAIN IN THESE
AREAS. THE 0000 UTC SOUNDINGS AT GYX AND WMW WERE VERY DRY...SO
THIS MAY DELAY THE ONSET OF PRECIPITATION IN THESE COLD AREAS.
THUS...A WINTER WEATHER ADVISORY WAS NOT ISSUED...BUT WILL
CONTINUE TO WATCH TRENDS.
THE MAIN FORECAST PROBLEM FOR THE OVERNIGHT WILL BE WIND. AS THE
FLOW BECOMES SOUTHEAST...A LOW LEVEL INVERSION (PROBABLY LESS THAN
1000 FEET) WILL SET UP AHEAD OF THE BEST SURFACE GRADIENT. THIS
SHOULD RESULT IN THE STRONGEST WINDS BEFORE DAYBREAK BEING LIFTED
UP AND OVER THE DEVELOPING COOL WEDGE...ESPECIALLY AWAY FROM THE
COAST. 0000 UTC SOUNDINGS ACROSS MID ATLANTIC STATES SHOW 50 TO 60
KNOT WINDS AT 3000 FEET...BUT THIS SHOULD BE WELL ABOVE THE
INVERSION HEIGHT LATE TONIGHT.
CONSIDERED EXTENDING THE WIND ADVISORY INTO INTERIOR SOUTHEAST NEW
HAMPSHIRE AND SOUTHWEST MAINE FOR LATE TONIGHT AND THURSDAY MORNING.
HOWEVER...AS MENTIONED ABOVE...THESE AREAS MAY REMAIN IN THE COOL
AIR LONG ENOUGH TO KEEP THE STRONGEST WINDS ABOVE THE SURFACE. DID
NOT OPT FOR THAT COURSE YET. HOWEVER... WIND GUSTS WERE INCREASED
TO 35 MPH IN THESE AREAS...ESPECIALLY IN THE HIGHER ELEVATIONS.
WILL CHECK THE 0000 UTC MODEL SUITE AND OBSERVATIONS TO THE SOUTHEAST.
MAY HAVE TO ISSUE A WIND ADVISORY FOR THE ABOVEMENTIONED AREAS
JUST AHEAD OF THE COOL FRONT...WHERE THE MIXED LAYER MAY BREAK FOR
A COUPLE OF HOURS OF STRONG WINDS.
LOWS ARE OCCURRING NOW OR HAVE OCCURRED...AND WOULD EXPECT RISING
TEMPERATURES FOR THE REMAINDER OF THE NIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
FOLLOWED THE STORM TRACK/INTENSITY FROM THE GFS. NICE PRESSURE
FALLS AND CONVECTION OCCURRING IN THE SOUTHEAST THIS AFTERNOON IN
THE VICINITY OF THE DEVELOPING STORM.
WINDS: STRONG SOUTHEAST GRADIENT SETS UP LATE TONIGHT/EARLY
THURSDAY. MIXING INCREASES EARLY THURSDAY MORNING...WITH WINDS OF
45-55 KTS DOWN TO AROUND 1 KFT PER LATEST MODEL SOUNDINGS. NOT ALL OF
THIS WILL MIX TO THE SURFACE...BUT ENOUGH WILL TO RAISE A WIND
ADVISORY FOR THE COASTLINE STARTING BY DAYBREAK.
WITH CONTINUED INCREASE IN MIXING DURING THE LATE MORNING/EARLY
AFTERNOON HOURS...HAVE KEPT THE ADVISORY GOING THROUGHOUT THE DAY
IN THE EVENT WSW GRADIENT WINDS GUST OVER 45 MPH.
QPF/HYDRO: EXPECT A QUICK 1 TO 1.5 INCHES RAINFALL WITH THIS
SYSTEM. NERFC BRINGS THE PEMI TO ITS 9' FLOOD STAGE WITH ALL OTHER
RIVERS REMAINING BELOW FS. WILL NOT BE ISSUING WATCHES AT THIS
TIME...AS RAINFALL APPEARS TO BE BELOW FFG IN ALL AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
CLEARING WILL TAKE PLACE THURS NIGHT AS A DOWNSLOPING WLY FLOW
TAKES HOLD AND CONTINUES THRU FRI. OVER THE WEEKEND WILL NEED TO
WATCH A LOW PRES SYSTEM MODELS SAY WILL PASS WELL S AND E OF NEW
ENGLAND AND HAVE HIGH CONFIDENCE WITH THIS SCENARIO SINCE MODELS
SHOWING GOOD CONTINUITY WITH TRACK. A BAND OF SNOW SHOWERS MAY
WORK THEIR WAY ACROSS THE CWA SAT AND SAT NGT AS A WEAK UPPER S/WV
TROF MOVES ACROSS THE AREA...NOT FROM THE EFFECTS OF THE OFFSHORE
STORM. SOMEWHAT COLDER AIR IS EXPECTED LATE IN THE WEEKEND INTO
EARLY NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
IN THE NEAR TERM /REST OF TONIGHT/...VFR CONDITIONS ACROSS THE
FORECAST AREA AS HIGH PRESSURE EXITS SOUTH OF NOVA SCOTIA. MVFR
CONDITIONS ARE AS CLOSE AS SOUTHWEST NEW HAMPSHIRE AS THE RAIN
SHIELD IS ABOUT TO MOVE INTO SOUTHWEST AREAS. WOULD EXPECT A
PROGRESSION FROM MVFR TO IFR TO LIFR WITH THE ADVANCING RAIN
SHIELD.
THE SURFACE GRADIENT WILL ALSO INCREASE TONIGHT...BUT WAIT UNTIL
AFTER 0900 UTC THURSDAY TO START GUSTING. MEANWHILE...UPSTREAM
0000 UTC SOUNDINGS ARE SHOWING 35 TO 45 KNOT WINDS AT 2000 FEET.
HAVE INCLUDED LOW LEVEL WIND SHEAR BETWEEN 0600 UTC AND 1000 UTC
THURSDAY AS WINDS INCREASE ABOVE THE STRONG INVERSION.
IN THE SHORT TERM /THURSDAY/...CONDITIONS IMPROVE WITH THE WIND
SHIFT AROUND 15Z...WHEN ALL AREAS WILL QUICKLY SWITCH TO THE WSW.
LONG TERM...GENERALLY VFR CONDITIONS.
&&
.MARINE...
IN THE NEAR TERM /REST OF TONIGHT/...THE GRADIENT HAS BEEN SLOWLY
INCREASING THIS EVENING AS THE SURFACE HIGH CONTINUES TO MOVE AWAY
SOUTH OF NOVA SCOTIA AND LOW PRESSURE APPROACHES THE OHIO VALLEY.
THE GRADIENT SHOULD PEAK BETWEEN 0900 AND 1400 UTC THURSDAY. WHILE
THE SOUTHEAST FLOW SHOULD LIMIT THE AMOUNT OF MIXING FROM ABOVE...THE
GRADIENT DEFINITELY SUPPORTS GALE FORCE WINDS OVER THE OCEAN BEFORE
DAYBREAK...AND GUSTS TO 45 KNOTS WERE ADDED TO ANZ154 FOR THIS
REASON.
IN THE SHORT TERM /THURSDAY/...GALES ARE UP THROUGH THURSDAY AND
MAY BRIEFLY APPROACH STORM FORCE THURSDAY MORNING. ALSO...HAVE
USED PREFERRED GFS SWAN GRIDS WHICH PICKS UP ON THE BUILDING
WAVES MUCH BETTER THAN THE WAVEWATCH MODEL.
LONG TERM...WEST TO SOUTHWEST FLOW THURS NIGHT WILL BE STG ENOUGH
TO SUPPORT SCA CRIT AND THEN WILL DIMINISH FRI AND FRI NIGHT AS
SFC HIGH PRES BUILDS OVER THE AREA. AN OCEAN STM IS EXPECTED TO
PASS WELL S AND E OF NEW ENGLAND LATE SAT ALLOWING WINDS TO
APPROACH SCA CRIT SAT NIGHT BUT DIMINISH AGAIN ON SUN.
&&
.TIDES/COASTAL FLOODING...
HIGHEST ASTRO TIDES OF THE MONTH WILL OCCUR ARND 11 AM THU MRNG
DUE TO THE PRESENCE OF A FULL MOON. STRONG SOUTHEAST WINDS AND
WATER LEVEL CONTRIBUTION DUE TO LOW ATMOS PRESSURE WILL OCCUR NEAR
THE TIME OF HIGH TIDE. THIS WILL ALLOW FOR A STORM SURGE OF 1-1.5
FEET. WILL ISSUE COASTAL FLOOD WARNINGS FOR THE REGION FROM PORTLAND
SOUTH.
WATCHES REMAIN IN EFFECT FURTHER UP THE COAST...WHICH NEEDS A HIGHER
12.5' TIDE IN PORTLAND HARBOR BEFORE THE ONSET OF FLOODING. HAVE
NOT SEEN ENOUGH THIS EVENING TO UPGRADE THE WATCH TO A WARNING FOR
THE MID COAST JUST YET.
BIG QUESTION REMAINS THE TIMING OF THE WIND SHIFT. WINDS ARE EXPECTED
TO BECOME SW ABOUT AN HOUR BEFORE HIGH TIDE...WHICH WILL BE BENEFICIAL
AS COMPARED TO STRONG SE WINDS AT THE TIME OF HIGH TIDE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY FROM 6 AM TO 3 PM EST THURSDAY FOR MEZ023>028.
COASTAL FLOOD WATCH THURSDAY MORNING FOR MEZ025>028.
COASTAL FLOOD WARNING FROM 10 AM TO NOON EST THURSDAY FOR
MEZ023-024.
NH...WIND ADVISORY FROM 6 AM TO 3 PM EST THURSDAY FOR NHZ014.
COASTAL FLOOD WARNING FROM 10 AM TO NOON EST THURSDAY FOR
NHZ014.
MARINE...GALE WARNING FROM 3 AM TO 7 PM EST THURSDAY FOR ANZ150>154.
&&
$$
