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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1031 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/...
UPDATES MAINLY TO POPS AND CLOUD COVER. INCREASED POPS FOR MUCH
OF THE CWA...BUT CAPPED THEM AT CHC.

A COLD FRONT DRAWS CLOSER THIS AFTERNOON. MORE IMPORTANTLY...A
MID LEVEL SHORTWAVE SHOULD BE ON OUR DOORSTEP AT 18Z AND CLEAR THE
CWA BY AROUND 3Z. BOTH THE 00Z NAM AND GFS SUPPORT THIS TIMING AT
H5. AS SURFACE BASED CAPE INCREASES...THE WAVE SHOULD SERVE AS A
TRIGGER...PARTICULARLY WHERE CIN IS SUFFICIENTLY ERODED AND NEAR A
PRE-FRONTAL SURFACE TROUGH. 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 /15Z THURSDAY THROUGH MONDAY/...
A COLD FRONT APPROACHES THIS AFTERNOON AND MOVES THROUGH THIS 
EVENING.

MORNING STRATUS IS EXPECTED TO BURN OFF FROM WEST TO EAST. KGON AND 
KISP WILL HOLD ON THE LONGEST.

THEN VFR OUTSIDE OF ANY CONVECTION. DO EXPECT A BROKEN LINE OF 
THUNDERSTORMS TO APPROACH NYC METRO AROUND 19Z FROM THE NORTH. WILL 
INCLUDE VICINITY FOR NOW BASED ON LOW TO MEDIUM CONFIDENCE.

FOR TONIGHT...SOME PATCHY FOG IS POSSIBLE OUTSIDE OF NYC TERMINALS. 
WILL NEED TO WATCH THIS.

SOUTH TO SOUTHWEST WINDS TODAY WILL EVENTUALLY SHIFT TO THE NORTH AND 
LIGHTEN TONIGHT. COASTAL GUSTS EXPECTED THIS AFTERNOON.
 
...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: STRATUS SHOULD SCOUR OUT BY NOON. POSSIBLE 
THUNDERSTORMS NEAR THE AIRPORT AFTER 19-20Z. THEY WOULD LIKELY 
APPROACH FROM THE NORTH.

KLGA FCSTER COMMENTS: STRATUS SHOULD SCOUR OUT BY NOON. POSSIBLE 
THUNDERSTORMS NEAR THE AIRPORT AFTER 19-20Z. THEY WOULD LIKELY 
APPROACH FROM THE NORTH.

KEWR FCSTER COMMENTS: STRATUS SHOULD SCOUR OUT BEFORE NOON. POSSIBLE 
THUNDERSTORMS NEAR THE AIRPORT AFTER 19-20Z. THEY WOULD LIKELY 
APPROACH FROM THE NORTH.

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

KTEB FCSTER COMMENTS: STRATUS SHOULD SCOUR OUT BEFORE NOON. POSSIBLE 
THUNDERSTORMS NEAR THE AIRPORT AFTER 19-20Z. THEY WOULD LIKELY 
APPROACH FROM THE NORTH.

KHPN FCSTER COMMENTS: STRATUS SHOULD SCOUR OUT BEFORE NOON. POSSIBLE 
THUNDERSTORMS NEAR THE AIRPORT AFTER 19Z. THEY WOULD LIKELY APPROACH 
FROM THE NORTH OR DEVELOP NEARBY.

KISP FCSTER COMMENTS: STRATUS SHOULD SCOUR OUT EARLY AFTERNOON. 
THUNDERSTORMS MAY APPROACH FROM THE NORTH LATE...BUT SHOULD WEAKEN 
BEFORE THEY ARRIVE AT THE AIRPORT. HOWEVER...CANNOT RULE OUT THUNDER 
LATE THIS AFTERNOON. 

.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...JMC/JC
SHORT TERM...JMC
LONG TERM...MALOIT
AVIATION...BC/PW
MARINE...JMC/MALOIT
HYDROLOGY...JMC/MALOIT

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