National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 211046
AFDOKX

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

.SYNOPSIS...
A FRONTAL BOUNDARY REMAINS JUST NORTH OF THE AREA TODAY THROUGH WEDNESDAY.
A COLD FRONT WILL PASS THROUGH THE AREA THURSDAY EVENING INTO
THURSDAY NIGHT. HIGH PRESSURE WILL RETURN FOR THE WEEKEND AND EARLY
NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
MINOR UPDATE TO TEMPS/DEWPTS TO REFLECT CURRENT OBS TRENDS.
OTHERWISE...WILL CONTINUE TO MONITOR FOG/STRATUS EARLY THIS
MORNING. LACK OF OBS HAS MADE IT MORE DIFFICULT EARLY THIS MORNING
TO ASCERTAIN EXTENT OF FOG THIS MORNING...BUT WILL MAINTAIN DENSE
FOG ADVISORY FOR NOW.

FRONTAL BOUNDARY REMAINS TO THE NORTH AS RIDGE BUILDS ALOFT. THE
FRONT WILL MOVE LITTLE AS IT REMAINS PARALLEL TO UPPER FLOW.

A GENERAL SOUTH TO SOUTHWEST FLOW PREVAILS...AND EXPECT
TEMPERATURES AWAY FROM THE SOUTH FACING SHORES TO SOAR TODAY. H8
HPA TEMPS 12-16C...AND FORECAST SOUNDINGS INDICATE TEMPS TO 30C OR
GREATER DURING MAX HEATING. MOS TEMPS GENERALLY ACCEPTED WITH 80S
MANY LOCATIONS...EXCEPT 70S ERN LONG ISLAND AND SERN CT.

MARGINAL INSTABILITY IS EXPECTED TO BUILD BY AFTERNOON...ASSUMING
DEW POINTS REMAIN IN THE MIDDLE 60S. HOWEVER...THESE DEW POINTS
LIKELY MIX OUT SLIGHTLY AS LAPSE RATES STEEPEN. THERMAL TROUGH
COULD BE THE FOCUS FOR SOME CONVECTION...BUT THE BULK OF THE
SHOWERS AND TSTMS SHOULD RIDE ALONG THE FRONT. AS SUCH...INTERIOR
SECTIONS SHOULD SEE HIGHEST CHANCES FOR PRECIP THIS
AFTERNOON...BUT MESOSCALE MODEL FCST REFLECTIVITY MOVING SE TOWARD
CSTL LOCALES BY EVENING...ALTHOUGH LIKELY WEAKENING AS THEY HIT THE
MARINE LAYER.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
ANY LINGERING CONVECTION THIS EVENING SHOULD DIMINISH IN COVERAGE
AS THE NIGHT PROGRESSES. ALTHOUGH FRONTAL BOUNDARY NEARBY COULD
TRIGGER AN ISOLATED SHOWER OR TSTM OVERNIGHT. MAIN ISSUE TONIGHT
WILL BE THE DEVELOPMENT OF FOG ONCE AGAIN AS SOUTHERLY WINDS
PREVAIL AND THE AIRMASS REMAINS QUITE MOIST.

LOWS WILL BE QUITE WARM...60S PER MOS.

FOR WEDNESDAY...RIDGE SLOWLY SHIFTS EAST AS UPSTREAM TROUGH
FINALLY MAKES EASTWARD PROGRESS. HOWEVER...ANOTHER WARM DAY IS ON
TAP. MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST PARTIAL
SUNSHINE. ONCE AGAIN...CONVECTION SHOULD BE SCATTERED AT BEST WITH
WEAK TO MARGINAL INSTABILITY IN PLACE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A COLD FRONT IS EXPECTED TO DROP SOUTHEAST FROM NEAR THE CANADIAN
BORDER WEDNESDAY NIGHT INTO THURSDAY MORNING. THE COLD FRONT IS
EXPECTED TO MOVE ACROSS THE AREA THURSDAY EVENING TRIGGERING SCT
SHOWERS AND THUNDERSTORMS. THIS FRONT WILL THEN MOVE OFFSHORE BY
FRIDAY MORNING WITH A WAVE OF LOW PRESSURE MOVING NORTHEAST ALONG
IT...KEEPING SHOWERS ACROSS THE AREA THROUGH FRIDAY AFTERNOON.

EXPECT HIGHS ON THURSDAY TO BE IN THE MID TO UPPER 70S WITH LOWS
THURSDAY NIGHT IN UPPER 50S TO AROUND 60.

FRIDAY NIGHT THROUGH MONDAY...AN AREA OF HIGH PRESSURE WILL
DROP SOUTHEAST FROM CENTRAL CANADA INTO THE CENTRAL US AND BUILD
EASTWARD THROUGH MEMORIAL DAY. HIGHS SATURDAY THROUGH MEMORIAL DAY
ARE EXPECTED TO BE IN THE UPPER 60S TO AROUND 70 WITH LOWS IN THE
MID 40S TO LOWER 50S.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
A FRONTAL BOUNDARY DRAPED FROM W TO E THROUGH NEW ENGLAND WILL
REMAIN NEARLY STATIONARY TODAY. IT MAY SINK SLIGHTLY S BUT IS
EXPECTED TO REMAIN N OF THE TERMINALS.

FOG HAS FINALLY BECOME MORE WIDESPREAD EARLY THIS MORNING. CONDS
RANGING MVFR TO LIFR OUTSIDE OF NYC TERMINALS WHERE CONDS REMAIN
MAINLY VFR WITH THE EXCEPTION OF KJFK. EXACT TIMING OF IMPROVEMENT
IS TRICKY BUT VFR SHOULD RETURN BETWEEN 14-17Z ALL TERMINALS. VFR
THEN EXPECTED INTO THE EVE BEFORE FOG/STRATUS RETURNS.

MEANWHILE...A COLD FRONT WILL SLOWLY SAG DOWN FROM THE NORTH WITH
A SFC TROUGH DEVELOPING IN THE LEE OF THE APPALACHIANS. CONVECTION
WILL LIKELY FIRE NEAR BOTH 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.

     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)

KJFK FCSTER COMMENTS: TIMING OF FOG/STRATUS IMPROVEMENT THIS
MORNING IS UNCERTAIN. MAY BE +/- 1-2 HOURS.

KLGA FCSTER COMMENTS: FOG/STRATUS MAY NOT OCCUR THIS MORNING. IF
IT DOES...TIMING OF IMPROVEMENT MAY BE +/- 1-2 HOURS.

KEWR FCSTER COMMENTS: FOG/STRATUS MAY NOT OCCUR THIS MORNING. IF
IT DOES...TIMING OF IMPROVEMENT MAY BE +/- 1-2 HOURS.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES  SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: IFR FOG/STRATUS MAY NOT OCCUR THIS MORNING.
IF IT DOES...TIMING OF IMPROVEMENT MAY BE +/- 1-2 HOURS.

KHPN FCSTER COMMENTS:TIMING OF FOG/STRATUS IMPROVEMENT THIS
MORNING IS UNCERTAIN. MAY BE +/- 1-2 HOURS.

KISP FCSTER COMMENTS: TIMING OF FOG/STRATUS IMPROVEMENT THIS
MORNING IS UNCERTAIN. MAY BE +/- 1-2 HOURS.

.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...
DENSE FOG ACROSS THE WATERS THIS MORNING SHOULD IMPROVE SOME BY
AFTERNOON. SOUTH WINDS PREVAIL THROUGH THE DAY TODAY...BUT SUB SCA
CONDITIONS ARE ANTICIPATED.

CONTINUED SOUTH TO SOUTHWEST FLOW IS FORECAST FOR TONIGHT AND
WEDNESDAY AS A FRONTAL BOUNDARY REMAINS TO THE NORTH. DEEP LOW
LEVEL INVERSION AND MINIMAL TEMP/DEW POINT SPREAD WILL WARRANT
INCLUSION OF FOG OVER THE WATERS TONIGHT AND POSSIBLY INTO
WEDNESDAY.

SEAS WILL REMAIN BELOW 5 FT OVER THE OCEAN WATERS...1 FT OR LESS
ELSEWHERE TODAY AND LIKELY TONIGHT.

LATEST WAVE WATCH III GUIDANCE FOR THE OCEAN WATERS SUGGEST 5 TO
6 FT SEAS BY WEDNESDAY DUE TO PERSISTENT SOUTH FLOW AND POSSIBLE
SOUTHERLY SWELL. HOWEVER...WAVE WATCH HAS BEEN OVERFORECASTING
SEAS BY A FOOT OR TWO...SO CONFIDENCE IN THIS HAPPENING IS NOT
HIGH AT THIS TIME.

SEAS EXPECTED TO BE ABOVE SCA LEVELS WEDNESDAY NIGHT...WITH 25 KT
WIND GUSTS POSSIBLE ON THE OCEAN WATERS BY WEDNESDAY EVENING. A COLD
FRONT WILL MOVE ACROSS THE AREA WATERS THURSDAY EVENING INTO
THURSDAY NIGHT...WITH HIGH PRESSURE BUILDING IN AT THE SURFACE ON
LATE ON FRIDAY. WINDS COULD BE BELOW SCA LEVELS BY FRIDAY
MORNING...WITH SEAS REMAINING ABOVE SCA CRITERIA THROUGH SATURDAY
MORNING.

&&

.HYDROLOGY...
ISOLATED TO SCT SHOWERS OR TSTMS LATE IN THE DAY TODAY...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.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.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.

&&

$$