Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 280825
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
425 AM EDT THU MAY 28 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH TODAY...PASS TONIGHT AND DISSIPATE
OFFSHORE ON FRIDAY. THE BERMUDA HIGH BUILDS BACK TOWARDS THE
REGION FRIDAY NIGHT AND SATURDAY. A COLD FRONT APPROACHES FROM THE
NORTHWEST SATURDAY NIGHT...THEN CROSSES THE AREA ON SUNDAY. THIS
FRONT STALLS TO OUR SOUTH INTO TUESDAY WITH WAVES OF LOW PRESSURE
RIDING ALONG IT...AS HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN
CANADA. THIS HIGH THEN BUILDS DOWN INTO THE TRI-STATE FROM LATE
TUESDAY INTO WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
REMNANTS OF THE FIRST FRONT SHOW UP ON IR FROM ERN ME THRU THE
CWA AND INTO THE CAROLINAS. THIS WILL PROVIDE SOME LLVL
CONVERGENCE THRU THIS MRNG...AND COULD PRODUCE A FEW SHWRS OR AN
ISOLD TSTM. THE LIMITING FACTOR IS A LACK OF INSTABILITY. THE
MARINE INFLUENCE RESULTS IN MINUSCULE SBCAPE INVOF THE
BOUNDARY...HOWEVER THERE IS A FEW HUNDRED J/KG OF ELEVATED CAPE.
AS A RESULT HAVE AROUND A 30 POP FOR ACTIVITY THIS MRNG.

THE SECOND FRONT DRAWS CLOSER THIS AFTN. MORE IMPORTANTLY...A MID
LVL SHRTWV SHOWING UP ON STLT ACROSS WRN NY STATE IS ON THE
DOORSTEP AT 18Z AND CLEARS THE CWA BY AROUND 3Z. BOTH THE 00Z NAM
AND GFS SUPPORT THIS TIMING AT H5. AS SBCAPE INCREASES...THE WAVE
SHOULD SERVE AS A TRIGGER...PARTICULARLY WHERE CIN IS
SUFFICIENTLY ERODED. ANYWHERE FROM NERN NJ THRU THE CITY INTO
INTERIOR CT AND THE LWR HUDSON VALLEY WILL BE IN THIS ZONE PER THE
LATEST DATA. LI AND ERN CT SHOULD BE TOO STABLE FOR MUCH
INITIATION...AND THE FOCUS WILL LIKELY BE ON ACTIVITY SUSTAINING
WITH STORM MOTION SELY AROUND 10KT.

AMT OF DESTABILIZATION INLAND WILL NEED TO BE FOLLOWED ON A
MESOSCALE BASIS THRU THE DAY AS CLOUD COVER AND PENETRATION OF
THE MARINE LAYER WILL DICTATE WHERE THE ZONE OF LIKELY INITIATION
IS.

0-6KM SHEAR DECREASES THRU THE DAY. THE BEST WINDOW FOR ORGANIZED
CELLS MAY THEREFORE BE EARLIER IN THE DAY WITH A BRN AROUND 45 AT
18Z. BY 00Z...MULTICELLULAR DEVELOPMENT BECOMES FAVORED WITH LESS
CAPE/SHEAR BALANCE. POTENTIAL FOR ANY WEAK TORS LOOKS TO REMAIN N
OF THE CWA ATTM WHERE THE EHI IS HIGHER.

ANY CONVECTION SHOULD DECLINE TNGT WITH THE PASSAGE OF THE
BOUNDARY...SUBSIDENCE AND STABLE NE FLOW.

THERE IS A MDT RISK FOR RIPS AT THE OCEAN TODAY.

&&

.SHORT TERM /FRIDAY/...
THE REMNANTS OF THE COLD FRONT WILL FIZZLE OFFSHORE...ALLOWING
EARLY NE WINDS TO VEER THRU THE DAY BECOMING S BY AFTN. WITH A
STABLE AIRMASS OVER THE REGION...HAVE MAINTAINED THE DRY FCST.
MODEL TIME HEIGHTS REVEAL A BIT OF A CHALLENGE WRT TO CLOUD
COVER...AS THE NAM HAS SIGNIFICANTLY MORE MOISTURE IN THE LOWEST
3-4K FT THAN THE GFS. HAVE GONE CLOSER TO THE GFS FOR NOW BASED
ON THE AMT OF SUBSIDENCE EXPECTED AND THE NAM LLVL MOISTURE BIAS.
TEMPS WILL BE COOLER AND A BLEND OF THE GUIDANCE WAS USED.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A PROTRUSION OF THE DEEP LAYERED RIDGE OFFSHORE BUILDS OVER THE AREA
FRIDAY NIGHT...THEN SLIDES OFF TO THE EAST ON SATURDAY WITH SW FLOW
SETTING UP ALOFT. IT SHOULD BE DRY FRIDAY NIGHT DUE TO SUBSIDENCE
UNDER THE RIDGE...THEN SHOULD HAVE ENOUGH FORCING OVER NW 1/2 OF THE
CWA DUE TO LEE/THERMAL DURING THE DAY TO WARRANT SLIGHT CHANCE TO
CHANCE POPS. WITH CAPE FORECAST TO 500-1500 J/KG OVER MOST OF THIS
AREA SATURDAY AFTERNOON A FEW STRONG STORMS CANNOT BE RULED OUT.

A PASSING SHORTWAVE IN THE SW FLOW ALOFT SATURDAY NIGHT TO WARRANT
LIKELY POPS OVER FAR NW ZONES AND SLIGHT CHANCE TO CHANCE POPS FOR
SHOWERS/THUNDERSTORMS OVER THE REMAINDER OF THE NW 3/4 OF THE CWA.

INCREASE POPS ON SUNDAY TO LIKELY THROUGHOUT FOR SHOWERS WITH A
SLIGHT CHANCE OF THUNDERSTORMS - CURRENT FORECAST CAPES ARE LESS
THAN 500 J/KG - WITH THE PASSAGE OF A COLD FRONT AND A COUPLE OF
SHORTWAVES IN SW FLOW ALOFT.

FOR SUNDAY NIGHT CONTINUE WITH LIKELY POPS FOR SHOWERS WITH A WAVE
OF LOW PRESSURE RIDING ALONG THE FRONT TO THE SOUTH AND THE PASSAGE
OF A 700-500 HPA SHORTWAVE IN WSW FLOW ALOFT.

CONTINUE WITH CHANCE POPS FOR SHOWERS MONDAY/MONDAY NIGHT WITH MORE
SHORTWAVES PASSING ALOFT AND ADDITIONAL WEAK WAVES OF LOW PRESSURE
PASSING TO THE SOUTH.

ON TUESDAY HAVE COMPETITION BETWEEN NORTHERN STREAM SHORTWAVE
(INTENSITY VARIES BETWEEN THE MODELS)...AND SUBSIDENCE FROM HIGH
PRESSURE BUILDING DOWN FROM SE CANADA. NOTING GFS IS WEAKER WITH
SHORTWAVE THAN ECMWF OR CMC - HAVE CHANCE POPS FOR SHOWERS ON
TUESDAY OVER S ZONES AND SLIGHT CHANCE POPS OVER N ZONES.

A DEEP LAYERED RIDGE BEGINS TO BUILD IN FROM THE MS RIVER VALLEY
TUESDAY NIGHT/WEDNESDAY WITH ASSOCIATED SUBSIDENCE KEEPING THINGS
DRY.

FOR TEMPERATURES FRIDAY NIGHT-WEDNESDAY...

A BLEND OF MAV/ECS/MET GUIDANCE AND NAM 2-METER TEMPERATURES WAS
USED FOR LOWS FRIDAY NIGHT...WITH VALUES FORECAST TO BE AROUND 5-10
DEGREES ABOVE NORMAL.

FOR HIGHS SATURDAY A MIX DOWN FROM 975 TO 875 HPA PER BUFKIT
SOUNDINGS WAS BLENDED WITH A MIX OF MET/ECS/MAV GUIDANCE AND NAM 2-
METER TEMPERATURES...WITH HIGHS FORECAST TO BE AROUND 5 DEGREES
ABOVE NORMAL.

A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED FOR
TEMPERATURES FROM SATURDAY NIGHT-WEDNESDAY...WITH NAM 2-METER
TEMPERATURES BLENDED IN SATURDAY NIGHT AS WELL. TEMPERATURES SHOULD
BE ABOVE NORMAL SATURDAY NIGHT...NEAR NORMAL SUNDAY AND SUNDAY NIGHT
     THEN BELOW NORMAL MONDAY-TUESDAY. NEAR NORMAL TEMPERATURES ARE
CURRENTLY FORECAST TUESDAY NIGHT AND WEDNESDAY.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE REMAINS ACROSS THE NORTH ATLANTIC. MEANWHILE...AN
AREA OF LOW PRESSURE WILL MOVE THROUGH EASTERN CANADA TODAY BRINGING
A WEAKENING COLD FRONT TOWARD THE AREA THIS AFTERNOON. THE FRONT
IS EXPECTED TO CROSS THE LOWER HUDSON VALLEY DURING THE LATE
AFTERNOON/EVENING...AND MOVE THROUGH THE NYC AREA TERMINALS
SHORTLY AFTER 00Z FRIDAY. THERE IS A LOW CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS WITH THE FRONT.

STRATUS DEVELOPS THIS MORNING WITH MVFR/IFR CEILINGS BETWEEN 800
AND 2000 FT. LOCAL MVFR FOG IS ALSO POSSIBLE. CEILINGS BECOME VFR
AFTER 15Z. MODERATE CONFIDENCE IN THE FORECAST OF STRATUS AND
FOG.

...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 LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

KLGA FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

KEWR FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

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

KTEB FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

KHPN FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

KISP FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF
IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY
LIKELY EXPECTED BETWEEN 14Z AND 15Z.

.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
.THU NIGHT...COLD FRONT MOVES THROUGH EARLY IN THE EVENING WITH THE
WIND SHIFTING TO NW TO N. VFR.
.FRI...VFR. LGT NE WINDS VEERING THRU THE DAY.
.SAT...MRNG MVFR OR LOWER POSSIBLE. CHC SHWRS AND TSTMS IN THE
AFTN AND OVERNIGHT WITH MVFR OR LOWER. STRONG SLY FLOW.
.SUN...MVFR OR LOWER IN SHOWERS/TSTMS POSSIBLE. SHIFTING WINDS TO
THE E/NE.
.MON...POSSIBLE IMPROVEMENT TO VFR IF SHOWERS/TSTMS MOVE TO THE
SOUTH. E/NE FLOW.

&&

.MARINE...
THE SCA WAS EXTENDED ON THE OCEAN TODAY WITH SEAS IN THE 3-5FT
RANGE AND SOME GUSTS TO 25KT POSSIBLE...ESPECIALLY IN THE AFTN.
SEAS MAY REMAIN CLOSE TO THE 5FT THRESHOLD TNGT...BUT IT WAS TOO
MRGNL TO EXTEND THE SCA AT THIS POINT. ALL AREAS BLW SCA LVLS ON
FRI.

SUB-SMALL CRAFT CONDITIONS ARE EXPECTED ON ALL WATERS FRIDAY NIGHT.
S FLOW INCREASES SATURDAY AFTERNOON WITH GUSTS UP TO 20 KT POSSIBLE
ON ALL WATERS. THIS COULD BE SUFFICIENT TO BRING SEAS ON THE COASTAL
OCEAN WATERS TO AROUND 5 FT. SEAS COULD THEN REMAIN AT SCA LEVELS ON
THE COASTAL OCEAN WATERS SATURDAY NIGHT-MONDAY. AT THIS TIME SUB-
SMALL CRAFT CONDITIONS ARE EXPECTED FOR LONG ISLAND SOUND/NEW YORK
HARBOR/THE BAYS OF LONG ISLAND SATURDAY NIGHT-MONDAY.

&&

.HYDROLOGY...
WIDESPREAD SIGNIFICANT RAINFALL IS NOT EXPECTED TODAY...HOWEVER
ANY TSTMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING LOCALLY HVY
RAIN.

IT SHOULD BE DRY FRIDAY NIGHT AND SATURDAY MORNING.

THERE IS THE POTENTIAL FOR A WIDESPREAD SIGNIFICANT RAINFALL FROM
LATE SATURDAY THROUGH TUESDAY ACROSS THE TRI-STATE. AT THIS TIME IT
IS TOO EARLY TO SPECIFY ANY AMOUNTS. IN ADDITION...FROM LATE
SATURDAY THROUGH SUNDAY...ANY STRONGER CONVECTION COULD PRODUCE
LOCALLY HEAVY RAINFALL...WHICH COULD RESULT IN AT LEAST THE MINOR
FLOODING OF URBAN/POOR DRAINAGE AREAS.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350-
     353-355.

&&

$$
SYNOPSIS...JMC/MALOIT
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...MALOIT
AVIATION...BC
MARINE...JMC/MALOIT
HYDROLOGY...JMC/MALOIT


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