Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 020847 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 447 AM EDT TUE SEP 2 2014 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE WEST TODAY...THEN CROSSES THE TRI-STATE TONIGHT. WEAK HIGH PRESSURE BUILDS IN ON WEDNESDAY...THEN REMAINS OVER THE REGION INTO FRIDAY. A COLD FRONT WILL APPROACH FRIDAY NIGHT AND MOVE ACROSS THE REGION SATURDAY AND SATURDAY NIGHT. HIGH PRESSURE RETURNS FOR THE START OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONVECTIVE FORECAST FOR TODAY IS A CHALLENGING ONE. WHILE A PRE- FRONTAL TROUGH WILL DEVELOP AND REMAIN OVER MAINLY WESTERN/NORTHERN ZONES...APPEARS SHOULD HAVE A WEAK CAP DEVELOP AROUND 650 HPA. SO EVEN WITH 1500-2500 J/KG OF CAPE FORECAST...THE WEAK CAP COUPLED WITH BEST DYNAMIC FORCING PROGGED TO OUR N...AND RELATIVELY WEAK SHEAR 20 KT OR LESS UNTIL MAYBE VERY LATE IN THE DAY OVER FAR W ZONES AS LOW-MID LEVEL JET APPROACHES THERE. APPEARS BEST CHANCE FOR ANY CONVECTION IS OVER AREAS N/W OF NYC LATE THIS AFTERNOON WITH ARRIVAL OF LOW-MID LEVEL JET. GIVEN ABOVE...FEEL THAT MOST LIKELY CAP HOLDS ON OVER THE SE 2/3 OF THE CWA...SO HAVE GONE WITH A DRY FORECAST THERE. HAVE CHANCE POPS BY LATE AFTERNOON OVER MAINLY ORANGE AND PUTNAM COUNTIES AND SLIGHT CHANCE POPS IN BETWEEN. ANY CONVECTION THAT DOES FORM WILL BE MAINLY OF THE PULSE VARIETY...WITH SOME MULTI-CELLULAR STRUCTURES POSSIBLE BY LATE AFTERNOON OVER MAINLY ORANGE COUNTY WITH ARRIVAL OF LOW-MID LEVEL JETS. BASED ON THIS FEEL SEVERE THREAT IS MINIMAL THIS AFTERNOON...BUT CANNOT BE COMPLETELY RULED OUT. FOR HIGHS TODAY...USED A BLEND OF MAV/MET GUIDANCE...NAM 2-METER TEMPERATURES AND MIXING DOWN FROM 875-850 HPA PER BUFKIT SOUNDINGS. SHOULD SEE VALUES AROUND 10-15 DEGREES ABOVE NORMAL - FROM AROUND 90 TO THE MID 90S INLAND/NYC HEAT ISLAND...AND MID TO UPPER 80S NEAR THE COAST. HEAT INDICES SHOULD REACH THE MID-UPPER 90S ACROSS URBAN NE NJ AND NYC THIS AFTERNOON. HOWEVER...FALL SHORT OF HEAT ADVISORY CRITERIA. THERE IS A MODERATE RISK OF THE METEOROLOGICAL ENHANCEMENT OF RIP CURRENT FORMATION AT ATLANTIC BEACHES TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... REGION WILL BE IN THE RIGHT REAR QUADRANT OF 80-90 KT 300 HPA JET...PASSING OF STRENGTHENING LOW-MID LEVEL JETS IN THE EVENING...AND THE AREA UNDER DIFFLUENT FLOW IN THE MID LEVELS...COUPLED WITH PRECIPITABLE WATERS FORECAST TO INCREASE TO AROUND 2 INCHES...THEN HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL IN ANY STORMS THAT DO FORM THIS EVENING. REFER TO HYDROLOGY SECTION OF THE AFD FOR FURTHER DETAILS. HOWEVER...WILL BE WORKING AGAINST DIMINISH CAPE WITH THE LOSS OF SOLAR HEATING...WITH BEST DYNAMICS PASSING TO THE N...BELIEVE THAT ANY SEVERE POTENTIAL RAPIDLY DIMINISHES DURING THE EARLY EVENING HOURS...AND IT WAS NOT ALL THAT HIGH TO BEGIN WITH. 700-500 HPA SHORTWAVES LIFTS TO THE N/E OF THE AREA TONIGHT...WITH ZONAL FLOW DEVELOPING WEDNESDAY...ALLOWING FOR THINGS TO DRY OUT LATE TONIGHT BEHIND THE SHORTWAVES. FOR LOWS TONIGHT...USED A BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES...WITH VALUES FORECAST TO BE AROUND 5 DEGREES ABOVE NORMAL. FOR HIGHS WEDNESDAY USED A BLEND OF MIXING DOWN FROM 850-825 HPA PER BUFKIT SOUNDINGS...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV/MET GUIDANCE. THIS YIELDS HIGHS AROUND 5-10 DEGREES ABOVE NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE OVER THE REGION WEDNESDAY NIGHT THROUGH FRIDAY WILL KEEP CONDITIONS SUNNY AND DRY. AS THE HIGH MOVES OFFSHORE ON THURSDAY...EXPECT HUMIDITY LEVELS TO INCREASE THURSDAY NIGHT AND FRIDAY. A COLD FRONT WILL APPROACH THE AREA FRIDAY NIGHT INTO SATURDAY...PUSHING OFFSHORE SOMETIME SATURDAY NIGHT. EXPECT SHOWERS AND THUNDERSTORMS TO ACCOMPANY THE FRONT. MOST OF THE MODELS ARE IN GOOD AGREEMENT ON THE TIMING OF THE FRONT. HOWEVER...A FEW OF THE MODELS WANT TO LINGER SOME PRECIPITATION INTO SUNDAY BEHIND THE FRONT. FOR NOW...DO NOT WANT TO RULE THIS OUT...SO WILL KEEP SOME CHANCE/SLIGHT CHANCE POPS IN FOR NOW. HIGH PRESSURE OVER CANADA WILL BUILD SOUTH BEHIND THE COLD FRONT...BRINGING COOLER AND LESS HUMID CONDITIONS TO THE REGION FOR THE START OF NEXT WEEK. TEMPERATURES THURSDAY THROUGH SATURDAY WILL REMAIN ABOVE NORMAL WITH HIGHS IN THE MIDDLE TO UPPER 80S. SLIGHTLY COOLER CONDITIONS CAN BE EXPECTED RIGHT ALONG THE COASTAL SECTIONS. TEMPERATURES THEN FALL BELOW NORMAL SUNDAY THROUGH TUESDAY WITH HIGHS ONLY IN THE 70S. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/...
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MVFR/IFR STRATUS/FOG LIKELY ALONG EASTERN TERMINALS...POSSIBLE ACROSS INTERIOR TERMINALS. ANY STRATUS/FOG SHOULD BURNS OFF IN THE MORNING...WITH VFR CONDS IN AFTN. LIGHT AND VRB WINDS THE REMAINDER OF THE NIGHT THRU THE COMING MORNING...GIVING WAY TO AFTN SEABREEZE DEVELOPMENT ALONG THE COAST. INCREASING CHANCE FOR SCT SHRA/TSRA THE COMING EVENING ACROSS NYC TERMINALS AND TO THE W & NW WITH APPROACHING COLD FRONT. WILL MAINTAIN PROB30 NOW...GENERALLY THINKING BETWEEN 01-07Z. ...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: LOW CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK...MAINLY VFR CONDITIONS FOR THE PERIOD. SEA BREEZE DEVELOPMENT BETWEEN 17-19Z. PCPN ISOLATED IN NATURE THIS EVENING. KLGA FCSTER COMMENTS: LOW CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK...MAINLY VFR CONDITIONS FOR THE PERIOD. GUSTS MAY BE MORE OCNL THIS AFTN. PCPN ISOLATED IN NATURE THIS EVENING. KEWR FCSTER COMMENTS: LOW CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK...MAINLY VFR CONDITIONS FOR THE PERIOD. GUSTS MAY BE MORE OCNL THIS AFTN. PCPN ISOLATED IN NATURE THIS EVENING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: LOW CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK...MAINLY VFR CONDITIONS FOR THE PERIOD. PCPN ISOLATED-SCT IN NATURE THIS EVENING. KHPN FCSTER COMMENTS: MOD CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK. PCPN ISOLATED-SCT IN NATURE THIS EVENING. KISP FCSTER COMMENTS: MOD CONFIDENCE OF STRATUS/FOG FORMATION AROUND DAYBREAK. OCNL GUSTS PSBL THIS AFTN WITH SEA BREEZE DEVELOPMENT...GENERALLY AFTR 18/19Z. LOW CONFIDENCE OF ANY PCPN THIS EVENING. .OUTLOOK FOR 09Z WED THROUGH FRI... .TUE NIGHT...MAINLY VFR. WINDS SHIFTING SW TO NW BEHIND FRONT BETWEEN 06-12Z. .WED-FRI NIGHT...VFR CONDITIONS ARE EXPECTED. .SAT...SUB VFR POSSIBLE IN SCATTERED SHRA/TSRA.
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&& .MARINE... WINDS WILL BE 15 KT OR LESS ON THE WATERS THROUGH WEDNESDAY. THERE IS SOME POTENTIAL THAT SEAS COULD BUILD TO 5 FT ON ANZ-350 TONIGHT...WITH TIGHTENING OF PRESSURE GRADIENT AHEAD OF THE FRONT...AND RESIDUAL 1-2 FT SWELLS. HOWEVER CONFIDENCE IN THIS IS NOT ALL THAT HIGH...SO DO NOT REFLECT IN FORECAST AT THIS TIME. SEAS SHOULD COME DOWN ON WEDNESDAY WITH A WEAKENING PRESSURE GRADIENT OVER THE AREA. GENERALLY LOOKING AT SUB-SCA CONDITIONS ON THE AREA WATERS WEDNESDAY NIGHT THROUGH THE WEEKEND. A COLD FRONT WILL PUSH ACROSS THE WATERS SATURDAY NIGHT INTO SUNDAY...WHICH WILL RESULT IN HIGHER WINDS AND SEAS. && .HYDROLOGY... SPOTTY SHRA/TSTMS MAINLY OVER AREAS N/W OF NYC...COULD PRODUCE ISOLATED LOCALLY HEAVY RAINFALL. AREAS EXPERIENCING LOCALLY HEAVY RAINFALL COULD EXPERIENCE MINOR URBAN/POOR DRAINAGE FLOODING. OUTSIDE OF AREAS EXPERIENCING LOCALLY HEAVY RAINFALL...LESS THAN 0.2 INCHES OF BASIN AVERAGE PRECIPITATION IS EXPECTED FROM ANY PRECIPITATION THAT DOES FALL THIS AFTERNOON AND TONIGHT. IT SHOULD THEN BE DRY FROM WEDNESDAY THROUGH AT LEAST FRIDAY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...BC/MALOIT NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...BC AVIATION...SEARS MARINE...BC/MALOIT HYDROLOGY...BC/MALOIT

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