FXUS61 KOKX 270307
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1007 PM EST THU NOV 26 2009
.SYNOPSIS...
LOW PRESSURE WELL OFF THE SOUTHERN MID ATLANTIC COAST THIS EVENING
WILL DEEPENS AND MOVE TO THE GULF OF MAINE BY FRIDAY NIGHT.
THE LOW WILL CONTINUE TO MOVE SLOWLY NORTH FRIDAY NIGHT INTO
SATURDAY AS HIGH PRESSURE BUILDS OVER THE SOUTHEAST. THE HIGH WILL
MOVE OFF THE COAST ON SUNDAY...FOLLOWED BY AN APPROACHING COLD
FRONT SUNDAY NIGHT AND MONDAY. HIGH PRESSURE WILL BUILD OVER THE
AREA TUESDAY AND WEDNESDAY. ANOTHER STORM WILL MOVE INTO THE MID
ATLANTIC REGION ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE OFFSHORE LOW WILL MOVE TO EAST OF MONTAUK POINT BY MORNING.
LOOKING AT CURRENT RADAR AND 18Z MODEL GUIDANCE...IT APPEARS
THAT MID LEVEL FRONTOGENETIC FORCING NW OF THE OFFSHORE LOW WILL
STRENGTHEN OVER THE AREA ESPECIALLY AFTER MIDNIGHT...SO SHOWERS
ALREADY MAINLY OVER THE OCEAN WATERS SHOULD BECOME MORE WIDESPREAD
ACROSS LONG ISLAND AND SOUTHERN CT ESPECIALLY AFTER MIDNIGHT.
THIS MAY ALSO SLOW EASTWARD PROGRESS OF COLD FRONT AND ASSOCIATED
BAND OF SHOWERS MOVING ACROSS CENTRAL PA...SO HAVE CUT BACK POP
TO CHANCE FROM NYC WEST. PATCHY RADIATION FOG IN CLEAR SLOT
BETWEEN THE OFFSHORE LOW AND THE COLD FRONT ATTM ALLOWED TEMPS TO
DROP INTO THE 30S AND CLOSE TO DEWPOINTS MAINLY IN ORANGE
COUNTY...SO PATCHY VALLEY FOG SHOULD CONTINUE THERE UNTIL SKIES
CLOUD OVER AFTER MIDNIGHT.
THERE WILL BE SOME ELEVATED INSTABILITY DEVELOPING ACROSS THE
EASTERN HALF OF THE AREA AS THE LOW TRACKS NORTH LATE TONIGHT...
AND AN ISOLATED THUNDERSTORM WILL BE POSSIBLE THERE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
WITH UPPER LOW OVER THE AREA FRIDAY SHOWERS CONTINUE DURING THE
DAY...AND AS SURFACE LOW CONTINUES TO RAPIDLY DEEPEN WESTERLY
WINDS WILL INCREASE...AND GUSTS DEVELOP WITH DAYTIME MIXING.
SHOWERS END FRIDAY NIGHT WITH THE UPPER LOW AND SURFACE MOVING
EAST. COLD ADVECTION SETS UP AND GUSTY WINDS CONTINUE.
PRECIPITATION WILL END BEFORE ENOUGH COLD AIR GETS INTO THE REGION
FOR WIDESPREAD SNOW. MAY SEE SOME WET FLAKES MIXED IN ACROSS
HIGHER ELEVATIONS OF ORANGE COUNTY.
SATURDAY WINDS REMAIN STRONG WITH SUSTAINED WINDS AROUND 20 KT AND
GUSTS ABOUT 30...UNDER ADVISORY LEVELS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AN ACTIVE WEATHER PATTERN IS SHAPING UP FOR NEXT WEEK...BUT BEFORE
THEN A BROAD UPPER LEVEL RIDGE OVER THE EASTERN HALF OF THE COUNTRY
WILL PROVIDE A DRY START FOR SAT NIGHT INTO SUN WITH TEMPERATURES
SLIGHTLY ABOVE SEASONABLE LEVELS.
A FAST FLOW IN THE NORTHERN BRANCH OF THE POLAR JET THEN DEVELOPS
EARLY NEXT WITH A SERIES OF AMPLIFYING PAC SHORT WAVES TRACKING FROM
WEST TO EAST ALONG THE US/CANADIAN BORDER. MODELS ARE IN FAIRLY GOOD
AGREEMENT WITH ACKNOWLEDGING THESE FEATURES...HOWEVER...THE
INTERACTION WITH A SOUTHERN BRANCH CLOSED LOW POSES PROBLEMS WITH A
STORM SYSTEM FOR THE MIDDLE OF NEXT WEEK. GLOBAL MODEL CONSENSUS IS
FOR THIS SYSTEM TO WRAP UP INTO A STRONG DOUBLE-BARRELED LOW
PRESSURE SYSTEM...WITH THE PRIMARY LOW BEING WEST OF THE
APPALACHIANS TRACKING NE WED NIGHT INTO THU. THE 12Z GFS ON THE
OTHER HAND IS MORE PROGRESSIVE WITH THE NORTHERN BRANCH CLOSED
LOW...RESULTING IN THE COASTAL LOW BEING THE PRIMARY AND
CONSIDERABLY DEEPER THAN THE MODEL ENSEMBLE. BASED ON THIS
SCENARIO...THE GFS LOOKS TO BE TOO DEEP WITHOUT THE TWO STREAMS
PHASING AS IT PRODUCES A 979 MB LOW EAST OF CAPE COD THU AFT. FOR
NOW...THIS SOLUTION HAS BEEN BEEN DISCOUNTED WITH THE STRONGER
INTERIOR LOW PREFERRED.
THUS...AFTER DRY WEATHER TO END THIS WEEKEND...A FRONTAL SYSTEM
MOVES ACROSS THE AREA MON EVE...WITH WARM ADVECTION AND POST FRONTAL
RAINS MON AFT INTO TUE MORNING. HIGH PRESSURE THEN RETURNS TUE-WED
WITH SEASONABLE TEMPS. RAINS RETURN WED NIGHT INTO THU WITH THE
AFOREMENTIONED INLAND LOW. BASED ON THE DISCUSSED TRACK AND LACK OF
A POLAR HIGH TO THE NORTH...KEPT ALL PCPN IN THE FORM OF RAIN.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
LOW PRES EAST OF THE CAROLINA COAST WILL TRACK NORTH TONIGHT...
ENDING UP OVER CAPE COD BY FRI MORNING. MEANWHILE...A COLD FRONT
APPROACHES FROM THE WEST...BRINGING MORE MOISTURE TO THE REGION.
GENERALLY MVFR CIGS WITH IFR CIGS ACROSS EASTERN TERMINALS
KISP/KGON. CIGS WILL GENERALLY REMAIN AT MVFR THROUGH LATE FRI
MORNING.
PRECIP WILL DEVELOP BY MIDNIGHT...AND CIGS/VSBYS WILL LOWER TO
IFR IN HEAVIER SHOWERS. A RUMBLE OF THUNDER IS POSSIBLE AT EASTERN
TERMINALS THAT WILL BE CLOSER TO THE PROXIMITY OF THE LOW...BUT
CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT MENTIONING IN THE TAF.
WITH PASSAGE OF COLD FRONT THAT WILL BECOME ENVELOPED WITHIN THE
LOW...WINDS WILL SHIFT TO THE NORTH...THEN NORTHWEST...INCREASING
TO 10-15 KT. BY FRI AFTERNOON...LOW PRES WILL RAPIDLY INTENSIFY AS
IT TRACKS TOWARDS THE GULF OF MAINE. THE PRES GRADIENT WILL
STRENGTHEN OVER THE REGION...AND NORTHWEST WINDS WILL SHIFT
WEST...INCREASING TO 15-20 KT WITH 20-25 KT GUSTS. BY FRI NIGHT...
WEST WINDS WILL INCREASE TO AROUND 20 KT WITH 30 KT GUSTS.
OUTLOOK 00Z SATURDAY THROUGH TUESDAY...
FRI NIGHT-SAT NIGHT...WNW WINDS 20-30 KT WITH 30-35 KT GUSTS. VFR.
SUN...VFR WITH DIMINISHING WINDS.
SUN NIGHT-MON NIGHT...SUB-VFR POSSIBLE.
TUE...VFR.
&&
.MARINE...
AS A COASTAL OFF NORTH CAROLINA DEEPENS AND TRACKS TO THE
NORTH...BEING SOUTH AND EAST OF MONTAUK POINT BY FRIDAY
MORNING...OCEAN SEAS WILL BUILD TO SMALL CRAFT LEVELS AFTER
MIDNIGHT...MAINLY IN A SE SWELL. WINDS AND GUSTS WILL REMAIN
BELOW SMALL CRAFT LEVELS TONIGHT. AS THE LOW CONTINUES TO DEEPEN
AND MOVE TO THE GULF OF MAINE DURING FRIDAY WINDS AND GUSTS ARE
EXPECTED TO INCREASE WITH GUSTS REACHING GALE FORCE ON ALL THE
WATERS BY FRIDAY AFTERNOON. THE LOW TRACKS SLOWLY NORTH INTO
SOUTHEASTERN CANADA FRIDAY NIGHT AND SATURDAY. GALE FORCE GUSTS
WILL CONTINUE ON ALL THE WATERS INTO SATURDAY. WINDS MAY START TO
DIMINISH SATURDAY AFTERNOON AS THE LOW MOVE OUT AND HIGH PRESSURE
STARTS TO BUILD INTO THE WATERS.
SHOWERS WILL SPREAD INTO THE AREA TONIGHT...AND WITH SOME ELEVATED
INSTABILITY AN ISOLATED THUNDERSTORM WILL BE POSSIBLE LATE.
OTHERWISE SHOWERS WILL BE WIDESPREAD TONIGHT INTO FRIDAY...THEN
TAPER OFF FRIDAY NIGHT AS THE LOW TRACK INTO CANADA.
WINDS AND SEAS CONTINUE TO SUBSIDE ON THE BACKSIDE OF LOW PRES OVER
THE CANADIAN MARITIMES SAT NIGHT INTO SUN. SEAS MAY LINGER AROUND 5
FT THROUGH SUN AFT IN THE WESTERLY FLOW...BUT OTHERWISE CONDITIONS
WILL BE BELOW SCA CRITERIA.
A COLD FRONT THEN PUSHES THROUGH MON NIGHT WITH SEVERAL DAYS OF NW
FLOW TO FOLLOW. MARGINAL POST-FRONTAL SCA WIND GUSTS POSSIBLE MON
NIGHT INTO THE FIRST HALF OF TUE.
&&
.HYDROLOGY...
RAINFALL FROM TONIGHT THROUGH FRIDAY NIGHT WILL RANGE FROM LESS
THAN 1/10 INCH WEST OF NYC...TO 1/2 TO 3/4 INCH OVER EASTERN LONG
ISLAND/CT. NO SIGNIFICANT HYDROLOGIC IMPACT IS EXPECTED.
&&
.TIDES/COASTAL FLOODING...
STRONG WEST WINDS WILL LIKELY BRING TIDAL DEPARTURES OF 2 TO 3 FT
BELOW NORMAL FRIDAY NIGHT AND SATURDAY. THIS WILL LIKELY CAUSE
BLOWOUT TIDES AT NEAR SHORE LOCATIONS...AND A LOW WATER ADVISORY
MAY BE NEEDED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...GALE WARNING FROM 6 AM FRIDAY TO 6 AM EST SATURDAY FOR ANZ330-
335-338-340-345-350-353-355.
SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ350-353-355.
&&
$$
