-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 221153
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
753 AM EDT WED MAY 22 2013

.SYNOPSIS...
A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST...THEN PASS THROUGH
THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN
BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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ISOLATED TSTM CONTINUE TO SINK SE ACROSS LONG ISLAND ALONG AN
OUTFLOW BOUNDARY FROM EARLIER CONVECTION. EXPECTATION IS FOR THIS
ACTIVITY TO CONTINUE TO PUSH SE THROUGH 10 AM. OTHERWISE...PLENTY
OF CLOUDS AND FOG IN THE MORNING WHICH SHOULD GRADUALLY BURN OFF
THIS MORNING INTO EARLY AFTERNOON AS A WARM FRONT JUMPS NORTH OF THE
REGION. CAMS INDICATING SCATTERED SHOWERS AND TSTMS DEVELOPS WEST
OF THE REGION THIS AFTERNOON...THEN MOVING EAST INTO THE REGION
LATER THIS AFTERNOON AND EVENING. DEPENDING ON AMOUNT OF
SUNSHINE...POTENTIAL EXISTS FOR ISOLATED STRONG TO SEVERE
STORMS...MAINLY ACROSS NORTHWESTERN INTERIOR AREAS.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
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SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS
THE UPPER LEVEL TROF AND ASSOCIATED SURFACE COLD FRONT APPROACH
THE AREA.

HIGHS TODAY WILL BE IN THE MID 80S...EXCEPT ALONG THE COAST. WITH
HIGHS ON THURSDAY IN THE MID TO UPPER 70S.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE
EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM
SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE
COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES
AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS
AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD
RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH
MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE
ALSO TRENDED A BIT SLOWER WITH PCPN GRADUALLY TAPERING OFF FRI
AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE
CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN
FURTHER.

AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION
THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO
MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM
DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF
APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD
DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT
WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED
WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF
INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE
COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE
THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN
THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD
PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH
FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS.
AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED
HIGHER AMOUNTS.

A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD ADVECTION.
HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID
ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL
DEGREES BELOW SEASONABLE LEVELS.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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A FRONTAL BOUNDARY OVER THE AREA TERMINALS WILL LIFT NORTH LATER THIS
MORNING.

MOST OF THE AREA TERMINALS ARE MVFR TO IFR...WITH SOME SUB-IFR IN
SPOTS. VERY DIFFICULT FORECAST OVER THE NEXT 2-3 HOURS CIGS VARYING
FROM 300 FT TO 1500 FT ACROSS THE AREA AND VARIABLE WINDS ANYWHERE
FROM 6KT TO 15 KT. ALL THIS COURTESY OF A FRONTAL BOUNDARY DRAPED
OVER THE AREA TERMINALS. MOST OF THE MESOSCALE MODELS INDICATE THIS
FRONTAL BOUNDARY EITHER LIFTING NORTH BETWEEN 15Z-16Z. ONCE THIS
OCCURS...WE SHOULD IMPROVE TO VFR AND WINDS WILL BECOME SOUTHERLY
AROUND 10-14KT. UNTIL THEN HOWEVER...EXPECT A LOW CONFIDENCE
FORECAST.

SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z TODAY...MAINLY
NORTH AND WEST OF THE NEW YORK TERMINALS...HOWEVER DUE TO LOW
CONFIDENCE OF TIMING AND PLACEMENT...HAVE NOT INCLUDED ANY SHOWERS
OR THUNDERSTORMS IN THE TAFS.

IT COULD BE ANOTHER TRICKY NIGHT FORECASTING SUB-VFR CONDITIONS.
LATEST GUIDANCE IS HINTING AT IFR OR LESS CONDITIONS AT THE OUTLYING
TERMINALS...HOWEVER GUIDANCE DIFFERS ON TIMING AND JUST HOW LOW CIGS
AND VSBYS GET. WILL HOLD OFF IN LOWERING CONDITIONS TOO MUCH WITH
LOW CONFIDENCE HOWEVER THIS WILL NEED TO BE MONITORED. HIGHEST
CONFIDENCE OF IFR OR LOWER CONDITIONS WILL BE AT KGON.

...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: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

KLGA FCSTER COMMENTS: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

KEWR FCSTER COMMENTS: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

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

KTEB FCSTER COMMENTS: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

KHPN FCSTER COMMENTS: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

KISP FCSTER COMMENTS: AMENDMENTS EXPECTED THROUGH 15Z FOR CHANGING
FLIGHT CATEGORIES IN STRATUS AND/OR FOG. HIGH CONFIDENCE OF WINDS
SHIFTING TO THE SOUTH BETWEEN 14Z AND 16Z.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
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&&

.MARINE...
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DENSE FOG ACROSS THE WATERS WILL CONTINUE THROUGH THIS MORNING.
E/SE WINDS THIS MORNING SHOULD BECOME S-SW THIS AFTERNOON...AND
CONTINUE THROUGH TONIGHT. SEAS SLOWLY BUILD THIS AFTERNOON TO SCA
LEVELS AND REMAIN ABV SCA LEVELS THROUGH THURSDAY.

A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY
THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE
WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS
THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE
SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY
SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS
SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH
SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST
THE MODELS.
-- End Changed Discussion --

&&

.HYDROLOGY...
SCT SHOWERS/TSTMS THIS AFTERNOON 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.

SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE
THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN
RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS.
THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD
RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE
LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT.

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...
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CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ330-335-
     338-340-345-350-353-355.
     SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT
     THURSDAY FOR ANZ350-353-355.
-- End Changed Discussion --

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...DW
AVIATION...
MARINE...
HYDROLOGY...