Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 061944 AAA AFDOKX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NEW YORK NY 344 PM EDT MON JUL 6 2015 .SYNOPSIS... A DIFFUSE WARM FRONT GRADUALLY MOVES NORTH INTO THE REGION THROUGH TUESDAY. A COLD FRONT MOVES ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A SERIES OF LOW PRESSURE SYSTEMS. HIGH PRESSURE RETURNS FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND WITH A RETURN TO UNSETTLED WEATHER FOR THE START OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... WARM FRONT IS DIFFICULT TO LOCATE IN THE SFC WND AND DEW PT OBSERVATIONS. SFC PRESSURE PATTERN SUGGESTS PERHAPS SOUTH JERSEY? REGARDLESS, FLOW IS VERY MOIST AND MARITIME TROPICAL LIKE. ISOLATED SHOWERS OVER CENTRAL JERSEY WILL PROBABLY CLIP THE WESTERN PART OF THE FCST AREA THIS EVENING. MAIN SHOWERS AND STORMS ARE CONFINED TO VA INTO CENTRAL PA WHERE A WEAKENING UPPER LOW OVER EASTERN OHIO AND A FAIRLY WELL DEFINED VORT MAX NEAR KNOXVILLE TN (BOTH SEEN IN THE WATER VAPOR IMAGERY) HELP PROVIDE DYNAMICS TO THE INSTABILITY. THE PSEUDO MCV FEATURE OVER NORTH- CENTRAL VA APPEARS TO HAVE WEAKENED AND IS NOW DIFFICULT TO LOCATE IN THE VISIBLE IMAGERY. HAVE CONFINED ANY MENTION OF POPS TO FAR WESTERN ZONES FOR THIS EVENING AND FOR AFTER MIDNIGHT. SOME FOG IS POSSIBLE WITH THE MOIST ONSHORE FLOW. USED "PATCHY" WORDING, BUT NOT EXPECTING AN IMPACTS. THE POSSIBLE EXCEPTION IS THE SOUTH SHORE OF LONG ISLAND. NARRE-TL IS POINTING FOR THE JERSEY COAST. WITH IT BEING CLIMATOLOGICALLY UNFAVORABLE FOR FOG, WILL HOLD OFF ON ANYTHING MORE THAN PATCHY. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... WARM AND HUMID WITH SIGNIFICANT CLOUD COVER. WITH A MARITIME TROPICAL AIR MASS OVER THE REGION, THE APPROACH OF THE WEAKENING SHORT WAVE CONTINUES TO HAVE THE POTENTIAL TO GENERATE SHOWERS AND AN ISOLATED TSTM...ESPECIALLY TUESDAY AFTERNOON. THE HIGHEST POPS ARE NW WHERE NWP AND 15Z SREF MEAN ARE FOCUSED. INSTABILITY IS BETTER THAN TODAY WITH FORECAST SFC BASED CAPES OF 500-1500 J/KG (HIGHEST IN GFS). FCST HIGHS SHOULD BE A FEW DEGREES ABOVE NORMAL AND ARE CLOSE TO THE SLIGHTLY WARMER NAM MOS. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... COLD FRONT SLOWLY WORKS ITS WAY ACROSS THE AREA WEDNESDAY AND SHOULD BE SOUTH OF THE REGION BY WEDNESDAY EVENING. THERE WILL BE ABUNDANT LOW LEVEL MOISTURE ACROSS THE REGION WITH SFC DEW POINTS AROUND 70 AND PWATS OVER 2". AS A RESULT...CAN EXPECT HEAVY RAIN AT TIMES...AND WITH TRAINING OF CELLS...AT LEAST MINOR URBAN/SMALL STREAM FLOODING IS POSSIBLE. THERE IS LITTLE CONSENSUS AMONG THE MODELS AS TO TIMING AND STRENGTH OF STORMS...SO WILL KEEP POPS CAPPED AT CHANCE FOR NOW WITH NEST CHANCES IN THE AFTERNOON/EVENING. 12Z NAM HAS LITTLE QPF OVER THE AREA...GENERALLY LESS THAN 1/4"...WHILE THE 12Z ECMWF IS SIMILAR IN TERMS OF LESS THAN 1/4" WIDESPREAD QPF...AREAL COVERAGE IS MORE WIDESPREAD THAN THE NAM. THE 12Z GFS DEVELOPS SFC LOW PRES OVER THE DELMARVA WEDNESDAY EVENING...AND IF IT WERE TO TRACK CLOSE ENOUGH TO SOUTHERN PORTIONS OF NE NJ...NYC...AND LONG ISLAND...THOSE AREAS COULD PICK UP AROUND AN INCH WEDNESDAY NIGHT WHILE THE OTHER MODELS HAVE THE REGION DRYING OUT. MAINLY...THIS APPEARS TO BE DUE TO A STRONG H5 SHORTWAVE NOTED IN THE GFS PASSING THROUGH THE REGION...WHILE THE ECMWF HAS A WEAKER SHORTWAVE MUCH FARTHER SOUTH. THIS IS A FLUID SITUATION...AND FURTHER MODEL RUNS WILL BE NEEDED. CONDS DRY OUT BY THURSDAY MORNING...BUT THEN ANOTHER WAVE OF LOW PRES MOVES THROUGH THE REGION IN THE AFTERNOON...TOUCHING OFF SOME MORE SHOWERS/STORMS IN THE AFTERNOON/EVENING. HIGH PRES THEN BUILDS IN THEREAFTER WITH DRY CONDS FOR THURSDAY THROUGH SUNDAY. TEMPS WILL BE MILD WITH HIGHS GENERALLY IN THE 80S AND LOWS IN THE UPPER 60S/LOW 70S. THE HIGH MOVES OFFSHORE ON SUNDAY...AND THE NEXT WAVE OF LOW PRES APPROACHES FOR SUNDAY NIGHT/MONDAY. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY. A WARM FRONT APPROACHES FROM THE SOUTHWEST TONIGHT. VFR INTO EARLY THIS EVENING. WITH 2ND NIGHT OF ONSHORE FLOW AND A FAVORABLE S-SE WIND DIRECTION AHEAD OF THE APPROACHING WARM FRONT...MVFR CONDS SHOULD DEVELOP AROUND 03Z. CONDS THEN LOWER TO IFR MAINLY AFTER MIDNIGHT. LIFR CONTINUES TO BE EXPECTED AFTER 06Z AT KGON/KISP/KBDR AND CANNOT RULE IT OUT FOR KJFK. WINDS THROUGHOUT MUCH OF THE TAF PERIOD WILL BE OUT OF THE SE...GENERALLY 10 KT OR LESS. 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: WIND DIRECTION MAY VARY BETWEEN 140 AND 170 TRUE THROUGH THE EARLY EVENING. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KLGA FCSTER COMMENTS: AN OCCASIONAL GUST TO AROUND 20 KT POSSIBLE THIS AFTERNOON. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KEWR FCSTER COMMENTS: WIND DIRECTION MAY VARY BETWEEN 140 AND 170 TRUE THROUGH THE EARLY EVENING. ISO SHOWER POSSIBLE THROUGH 23Z. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KTEB FCSTER COMMENTS: ISO SHOWER POSSIBLE THROUGH 23Z. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KHPN FCSTER COMMENTS: TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KISP FCSTER COMMENTS: TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. .OUTLOOK FOR 18Z TUE THROUGH SAT... .TUE AFTN...CHANCE OF SHRA/TSTMS WITH MVFR OR LOWER CONDITIONS AT TIMES... ESPECIALLY FROM NYC METRO NORTH/WEST. .TUE NIGHT...MVFR/IFR CONDS POSSIBLE IN FOG. .WED...SHRA/TSTMS POSSIBLE WITH MVFR OR LOWER CONDITIONS AT TIMES. .THU-FRI...CHANCE OF SHOWERS WITH MVFR OR LOWER CONDITIONS AT TIMES. .SAT...VFR. && .MARINE... RATHER TRANQUIL THROUGH TUESDAY...THOUGH WINDS ARE EXPECTED TO INCREASE. FOG COULD AFFECT THE WATERS LATE TONIGHT AND TUESDAY MORNING ALONG THE SOUTH SHORE OF LONG ISLAND WITH VISIBILITY REDUCED TO 1 TO 3 NM...AND POSSIBLY BELOW 1 NM AT TIMES. A COLD FRONT MOVES ACROSS THE WATERS ON WEDNESDAY...FOLLOWED BY A SERIES OF LOW PRESSURE WAVES THROUGH THURSDAY NIGHT. THIS WILL KEEP AT LEAST A CHANCE FOR SHOWERS/TSTMS IN THE FORECAST. HIGH PRES BUILDS IN FOR THE END OF THE WEEK AND THE WEEKEND WITH DRY CONDS. THE GRADIENT OVER THE WATERS SHOULD REMAIN RELAXED ENOUGH TO KEEP CONDS BELOW SCA LEVELS DURING THIS TIME. && .HYDROLOGY... SUMMER CONVECTION IS FCST FOR TUESDAY AND WEDNESDAY (MORE LIKELY) AFTNS. WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES...HEAVY RAINFALL IS POSSIBLE. WITH THE CONVECTION ALSO BEING RATHER SLOW MOVING...LOCALIZED URBAN AND POOR DRAINAGE FLOODING COULD OCCUR...WITH A LOW PROBABILITY OF FLASH FLOODING. THIS HAZARDS IS HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK TEXT PRODUCT FROM FAIRFIELD AND NASSAU COUNTIES ON WEST...INCLUDING NYC FOR WEDNESDAY AFTERNOON AND EVENING. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MPS/TONGUE NEAR TERM...TONGUE SHORT TERM...TONGUE LONG TERM...MPS AVIATION...DS MARINE...MPS/TONGUE HYDROLOGY...MPS/TONGUE

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