517
FXUS61 KOKX 162015
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
415 PM EDT FRI OCT 16 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM WATCH ISSUED FOR NE NJ, THE LOWER HUDSON
VALLEY, NYC, SW CT, AND WESTERN LI. THE WATCH IS IN EFFECT UNTIL
10 PM EDT.
FREEZE WATCH ISSUED FOR PORTIONS OF THE LOWER HUDSON VALLEY, NE
NJ, AND INTERIOR SOUTHERN CT FOR SATURDAY NIGHT.
GALE WATCH ISSUED FOR THE OCEAN WATERS BEYOND 20NM SATURDAY
NIGHT, ELSEWHERE GALE WATCHES CONVERTED TO SMALL CRAFT
ADVISORIES TONIGHT THROUGH SATURDAY NIGHT.
KEY MESSAGES
1) A STRONG COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING,
PRECEDED BY A LINE OF SHOWERS AND A FEW STRONG, TO POSSIBLY
SEVERE THUNDERSTORMS. DAMAGING WINDS GUSTS ARE POSSIBLE WITH
ANY SEVERE STORMS.
2) THE COOLEST AIR MASS OF THE SEASON SO FAR MOVES IN THIS WEEKEND
ALONG WITH GUSTY NNW WINDS LATE TONIGHT INTO SATURDAY.
3) COASTAL LOW TO FORM ALONG THE MID ATLANTIC COAST SUNDAY AND
TO LINGER THROUGH MUCH OF THE WEEK.
DISCUSSION
KEY MESSAGE 1
SEVERE THUNDERSTORM WATCH IN EFFECT THROUGH 10 PM FOR THE LOWER
HUDSON VALLEY, NE NJ, NYC, SW CT, AND WESTERN LI.
AN AMPLIFYING UPPER TROUGH ACROSS EASTERN CANADA INTO THE GREAT
LAKES AND OHIO VALLEY STATES WILL SEND A STRONG COLD FRONT
ACROSS THE AREA THIS EVENING. ENHANCED W/SW WINDS AHEAD OF THE
TROUGH WITH 45 TO 55 KT OF DEEP-LAYERED SHEAR AND MARGINAL
INSTABILITY WILL PRODUCE A LINE OF SHOWERS AND A FEW
THUNDERSTORMS ALONG OR JUST AHEAD OF THE FRONT. LOW CLOUDS
WHICH HAVE PERSISTED ACROSS THE REGION MUCH OF THE DAY WILL
DISSIPATE AND LIFT OUT AHEAD OF THE APPROACHING COLD FRONT. THE
GREATEST UNCERTAINTY IS WHETHER THE AIRMASS CAN DESTABILIZE
SUFFICIENTLY FOR CONVECTION TO BRING THESE STRONGER WIND DOWNS
TO THE SURFACE. SPC HREF MAX SB CAPE VALUES ARE 500-750 J/KG.
LATEST SPC MESOANALYSIS SHOWS THESE VALUES OVER SOUTH CENTRAL
PA, WHICH ARE FORECAST TO EXPAND NORTH AND EAST THE NEXT FEW
HOURS. THE ONE OFFSETTING FACTOR TO THE LACK OF INSTABILITY IS
THE STRONG VERTICAL WIND SHEAR, WHICH MAY BE THE REASON MANY OF
THE CAMS ARE STILL POINTING TOWARD A FINE LINE OF CONVECTION
MOVING INTO THE NW PORTIONS OF THE LOWER HUDSON VALLEY BY 6 PM,
THEN RACING THE LINE SOUTH AND EAST TOWARD THE CT COAST, NYC
METRO, AND WESTERN LI FROM 7 TO 8 PM. THE LINE LIKELY WEAKENS
HEADING EAST DUE TO DECREASING INSTABILITY. SHEAR PROFILES ARE
MAINLY UNIDIRECTIONAL, WITH SOME INCREASE IN LOW-LEVEL HELICITY,
BUT MAIN IMPACT WILL BE STRONG GUSTY WINDS, POSSIBLE BOWING
LINE SEGMENTS. TORNADO THREAT IS LOW (LESS THAN 5 PERCENT) FROM
NYC NORTH AND WEST.
WHAT IS LEFT OF THE DECAYING LINE LIKELY PASSES OFFSHORE IN THE
9 TO 10 PM TIME FRAME. HOWEVER, MODELS CONTINUE TO SUPPORT OF
PERIOD OF POSE-FRONTAL RAIN AFTER MIDNIGHT ACROSS COASTAL
LOCATIONS WITH THE APPROACH OF THE UPPER TROUGH AND JET
DYNAMICS. THE BEST CHANCE AT THIS TIME LOOKS TO BE EAST OF THE
LOWER HUDSON VALLEY AND NYC. MUCH OF THE RAIN WILL PUSH EAST OF
THE AREA BY MID TO LATE MORNING HOURS.
EXPECT A QUICK QUARTER TO HALF-INCH OF RAINFALL WITH THE HEAVIER
SHOWERS OR THUNDERSTORMS THIS EVENING, THEN LIGHTER AMOUNTS
OVERNIGHT AT THE COAST WITH ANY RAIN.
MUCH COLDER AIR FOLLOWS BEHIND THE COLD FRONT FOR THE WEEKEND
WITH HIGHS ONLY GETTING INTO THE 50S FOR SATURDAY, ABOUT 10
DEGREES BELOW NORMAL.
GUST NW WINDS DEVELOP LATE TONIGHT WITH GUSTS 20 TO 30 MPH
THROUGH THE DAY SATURDAY BEFORE GRADUALLY SUBSIDING SATURDAY
EVENING.
KEY MESSAGE 2
FREEZE WATCH IN EFFECT SATURDAY NIGHT FOR PORTIONS OF THE
INTERIOR AS STRONG HIGH PRESSURE BUILDS IN FROM THE WEST. LOWS
ACROSS THE WATCH AREA AREA FORECAST TO GET CLOSE TO FREEZING
WITH THE MID 30S TO AROUND 40 ELSEWHERE. THE ONE LIMITING FACTOR
WILL BE NORTH WINDS WHICH LIKELY STAY UP ENOUGH TO KEEP COASTAL
LOCATIONS FROM GETTING TO FREEZING. SHOULD WINDS DROP OFF MORE
THAN CURRENTLY FORECAST, FREEZING TEMPERATURES AND FROST MAY
NEED TO BE EXPANDED SOUTH.
AVIATION /20Z FRIDAY THROUGH WEDNESDAY/
A COLD FRONT MOVES THROUGH LATE DAY INTO EARLY EVENING.
IFR/MVFR TO START, THEN VFR LATE AFTERNOON MAINLY FOR THE CITY
TERMINALS. LINE OF SHOWERS WITH POTENTIAL THUNDERSTORMS
ANTICIPATED FOR MOST TERMINALS IN THE 22-00Z TIME FRAME, EXCEPT
NO CHANCE OF THUNDER ANTICIPATED FOR KISP/KGON. WESTERLY GUSTS
WITH THIS LINE OF SHOWERS WOULD MOSTLY LIKELY END UP 30-40KT.
WINDS UP TO THIS POINT MAINLY SW WITH GUSTS AROUND 20KT
DEVELOPING IN THE AFTERNOON.
VFR FOR ALL BY MIDNIGHT TONIGHT WITH NW-N WINDS GUSTING MOSTLY
20-25KT. SHOWERS EXPECTED FOR KISP/KGON THROUGH THE OVERNIGHT
HOURS, BUT COULD BE POSSIBLE ELSEWHERE EXCEPT KSWF THROUGH THE
NIGHT.
...NY METRO (KEWR/KLGA/KJFK/KTEB) TAF UNCERTAINTY...
IFR COULD LAST UNTIL AROUND 19Z. TIMING OF FLIGHT CATEGORY
CHANGES COULD BE OFF BY 1-2 HOURS. THUNDERSTORM THREAT TIMING
COULD BE OFF BY ABOUT AN HOUR. ISOLATED GUSTS 40 TO 50 KT ARE
POSSIBLE WITH ANY THUNDERSTORM.
CHANCE OF MVFR IN SHOWERS THROUGH TONIGHT.
OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY
SATURDAY PM: VFR. N WINDS G25-30KT, DIMINISHING IN THE EVENING.
SUNDAY-MONDAY: VFR.
TUESDAY-WEDNESDAY: VFR LIKELY, A CHANCE OF MVFR IN -SHRA AND A
CHANCE OF NE WIND G25-30KT.
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FORECASTS,
CAN BE FOUND AT: HTTPS:/WWW.WEATHER.GOV/ZNY/N90
MARINE
GALE WATCH CONVERTED TO SCA FOR ALL WATERS, EXCEPT THE OUTER
OCEAN ZONES, WHERE THE GALE WATCH HAS BEEN DELAYED UNTIL
SATURDAY NIGHT.
EXPECT A PROLONGED PERIOD OF ROUGH CONDITIONS, PARTICULARLY ON
THE OCEAN WATERS THROUGH THE PERIOD. A STRONG COLD FRONTAL
PASSAGE THIS EVENING WILL RESULT IN A STRONG N FLOW LATER
TONIGHT THROUGH SATURDAY. WINDS DIMINISH SOME SATURDAY NIGHT ON
THE NON-OCEAN WATERS AND THE REMAINING WATERS ON SUNDAY.
HOWEVER, DUE TO LOW PRESSURE NEARLY STATIONARY ALONG THE MID
ATLANTIC SUNDAY INTO NEXT WEEK, THERE IS THE POTENTIAL FOR
GALES ON THE OCEAN AND SCA CONDITIONS ELSEWHERE.
OKX WATCHES/WARNINGS/ADVISORIES
CT...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING
FOR CTZ005>008.
NY...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING
FOR NYZ067-068.
NJ...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING
FOR NJZ002.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ331-332-
340-345.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ335-338.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT SUNDAY FOR ANZ350-353-355.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
ANZ380-383-385.
DISCUSSION...DW
AVIATION...JC
MARINE...DW
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