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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 210700
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
300 AM EDT TUE MAY 21 2013

.SYNOPSIS...
A WARM FRONT NORTH OF THE AREA WILL SINK SOUTH CLOSER TO THE AREA
LATER TODAY...THEN LIFT BACK NORTH AS A WARM FRONT ON WEDNESDAY.
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE AREA UNTIL A COLD
FRONT MOVES THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL RETURN FOR
THE WEEKEND AND EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
BROKEN TO SCATTERED STRATUS REMAINS OVER LONG ISLAND FROM NEAR
ISLIP AND EAST. FOG BANK SOUTH OF LONG ISLAND STILL EXPECTED TO
EXPAND NORTHWARD TONIGHT. WILL CONTINUE WITH THE DENSE FOG ADVY
ALTHOUGH DELAYED DENSE FOG IN FORECAST PER OBS/ SAT IMAGERY.
DO NOT EXPECT MUCH CHANGE IN TEMPS OVERNIGHT FROM CURRENT
READINGS...MAINLY LOWER 60S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
FRONTAL BOUNDARY WILL REMAIN TO THE NORTH ON TUE AS RIDGE PREVAILS
ACROSS THE NORTHEAST AHEAD OF UPSTREAM TROUGH...THEN DROP S INTO
SOUTHERN CT AND PERHAPS ERN LONG ISLAND TUE NIGHT. THE FRONT
SHOULD BE PRECEDED BY DIURNAL CONVECTION MAINLY INLAND LATE TUE
AFTERNOON AND EARLY EVENING...THEN A GENERAL CHANCE FOR SHOWERS
AND ISOLD THUNDER LATER TUE NIGHT.

TUE SHOULD FEATURE MORE SUNSHINE THAN TODAY AFTER MORNING FOG
BURNS OFF...AND WITH ARE MORE FIRMLY ENTRENCHED IN THE WARM SECTOR
EXPECT HIGHS IN THE 80S INLAND AND ALONG THE NORTH SHORE OF WRN
LONG ISLAND...AND 70S IN COASTAL CT AND THE REST OF LONG ISLAND.

LOW CLOUDS AND FOG SHOULD REDEVELOP TUE NIGHT...MAINLY LATER AT
NIGHT AS IT WILL TAKE BLYR LONGER TO COOL DOWN CLOSER TO
DEW POINTS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS COMING INTO BETTER AGREEMENT ABOUT THE MAIN FEATURES OF THE
WEEK. LONG TERM STARTS OUT WITH UPPER RIDING OVER THE AREA WITH
A MIDWEST TROUGH BEGINNING TO PHASE WITH A CANADIAN TROUGH. A WARM
FRONT WILL BE TO THE NORTH OF THE AREA BY WEDNESDAY...EXTENDING FROM
A LOW PRESSURE AREA OVER THE MIDWEST.

A WARM SOUTHERLY FLOW SETS UP BEHIND THE WARM FRONT...ALLOWING TEMPS
ON WEDNESDAY TO WARM TO ABOVE NORMAL VALUES. THERE IS A WIDE RANGE
OF HIGH TEMP VALUES ON WED...NAM 2M TEMPS HAS HIGHS IN THE LOWER 90S
OUT WEST...WHICH COULD POSSIBLY BE DUE TO DIFFERENCES IN CLOUD
COVER. HAVE LEANED TOWARD THE WARMER MET...NOT AS WARM AS THE
NAM...WITH HIGHS IN THE MIDDLE 70S TO MIDDLE TO UPPER 80S. LOWS
WILL BE SLIGHTLY ABOVE NORMAL.

ALSO ON WEDNESDAY...WITH THE MOIST SOUTHERLY FLOW NEAR THE WARM
FRONTAL BOUNDARY...THUNDERSTORMS ARE POSSIBLE. ML AND SFC CAPE WEST
OF NYC WILL BE REACHING ABOVE 1000 J/KG IN THE AFTERNOON ALONG WITH
DECENT LOW LEVEL LAPSE RATES. EVEN WITH THE FRONT NEARBY...LIFT MAY
NOT BE STRONG ENOUGH TO GENERATE ANY WIDESPREAD THUNDERSTORMS. ANY
THUNDERSTORMS THAT DO DEVELOP MAY PRODUCE HEAVY RAIN WITH PW ABOVE
1.5 INCHES. ONLY HAVE CHANCE POPS IN WED AS THERE IS SOME
DISCREPANCY ON THE TIMING OF THE PRECIP APPROACHING THE AREA AND THE
COVERAGE OF IT.

DEEP TROUGH THEN DEVELOPS OVER THE MIDWEST ON THURSDAY AND TRACKS
EAST WITH THE ASSOCIATED LOW PRESSURE TRACKING NE INTO CANADA AND
DRAGGING A COLD FRONT SOUTH OF IT. COLD FRONT APPROACHES THURSDAY
EVENING WITH A PRE FRONTAL TROUGH DEVELOPING AHEAD OF IT...ONCE
AGAIN TRIGGERING SCT SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE
SLIGHTLY LESS THAT WED BUT BETTER LIFT WILL BE EVIDENT. STILL NOT
EXPECTING ANYTHING SEVERE BUT MAY SEE STRONG STORMS THAT WED. DO
HAVE LIKELY POPS IN FOR THURSDAY AFTERNOON AND EVENING AS MODELS ARE
IN GOOD AGREEMENT OF THE TIMING OF THE RAINFALL. TEMPS WILL BE
COOLER THAN WEDNESDAY...A FEW DEGREES ABOVE NORMAL.

THE TROUGH MOVES EAST AND RAIN ENDS WEST TO EAST BY FRIDAY AFTERNOON
WITH HIGH PRESSURE BUILDING IN ITS WAKE AND WINDS SHIFTING TO THE
NORTHWEST. MEMORIAL DAY WEEKEND WILL BE DRY WITH TEMPS RIGHT AT
NORMAL. HIGHS WILL WILL BE IN THE UPPER 60S TO LOWER 70S FRI-MON.
LOWS WILL BE IN THE MIDDLE 40S TO LOWER 50S.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
WARM...MOIST AIR OVER THE REGION IS RESULTING IN THE FORMATION OF
FOG. CONDS RANGING FROM VFR TO LIFR ACROSS THE AREA...BUT VSBYS
HAVE BEEN TRENDING DOWN AND EXPECT THIS TO CONTINUE THROUGH
SUNRISE. SW FLOW TYPICALLY DOES NOT PRODUCE WIDESPREAD LIFR/VLIFR
FOG...BUT THE BEST CHANCE WOULD BE AT KBDR/KISP/KGON WITH THE FLOW
OFF THE WATER. KHPN IS ALSO EXPECTED TO DROP TO THESE LEVELS AS
WELL. THE REST OF THE TERMINALS SHOULD EVENTUALLY REACH AT LEAST
IFR...BUT TIMING AND DURATION IS UNCERTAIN. AMENDMENTS MAY BE
NEEDED THROUGH INTO THE DAYLIGHT HOURS. PATCHY LIFR STRATUS MAY
ALSO DEVELOP...HOWEVER IT`S A BIT DIFFICULT TO SEE ON IR SAT DUE
TO THIN HIGH CLOUDS. CONDS GRADUALLY IMPROVE TO VFR BY MIDDAY.

MEANWHILE...A COLD FRONT WILL SLOWLY SAG DOWN FROM THE NORTH WITH
A SFC TROUGH DEVELOPING IN THE LEE OF THE APPALACHIANS. CONVECTION
MAY FIRE ON EITHER OF THESE BOUNDARIES...BUT THERE`S SOME QUESTION
HOW FAR S AND W TSTMS WILL MAKE IT BEFORE THE FIZZLE DUE TO THE
LOSS OF DAYTIME HEATING. ONLY HAVE TEMPO AT KSWF LATE THIS
AFTN/EARLY EVE FOR THIS.

FOG/STRATUS LIKELY TONIGHT...HOWEVER TIMING IS UNCERTAIN.

.OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
.TUE NGT...BECOMING IFR WITH FOG AND STRATUS.
.WED-FRI...SCT SHOWERS/TSTMS. AT NIGHT...IFR POSSIBLE
WITH STRATUS/FOG.
.SAT...VFR.
-- End Changed Discussion --

&&

.MARINE...
SEAS REMAIN BELOW 5 FT...SO HAVE CANCELLED SCA FOR HAZ SEAS.

DENSE FOG IS EXPECTED AND ADVISORY REMAINS THROUGH THE MORNING.
THE DENSE FOG COULD LAST ON THE OCEAN INTO TUE NIGHT OR WED
MORNING.

SEAS AND SOUTHERLY WINDS WILL INCREASE ON WED VIA A TIGHTENING
PRESSURE GRADIENT. SEAS COULD BE ABOVE 5 FT BY WED
AFTERNOON...WITH 25 KT WIND GUSTS POSSIBLE ON THE OCEAN WATERS BY
WED EVENING. A COLD FRONT WILL MOVE ACROSS LATE THU NIGHT...WITH
HIGH PRESSURE BUILDING IN AT THE SURFACE ON FRI. WINDS COULD BE
BELOW SCA CRITERIA BY EARLY FRI MORNING...WITH SEAS REMAINING
ABOVE 5 FT THROUGH FRI AFTERNOON. SOME UNCERTAINTY EXISTS ON THE
TIMING OF THE COLD FROPA AND THE INCREASE OF WINDS ON WED.

&&

.HYDROLOGY...
ISOLD TO WIDELY SCT SHOWERS OR TSTMS LATE IN THE DAY TUE...MAINLY
INLAND. IMPACTS WILL BE MINIMAL.

SCT SHOWERS/TSTMS WED-THU WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY
RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN
AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER
AMTS IN TSTMS.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ009>012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ071-
     078>081-177-179.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ330-335-338-340-
     345-350-353-355.

&&

$$