National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 172007
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
407 PM EDT MON JUN 17 2013

.SYNOPSIS...
A COLD FRONT MOVES INTO THE REGION TODAY...THEN REMAINS NEARLY
STATIONARY ACROSS THE AREA INTO TUESDAY. THE COLD FRONT PUSHES
SOUTHEAST OF THE REGION TUESDAY NIGHT...WITH A WEAK WAVE OF LOW
PRESSURE PASSING SOUTH ON WEDNESDAY. HIGH PRESSURE BUILDS OVER
THE AREA FOR THE MIDDLE TO THE END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SEVERE THUNDERSTORM WATCH 321 IN EFFECT UNTIL 9PM FOR SOUTHERN
CONNECTICUT AND THE LOWER HUDSON VALLEY.

A BAND OF SCATTERED SHOWERS/THUNDERSTORMS CURRENTLY MOVING ACROSS
SOUTHERN ZONES. THESE SHOULD WEAKEN AS THEY HEAD FURTHER SOUTH AND
EAST OVER THE NEXT HOUR OR TWO. ALL EYES THEN MOVE TO ANOTHER LINE
OF SHOWERS AND THUNDERSTORMS MOVING ACROSS UPSTATE NY. LATEST HRRR
RUNS INDICATE THESE STORMS WILL MAKE IT INTO THE REGION BETWEEN 21
AND 00 UTC. MODERATE INSTABILITY STILL EXISTS WITH 1500 TO 2000
J/KG OF MUCAPE ALONG WITH 0-6 KM BULK SHEAR BETWEEN 40 TO 50 KT.
THE PRIMARY THREAT FROM THESE STORMS WILL BE DAMAGING WINDS AND
LARGE HAIL. THERE SHOULD BE A GRADUAL WEAKENING TREND WITH THE
CONVECTION AS IT APPROACHES THE COAST TOWARDS 00 UTC.

AFTER 03 UTC...MOST OF THE SHOWERS/STORM ACTIVITY WILL DISSIPATE
WITH LOSS OF DAYTIME HEATING/INSTABILITY. PARTLY TO MOSTLY CLOUDY
SKY CONDITIONS EXPECTED FOR THE REMAINDER OF THE NIGHT. THE
CONVECTION MAY BRING A WIND SHIFT WITH NW WINDS...BUT SOME
UNCERTAINTY IN HOW FAR SOUTH THIS BOUNDARY MOVES. FOR LOW
TEMPERATURES...A MAV/MET BLEND USED WHICH YIELDS READINGS IN THE
UPPER 50S AND LOWER 60S EXCEPT HIGHER IN NEW YORK CITY.

THERE IS A MODERATE RISK OF RIP CURRENTS INTO THIS EVENING.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
NORTHERN STREAM TROUGH AXIS MOVES INTO THE REGION ON TUESDAY. THIS
COUPLED WITH A STALLED BOUNDARY IN THE AREA WILL PRODUCE MORE
SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND
EARLY EVENING.

THERE ARE STILL SOME DISCREPANCIES WITH THE LATEST MODEL OUTPUT
AND IT APPEARS MUCH OF THIS HINGES ON WHERE EXACTLY BOUNDARY
STALLS. FOR NEW YORK CITY AND INTERIOR SECTIONS...FORECAST MODELS
DO INDICATE BETWEEN 1000 TO 2000 J/KG OF CAPE. AT THE
COAST...BETWEEN 500 AND 1000 J/KG OF CAPE FORECAST. THE NAM IS
SLIGHTLY HIGHER ACROSS THE REGION. THE REGION WILL ALSO BE NEAR
THE LEFT EXIT REGION OF A 100+ KT 250 HPA JET...AND HAVE 40-50 KT
OF 0-6 KM BULK SHEAR. IF WE DO REALIZE THE HIGHER INSTABILITY...HAVE
THE POTENTIAL FOR A FEW STRONG TO SEVERE STORMS WITH THE MAIN
THREAT BEING DAMAGING WINDS. HAVE CAPPED POPS AT 50 PERCENT AT
THIS TIME.

FOR HIGHS TUESDAY...GENERALLY USED A MAV/MET BLEND WITH MORE
WEIGHT ON THE MAVS. THIS YIELDS HIGHS IN THE UPPER 70S AND LOWER
80S...WARMEST IN NE NJ AND NYC.

STILL COULD SEE A FEW SHOWERS AND STORMS BEFORE MIDNIGHT WITH MOST
OF THE ACTIVITY SHIFTING SOUTH OF THE REGION AFTER MIDNIGHT AS
THE MAIN COLD FRONT SHIFTS SOUTH. THE UPPER LEVEL TROUGH AXIS ALSO
WILL BE SHIFTING SOUTH AND EAST AND TAKING THE BEST FORCING
WITH IT.

LOWS TUESDAY NIGHT IN THE UPPER 50S AND LOWER 60S WITH A MOSTLY
CLOUDY SKY CONDITION.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ANY SHOWERS TAPER OFF EARLY WEDNESDAY MORNING AS HIGH PRES BUILDS
INTO THE REGION BEHIND THE DEPARTING COLD FRONT. THIS HIGH WILL THEN
DOMINATE THE WEATHER PATTERN FOR THE REST OF THE WEEK...WITH MAINLY
DRY CONDS WITH SEASONAL TEMPERATURES THROUGH FRIDAY.

THE HIGH MOVES OFFSHORE LATE FRIDAY...AND THEN A WARM FRONT WILL
LIFT NORTH THROUGH THE REGION BEHIND THE HIGH. THIS WILL BRING
WARMER AND MORE UNSETTLED WEATHER TO THE REGION WITH TEMPS WARMING
INTO THE 80S.

MCS ACTIVITY OVER THE MIDWEST BECOMES MORE LIKELY STARTING THIS
WEEKEND. THE REMNANTS OF THOSE SYSTEMS WILL WEAKEN AS THEY TRACK
EAST...BUT THERE MAY BE ENOUGH UPPER LEVEL ENERGY AND SFC
INSTABILITY FOR ISO-SCT AFTERNOON/EVENING TSTMS...MAINLY OVER
WESTERN PORTIONS OF THE CWA.

THE BEST CHANCES FOR WIDESPREAD SHRA/TSRA ACTIVITY WILL BE LATE
SUNDAY AND SUNDAY NIGHT AS LOW PRES DEVELOPS ALONG A WARM FRONT
LIFTING NORTH THROUGH THE REGION.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
FIRST ROUND OF CONVECTION EXITING OFF THE LI COAST...WITH A SECOND
ROUND THIS EVENING AS A WEAK COLD FRONT DROPS SE ACROSS UPSTATE
NY AND NEW ENGLAND. DUE TO STRONG WIND SHEAR ALOFT AND HIGH
INSTABILITY...SOME OF THESE STORMS COULD BECOME STRONG...AND
POSSIBLY SEVERE. THE MAIN SEVERE THREAT APPEARS TO BE TO THE
NORTH OF THE NYC TERMINALS AT THIS TIME. HOWEVER...THIS COULD
CHANGE WITH THE POTENTIAL FOR STRONGER CONVECTION TO REACH THE NYC
METRO AREA.

S/SW WINDS AT 8 TO 12 KT...G20KT FOR THE REST OF THIS AFTERNOON...
BECOMING LIGHT AND VARIABLE THIS EVENING AS A COLD FRONT STALLS
CLOSE TO THE AREA...THEN E/SE WED MORNING DEPENDING ON THE
PROXIMITY OF THE FRONT. THERE IS UNCERTAINTY WITH THE GUIDANCE AS
TO THE LOCATION OF THE FRONT TUE MORNING...WHICH WILL DEPEND OF
THE AMOUNT OF SOUTHWARD PROGRESS IT MAKES THIS EVENING. WINDS ON
TUE MAY VARY CONSIDERABLY FROM EITHER A LIGHT E/SE TO W/SW FLOW.

GENERALLY VFR...BUT MVFR/IFR IN ANY CONVECTION. RESIDUAL LOW-LEVEL
MOISTURE AND AN ONSHORE FLOW TONIGHT INTO TUE MAY ALSO RESULT IN
FOG/HAZE...ESPECIALLY OUTSIDE OF THE NYC TERMINALS.

POTENTIAL FOR ANOTHER ROUND OF STRONG CONVECTION TUE AFT...BUT
THIS WILL HEAVILY DEPEND ON THE LOCATION OF THE FRONT.

     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 DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

KLGA FCSTER COMMENTS: AMENDMENTS LIKELY DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

KEWR FCSTER COMMENTS: AMENDMENTS LIKELY DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

KTEB FCSTER COMMENTS: AMENDMENTS LIKELY DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

KHPN FCSTER COMMENTS: AMENDMENTS LIKELY DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

KISP FCSTER COMMENTS: AMENDMENTS LIKELY DUE TO THE TIMING AND
LOCATION OF CONVECTION THIS AFT AND EVE.

.OUTLOOK FOR 18Z TUE THROUGH SAT...
.TUE...SCT SHOWERS AND TSTMS COULD BRING MVFR OR LOWER CONDITIONS.
.WED-SAT...VFR.
-- End Changed Discussion --

&&

.MARINE...
WITH A RELATIVELY LIGHT PRESSURE GRADIENT OVER THE REGION EXPECT
WINDS TO GENERALLY BE 15 KT OR LESS THROUGH TUESDAY...OUTSIDE OF
AFTERNOON SEABREEZES EACH DAY AND ANY THUNDERSTORMS. WAVES SHOULD
REMAIN BELOW SCA LEVELS ON THE OCEAN WATERS THROUGH TUESDAY NIGHT.

HIGH PRES BUILDS OVER THE WATERS STARTING ON WEDNESDAY AND MOVES
OFFSHORE ON SATURDAY. WINDS/WAVES WILL REMAIN BELOW SCA CRITERIA
THROUGH THE PERIOD.

&&

.HYDROLOGY...
BASIN AVERAGE QPF FROM ANY SHRA/TSTMS THIS AFTERNOON/EARLY EVENING
SHOULD BE LESS THAN .1 INCHES. THE PROBABILITY OF LOCALLY HEAVY
RAINFALL...AND HENCE ANY SIGNIFICANT HYDROLOGIC IMPACT IS LOW.

THERE IS THE POTENTIAL FOR 1/3-2/3 AN INCH OF BASIN AVERAGE
QPF...WITH LOCALLY HIGHER AMOUNTS POSSIBLE WITH CONVECTION
TUESDAY/TUESDAY EVENING. WITH PRECIPITABLE WATERS OF 1.25-1.5
INCHES...THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH
ANY STRONGER CONVECTION. THIS COULD CAUSE MINOR FLOODING OF
URBAN/POOR DRAINAGE AREAS.

THE PROBABILITY FOR WIDESPREAD SIGNIFICANT RAINFALL IS LOW FROM
THE MIDDLE THROUGH THE END OF THE WEEK.

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...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...MPS/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...MPS
AVIATION...DW
MARINE...MPS/DS
HYDROLOGY...MPS/DS