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000
FXUS61 KOKX 200447
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1247 AM EDT MON MAY 20 2013

.SYNOPSIS...
A WARM FRONT WILL SLOWLY APPROACH OVERNIGHT...THEN LIFT TO THE
NORTH TODAY. THIS FRONT WILL THEN REMAIN NEARBY THROUGH MID
WEEK...POSSIBLY SINKING SOUTH ON TUESDAY AND LIFTING BACK NORTH AS
A WARM FRONT ON WEDNESDAY. A COLD FRONTAL PASSAGE WILL OCCUR LATE
IN THE WEEK. HIGH PRESSURE WILL RETURN NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LIGHT RAIN STILL LINGERING MAINLY ACROSS SUFFOLK COUNTY AND
SOUTHERN CT. MINOR UPDATE TO TEMPS AND DEW POINTS TO REFLECT
LASTEST OBSERVATION TRENDS.

STRONGEST LLJ ENERGY CONTINUES TO MOVE EAST WITH AXIS OF STEADY
LIGHT RAIN PUSHING EAST. IN ITS WAKE...CONTINUED WEAK THETA-E
ADVECTION AND AN APPROACHING DIFFUSE WARM FRONT WILL LIKELY
MAINTAIN DRIZZLE AND ISOLATED SHOWER ACTIVITY INTO THE OVERNIGHT.
THE DRIZZLE ACTIVITY MAY TAPER ONCE THE WARM FRONT PUSHES TO THE
NORTH OR WASHES OUT. TEMPS SHOULD REMAIN NEARLY STEADY TONIGHT IN
THE MID AND UPPER 50S...AND COULD SLOWLY INCREASE TOWARD DAYBREAK.
AS HIGHER DEWPOINT AIR ADVECTS IN...POTENTIAL FOR FOG WILL ALSO
INCREASE OVERNIGHT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE REGION WILL BE WARM SECTORED TODAY. EXPECT AT LEAST
PARTIAL CLEARING TO OCCUR...WHICH WILL DETERMINE AMT OF DAYTIME
HEATING/INSTABILITY. FORCING RELATIVELY WEAK...SO EXPECT ONLY
ISOLD TO SCT SHOWERS IN THE AFTERNOON. WITH WEAK STEERING FLOW
AND PW NEAR 1.5 INCHES...ANY SHOWER/TSTM COULD DUMP LOCALLY HEAVY
RAIN. HIGH-RES MESOSCALE MODELS SUCH AS SPC WRF AND HIGH-RES ARW
AGREE ON THIS SCENARIO.

EXPECT DAYTIME HIGHS TO REACH THE LOWER 80S FROM NYC NORTH/WEST
AND INTO THE 70S ELSEWHERE. TEMPS COULD BE A COUPLE DEG HIGHER IF
MORE AFTERNOON SUNSHINE TAKES PLACE THAN FCST.

ANY CONVECTION SHOULD WANE MON EVENING. IT NOW APPEARS THAT A BACK
DOOR COLD FRONT APPROACHING FROM NEW ENGLAND SHOULD HOLD OFF UNTIL
TUE MORNING...SO WITH AREA REMAINING IN THE WARM SECTOR WOULD
EXPECT REDEVELOPMENT OF FOG...ESPECIALLY ALONG THE COAST.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE MODELS/ENSEMBLES ARE IN DECENT GENERAL AGREEMENT
WITH THE REGION LYING ON THE NORTHERN PERIPHERY OF EAST COAST
RIDGING DURING THE MIDWEEK...WITH PHASING EASTERN CANADIAN AND
CENTRAL US TROUGHS...EVENTUALLY TRANSLATING A DEEP TROUGH TO THE
EAST COAST FOR THE END OF THE WEEK/WEEKEND.

FOR TUESDAY THROUGH THURSDAY...MODELS CONTINUE TO DIFFER IN LOCATION
OF A FRONTAL BOUNDARY. THE PREDICTABILITY ISSUES ARE BASED ON
SUBTLE DIFFERENCES IN INTERACTION OF THE UPPER ENERGIES AND
RELATIONSHIP WITH EAST COAST RIDGING. THE LOCATION OF UPPER
CONFLUENCE WILL DETERMINE HOW STRONGLY CANADIAN HIGH PRESSURE BUILDS
SE INTO NEW ENGLAND...AND THE TIMING AND MOVEMENT OF A BACK DOOR
COLD FRONT. LATEST GUIDANCE PUSHES THE BACKDOOR COLD FRONT SOUTH
THROUGH THE REGION ON TUESDAY...AND THEN BACK NORTH AS A WARM FRONT
ON WEDNESDAY.

TO THE SOUTH OF THE FRONT...AN UNSEASONABLY WARM AND MOIST AIR MASS
WILL BE IN PLACE. DEPENDING ON THE TIMING AND LOCATION OF THE
FRONTAL BOUNDARY...SHORTWAVES AT THE SOUTHERN EDGE OF THE
WESTERLIES...FAVORABLE INSTABILITY AND WIND FIELDS PRESENT THE
POTENTIAL FOR CONVECTIVE COMPLEXES TO DEVELOP AND PROPAGATE ALONG
THIS BOUNDARY. ANY MCS WOULD BRING THE THREAT FOR FLASH FLOODING AND
SEVERE WEATHER.

BY THE END OF THE WEEK...MODELS ARE SIGNALING VARYING DEGREES OF
PHASING OF THE MIDWEST UPPER TROUGH AND EASTERN CANADIAN UPPER
TROUGH. MODELS HAVE TRENDED FASTER WITH THIS PHASED ENERGY WORKING
TO THE EAST COAST. HAVE TRENDED COLD FRONTAL PASSAGE A BIT SOONER AS
A RESULT...SOME TIME LATE THU THROUGH FRI...WITH SHOWER AND
THUNDERSTORM ACTIVITY FINALLY EXITING IN IT WAKE. DEGREE OF PHASING
OF UPPER ENERGIES WILL DETERMINE TIMING AND ACTIVITY ALONG THE FRONT.

MODEL GUIDANCE IS SIGNALING A DRIER AND SLIGHTLY BELOW SEASONABLE
WEEKEND...WITH EAST COAST MEAN TROUGHING AND CANADIAN HIGH PRESSURE
BUILDS INTO THE REGION.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A NEARLY STATIONARY FRONT WILL REMAIN SOUTH OF THE AREA...ALONG THE
PENNSYLVANIA AND MARYLAND BORDER TO THE DELMARVA...OVERNIGHT AND
SLOWLY WEAKEN. THE FRONT WILL REDEVELOP TO THE NORTH OF THE
TERMINALS AS A WARM FRONT MID TO LATE MONDAY MORNING...13Z TO 15Z.
THE AREA WILL THEN BE IN THE WARM SECTOR AHEAD OF LOW PRESSURE
MOVING INTO THE UPPER MIDWEST. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE IN THE AFTERNOON. THE WIND WILL BE
SOUTHERLY...AND BECOME MORE SOUTHWESTERLY LATE MONDAY AFTERNOON INTO
THE EARLY EVENING. SEA BREEZE INFLUENCE IS LIKELY.

WIDESPREAD FOG AND DRIZZLE...WITH LOW CLOUDS WILL PERSIST THROUGH
THE OVERNIGHT WITH IFR TO LIFR CONDITIONS...AND AT TIME VLIFR.
CONDITIONS IMPROVE AFTER 13Z...TIMING OF THE IMPROVEMENTS IS NOT
CERTAIN.

.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MONDAY NIGHT...MAINLY VFR...MVFR OR LOWER CONDITIONS POSSIBLE IN
FOG...MAINLY EAST OF THE NEW YORK CITY TERMINALS.
.TUESDAY-FRIDAY...CHANCE OF MVFR OF LOWER CONDITIONS IN
SHOWERS/TSTMS.

&&

.MARINE...
AS A WARM FRONT APPROACHES LATE THIS EVENING...SE-S WINDS WILL
INCREASE TO 15 TO 20 KT...MAINLY ACROSS THE OCEAN WATERS. OCEAN
SEAS OF 3-4 FT...SHOULD REACH SCA CRITERIA OF 5 FT THIS
EVENING. SCA LEVEL OCEAN SEAS SHOULD LAST INTO MON
AFTERNOON...POSSIBLY INTO MON EVENING OUT EAST.

WITH EXPECTATION OF A FRONTAL BOUNDARY TO BE MEANDERING ACROSS THE
REGION DURING THE MID WEEK PERIOD...SUB SCA WINDS ARE EXPECTED.
WILL HAVE TO MONITOR MAGNITUDE OF SOUTHERLY SWELLS THROUGH MID
WEEK...BUT SEAS SHOULD LIKELY REMAIN BELOW SCA WITH WEAK FLOW.
A STRENGTHENING S-SW FLOW ON THU COULD BUILD OCEAN SEAS TO SCA...
PARTICULARLY OUT EAST. HAVE UNDERCUT WAVEWATCH BY 1-2 FT DURING
THIS TIME PERIOD DUE TO THE USUAL WARM SEASON BIAS.

COLD FRONTAL PASSAGE SOMETIME THU NIGHT INTO FRI...WITH WIND SHIFT
TO THE NW BEHIND IT. A GRADUAL SUBSIDING OF SOUTHERLY SWELLS WOULD
BE EXPECTED BEHIND THE FRONT.

&&

.HYDROLOGY...
UP TO 1/4 INCH QPF EXPECTED THROUGH TONIGHT. SCT SHOWERS/TSTMS MON
THROUGH FRI ARE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH
AN ATTENDANT LOW END FLASH FLOOD THREAT.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THIS MORNING FOR ANZ355.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350-
     353.

&&

$$