Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 212353 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 753 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/... GRIDS UPDATED TO ADJUST POPS ACROSS ERN LI WHERE WEAK TSTM COMPLEX IS ROLLING THRU. TEMPS AND OTHER HOURLY FIELDS ADJUSTED. FCST FOR SCT PCPN STILL LOOKS ON TRACK...HOWEVER SLOW MOVEMENT OF ACTIVITY WILL RESULT IN POCKETS OF LINGERING PCPN...PARTICULARLY OVER NJ AND THE LOWER HUDSON VALLEY. 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/... 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. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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LOW PRESSURE REMAINS SOUTH OF LONG ISLAND INTO WEDNESDAY EVENING. MAINLY VFR...WITH A FEW POCKETS OF MVFR THIS EVENING. THEN MVFR DEVELOPS THROUGHOUT OVERNIGHT AND CONTINUES THROUGH THE REMAINDER OF THE TAF PERIOD. SMALL CHANCE OF POCKETS OF IFR LATE TONIGHT/EARLY WEDNESDAY MORNING - CONFIDENCE IN LOCATION AND OCCURRENCE TO LOW TO PLACE IN ANY TAF. ALSO CANNOT RULE OUT ISOLD TSTM OVERNIGHT...BUT ONCE AGAIN CONFIDENCE IN OCCURRENCE AT ANY GIVEN LOCATION IS TOO LOW TO REFLECT IN TAFS. PRECIPITATION TOMORROW WILL BE RATHER SPOTTY...WILL NOT BE RAINING CONTINUOUSLY...AND PROBABLY WILL NOT RAIN AT LEAST HALF THE TIME IN ANY GIVEN HOUR...SO WENT WITH VCSH FOR NOW. WILL REFINE LATER WHEN TIMING OF PRECIPITATION BECOMES MORE APPARENT. WINDS BECOME NE THROUGHOUT TONIGHT...INCREASE TO AROUND 10KT LATE TONIGHT...THEN BECOME GUSTY OUT OF THE NE-NNE WEDNESDAY WITH GUSTS UP TO 20-25KT BY MID MORNING AT ALL BUT KSWF...WHERE THE GUSTS SHOULD HOLD OFF UNTIL AFTERNOON. 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: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. KLGA FCSTER COMMENTS: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. KEWR FCSTER COMMENTS: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. VCTS THROUGH 2Z. KTEB FCSTER COMMENTS: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. VCTS THROUGH 2Z. KHPN FCSTER COMMENTS: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. KISP FCSTER COMMENTS: TIMING OFF ONSET OF MVFR AND CHANGES IN WIND SPEED/DIRECTION/GUSTS COULD BE OFF +/- 1-3 HOURS. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...MVFR OR LOWER CONDITIONS IN SHRA. N-NW WINDS G25-30KT LIKELY. .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... 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. && .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... 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. && $$ SYNOPSIS...JM NEAR TERM...JMC/JM SHORT TERM...JM LONG TERM...DW AVIATION...MALOIT MARINE...JM/DW HYDROLOGY...JM/DW

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