Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 301806
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
206 PM EDT SAT MAY 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THIS
EVENING. A COLD FRONT APPROACHES TONIGHT...MOVES NEAR THE REGION
SUNDAY...AND STALLS IN THE VICINITY SUNDAY NIGHT. THE FRONT LIFTS
BACK NORTH ON MONDAY AS A WAVE OF LOW PRESSURE MOVES ACROSS THE
AREA MONDAY NIGHT INTO TUESDAY MORNING. HIGH PRESSURE WILL THEN
BUILD IN FROM THE NORTH LATE TUESDAY INTO WEDNESDAY...AND SHIFT TO
THE SOUTH THURSDAY INTO FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH TEMPERATURES REACHING
THE MIDDLE 80S FROM THE CITY NORTH AND WEST AND THE MID TO UPPER
70S FURTHER EAST WITH ONSHORE SOUTHERLY FLOW.

IT WILL BE BREEZY THIS AFTERNOON AND EVENING WITH SOUTHERLY WINDS
GUSTS TO 25 MPH FOR MANY LOCATIONS AND 30 TO 35 MPH POSSIBLE ALONG
THE SOUTH SHORE OF LI/NYC.

WITH THE APPROACH OF A COLD FRONT FROM THE NORTHWEST AND
DIFFERENTIAL HEATING...A FEW SHOWERS AND THUNDERSTORMS WILL
DEVELOP OR ADVECT ACROSS THE NW INTERIOR LATE THIS AFTERNOON INTO
EARLY EVE. SURFACE CAPE VALUES OF 1500-2000 J/KG NOTED ACROSS THIS
AREA THIS AFTERNOON WITH CONVECTIVE INITIATION TAKING PLACE
ACROSS E PA. WEAK SHEAR FIELDS WILL KEEP THIS ACTIVITY
PULSEY...BUT CANT RULE OUT A STRONG STORM. CONVECTION LIKELY
DISSIPATES THIS EVENING AS IT MOVES EAST WITH LOSS OF DAYTIME
HEATING AND WITH A STRONG MARINE LAYER WORKING NORTHWEST OF THE
NYC/NJ METRO THIS AFTERNOON/EVENING.

POPS INCREASE LATE TONIGHT FROM WEST TO EAST AS THE FRONT SLOWLY
SINKS SOUTH TOWARDS THE REGION. THERE MAY BE JUST ENOUGH ELEVATED
INSTABILITY AS WELL SO HAVE MENTIONED SLIGHT CHANCE OF A
THUNDERSTORM. LOWS WILL BE IN THE 60S. PATCHY FOG IS ALSO POSSIBLE
OVERNIGHT DUE TO WARM AND MOIST AIR MASS IN PLACE.

THERE IS A HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES
TODAY. STRONGEST RIP CURRENTS WOULD OCCUR DURING THE LATE
AFTERNOON INTO EVENING AS THE SOUTHERLY WINDS INCREASE.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE FRONT WILL BE SLOW TO MOVE SOUTH THROUGH THE REGION ON SUNDAY.
IN FACT...MODELS HAVE SLOWED THE TIMING DOWN FROM PREVIOUS
FORECASTS. THIS MAKES SENSE GIVEN THE DEEP RIDGING OVER THE
WESTERN ATLANTIC. BROKEN SKY COVER SHOULD ALLOW FOR DECENT
INSTABILITY TO DEVELOP AWAY FROM THE COAST. SHOWERS AND
THUNDERSTORMS ARE LIKELY FROM THE CITY NORTH AND WEST AND ACROSS
SOUTHERN CONNECTICUT...IN CLOSEST PROXIMITY TO THE FRONT. LONG
ISLAND MAY NOT SEE MUCH ACTIVITY DURING THE DAY ON SUNDAY. LOCALLY
HEAVY RAINFALL IS POSSIBLE IN ANY STORM WITH PRECIPITABLE WATERS
BETWEEN 1.5 TO 1.7 INCHES. NOT EXPECTING ANY SEVERE
WEATHER...ALTHOUGH AN ISOLATED DAMAGING WIND GUST CANNOT BE RULED
OUT.

THE FRONT WILL LIKELY STALL IN THE VICINITY OF THE REGION SUNDAY
NIGHT. SHOWERS ARE LIKELY WITH A FEW STORMS AS WELL. THE BEST
CHANCE AGAIN REMAINS FROM THE CITY NORTH AND WEST. A WEAK WAVE OF
LOW PRESSURE DEVELOPING TO OUR WEST ALONG THE FRONT. THIS WAVE OF
LOW PRESSURE APPROACHES MONDAY AND MOVES THROUGH MONDAY NIGHT.
THE FRONT LIKELY LIFTS BACK NORTH DURING THE DAY MONDAY. THE
MODELS ALSO HAVE ALSO COME INTO BETTER AGREEMENT WITH THE TIMING
AND AMPLITUDE OF A CLOSED LOW DEEPENING ACROSS THE GREAT LAKES
REGION MONDAY NIGHT. THE REGION ALSO WILL BE LOCATED IN THE RIGHT
ENTRANCE REGION OF AN 80 KT UPPER LEVEL JET PROVIDING SOME LARGE
SCALE ASCENT MONDAY INTO MONDAY NIGHT. SHOWERS WILL CONTINUE WITH
A FEW THUNDERSTORMS AS THERE SHOULD BE JUST ENOUGH INSTABILITY.
PRECIPITABLE WATER VALUES MAY ACTUALLY INCREASE A BIT FROM SUNDAY
WITH DEEP SW FLOW TAPPING INTO THE GULF OF MEXICO SO LOCALLY
HEAVY RAINFALL CONTINUES TO BE POSSIBLE MONDAY INTO MONDAY NIGHT.

HIGHS ON SUNDAY WILL BE IN THE UPPER 70S TO LOWER 80S...WARMEST
INVOF THE NYC METRO. HAVE INCREASED TEMPERATURES BY SEVERAL
DEGREES FROM PREVIOUS FORECAST ON MONDAY WITH THE EXPECTATION THE
FRONT WILL LIFT BACK NORTH. HIGHS WILL BE IN THE UPPER 60S TO
LOWER 70S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
WAVE OF LOW PRESSURE AND ASSOCIATED FRONTAL SYSTEM CLEAR THE
REGION ON TUESDAY. THE ECMWF CONTINUES TO THE BE SLOWEST WITH THIS
AND KEEPS SHOWERS GOING ACROSS EASTERN ZONES THROUGH THE EARLY
AFTERNOON. FOR NOW HAVE CHANCE POPS...BUT MAY EVENTUALLY NEED TO
INCREASE POPS FOR TUESDAY...ESPECIALLY OVER EASTERN ZONES.

HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW WITH DRIER
WEATHER WEDNESDAY INTO THURSDAY. TEMPS RETURNING TO NORMAL.
FRIDAY LIKELY REMAINS DRY AS WELL WITH THE HIGH OFFSHORE AND THE
NEXT COLD FRONT WELL OFF TO THE NW.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
SOUTHERLY FLOW WILL PREVAIL AS HIGH PRESSURE REMAINS OFFSHORE...
WHILE A COLD FRONT APPROACHES FROM NORTHWEST. THE FRONT WILL MOVE
NEAR THE NYC METRO TERMINALS AFTER DAYBREAK SUNDAY.

SOUTHERLY FLOW WILL INCREASE THIS AFTERNOON TO 12-29 KT WITH
GUSTS WELL INTO THE THE 20S. KJFK/KISP COULD SEE OCNL GUSTS UP TO
30 KT BETWEEN 20Z-24Z...AND COULD ALSO SEE A BRIEF PD OF LLWS
AFTER DARK AS SFC WINDS DIE OFF BUT REMAIN AT 30-40 KT ONLY A FEW
HUNDRED FT AGL.

CANNOT RULE OUT A LATE DAY SHOWER/TSTM NEAR KSWF. THEN EXPECT A
RETURN OF LOW STRATUS AND FOG WITH IFR CONDS LATE TONIGHT INTO MID
MORNING SUNDAY. LIFR CONDS MAY BE POSSIBLE AT KJFK/KISP/KBDR/KGON.
SHOWERS AND A FEW TSTMS WITH MVFR AND LOCAL IFR VSBY ARE THEN
POSSIBLE LATE SUNDAY MORNING INTO THE EARLY AFTERNOON FROM NYC
METRO NORTH/WEST.

.OUTLOOK FOR 18Z SUNDAY THROUGH THU...
.SUNDAY AFTERNOON-TUE...CHANCE OF LOW STRATUS WITH IFR CIGS
DEVELOPING LATE EACH NIGHT AND MORNING. MVFR TO IFR CONDS ALSO
POSSIBLE AT TIMES IN SHOWERS/TSTMS.
.TUE NIGHT...BECOMING VFR.
.WED-THU...VFR.

&&

.MARINE...
STRATUS/FOG LAYER CONTINUES TO PUSH OUT OF THE EASTERN WATERS
THIS AFTERNOON.

WIND GUSTS OF 25 TO 30 KT EXPECTED ACROSS THE WESTERN OCEAN
WATERS...LOWER HARBOR...AND SOUTH SHORE BAYS OF LI WITH A
DEVELOPING COASTAL JET. 4 TO 5 FT SEAS LIKELY ON THE OCEAN WATERS
LATE THIS AFTERNOON INTO EVENING. SCA FOR THIS AFTERNOON INTO
EVENING FOR THESE LOCATIONS. ELSEWHERE WINDS AND SEAS REMAIN JUST
BELOW SMALL CRAFT LEVELS INTO TONIGHT.

WITH A PROLONGED SOUTHERLY FLOW...BY SUNDAY MORNING SEAS ON THE
OCEAN WATERS WILL LIKELY BUILD TO 5 FT AND REMAIN INTO SUNDAY
NIGHT...AND POSSIBLY INTO MONDAY AS THE SOUTHERLY FLOW REMAINS
AHEAD OF AN APPROACHING COLD FRONT.

WINDS SHIFT TO EASTERLY AND SUBSIDE SOMEWHAT ON TUESDAY...BUT A
LINGERING SWELL MAY KEEP OCEAN SEAS AT SCA LEVELS THROUGH THE
DAY...AND PROBABLY THROUGH MOST OF WED AS WELL.

&&

.HYDROLOGY...
FORECAST RAIN AMOUNTS FROM SUNDAY THROUGH MONDAY NIGHT CURRENTLY
RANGE FROM 1.25 TO AROUND 2 INCHES. AS USUAL...LOCALLY HIGHER
AMOUNTS WILL BE POSSIBLE IN THUNDERSTORMS. MINOR URBAN/POOR
DRAINAGE/SMALL STREAM FLOODING WOULD BE MOST LIKELY. THERE IS A
LOW CHANCE FOR FLASH FLOODING SUNDAY AND THEN AGAIN ON MONDAY INTO
MONDAY NIGHT...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN
THE HAZARDOUS WEATHER OUTLOOK...ESPECIALLY WITH ANTECEDENT DRY
CONDITIONS FOR THE PAST MONTH OR SO.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ338-
     345-353-355.

&&

$$
SYNOPSIS...DS
NEAR TERM...DS/NV
SHORT TERM...DS
LONG TERM...JC/DS
AVIATION...GOODMAN
MARINE...DS/NV
HYDROLOGY...DS


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