Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 280254
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1054 PM EDT WED MAY 27 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT...THEN MOVE
ACROSS THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE WILL RETURN ON
FRIDAY...QUICKLY MOVING INTO THE WESTERN ATLANTIC LATE FRIDAY
AFTERNOON INTO THE WEEKEND. A SLOW MOVING COLD FRONT APPROACHING
FROM THE WEST WILL EVENTUALLY MOVE IN SATURDAY NIGHT AND STALL
NEARBY FOR SUNDAY INTO EARLY NEXT WEEK. HIGH PRESSURE WILL BUILD
IN FROM THE NORTH LATE TUESDAY INTO THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
MOST OF THE THUNDERSTORMS ACROSS THE LOCAL AREA HAVE ENDED...AND
SOME SHOWERS EXTENDING FROM EASTERN PORTIONS OF THE LOWER HUDSON
VALLEY...INTO NYC...AND INTO SOUTHERN PORTIONS OF NORTHEAST NJ
WILL TRACK EAST AND DISSIPATE GOING THROUGH THE EVENING. BY
MIDNIGHT...MOST OF THE ACTIVITY WILL TAPER OFF.

WITH ABUNDANT LOW LEVEL MOISTURE DUE TO THE SHOWERS/TSTMS THAT
OCCURRED THIS EVENING...AND INCREASING LOW LEVEL MOISTURE DUE TO
CONTINUED ONSHORE FLOW...CAN EXPECT AT LEAST PATCHY FOG TO
DEVELOP. WILL INCLUDE THE PATCHY FOG FOR THE INTERIOR DUE TO THE
RAINFALL AS WELL AS FOR COASTAL AREAS.

LOWS TONIGHT WILL GENERALLY DROP INTO THE LOW TO MID 60S...WITH
THE WARMEST TEMPS IN/AROUND NYC.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MODELS DIFFER ON COVERAGE/EXTENT OF CONVECTION WITH A COLD FRONT
ON THURSDAY. ALSO DIFFER ON TIMING WITH THE GFS/ECMWF FASTER THAN
THE NAM/CMC-REG. NOTING 700-500 HPA FLOW HAS A FAIRLY DECENT
PERPENDICULAR COMPONENT TO THE FRONT...LEANED TOWARDS THE FASTER
TIMING OF THE GFS/ECMWF FOR POPS. WITH A WEAKENING FRONT
THOUGH...DID NOT FEEL COMFORTABLE GOING WITH HIGHER THAN CHANCE
POPS AT THIS TIME. PROBABILITIES ARE GENERALLY HIGHER FROM NYC AND
AREAS JUST NORTH/WEST.

WITH LESS MLCAPE...500-1000 J/KG OVER THE INTERIOR THAN
TODAY...AND THE BEST DYNAMIC FORCING FORECAST TO THE N OF THE
REGION...DO NOT THINK THERE IS AS MUCH OF A THREAT FOR SEVERE
WEATHER. THOUGH AN ISOLATED STRONG TO SEVERE STORM OR TWO CANNOT
BE COMPLETELY RULED OUT.

HIGHS ON THU SHOULD BE IN THE 80S INLAND...AND IN THE 70S NEAR THE
COAST...MAINLY PER WARMER NAM MOS GUIDANCE. WOULD NOT BE
SURPRISING IF A FEW LOCATIONS IN NE NJ APPROACHED 90. DEWPOINTS
ON THURSDAY SHOULD BE A TAD LOWER THAN TODAY...MAINLY IN THE LOWER
60S.

A WEAK COLD FRONT WILL MOVE ACROSS THURSDAY NIGHT. LITTLE TO NO
PRECIPITATION IS EXPECTED WITH THE FRONT. LOWS SHOULD BE IN THE
60S IN MOST PLACES...EXCEPT MID/UPPER 50S IN THE VALLEYS WELL
NORTH/WEST OF NYC.

THERE IS A MODERATE RISK FOR RIP CURRENTS AT OCEAN BEACHES ON
THURSDAY.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
RIDGING TREND RESUMES ALOFT WITH JET STREAM WELL NORTH
OF THE REGION FOR FRIDAY. THIS RIDGE SHIFTS SLOWLY OFFSHORE AND
BECOMES LESS AMPLIFIED AS A LONGWAVE TROUGH PUSHES EASTWARD ACROSS
SOUTHERN CANADA. THE SAME PATTERN REMAINS THROUGH THE FIRST HALF OF
THE WEEKEND AND THEN THE JET PUSHES FARTHER SOUTH INTO THE REGION
FOR THE REST OF THE WEEKEND INTO EARLY NEXT WEEK. THE MID LEVEL
RIDGE WILL BECOME MORE BROAD SUNDAY WITH A SHORTWAVE MOVING IN EARLY
NEXT WEEK. THE RIDGING RESUMES BY MID NEXT WEEK WITH JET STREAM ONCE
AGAIN MOVING WELL NORTH OF THE REGION.

AT THE SURFACE...HIGH PRESSURE FROM THE CANADIAN MARITIMES QUICKLY
SETTLES INTO THE WESTERN ATLANTIC LATE AFTERNOON FRIDAY AND INTO THE
WEEKEND. THE INFLUENCE OF THE HIGH WILL LESSEN WITH TIME AS A SLOW
MOVING COLD FRONT APPROACHES FROM THE WEST. THE PARENT LOW ATTACHED
TO THIS FRONT WILL NOT BE THAT STRONG...SLOWLY DEEPENING WITH
EASTWARD PROGRESS THROUGH SATURDAY AND THEN DEEPENS MORE WITHIN THE
CANADIAN MARITIMES SUNDAY THROUGH SUNDAY NIGHT. THE COLD FRONT WILL
BE MOVING WITHIN CLOSER PROXIMITY OF THE REGION THROUGH THIS TIME.
THE FRONT WILL THEN STALL NEAR THE REGION WITH LOW PRESSURE AND
INVERTED TROUGH DEVELOPING AT THE SURFACE TO THE SOUTHWEST OF THE
REGION ALONG THE FRONT. HIGH PRESSURE RETURNS LATE TUESDAY FROM THE
CANADIAN MARITIMES...BUT ONCE AGAIN BECOMES RE-ESTABLISHED QUICKLY
OFFSHORE INTO THE WESTERN ATLANTIC.

IN TERMS OF WEATHER...CONDITIONS REMAIN DRY FRIDAY AND FRIDAY NIGHT.
HOWEVER...WITH THE MOIST SOUTHERLY FLOW FRIDAY NIGHT INTO SATURDAY
MORNING...EXPECTING SOME PATCHY FOG ACROSS THE REGION...ESPECIALLY
COASTAL REGIONS. SOME MODELS ARE SHOWING THIS MOISTURE AS VERY LIGHT
QPF. THERE WILL BE A GRADUAL INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS FIRST NORTH AND WEST OF NYC SATURDAY AHEAD OF THE COLD
FRONT. THE CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE SATURDAY
NIGHT ACROSS THE WHOLE FORECAST REGION WITH SHOWERS BECOMING LIKELY
SUNDAY AND SUNDAY NIGHT. THUNDERSTORMS WILL BE MORE LIMITED SUNDAY
AND SUNDAY NIGHT WITH DECREASING INSTABILITY WITH A MORE NORTHERLY
AND EASTERLY FLOW DEVELOPING DURING THE DAY. WITH THE FRONT STALLING
NEAR THE REGION...CHANCES FOR SHOWERS REMAIN INTO EARLY NEXT
WEEK...BEFORE BECOMING MORE MINIMAL TUESDAY AS THE FRONT PUSHES
FARTHER SOUTH OF THE AREA WITH MAINLY DRY CONDITIONS RETURNING LATE
TUESDAY NIGHT INTO NEXT WEDNESDAY.

THE AIR MASS WILL STAY MOSTLY AS MARITIME TROPICAL THROUGH THE
LONG TERM BUT A LITTLE COOLER FOR MONDAY AND TUESDAY NEXT WEEK.
THE HIGHS ARE FORECAST TO BE AROUND OR SLIGHTLY MORE THAN 5
DEGREES ABOVE NORMAL ON AVERAGE FRIDAY AND SATURDAY...NEAR NORMAL
FOR SUNDAY...AROUND 5 DEGREES BELOW NORMAL MONDAY AS WELL AS A FEW
DEGREES BELOW NORMAL TUESDAY. TEMPERATURE RETURN TO NEAR NORMAL BY
MID NEXT WEEK. LOWS AT NIGHT OVERALL ARE FORECAST TO BE NEAR TO
ABOVE NORMAL.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE REMAINS ACROSS THE NORTH ATLANTIC. MEANWHILE A LOW
WILL BE MOVING THROUGH EASTERN CANADA OVERNIGHT THROUGH THURSDAY
BRINGING A WEAKENING COLD FRONT TOWARD THE AREA THURSDAY AFTERNOON.
THE FRONT IS EXPECTED TO CROSS THE LOWER HUDSON VALLEY LATE IN THE
AFTERNOON...AND POSSIBLY MOVE THROUGH THE NYC AREA TERMINALS RIGHT
AROUND 00Z FRIDAY. THERE IS A LOW CHANCE OF SHOWERS AND ISOLATED
THUNDERSTORMS WITH THE FRONT.

VFR UNTIL LATE TONIGHT WHEN MARGINAL CEILINGS IN STRATUS ARE
EXPECTED WITH CEILINGS 1000 TO 2000 FT. LOCAL MARGINAL VFR FOG IS
ALSO POSSIBLE. ANY MARGINAL VFR CEILINGS BECOME VFR AFTER 15Z
THURSDAY. MODERATE CONFIDENCE IN THE FORECAST OF STRATUS AND FOG.

.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THU NIGHT...COLD FRONT MOVES THROUGH EARLY IN THE EVENING WITH THE
WIND SHIFTING TO NW TO N. VFR.
.FRI...VFR. LGT NE WINDS VEERING THRU THE DAY.
.SAT...MRNG MVFR OR LOWER POSSIBLE. CHC SHWRS AND TSTMS IN THE
AFTN AND OVERNIGHT WITH MVFR OR LOWER. STRONG SLY FLOW.
.SUN...MVFR OR LOWER IN SHOWERS/TSTMS POSSIBLE. SHIFTING WINDS TO
THE E/NE.
.MON...POSSIBLE IMPROVEMENT TO VFR IF SHOWERS/TSTMS MOVE TO THE
SOUTH. E/NE FLOW.

&&

.MARINE...
WINDS ON THE OCEAN WILL DIMINISH TO 10-15 KT WITH GUSTS UP TO 20
KT...AND TO 5-10 KT ON ALL OTHER WATERS. OCEAN SEAS WILL CONTINUE
TO BUILD TO 5 FT...AND WILL REMAIN ABOVE 5 FT THROUGH THURSDAY
MORNING. WILL EXTEND THE SCA ON THE OCEAN WATERS THROUGH 11 AM
THURSDAY. OCNL GUSTS TO 25 KT POSSIBLE IN THE AFTERNOON ON THE
OCEAN WATERS...BUT MOST GUSTS WILL BE AROUND 20 KT.

COLD FRONT MOVES ACROSS THE WATERS LAE THURSDAY/THURSDAY NIGHT.
CONDS FALL BELOW SCA CRITERIA.

PERSISTENT SOUTHERLY FETCH COULD BUILD SEAS ON THE OCEAN TO 5 FT
SATURDAY...AND REMAIN THERE FOR THE REST OF THE FCST PERIOD...EVEN
AS WINDS SWITCH TO MORE EASTERLY SUNDAY INTO EARLY NEXT WEEK.

&&

.HYDROLOGY...
ON THURSDAY...THERE IS THE POTENTIAL FOR LESS THAN 1/4 OF AN INCH
OF BASIN AVERAGE RAINFALL. HOWEVER...WITH STORM MOTION OF AROUND
10 KT AND PRECIP EFFICIENCY NEAR 1.25 INCHES...THERE IS STILL
POTENTIAL FOR SLOW MOVING STORMS PRODUCING LOCALLY MODERATE TO
HEAVY RAINFALL...ESPECIALLY OVER SOUTHERN CT. THIS COULD RESULT IN
THE MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS...ESPECIALLY IF IT
OCCURS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL TODAY.

THERE IS POTENTIAL FOR HEAVY RAIN SUNDAY AND SUNDAY NIGHT
WITH PW FORECAST TO REACH UP TO NEAR 1.75 INCHES. THERE WILL BE
POTENTIAL AS WELL FOR AN EXTENDED WIDESPREAD RAINFALL LATE THIS
WEEKEND INTO EARLY NEXT WEEK WITH A COLD FRONT STALLING NEARBY.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR ANZ350-353-
     355.

&&

$$
SYNOPSIS...GOODMAN
NEAR TERM...MPS
SHORT TERM...GOODMAN
LONG TERM...JM
AVIATION...MET
MARINE...MPS
HYDROLOGY...GOODMAN/JM



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