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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 201546
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1146 AM EDT MON MAY 20 2013

.SYNOPSIS...
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A WARM FRONT NORTH OF THE AREA SINK SOUTH CLOSER TO THE AREA ON
TUESDAY...THEN LIFT BACK NORTH AS A WARM FRONT ON WEDNESDAY. A
WARM AND HUMID AIR MASS WILL THEN REMAIN UNTIL A COLD FRONT MOVES
THROUGH THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE WILL RETURN FOR
THE WEEKEND.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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CLEARING HAS BEGUN AND EXPECT PARTLY TO MOSTLY SUNNY THIS
AFTERNOON.

LOW PRESSURE RIDES ALONG A FRONT WELL TO THE NORTH TODAY.
WEAK FRONTAL BOUNDARY TO THE SOUTH SHOULD WEAKEN AND DISSIPATE
THIS MORNING.

HOW MUCH CLEARING OCCURS WILL DETERMINE THE AMOUNT OF DAYTIME
HEATING/INSTABILITY...WHICH WILL AID IN TSTM DEVELOPMENT THIS
AFTERNOON AND EVENING...HOWEVER...THINKING COVERAGE WILL BE ISOLD
TO WDLY SCT AT BEST. WITH PW NEAR 1.5 INCHES...ANY SHOWER/TSTM
COULD PRODUCE LOCALLY HEAVY RAIN. MAINTAINED CHANCE POP INLAND
NORTH/WEST OF NYC...BUT REDUCED POP ELSEWHERE AS MARITIME
INVERSION SHOULD INHIBIT MOST CONVECTION.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
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FRONTAL BOUNDARY REMAINS JUST TO THE NORTH AS RIDGE PREVAILS ACROSS
THE NORTHEAST AHEAD OF UPSTREAM TROUGH.

SOUTHWEST LOW LEVEL FLOW WILL LIGHTEN THIS EVENING...AND AMPLE
MOISTURE COULD LEAD TO THE DEVELOPMENT OF FOG ONCE AGAIN.
ANY LINGERING DIURNAL SHOWERS/TSTMS WILL DIMINISH IN
COVERAGE...AND MOST OF THE NIGHT SHOULD BE DRY.

WITH AREA IN THE WARM SECTOR...TEMPERATURES WILL REMAIN QUITE
MILD...50S TO AROUND 60.

ON TUESDAY...TEMPS WARM THROUGH THE 70S...TO AROUND 80 AWAY FROM
THE WATER...WITH 70S ELSEWHERE. ANY MORNING FOG WILL BURN OFF TO
PARTLY SUNNY SKIES. AFTERNOON SHOWERS OR THUNDERSTORMS ARE
POSSIBLE ONCE AGAIN.
-- End Changed Discussion --

&&

.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 DOES NOT BRING THE BACKDOOR COLD FRONT
THROUGH THE CWA TUESDAY NIGHT...BUT ITS STILL QUESTIONABLE WHETHER
IT SINKS INTO THE AREA OR REMAINS JUST N. HAVE TRENDED IN THIS
DIRECTION AND BROUGHT IT ABOUT HALFWAY THROUGH...BUT TEMPS TUE NIGHT
WILL BE AFFECTED BY THIS. THE BOUNDARY THEN LIFTS 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.

MODELS HAVE COME BETTER INTO LINE WITH THE PHASING OF THE MIDWEST
UPPER TROUGH AND EASTERN CANADIAN UPPER TROUGH AT THE END OF THE
WEEK. COLD FRONT LOOKS TO TRACK THROUGH THE AREA THU NIGHT. A
PRE-FRONTAL TROUGH IN THE WARM...MOIST AIR MASS PRECEDING THE FRONT
ON THU...WILL BE THE TRIGGER FOR SCT SHOWERS AND TSTMS DURING THE
AFTN AND EVE HOURS. THERE IS THE POTENTIAL FOR SOME STORMS TO BE
STRONG TO SEVERE BASED ON LATEST PROFILES. LINGERING SHOWERS ARE
POSSIBLE ON FRI WITH THE UPPER TROUGH MOVING THROUGH.

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 /15Z MONDAY THROUGH FRIDAY/...
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WARM FRONT NORTH OF THE REGION TODAY WITH MORNING FOG AND STRATUS
BURNING OFF BY EARLY AFTERNOON.

HIGH CONFIDENCE IN BECOMING VFR THIS AFTERNOON AS SOUTHWEST LOW
LEVEL FLOW ALLOWS THE MORNING FOG AND STATUS TO BURN OFF/MIX OUT.
AS OF 1330Z...IMPROVEMENT IS SEEN ON VISIBLE SATELLITE IMAGERY.
FIRST AREA TO IMPROVE WILL BE THE NYC METRO WITH EASTERN TERMINAL
HOLDING ON AN HOUR OR TWO MORE.

A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN THE LATE
AFTERNOON...MAINLY NORTH OF THE NY METRO.

PATTERN EXPECTED TO REPEAT ITSELF ON TUESDAY.

...NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: HIGH CONFIDENCE IN IMPROVEMENT TO VFR THIS
AFTERNOON. MAY BE SOONER...AN HOUR OR SO...THAN FCST.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN IMPROVEMENT TO VFR THIS
AFTERNOON. MAY BE SOONER THAN FCST. HIGH CONFIDENCE IN WIND FCST.

KLGA FCSTER COMMENTS: HIGH CONFIDENCE IN IMPROVEMENT TO VFR THIS
AFTERNOON. LOOKS LIKE IT WILL OCCUR SOONER THAN FCST.

KTEB FCSTER COMMENTS: HIGH CONFIDENCE IN IMPROVEMENT TO VFR THIS
AFTERNOON. MAY BE SOONER...AN HOUR OR SO...THAN FCST.

KHPN FCSTER COMMENTS: HIGH CONFIDENCE IN IMPROVEMENT TO VFR THIS
AFTERNOON. MAY BE SOONER...AN HOUR OR SO...THAN FCST.

KISP FCSTER COMMENTS: MODERATE CONFIDENCE IN IMPROVEMENT TO VFR
THIS AFTERNOON. MAY BE SOONER...AN HOUR OR SO...THAN FCST.

.OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
.TUE-FRI...DURING THE DAY...A CHANCE OF MVFR OF LOWER CONDITIONS
IN SHOWERS/TSTMS. AT NIGHT...A CHANCE OF MVFR OF LOWER CONDITIONS
IN LOW STRATUS/FOG.
-- End Changed Discussion --

&&

.MARINE...
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VSBYS CONTINUE TO IMPROVE ESPECIALLY ON THE WESTERN WATERS.
DENSE FOG ADVY WILL BE ALLOWED TO EXPIRE AT NOON...BUT PATCHY FOG
STILL POSSIBLE INTO THE AFTERNOON AND EVENING.

SEAS WERE 5.6 FT IN STEEP S-SE SWELL AT TEXAS TOWER BUOY 44066
LATE THIS MORNING...AND ARE UNLIKELY TO DECAY MUCH AS THEY ARRIVE
THIS AFTERNOON...SO SCA FOR HAZARDOUS OCEAN SEAS WILL CONTINUE.

MARGINAL SCA SEAS ARE POSSIBLE ON THE OCEAN INTO TONIGHT...BUT
WAVEWATCH IS STILL RUNNING A BIT HIGH...SO HAVE ONLY MEDIUM
CONFIDENCE IN EXTENDING THE ADVY INTO TONIGHT.

A GENERAL SOUTHERLY FLOW WILL PREVAIL TODAY THROUGH TUESDAY.
SEAS SHOULD SLOWLY SUBSIDE TONIGHT AND TUESDAY...WITH MAINLY SUB
SCA CONDITIONS ANTICIPATED.

DUE TO THE POOR PERFORMANCE OF WAVEWATCH OVER THE LAST 2 DAYS...HAVE
LOW CONFIDENCE IN ITS FORECAST DURING THE LONG TERM PERIOD. SCA FOR
SEAS MAY BE NEEDED ON THE OCEAN WATERS TUE NIGHT. AS THE PRES
GRADIENT INCREASES ON WED...SUSTAINED WINDS WILL INCREASE WITH SEAS
LIKELY AT SCA LEVELS. A STRONG INVERSION OVER THE WATERS WILL
INHIBIT WINDS ALOFT FROM MIXING DOWN...ALTHOUGH WINDS COULD REACH
SCA LEVELS ON THE OCEAN THU/THU EVE. THE PRES GRADIENT RELAXES AS A
COLD FRONT MOVES INTO THE WATERS THU NIGHT AND WINDS AND SEAS WILL
DIMINISH BELOW SCA LEVELS THROUGH THE REST OF THE PERIOD.
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&&

.HYDROLOGY...
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ISOLD TO WIDELY SCT SHOWERS AND TSTMS COULD PRODUCE LOCAL
DOWNPOURS TODAY...MAINLY WELL NORTH/WEST OF NYC.

SCT SHOWERS/TSTMS TUE-FRI ARE ALSO CAPABLE OF PRODUCING LOCALLY
HEAVY RAINFALL...WITH AN ATTENDANT LOW END FLASH FLOOD THREAT.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ330-335-338-340-
     345-350-353-355.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS
     EVENING FOR ANZ350-353-355.
-- End Changed Discussion --

&&

$$