Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 020056
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
856 PM EDT FRI AUG 1 2014

.SYNOPSIS...
A FRONTAL BOUNDARY OVER THE ATLANTIC COAST AND LOW PRESSURE TO
THE SOUTH WILL IMPACT THE AREA INTO MONDAY. HIGH PRESSURE WILL
THEN BUILD IN ON TUESDAY. A COLD FRONT WILL PASS THROUGH
ON WEDNESDAY.

&&

.NEAR TERM /TONIGHT/...
RADAR QUIET ATTM WITH ATMOSPHERE HAVING BEEN OVERTURNED BY
EARLIER CONVECTION...AND SHOULD REMAIN SO THIS EVENING. RAIN WITH
A COASTAL FRONT AND ASSOCIATED WAVE OF LOW PRESSURE TAKING SHAPE
OVER ERN NORTH CAROLINA IS SPREADING UP THE COAST. THE RAIN IS
CURRENTLY SPOTTY IN NATURE OVER COASTAL SOUTHERN NJ/DE AND MORE
WIDESPREAD TO THE SOUTH...AND SHOULD BEGIN TO RIDE UP INTO THE
AREA AFTER MIDNIGHT. THE 12Z ECMWF SOLUTION WITH A STRONGER SFC
WAVE OF LOW PRESSURE AND HEAVIER RAINFALL MAY HAVE SOME CREDENCE
GIVEN SFC OBS OVER ERN NORTH CAROLINA SHOWING A WEAK LOW CENTER
THERE AND SFC WINDS BACKING AROUND TO NORTH AT SOME INLAND
STATIONS...AND MSAS SHOWING BIGGEST 3-HRLY PRESSURE FALLS ALONG
THE DELMARVA COAST. DID NOT UPDATE POP GRIDS PAST MIDNIGHT...
WAITING TO SEE TRENDS THIS EVENING BEFORE GOING MORE HEAVILY WITH
THE ECMWF.

LOWS TONIGHT SHOULD BE IN THE LOWER TO MID 60S.

&&

.SHORT TERM /SATURDAY/...
NEXT FOCUS OF RAIN WILL BE THE STATIONARY FRONT BACKING IN FROM
THE EAST WITH THE WESTERN ATLANTIC HIGH PRESSURE EXPANDING
SLIGHTLY WESTWARD. SOME MODEL DIFFERENCES EXIST ON THE TIMING OF
WHEN THE PRECIP WILL REACH THE AREA WITH THE NAM THE SLOWEST AND
DRIEST FOR THE DAY ON SATURDAY. HIGHEST PRECIP AMOUNTS WILL BE
LONG ISLAND AND SOUTHEAST CT WITH THE FRONT POSITIONED JUST TO THE
SOUTH OF THE ISLAND. WILL CONTINUE CHANCE POPS ELSEWHERE THOUGH AS
SHOWERS SHOULD STILL BE ABLE TO DEVELOP WITH UPPER JET AND MID
LEVEL SHORTWAVE ENHANCEMENT. AS WELL...DEEP MOISTURE STREAMING
FROM THE SOUTH WILL BE IN PLACE SO ANY SHOWERS WILL PRODUCE
LOCALLY HEAVY RAINFALL.

VERY LOW CONFIDENCE ON ANY THUNDER FOR SATURDAY. LITTLE TO NO
INSTABILITY OR SHEAR...JUST MODERATE LIFT. EXPECT SHOWERS TO BE VERY
TROPICAL IN NATURE AND MAYBE AN ISOLATED LIGHTNING STRIKE OR TWO.
WIND PROFILES ALOFT ARE AGAIN LIGHT SO TRAINING OF CELLS IS LIKELY.

GUIDANCE FOR HIGHS ON SAT IS LOWER THAN PREVIOUS...POSSIBLY DUE TO
THE MODELS COMING INTO AGREEMENT FOR A RAINY DAY. WILL LOWER
HIGHS A FEW DEG FROM PREVIOUS FORECAST...WITH LOWER AND MID 70S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A SHORTWAVE WEAKENS AT THE BASE OF A 500MB TROUGH AXIS AS IT
APPROACHES THE FORECAST AREA...EVENTUALLY PASSING THROUGH SUNDAY
NIGHT INTO MONDAY MORNING. THIS WILL HELP SLOWLY NUDGE THE OFFSHORE
FRONTAL BOUNDARY FARTHER OUT TO SEA.

SOME SYNOPTIC LIFT WILL BE PRESENT THROUGH MONDAY WITH THE RIGHT
ENTRANCE OF AN UPPER JET STREAK IN THE VICINITY. LESS CERTAIN ARE
THE TIMING AND POSITION OF LOW-MID LEVEL SHORTWAVES THAT PASS
THROUGH/NEARBY THE CWA BEFORE THE TROUGH AXIS ALOFT PASSES THROUGH.
POPS THEREFORE CAPPED AT CHANCE...WHICH IS CLOSE TO WHAT A MODEL
BLEND WOULD PRODUCE. BEST OVERALL CHANCES OF RAINFALL WOULD BE
SATURDAY NIGHT INTO SUNDAY MORNING AND CLOSER THE OFFSHORE FRONTAL
BOUNDARY. MONDAY COULD EVEN TURN OUT TO BE COMPLETELY
DRY...ESPECIALLY IF THE ECMWF IS CORRECT WITH THE TROUGH AXIS
PASSING THROUGH SUNDAY NIGHT AND A LACK OF LOW-MID LEVEL SHORTWAVES
TRAILING IT ON MONDAY. DO NOT HAVE ENOUGH CONFIDENCE TO REMOVE POPS
ALTOGETHER ON MONDAY...SO HAVE LEFT THE PREVIOUS FORECAST OF SLIGHT
CHC/CHC POPS.

WEAK HIGH PRESSURE PROBABLY KEEPS TUESDAY AND THURSDAY DRY...BUT A
COLD FRONT AND CYCLONIC FLOW ALOFT COULD BRING AN ISOLATED
SHOWER/TSTM TO THE AREA ON WEDNESDAY.

CLOUDS AND AN ONSHORE FLOW WILL HOLD HIGH TEMPERATURES ON MONDAY
BELOW NORMAL...HIGHS OTHERWISE NEAR NORMAL FOR THE REST OF THE LONG
TERM FORECAST.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A FRONTAL BOUNDARY WILL REMAIN SOUTH OF THE REGION THROUGH THE
FORECAST PERIOD. A WAVE OF LOW PRESSURE MOVES ALONG THE FRONT
TOWARD SATURDAY MORNING...BRINGING RAIN TO THE TERMINALS WITH MVFR
CONDITIONS.

LIGHT SOUTHEAST WIND WILL BACK TO THE EAST TO NORTHEAST TONIGHT AS
THE WAVE OF LOW PRESSURE APPROACHES. THE WIND WILL THEN REMAIN FROM
THE EAST TO NORTHEAST THROUGH THE REMAINDER OF THE FORECAST.

...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: RAIN MOVES INTO THE AREA AROUND 09Z WITH MVFR
CONDITIONS. A PERIOD OF IFR CEILINGS IS POSSIBLE TOWARD 12Z.
IMPROVEMENT IS LIKELY AFTER 18Z.

KLGA FCSTER COMMENTS: RAIN MOVES INTO THE AREA AROUND 09Z WITH MVFR
CONDITIONS. IMPROVEMENT IS LIKELY AFTER 18Z.

KEWR FCSTER COMMENTS: RAIN MOVES INTO THE AREA AROUND 09Z WITH MVFR
CONDITIONS. IMPROVEMENT IS LIKELY AFTER 17Z.

KTEB FCSTER COMMENTS: RAIN MOVES INTO THE AREA AROUND 09Z WITH MVFR
CONDITIONS. IMPROVEMENT IS LIKELY AFTER 17Z.

KHPN FCSTER COMMENTS: RAIN MOVES INTO THE AREA AROUND 10Z WITH MVFR
CONDITIONS. A PERIOD OF IFR CEILINGS IS POSSIBLE TOWARD 12Z.
IMPROVEMENT IS LIKELY AFTER 19Z.

KISP FCSTER COMMENTS: RAIN MOVES INTO THE AREA AROUND 09Z WITH MVFR
CONDITIONS. A PERIOD OF IFR CEILINGS IS POSSIBLE TOWARD 12Z.

.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.SAT NIGHT...SHRA WITH MVFR OR LOWER CONDS LIKELY. LOW PROB FOR TSRA.
.SUN-SUN NIGHT...SHRA/TSRA POSSIBLE...MVFR OR LOWER CONDS
POSSIBLE.
.MON-WED...VFR. MVFR POSSIBLE IN ISOLD SHRA/TSTMS IN THE
AFTERNOON/EVENING.

&&

.MARINE...
THERE IS A GROWING CHANCE THAT MINIMAL SCA CRITERIA COULD BE
BRIEFLY MET SAT AFTERNOON IF THE WAVE OF LOW PRESSURE RIDING UP
THE COAST ALONG A NEARLY STATIONARY FRONT IS STRONGER THAN
EXPECTED. OTHERWISE...SUB-SCA CONDS ARE EXPECTED THROUGH WED.

&&

.HYDROLOGY...
HIGHEST AREAL RAINFALL TOTALS THROUGH SAT NIGHT OF AN INCH OR MORE
ARE EXPECTED OVER LONG ISLAND AND FAR SE CT. THESE AMTS MAY NEED
TO BE RAISED IF THE WAVE MOVING UP THE COAST IS STRONGER THAN
FCST. HEAVY DOWNPOURS ARE POSSIBLE THIS WEEKEND INTO MON VIA
NUMEROUS SHOWERS AND SLOW MOVEMENT/TRAINING OF CELLS. THIS COULD
ONCE AGAIN RESULT MAINLY IN URBAN/POOR DRAINAGE FLOODING.

&&

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

&&

$$






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