Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 281142
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
742 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/...
MADE MINOR CHANGES TO REFLECT THE LATEST TRENDS IN OBSERVATIONS
AND GUIDANCE. THE FORECAST APPEARS ON TRACK.

CONVECTION HAS DEVELOPED ALONG THE REMNANTS OF AN OLD FRONTAL
BOUNDARY STRETCHING FROM EASTERN ME THRU THE CWA AND INTO THE
CAROLINAS. THIS WILL PROVIDE SOME LOW LEVEL CONVERGENCE THIS
MORNING...AND COULD PRODUCE A FEW SHOWERS/ISOLATED THUNDERSTORM.
THE LIMITING FACTOR IS A LACK OF INSTABILITY...WITH ALMOST NO
SURFACE BASED CAPE...AND A FEW HUNDRED J/KG OF ELEVATED CAPE. AS
A RESULT HAVE AROUND A 30 POP FOR ACTIVITY THIS MORNING.

A COLD FRONT DRAWS CLOSER THIS AFTERNOON. MORE IMPORTANTLY...A
MID LEVEL SHORTWAVE SHOWING UP ON SATELLITE 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 SURFACE BASED
CAPEINCREASES...THE WAVE SHOULD SERVE AS A
TRIGGER...PARTICULARLY WHERE CIN IS SUFFICIENTLY ERODED. ANYWHERE
FROM NORTHEASTERN NJ THRU THE CITY INTO INTERIOR CT AND THE LOWER
HUDSON VALLEY WILL BE IN THIS ZONE PER THE LATEST DATA. LONG
ISLAND AND ERN CT SHOULD BE TOO STABLE FOR MUCH INITIATION...AND
THE FOCUS WILL LIKELY BE ON ACTIVITY SUSTAINING WITH STORM MOTION
SOUTHEASTERLY 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 BULK RICHARDSON
NUMBER 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 AT THIS TIME WHERE THE EHI
IS HIGHER.

ANY CONVECTION SHOULD DECLINE TONIGHT 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 AFTERNOON. WITH
A STABLE AIRMASS OVER THE REGION...HAVE MAINTAINED THE DRY
FORECAST. MODEL TIME HEIGHTS REVEAL A BIT OF A CHALLENGE WITH
RESPECT TO 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 LOW LEVEL 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 /12Z 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 CHANCE OF SHOWERS AND ISOLATED
THUNDERSTORMS WITH THE FRONT...HOWEVER IT APPEARS AT THIS TIME THAT
COVERAGE IS TOO LOW TO INCLUDE IN THE TAF.

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

WINDS REMAIN SOUTHERLY FOR MUCH OF THE DAY WITH SPEEDS AROUND 10 KT
WITH SOME GUSTS INTO THE TEENS THIS AFTERNOON. WINDS WILL BECOME
WESTERLY...THEN NORTHERLY AS THE FRONT MOVES ACROSS THE AREA. AS THE
WINDS BECOME MORE NORTHERLY LATE THIS EVENING...SPEED DIMINISH TO
LESS THAN 10 KT.

...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 12Z FRIDAY THROUGH MONDAY...
.FRI...VFR. LIGHT NE WINDS VEERING THRU THE DAY.
.SAT...MORNING MVFR OR LOWER POSSIBLE. CHANCE SHOWERS AND TSTMS
IN THE AFTERNOON 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...
MADE MINOR CHANGES TO REFLECT THE LATEST TRENDS IN OBSERVATIONS
AND GUIDANCE. THE FORECAST APPEARS ON TRACK.

THE SCA WAS EXTENDED ON THE OCEAN TODAY WITH SEAS IN THE 3-5FT
RANGE AND SOME GUSTS TO 25KT POSSIBLE...ESPECIALLY IN THE
AFTERNOON. SEAS MAY REMAIN CLOSE TO THE 5FT THRESHOLD
TONIGHT...BUT IT WAS TOO MARGINAL TO EXTEND THE SCA AT THIS
POINT. ALL AREAS BELOW SCA LEVELS 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 HEAVY
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...MALOIT/JMC
SHORT TERM...JMC
LONG TERM...MALOIT
AVIATION...BC
MARINE...MALOIT/JMC
HYDROLOGY...JMC/MALOIT


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