Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 212045 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 445 PM EDT TUE OCT 21 2014 .SYNOPSIS... LOW PRESSURE DEVELOPS OVER THE DELMARVA AREA...AND THEN WILL MEANDER SOUTH OF LONG ISLAND THROUGH MIDWEEK. THE LOW THEN TRACKS NORTHEASTWARD INTO THE CANADIAN MARITIME PROVINCES LATE THIS WEEK AND INTO THE WEEKEND. A COLD FRONT APPROACHES SATURDAY...THEN CROSSES THE AREA SATURDAY NIGHT. HIGH PRESSURE BUILDS INTO THE MID ATLANTIC STATES EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... DEEP UPPER LEVEL TROUGH AXIS APPROACHES TONIGHT AND MOVES TO JUST WEST OF THE REGION WITH MID LEVEL CUTOFF LOW MOVING TOWARDS THE DELMARVA. LOW AT THE SURFACE NEAR THE DELMARVA MOVES EAST AND OFFSHORE BY WEDNESDAY MORNING. BASICALLY...SCATTERED SHOWERS CONTINUE ACROSS THE REGION INTO THIS EVENING WITH ISOLATED CONVECTION DUE TO STEEP LAPSE RATES. COULD SEE SOME SMALL HAIL WITH ANY THUNDERSTORMS THAT FORM. WINDS ARE STILL LIGHT OVERALL BUT BECOME MORE NORTHERLY LATE TONIGHT. LATE TONIGHT...EXPECTING AN OVERALL INCREASE IN SHOWER COVERAGE WITH ISOLATED THUNDERSTORMS STILL A POSSIBILITY AS MUCAPE VALUES STILL COULD REACH 100-200 J/KG...CLOSER TO THE COAST. LOWS WERE TAKEN FROM MAV GUIDANCE...WHICH IS RELATIVELY WARMER THAN OTHER GUIDANCE...MID 40S TO MID 50S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... LOW BECOMES NEARLY VERTICALLY STACKED BUT STILL RESULTS IN A SLIGHT NEGATIVE TILT FOR CYCLOGENESIS TO OCCUR. THE LOW AT THE SURFACE SOUTH OF LONG ISLAND GRADUALLY INTENSIFIES WEDNESDAY AND WEDNESDAY NIGHT. WITH COLD POOL ALOFT...RAIN WILL BE INCREASING ACROSS THE REGION...ALTHOUGH INITIALLY IT LOOKS TO BE VERY LIGHT...PICKING UP IN INTENSITY WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. PRESSURE GRADIENT INCREASES THROUGH THE PERIOD WITH A GUSTY NORTHERLY FLOW DEVELOPING WEDNESDAY AND WEDNESDAY NIGHT. RAIN MAY BECOME INTERMITTENT AT TIMES WITH DRY INTERVALS. MODELS ARE HAVING DIFFICULTY PINPOINTING WHERE THE MORE CONSISTENT RAIN WILL OCCUR. && .LONG TERM /THURSDAY THROUGH TUESDAY/...
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STACKED LOW EAST OF LONG ISLAND THU MORNING WILL BE SLOW TO LIFT N/NE UP INTO THE CANADIAN MARITIMES THROUGH THE WEEKEND. ADDITIONAL SHORT WAVE ENERGY WILL THEN FEED INTO THE MEAN TROUGH OVER EASTERN NOAM SENDING A WEAK COLD FRONT ACROSS THE REGION SAT NIGHT. THEREAFTER... THERE ARE SIGNS THAT A MORE PROGRESSIVE PATTERN WILL ENSUE WITH THE FORECAST FOR A NEUTRAL NAO AND PNA. RAIN WILL LINGER ON THE BACKSIDE OF THE COASTAL LOW THU INTO THU NIGHT BEFORE CONDITIONS DRY OUT. GLOBAL MODELS HAVE TRENDED SLOWER WITH THE CLEARING WITH CLOUD COVER POSSIBLY REMAINING THROUGH SAT. HOWEVER...HAVE AIRED MORE OPTIMISTICALLY WITH CLEARING LATE FRI INTO FRI NIGHT. AS FOR THE COLD FRONTAL PASSAGE SAT NIGHT...HAVE MAINTAINED A DRY FRONTAL PASSAGE. THE 12Z ECMWF AND GFS DO HAVE SOME LIGHT QPF. PREFER TO SEE MORE RUN TO RUN CONTINUITY BEFORE ADDING ANY SHOWERS TO THE FORECAST. HIGH PRESSURE THEN BUILDS IN FROM SUN NIGHT INTO MON...FOLLOWED BY A COLD FRONT APPROACHING FROM THE MIDWEST ON TUE. THROUGHOUT THE PERIOD...GUSTY W-NW WINDS WILL PREVAIL WITH THE STRONGEST GUSTS LOOKING TO BE ON SUN BEHIND THE COLD FRONTAL PASSAGE. TEMPS WILL MODERATE FROM BELOW NORMAL ON THU WITH THE RAIN AND CLOUD COVER TO ABOVE NORMAL EARLY NEXT WEEK AS A WARM RIDGE BUILDS IN ALOFT AHEAD OF THE NEXT FRONTAL SYSTEM.
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&& .AVIATION /21Z TUESDAY THROUGH SUNDAY/...
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LOW PRESSURE REMAINS IN THE VICINITY INTO WEDNESDAY. MOSTLY VFR INTO THIS EVENING. TIMING OF MVFR CEILINGS AND PREVAILING -SHRA COULD BE OFF BY A FEW HOURS. SHRA/TSTMS COULD PASS THROUGH AT ANY TERMINAL AT ANY GIVEN TIME INTO THIS EVENING...BUT ANY TSTM ACTIVITY TOO SPARSE TO INCLUDE IN TAFS. EXCEPTION IS KISP WHERE HAVE EVIDENCE OF CELL CURRENTLY CLOSE ENOUGH TO WARRANT VCTS THROUGH 23Z. ESE-SE WINDS AROUND 10KT...BACKING TO NE THIS EVENING. COULD BE A FEW GUSTS 15-20KT THIS AFTERNOON. NE WINDS LIKELY GUSTING TO 20-25KT WEDNESDAY. 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: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. KLGA FCSTER COMMENTS: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. KEWR FCSTER COMMENTS: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. KTEB FCSTER COMMENTS: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. TEMPO CIGS 2000-3000 FT POSSIBLE UNTIL 23Z. KHPN FCSTER COMMENTS: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. -SHRA COULD PREVAIL FOR A TIME LATE THIS AFTERNOON. KISP FCSTER COMMENTS: A PERIOD OF LIGHT AND VARIABLE WINDS OF 1-2 HOURS COULD PRECEDE THE WIND SHIFT TO NE. WINDS COULD SHIFT NE A FEW HOURS EARLIER THAN FORECAST. VCTS POSSIBLE UNTIL 23Z. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...MVFR OR LOWER CONDITIONS IN SHRA. N-NW WINDS G25KT LIKELY AND G30KT POSSIBLE. .FRIIDAY-FRIDAY NIGHT...MOST LIKELY VFR...WITH LOW CHANCE SPOTTY MVFR. NW WINDS G20-25KT POSSIBLE. .SATURDAY-SATURDAY NIGHT...VFR. NW-W WINDS G25-30KT POSSIBLE. .SUNDAY...MAINLY VFR. NW WINDS G20-25KT POSSIBLE.
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&& .MARINE...
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WINDS LIGHT AND FROM THE E-SE WITH SUB SCA CONDITIONS THROUGH TONIGHT. WEAK PRESSURE GRADIENT PRESENT WITH LOW PRESSURE DEVELOPING SOUTH OF THE WATERS. THE PRESSURE GRADIENT TIGHTENS ON WED THROUGH WED NIGHT WITH LOW FURTHER DEEPENING. SCA CONDITIONS LIKELY BY WED AFTERNOON ON ALL WATERS. SEAS INCREASE TO 5 TO 6 FT ON THE COASTAL OCEAN WATERS WED AND WED NIGHT. THE HIGHER OCEAN SEAS CONTINUE INTO THU. SCA FOR OCEAN WED THROUGH THU AND OTHER WATERS WED AFTERNOON THROUGH WED NIGHT. A PROLONGED PERIOD OF SCA CONDITIONS ARE FORECAST ON THE OCEAN WATERS AS LOW PRESSURE EAST OF NEW ENGLAND THU LIFTS SLOWLY NE AND UP INTO THE CANADIAN MARITIMES BY THIS WEEKEND. AT THE SAME TIME...HIGH PRESSURE WILL SLOWLY WORK EAST AND INTO THE WATERS BY EARLY NEXT WEEK. THIS WILL RESULT IN A GUSTY W-NW FLOW. MARGINAL SCA GUSTS ARE POSSIBLE ON THE SOUND...HARBOR...AND SURROUNDING BAYS.
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&& .HYDROLOGY... A FEW SHOWERS...AND POSSIBLY A THUNDERSTORM...WILL RESULT IN LESS THAN A QUARTER OF AN INCH ON AVERAGE THROUGH TONIGHT. RAIN INCREASES LATE TONIGHT THROUGH WEDNESDAY...WITH AROUND 1/2 QPF FORECAST. LOCALIZED NUISANCE URBAN OR POOR DRAINAGE FLOODING IS POSSIBLE. PERIODS OF RAIN...BRIEFLY HEAVY IN SPOTS...COULD RESULT IN LOCALIZED NUISANCE URBAN OR POOR DRAINAGE FLOODING WED THROUGH THU. STORM TOTALS SHOULD AVERAGE BETWEEN 1 AND 2 INCHES PER ANALYSIS OF OPERATIONAL MODELS...AND SREF MEMBERS. THERE COULD BE SOME LOCALLY HIGHER AMOUNTS. THIS AMOUNT OF RAIN SHOULD NOT RESULT IN ANY SERIOUS LIFE THREATENING OR PROPERTY FLOODING ISSUES/CONCERNS. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 AM EDT THURSDAY FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 PM EDT THURSDAY FOR ANZ350-353-355.
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&& $$ SYNOPSIS...JM NEAR TERM...JM SHORT TERM...JM LONG TERM...DW AVIATION...MALOIT/JC MARINE...JM/DW HYDROLOGY...JM/DW

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