Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 030225
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1025 PM EDT MON MAY 2 2016

.SYNOPSIS...
AN AREA OF LOW PRESSURE OVER THE MID-ATLANTIC WILL TRACK
NORTHEAST TONIGHT...PASSING TO THE SOUTH AND EAST OF LONG ISLAND
ON TUESDAY. HIGH PRESSURE WILL THEN BRIEFLY FOLLOW FOR TUESDAY
NIGHT. A COMPLEX AND SLOW MOVING STORM SYSTEM WILL IMPACT THE TRI-
STATE FROM WEDNESDAY THROUGH SATURDAY. A COLD FRONT CROSSES THE
AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A PROLONGED PERIOD OF INCLEMENT WEATHER IS ON TAP AS AN UPPER
TROF AMPLIFIES ACROSS THE EASTERN HALF OF THE COUNTRY THROUGH MID
WEEK. PRECEDING THIS TROF...WILL BE SEVERAL WAVES OF LOW
PRESSURE...THE FIRST OF WHICH TRACKS NORTHEAST FROM THE MID-
ATLANTIC TONIGHT TO JUST SOUTH OF THE AREA BY MORNING. 12Z
GUIDANCE HAS COME INTO BETTER AGREEMENT..ALBEIT THERE ARE SOME
SMALL TIMING ISSUES...FOR A DECENT BANDED RAIN EVENT LATE TONIGHT
INTO TUE MORNING. MID LEVEL FRONTOGENESIS COUPLED WITH A VORT
APPROACHING FROM THE MID ATLANTIC WILL PRODUCE ABOUT HALF TO ONE
INCH OF RAINFALL. THE HIGHEST AMOUNTS ARE FORECAST ACROSS LI. THE
RAIN WILL DEVELOP AFTER MIDNIGHT FROM SW TO NE WITH ABOUT A 3 TO 5
HOUR PERIOD OF MODERATE TO OCCASIONALLY HEAVY RAINFALL.

LOWERED TEMPERATURES SLIGHTLY TO START ACROSS EASTERN PORTIONS OF
THE AREA IN RESPONSE TO CURRENT OBSERVATIONS.
OTHERWISE...TEMPERATURES ARE EXPECTED TO REMAIN NEARLY STEADY
THROUGH THE OVERNIGHT PERIOD. IN ADDITION...WITH LIGHT WINDS AND A
MOIST BOUNDARY LAYER THE POTENTIAL FOR PATCHY FOG CONTINUES
TONIGHT ALONG THE SOUTH SHORE OF LONG ISLAND AHEAD OF THE
APPROACHING RAIN.

DIURNAL TEMP RANGES WILL BE SMALL THE NEXT COUPLE OF
DAYS DUE TO THE CLOUD OVER AND NE FLOW. LOWS TONIGHT WILL BE IN
THE UPPER 40S TO LOWER 50S...WHICH IS A FEW DEGREES ABOVE NORMAL.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
MODERATE RAIN WILL QUICKLY EXIT THE AREA DURING THE MORNING
HOURS...MAINLY IMPACTING AREAS EAST OF THE HUDSON RIVER. THERE IS
THE POSSIBILITY THAT SOME LIGHT RAIN COULD LINGER INTO THE
AFTERNOON WITH THE EXIT REGION OF THE UPPER LEVEL JET IN CLOSE
PROXIMITY. GENERALLY THOUGH LOOKING AT LOW RAIN CHANCES BY
AFTERNOON WITH THE DEEP MOISTURE AND LIFT PASSING WELL TO THE
EAST AND ONLY LOW-LEVEL MOISTURE ON THE BACKSIDE OF THE LOW.
AN OVERRUNNING PATTERN IN THE LOW-LEVELS WILL MAINTAIN CLOUDY
CONDITIONS THROUGH TUE NIGHT WITH A EVEN A CHANCE OF SOME LIGHT
RAIN DEVELOPING OVERNIGHT.

ONCE AGAIN...DIURNAL TEMP RANGES WILL BE SMALL...WITH HIGHS TUE
IN THE 50S...WITH LOWS TUE NIGHT ABOUT 5 DEGREES COOLER. THIS
WILL EQUATE TO WELL BELOW NORMAL HIGHS AND LOWS JUST A FEW DEGREES
ABOVE NORMAL.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
GOOD AGREEMENT AMONG THE MODELS THE REGARDING CUTOFF LOW THAT MOVES
THROUGH THE GREAT LAKES WEDNESDAY AND THEN SLOWLY TRACKS SE TOWARDS
THE MIDDLE ATLANTIC COAST BY FRIDAY. THE LOW IS THEN PROGGED TO
SLOWLY LIFT AWAY FROM THE COAST ON SATURDAY AS A NEW NORTHERN STREAM
TROUGH DIGS INTO THE GREAT LAKES REGION. THIS WILL SEND A COLD FRONT
ACROSS ON SUNDAY.

FOR WEDNESDAY...MUCH OF THE GUIDANCE IS HINTING AT SOME SHOWER
ACTIVITY AS THERE IS SOME SHORTWAVE ENERGY IN THE MID TO UPPER
LEVEL. HOWEVER...DIFFERENCES EXIST IN ANY WAVE OF LOW PRESSURE THAT
DEVELOPS ON A STALLED BOUNDARY JUST OFFSHORE. TIMING DIFFERENCES ARE
DEPICTED WITH THE LATEST MODELS WHICH LEADS TO A LOW CONFIDENCE
FORECAST. HAVE CAPPED POPS AT CHANCE CATEGORY THROUGH THE
DAY...HIGHEST IN THE AFTERNOON AND EVENING.

FOR THURSDAY INTO FRIDAY...HAVE ALSO ELECTED TO REMAIN PERSISTENT
WITH THE PREVIOUS FORECAST WITH GENERALLY CHANCE POPS. TIMING ENERGY
WITHING THE CUTOFF LOW REMAINS DIFFICULT. IT WILL NOT BE A COMPLETE
WASH OUT...BUT PERIODS OF SHOWERS MAY OCCUR AT ANY TIME. THE LATEST
DETERMINISTIC AND ENSEMBLE GUIDANCE ARE SIGNALING THAT FRIDAY MAY BE
THE DAY WITH BETTER CHANCES FOR SHOWERS. THIS IS WHEN THE CUTOFF LOW
SLOWLY LIFTS NE TOWARDS THE AREA AND A WAVE OF LOW PRESSURE COULD
DEVELOP OFF THE DELMARVA.

THE CUTOFF LOW SHOULD PULL AWAY ON SATURDAY...SO WILL SHOW A
DOWNWARD TREND IN POPS. AS THE COLD FRONT MOVES THROUGH ON
SUNDAY...POPS INCREASE BACK TO CHANCE.

AS NOTED ABOVE...THERE REMAINS A GREAT DEAL OF UNCERTAINTY INTO THE
WEEKEND. THERE WILL PERIOD OF DRY CONDITIONS AND PERIODS OF
SHOWERS...BUT TIMING OF THESE FEATURES IS STILL DIFFICULT TO
PINPOINT AT THIS TIME.

BELOW NORMAL TEMPERATURES ARE FORECAST WEDNESDAY THROUGH FRIDAY.
TEMPERATURES COULD COME CLOSE TO SEASONABLE LEVELS FOR THE
WEEKEND.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE OVER THE MID ATLANTIC APPROACHES NY AIRSPACE
TONIGHT...AND WILL TRACK SOUTH OF LONG ISLAND LATE TONIGHT THROUGH
TUESDAY.

IFR CIGS POSSIBLE AT KJFK/KISP/KGON BEFORE RAIN MOVES IN THIS
EVENING...AS THIS HAS BEEN NOTED ALONG THE NJ COAST AND EASTERN
LI.

OTHERWISE...RAIN DEVELOPS FROM SW TO NE BETWEEN 04Z AND 08Z
TONIGHT...WITH CIGS/VSBY DROPPING BACK TO MVFR...THEN IFR/LIFR.
EMBEDDED THUNDERSTORMS POSSIBLE ACROSS NYC/NJ METRO AND LI
TERMINALS. NOT ENOUGH CONFIDENCE IN COVERAGE/TIMING TO PUT
EXPLICIT THUNDER IN TAFS. RA/TSRA ENDS BETWEEN 12Z AND 16Z FROM
SW TO NE.

CIGS WILL LIKELY BE SLOW TO IMPROVE TO MVFR THROUGH THE MORNING
INTO EARLY AFTERNOON...WITH VSBY LIKELY IMPROVING QUICKER TO MVFR
THEN VFR THROUGH THE MORNING. MVFR CIGS LIKELY TO CONTINUE
THROUGH THE DAY TUESDAY. LOW PROB OF IFR CIGS HOLDING ON THROUGH
THE DAY...AND ON THE FLIP SIDE THERE IS A LOW PROB OF VFR CIGS IN
THE LATE AFTERNOON.

LGT/VRB WINDS THIS EVENING...BECOME NE 8-12 KT LATE TONIGHT AND
CONTINUE INTO TUE AFT...POSSIBLY VEERING SE LATE TUE FOR COASTAL
TERMINALS.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.TUESDAY NIGHT...MVFR CONDS LIKELY. IFR CONDS IN FOG/STRATUS
POSSIBLE.
.WEDNESDAY THROUGH SATURDAY...PERIODS OF MVFR OR LOWER CONDS IN
RAIN/FOG/STRATUS.

&&

.MARINE...
SUB-SCA CONDS ARE FORECAST THROUGH TUE WITH THE POSSIBILITY OF A
BRIEF PERIOD OF SEAS AROUND 5 FT LATE TUE AFT/EARLY EVE.
CONFIDENCE IS LOW ENOUGH AT THIS TIME TO HOLD OFF ON THE ISSUANCE
OF AN SCA. NE WINDS INCREASE TO 10-15 KT ON THE OCEAN WATERS TUE
MORNING WITH GUSTS UP TO 20 KT...BEFORE SUBSIDING IN THE EVENING.

A RELAXED PRESSURE GRADIENT ON ALL COASTAL WATERS WILL LEAD TO WINDS
BELOW SCA LEVELS WEDNESDAY THROUGH SATURDAY. OCEAN SEAS MAY COME
CLOSE TO 5 FT AT TIMES WITH A PERSISTENT SE SWELL...MAINLY ON THE
WATERS EAST OF MORICHES INLET.

&&

.HYDROLOGY...
TOTAL RAINFALL AMOUNTS OF A QUARTER TO AN INCH IS FORECAST LATE
TONIGHT THROUGH TUESDAY MORNING. THE HIGHER AMOUNTS WILL LIKELY
FALL ACROSS NYC METRO AND LONG ISLAND...WITH THE LOWER END BEING
ACROSS NORTHERN PORTIONS OF THE LOWER HUDSON VALLEY. MINOR
NUISANCE FLOODING IN URBAN AREAS IS POSSIBLE.

PERIODS OF SHOWERS ARE POSSIBLE WEDNESDAY INTO THE WEEKEND.
CONFIDENCE ON THE TIMING AND AMOUNTS REMAIN LOW AT THIS TIME.

&&

.TIDES/COASTAL FLOODING...
THE HIGHEST SPRING TIDE OF THE YEAR IS APPROACHING WITH THE NEW
MOON ON FRIDAY. THE THREAT FOR MINOR COASTAL FLOODING WILL
INCREASE DURING THE EVENING HIGH TIDES WED INTO FRI...AND LIKELY
CONTINUE INTO THIS WEEKEND.

PERIODIC NE FLOW IS EXPECTED MID TO LATE WEEK AS A SERIES OF LOW
PRESSURE WAVES TRACKS TO THE SOUTH OF THE REGION. THE TIMING AND
STRENGTH OF THESE WAVES WILL PREDICATE POTENTIAL FOR MODERATE
COASTAL FLOODING...BUT THE THREAT IS THERE PARTICULARLY FOR THE
SOUTH SHORE BAYS OF LI/QUEENS.

&&

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

&&

$$
SYNOPSIS...FEB/DS/DW
NEAR TERM...FEB/DW
SHORT TERM...DW
LONG TERM...DS
AVIATION...NV
MARINE...DS/DW
HYDROLOGY...DS/DW
TIDES/COASTAL FLOODING...NV


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