Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 271437 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1037 AM EDT MON JUL 27 2015 .SYNOPSIS... A WEAK TROUGH WILL REMAIN ACROSS THE AREA THROUGH TUESDAY. HIGH PRESSURE WILL BUILD IN FOR THE MID WEEK. A COLD FRONT APPROACHES FROM THE WEST LATE WEDNESDAY NIGHT AND THURSDAY MORNING...THEN CROSSES THE TRI-STATE THURSDAY AFTERNOON AND EVENING. WEAK HIGH PRESSURE THEN BUILDS IN TO CLOSE THE WEEK...THEN GIVES WAY TO AN EASTWARD EXTENSION OF THE BERMUDA HIGH BY SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A WEAK SHORTWAVE REMAINS ACROSS UPSTATE NEW YORK INTO PENNSYLVANIA THIS MORNING...AND WILL BE GRADUALLY WEAKENING THROUGH THIS AFTERNOON AS THE TROUGH AXIS MOVING INTO NEW ENGLAND. MIXED LAYER CAPE OF 500 TO 1000 J/KG REMAINS ACROSS COASTAL CONNECTICUT...AND LONG ISLAND AND IS THE FOCUS OF SHOWERS AND THUNDERSTORMS THIS MORNING. WITH THE TROUGH IN THE VICINITY WILL CONTINUE WITH LIKELY POPS THIS MORNING FOR THE AREAS WITH THE HIGHEST CAPE. AND THEN CONTINUE WITH THE CHANCE POPS THIS AFTERNOON NORTH AND WEST AS THE MID AND UPPER LEVEL TROUGH MOVE THROUGH. MAIN THREAT WITH CONVECTION WILL BE BRIEF HEAVY DOWNPOURS AND THE POTENTIAL FOR LOCALIZED URBAN FLOODING DUE TO SLOW STORM MOTION. AN ISOLATED PULSE STRONG TO SEVERE STORM IS NOT OUT OF THE QUESTION THIS AFTERNOON...BASED ON MODEST INSTABILITY BUT RATHER WEAK WIND FIELDS. CONVECTION SHOULD DECREASE IN COVERAGE AND INTENSITY THIS EVENING AS SHORTWAVE AXIS MOVES FURTHER EAST AND INSTABILITY WANES. HIGHS TODAY GENERALLY IN THE LOWER TO MID 80S DUE TO ABUNDANT CONVECTIVE DEBRIS. THERE IS A MODERATE RISK FOR RIP CURRENT DEVELOPMENT AT ATLANTIC BEACHES TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... SHORTWAVE AXIS SLIDES EAST THIS EVENING...WITH ANOTHER SHORTWAVE DIGGING THROUGH NEW ENGLAND LATE TONIGHT INTO TUE MORNING. WITH SURFACE TROUGH LINGERING OVER THE REGION TONIGHT....WEAK INSTABILITY AND NEXT APPROACHING SHORTWAVE...CANT RULE OUT ISOLATED CONVECTION LATE TONIGHT INTO TUE MORNING. APPEARS NYC METRO/SW CT AND POINTS EAST WOULD BE MOST FAVORABLE BASED ON TROUGH POSITION. WARM AND MUGGY CONDITIONS TONIGHT. SHORTWAVE AXIS PIVOTS EAST IN THE AFTERNOON. CONVECTIVE POTENTIAL APPEARS TO WANE IN THE AFTERNOON AS MID-LEVELS WARM AND IN WAKE OF SHORTWAVE AXIS. INCREASING SUNSHINE FOR MUCH OF THE REGION AND RISING HEIGHTS SHOULD ALLOW FOR TEMPS TO WARM TO ABOVE NORMAL LEVEL ON TUESDAY...GENERALLY MID TO UPPER 80S AWAY FROM IMMEDIATE SOUTH COASTS. AFTERNOON SEABREEZE DEVELOPMENT SHOULD KEEP SOUTH COASTAL AREAS IN THE LOWER TO MID 80S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MAIN ISSUE IN THE LONG TERM WILL BE THE HEAT AND HUMIDITY THROUGH THURSDAY. DEEP LAYERED RIDGING BUILDS IN TUESDAY NIGHT-WEDNESDAY NIGHT...THIS SHOULD KEEP THINGS DRY THROUGH THEN...EXCEPT FOR MAYBE A SLIGHT CHANCE OF A LINGERING SHOWER AND/OR THUNDERSTORM OVER SE CT EARLY TUESDAY EVENING...IN RESPONSE TO A SHORTWAVE PASSING TO THE NE. THE RIDGE AXIS SLIDES OFFSHORE ON THURSDAY...EXACTLY HOW FAST WILL DETERMINE HOW QUICKLY AND HOW FAR E SHOWERS AND THUNDERSTORMS AHEAD OF A NORTHERN STREAM TROUGH MOVE INTO THE CWA. FOR NOW INCREASE POPS TO CHANCE OVER THE NW 2/3 OF THE CWA BY AFTERNOON AND SLIGHT CHANCE OVER THE SE 1/3. MODELS ARE STILL FORECASTING A MID LEVEL CAP FROM AROUND 675 TO 600 HPA AND THIS WILL SERVE AS LIMITING FACTOR FOR ANY STORMS BECOMING STRONG TO SEVERE. LOWS TUESDAY NIGHT SHOULD RUN AROUND 5 DEGREES OR SO ABOVE NORMAL BASED ON A BLEND OF ECS/MET/MAV GUIDANCE AND NAM 2-METER TEMPERATURES. HIGHS WEDNESDAY ARE FORECAST TO BE A FEW DEGREES HIGHER THAN PREVIOUSLY IN RESPONSE TO LOW LEVEL TEMPERATURES BEING FORECAST TO BE SLIGHTLY HIGHER THAN PREVIOUSLY. HIGHS SHOULD RUN MAINLY FROM THE LOWER TO MIDDLE 90S...WITH A FEW UPPER 90S POSSIBLE IN URBAN NE NJ AND POSSIBLY N/NW PORTIONS OF NYC...WITH UPPER 80S TO AROUND 90 ACROSS THE TWIN FORKS OF LONG ISLAND AND COASTAL SE CT. THIS IS BASED ON A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM850-800 HPA PER BUFKIT SOUNDINGS. NEAR RECORD HIGHS ARE POSSIBLE ON WEDNESDAY AS A RESULT. REFER TO THE CLIMATE SECTION OF THE AFD FOR DETAILS. HEAT INDICES ON WEDNESDAY SHOULD GENERALLY BE IN THE LOWER TO MID 90S...WITH UPPER 90S LIKELY ACROSS NYC/URBAN NE NJ...WITH VALUES OF 100 POSSIBLE THERE. LIMITING FACTOR ON THE HEAT INDEX WILL BE THE AFTERNOON DEWPOINTS...AND WITH POTENTIAL FOR MIXING TO AT LEAST 850 HPA...SHOULD SEE THE DEWPOINTS LOWER AS THE TEMPERATURE RISES. THE EXTENT OF THIS FALL OF IS UNCERTAIN AT THIS TIME...BUT AM CONFIDENT ENOUGH IN SOME FALL OFF THAT DEWPOINTS IN THE AFTERNOON OVER URBAN AREAS SHOULD REMAIN BELOW 70 DEGREES. FOR THIS REASON...BELIEVE THE RISK OF HEAT INDICES REACHING 105 IS VERY LOW...SOMETHING LESS THAN 10 PERCENT. TEMPERATURES WEDNESDAY NIGHT-THURSDAY ARE BASED ON A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WITH NAM 2-METER TEMPERATURES BLENDED IN AS WELL WEDNESDAY NIGHT. LOWS WEDNESDAY NIGHT SHOULD BE 5- 10 DEGREES ABOVE NORMAL AND HIGHS ON THURSDAY 5-10 DEGREES ABOVE NORMAL...BUT A FEW DEGREES COOLER THAN ON WEDNESDAY. HEAT INDICES IN URBAN AREAS ON THURSDAY SHOULD GENERALLY BE IN THE MIDDLE TO UPPER 90S. A NORTHERN STREAM SHORTWAVE PASSES TO THE NORTH THURSDAY EVENING...BRINGING WITH IT A CHANCE OF SHOWERS AND THUNDERSTORMS. IT SHOULD THEN BE DRY LATE THURSDAY NIGHT AND FRIDAY UNDER WSW FLOW ALOFT WITH NO SHORTWAVES FORECAST OVER THE AREA. A NORTHERN STREAM TROUGH BUILDS IN FRIDAY NIGHT AND SATURDAY...BUT THE LOW LEVELS APPEAR TO BE TO DRY TO SUPPORT ANY PRECIPITATION...SO ONLY AM FORECASTING SOME PASSING CLOUDS FOR NOW. ZONAL FLOW IS EXPECTED SATURDAY NIGHT...WITH WEAK RIDGING BUILDING IN ON SUNDAY...SO BOTH PERIODS SHOULD BE DRY AS WELL. TEMPERATURES THURSDAY NIGHT-SUNDAY SHOULD CONTINUE TO RUN ABOVE NORMAL...AND ARE BASED ON A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... DECAYING COLD FRONT MOVES IN THIS MORNING AND DISSIPATES. MAINLY VFR THOUGH THE PERIOD. A FEW SHRA/TSRA MAY BRIEFLY PRODUCE MVFR CIGS THIS AFTERNOON. HAVE INCLUDED A VCTS FOR KSWF IN THE TAF. ELSEWHERE...TOO MUCH UNCERTAINTY IN THE TIMING AND LOCATION OF SHRA/TSRA. SW-S FLOW 5-10 KT THROUGH MUCH OF THE PERIOD WITH SLIGHTLY HIGHER WINDS THIS AFTN FOR KJFK/KLGA. 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: POSSIBLE TSRA TODAY. KLGA FCSTER COMMENTS: POSSIBLE TSRA TODAY. KEWR FCSTER COMMENTS: POSSIBLE TSRA TODAY. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: POSSIBLE TSRA TODAY. KHPN FCSTER COMMENTS: POSSIBLE TSRA TODAY. KISP FCSTER COMMENTS: POSSIBLE TSRA TODAY. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .TUESDAY-THURSDAY...MAINLY VFR. 5-6SM HAZE DEVELOPMENT POSSIBLE. SW WINDS WITH AFTERNOON SEABREEZE DEVELOPMENT AT COASTAL TERMINALS. TSRA POSSIBLE THU AFTN/EVE. .FRIDAY...VFR. && .MARINE... UPDATED WITH CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE WATERS TODAY INTO TONIGHT. OTHERWISE WIND AND SEAS FORECAST IS ON TRACK. WIND AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT LEVELS THROUGH TUESDAY WITH A FAIRLY WEAK PRESSURE GRADIENT. A RELATIVELY RELAXED PRESSURE GRADIENT OVER THE WATERS TUESDAY NIGHT THROUGH FRIDAY SHOULD KEEP WINDS 10 KT OR LESS IN THIS TIME FRAME. A POSSIBLE EXCEPTION IS OVER THE COASTAL OCEAN WATERS WEDNESDAY NIGHT AND THURSDAY WHERE WINDS COULD REACH 15 KT AHEAD OF A COLD FRONT. BASED ON THESE WINDS...AND NO EXPECTED SIGNIFICANT SWELL...SEAS/WAVES SHOULD REMAIN BELOW SMALL CRAFT LEVELS TUESDAY NIGHT THROUGH FRIDAY. && .HYDROLOGY... ANY THUNDERSTORMS TODAY WILL BE VERY SLOW TO MOVE...WITH STORM MOTION FORECAST TO BE 10 KT OR LESS. AS A RESULT...THERE IS THE POTENTIAL FOR LOCALIZED URBAN/POOR DRAINAGE FLOODING. LOCAL AMOUNTS OF A QUARTER TO A THIRD OF AN INCH ARE POSSIBLE. MAINLY DRY TUESDAY NIGHT THROUGH THURSDAY MORNING. WHILE WIDESPREAD SIGNIFICANT RAINFALL IS NOT EXPECTED WITH ANY SHOWERS/THUNDERSTORMS THURSDAY AFTERNOON/EVENING...THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH ANY STRONGER CONVECTION. IF THIS WERE TO OCCUR...THAN LOCALIZED MINOR URBAN/POOR DRAINAGE FLOODING WOULD BE POSSIBLE. IT SHOULD THEN BE DRY FROM LATE THURSDAY NIGHT THROUGH THE END OF THE WEEK. && .CLIMATE... RECORD HIGHS FOR WEDNESDAY JULY 29 2015... LOCATION..........RECORD HIGH/YEAR.........FORECAST HIGH NEWARK....................100/1949.................97 BRIDGEPORT.................96/2002.................91 CENTRAL PARK...............99/1949.................95 LA GUARDIA.................97/1949.................97 J F KENNEDY................99/2002.................92 ISLIP......................96/2002.................93 && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/NV NEAR TERM...MET SHORT TERM...NV LONG TERM...MALOIT AVIATION...BC/JE MARINE...MET HYDROLOGY...MET CLIMATE...

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