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Area Forecast Discussion
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000
FXUS61 KOKX 252030
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
430 PM EDT FRI JUL 25 2014

.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT INTO SATURDAY. A WARM
FRONT MOVES THROUGH SATURDAY NIGHT...FOLLOWED BY A COLD FRONT
MONDAY. THE COLD FRONT MOVES ACROSS MONDAY NIGHT. HIGH PRESSURE
THEN BUILDS IN BEHIND THE COLD FRONT BY MID WEEK NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AN OVERALL BLOCKING PATTERN WILL LINGER...WITH AN UPPER LOW CENTERED 
JUST EAST OF THE HUDSON BAY INFLUENCING WEATHER ACROSS THE REGION 
THROUGH THE WEEKEND. ANOTHER UPPER LEVEL DISTURBANCE ROTATING AROUND 
THE BASE OF THE TROUGH WILL PASS THROUGH THE AREA TONIGHT...WITH 
ONLY A SLIGHT INCREASE IN CLOUDINESS EXPECTED.

AS THE SURFACE HIGH SHIFTS OFFSHORE...S/SW FLOW ACROSS THE AREA WILL
BRING A GRADUAL INCREASE IN MOISTURE OVERNIGHT...WITH LOWS
GENERALLY CLOSER TO NORMAL AND A FEW DEGREES WARMER THAN LAST
NIGHT.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
FOR SATURDAY...THERE WILL BE A MODERATE RISK OF RIP CURRENTS ALONG 
ATLANTIC FACING BEACHES.

AN APPROACHING UPPER LEVEL JET WILL LEAD TO SURFACE 
PRESSURE FALLS ACROSS THE EAST. MODELS GENERALLY SUGGEST A CORRIDOR 
OF FAVORABLE SURFACE CONVERGENCE DEVELOPING ACROSS NJ AND WEST OF 
NYC WHERE THUNDERSTORMS SHOULD INITIATE LATE IN THE AFTERNOON AS 
CINH ERODES. HIGH TEMPS WILL BE A FEW DEGREES WARMER THAN THE 
PREVIOUS DAY...PRIMARILY ACROSS THE INTERIOR WHERE THE MARITIME 
INFLUENCE WILL NOT BE FELT.

BY SATURDAY NIGHT INTO SUNDAY MORNING...A WARM FRONT WILL FINALLY 
MOVE NORTHEASTWARD/POLEWARD THROUGH THE FORECAST AREA. A
CONCURRENT SHORT WAVE ALOFT WILL AID IN THUNDERSTORM DEVELOPMENT
OVERNIGHT INTO THE MORNING. AS LOW LEVEL MOISTURE INCREASES AND
WEST-NORTHWEST FLOW ALOFT ADVECTS STEEPER MID-LEVEL LAPSE RATES
INTO THE REGION...INSTABILITY WILL INCREASE OVERNIGHT. THE
INCREASED INSTABILITY COMBINED WITH 30-40KT OF 0-6KM SHEAR MAY BE
SUFFICIENT FOR ISOLATED SMALL HAIL. ALTHOUGH A WEAK INVERSION WILL
EXIST AROUND 850 HPA...A BRIEFLY ROTATING STORM AND/OR WEAK
TORNADO NEAR THE WARM FRONT...ESPECIALLY ALONG THE SOUTH SHORE OF
THE NYC BOROUGHS AND LONG ISLAND CANNOT BE RULED OUT.
ADDITIONALLY...PWAT VALUES NEAR 1.85 INCH INDICATE HEAVY RAIN
POTENTIAL IN ANY THUNDERSTORMS THAT DEVELOP.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
RELATIVELY ACTIVE WEATHER PATTERN FEATURED IN THE LONG TERM AND HAS 
BEEN PRESENT AT OTHER TIMES THIS SUMMER...AN UPPER LEVEL TROUGH WILL 
BE SETTING UP ACROSS THE NORTHEAST. THIS LINGERS THROUGH MUCH OF THE 
LONG TERM PERIOD.

AT THE SURFACE...A PARENT LOW MOVING ACROSS SOUTHERN QUEBEC INTO 
NORTHERN NEW ENGLAND WILL HAVE AN ASSOCIATED WARM FRONT MOVING 
ACROSS EARLY SUNDAY. THE ASSOCIATED COLD FRONT WILL STAY NORTH AND 
WEST OF THE REGION THROUGH THE REST OF SUNDAY AND SUNDAY 
NIGHT...WITH AN AREA OF LOW PRESSURE APPROACHING THE AREA ALONG THE 
FRONT.

WITH SOME PATCHY FOG AND CONVECTION SUNDAY MORNING...THERE COULD BE 
A BRIEF RESPITE BEFORE ANOTHER ROUND OF CONVECTION DEVELOPS WITH 
AFTERNOON HEATING. SREF POPS WERE PREFERRED HERE AS THEY HAVE BEEN 
CONSISTENT FROM RUN TO RUN SHOWING HIGHER POPS ACROSS NYC AND THE 
INTERIOR. WE WILL BE IN THE WARM SECTOR. THE CONVECTION WILL SPREAD 
EASTWARD AT NIGHT ACROSS THE REST OF THE REGION INCLUDING THE 
COASTAL SECTIONS.

THERE WILL BE HIGHER LAYER PW SUNDAY AND SUNDAY NIGHT WITH AROUND 
1.5 TO 1.7 INCHES FROM SOUTHWEST ATMOSPHERIC FLOW. THE FLOW IS 
PARALLEL FROM LOWER TO MID LEVELS. THEREFORE...THERE COULD BE 
TRAINING OF CELLS AND SOME CELLS COULD PRODUCE HEAVY DOWNPOURS.

IN TERMS OF SHEAR 0-6KM...25-30 KT SUNDAY ALONG WITH CAPE OF 
1000-1500 J/KG WILL ALLOW FOR STRONGER CONVECTION TO DEVELOP. THE 
WINDS IN THE BOUNDARY LAYER WILL BE MORE ON THE LIGHT SIDE...MOSTLY 
BELOW 30 KT...SO SEVERE POSSIBILITY SEEMS MARGINAL AT THE MOMENT. 
BUT ANY HELICITY INCREASE FROM PERHAPS MORE VEERING LOW LEVEL 
PROFILES AS WELL AS ANY INCREASE IN THE SHEAR...WOULD INCREASE THE 
SEVERE POTENTIAL.

THE WAVE OF LOW PRESSURE MOVES NORTHEAST OF THE REGION MONDAY AND 
THIS WILL EVENTUALLY DRAG A COLD FRONT ACROSS MONDAY NIGHT. 
AGAIN...THERE COULD BE ANOTHER LULL IN ACTIVITY BEFORE THE NEXT 
BATCH OF CONVECTION DEVELOPS AND MOVES IN. THIS WILL BE ASSOCIATED 
WITH THE COLD FRONT.

SHEAR 0-6KM WILL BE A LITTLE HIGHER MONDAY WITH DEEPENING TROUGH 
MOVING IN WITH MAGNITUDE INCREASE OF ABOUT 5-10 KT COMPARED TO 
PREVIOUS DAY. COLDER AIR ALOFT WILL BE MOVING IN. CAPE THOUGH IS A 
LITTLE MORE LIMITED AND THIS IS LIKELY RELATED TO LESS MOISTURE FROM 
A LITTLE MORE WESTERLY FLOW.

AFTER THIS...WEATHER PATTERN BEGINS TO STABILIZE WITH HEIGHTS 
BUILDING AS THE UPPER LEVEL TROUGH BEGINS TO LIFT NORTH OF THE 
REGION. AT THE SURFACE...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM 
THE WEST.

THE HIGH PRESSURE CONTINUES TO BUILD IN AND THE UPPER LEVEL TROUGH 
AMPLITUDE CONTINUES TO WEAKEN WITH TIME THROUGH THE REST OF THIS 
PERIOD. THIS WILL ALLOW FOR A DRY AIRMASS TO ENCOMPASS THE REGION. 
TEMPERATURES WILL NOT DEVIATE TOO MUCH FROM NORMAL.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY HIGH PRESSURE WITH A WEAK SURFACE TROUGH IN THE AREA
INTO THIS EVENING.

VFR. LIGHT VARIABLE FLOW GIVES WAY TO SEA BREEZES.

     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: NO UNSCHEDULED AMENDMENTS EXPECTED.

KLGA FCSTER COMMENTS: SEA BREEZE MIGHT NOT PASS THROUGH UNTIL AROUND 
22Z.

KEWR FCSTER COMMENTS: SEA BREEZE MIGHT NOT PASS THROUGH UNTIL AROUND 
22Z.

KTEB FCSTER COMMENTS: SEA BREEZE MIGHT NOT PASS THROUGH UNTIL AROUND 
23Z.

KHPN FCSTER COMMENTS: SEA BREEZE MIGHT NOT PASS THROUGH UNTIL AROUND 
23Z.

KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

.OUTLOOK FOR 18Z SAT THROUGH WED...
.SAT AFTERNOON...VFR.
.SAT NIGHT-MON...VFR WITH A CHANCE OF SHRA/TSTMS WITH MVFR OR
LOWER POSSIBLE.
.TUE-WED...VFR.

&&

.MARINE...
RELATIVELY TRANQUIL CONDITIONS EXPECTED ACROSS THE WATERS THROUGH
SATURDAY. INCREASING SOUTHERLY FLOW AHEAD OF A WARM FRONT SATURDAY
NIGHT IS EXPECTED...WITH SOUTHERLY WINDS CONTINUING SUNDAY INTO
MONDAY AHEAD OF A COLD FRONT. WINDS SHIFT BEHIND THE COLD FRONT
MONDAY NIGHT INTO TUESDAY.

SEAS BUILD SATURDAY NIGHT IN RESPONSE TO THE INCREASING SOUTH
FLOW. SCA SEAS ARE FORECAST TO BEGIN SUNDAY AFTERNOON AND CONTINUE
THROUGH MONDAY NIGHT BEFORE SUBSIDING BELOW GOING INTO TUESDAY. WAVE
WATCH III OUTPUT COULD BE TOO FAST WITH INCREASING SEAS SO FUTURE
FORECASTS MAY HAVE THIS SCA POTENTIAL BEGINNING MORE SUNDAY NIGHT
AS OPPOSED TO SUNDAY AFTERNOON.

&&

.HYDROLOGY...
UNSETTLED WEATHER WITH SCATTERED TO NUMEROUS SHOWERS/TSTMS ARE 
FORECAST SATURDAY NIGHT THROUGH MONDAY. ANY OF THESE STORMS HAVE THE 
POTENTIAL TO PRODUCE HEAVY DOWNPOURS. SIGNIFICANT UNCERTAINTY STILL 
EXISTS WITH TIMING AND AMOUNTS THOUGH. IT LOOKS LIKE THE HIGHER
POTENTIAL FOR HEAVY RAIN IS SUNDAY AND SUNDAY NIGHT WITH HIGHER
PWATS OF 1.5 TO 1.7 INCHES ACROSS THE REGION.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MMD/JM
NEAR TERM...MMD
SHORT TERM...MMD
LONG TERM...JM
AVIATION...JC/MET
MARINE...MMD/JM
HYDROLOGY...JM







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