Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 311119 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 719 AM EDT THU JUL 31 2014 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF THE NORTHEAST COAST THROUGH FRIDAY WHILE WEAK DISTURBANCE MOVES THROUGH THE REGION. A FRONTAL BOUNDARY WILL BACK IN FROM THE OCEAN THIS WEEKEND AND IMPACT THE AREA THROUGH THE BEGINNING OF THE WEEK. HIGH PRESSURE THEN BUILDS INTO THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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FORECAST FOR THE DAY CURRENTLY ON TRACK. TWEAKED TEMPS AND DEW POINTS FOR CURRENT OBS BUT TREND WAS ON TRACK. A FEW LIGHT SHOWERS HAVE DEVELOPED IN THE LWR HUDSON VALLEY AND NE NJ...CONSISTENT WITH OUR SLIGHT CHANCE POPS SO NO CHANGES WERE MADE THERE. OTHERWISE...UPPER LOW CONTINUES TO SPIN SOUTH OF HUDSON BAY WITH NEXT WEAK SHORTWAVE PIVOTING THROUGH THIS MORNING INTO EARLY AFTERNOON. CONSIDERABLE DIURNAL CU AND MEAN TROUGHING SHOULD KEEP TEMPS A FEW DEGREES BELOW SEASONABLE NORMS...GENERALLY UPPER 70S TO LOWER 80S. WITH LIMITED MOISTURE/INSTABILITY TO WORK WITH...OVERALL SHRA ACTIVITY TODAY SHOULD BE LOW IN COVERAGE. A FEW SHOWER POSSIBLE WELL N&W THIS MORNING WITH A WEAK LLJ. MOST ACTIVITY SHOULD BE N&W OF NYC METRO DEVELOPING FROM EARLY AFTERNOON INTO EARLY EVE...ALONG WEAK PRE-FRONTAL TROUGH AND OFF HIGHER ELEVATIONS OF EASTERN PA AND HILLS OF NJ/LOWER HUDSON VALLEY...DRIFTING NE. IN-SITU TSTM DEVELOPMENT LOOKS TO BE ISOLATED IN LOW CAPE ENVIRONMENT...BUT MODERATE SHEAR/WIND FIELDS COULD SUSTAIN ACTIVITY DEVELOPING TO THE W/SW AND DRIFTING NE. THERE IS A LOW THREAT FOR RIP DEVELOPMENT THIS MORNING...BECOMING THERE MODERATE RISK THIS AFTERNOON WITH AFTERNOON SEABREEZE DEVELOPMENT AND 3 FT S/SE SWELLS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... ANY SHOWER ACTIVITY WILL TAPER OFF IN THE EVENING. TEMPS NEAR SEASONABLE AS MOISTURE LEVELS GRADUALLY INCREASE WITH LIGHT ONSHORE FLOW...GENERALLY IN THE 60S. PATCHY FOG POSSIBLE ACROSS OUTLYING AREAS AS A RESULT. DEEP TROUGHING ACROSS EASTERN 1/2 OF THE US...DEEPENS SOUTHERLY FLOW UP THE EAST COAST. INCREASING MOISTURE/INSTABILITY ALONG WITH SOUTHERN STREAM SHORTWAVE ENERGY RIDING UP THE COAST AND WEAK RIGHT REAR JET LIFT WILL PRESENT A BETTER CHANCE FOR DIURNAL SHRA/TSRA ACTIVITY FOR NYC METRO AND PARTICULARLY POINTS N&W FRI AFT/EVE. OVERALL SHEAR LOOKS WEAK...SO WOULD EXPECT CONVECTION TO BE MORE PULSE IN NATURE...BUT CANT RULE OUT A FEW STRONG STORMS. 15 KT SSE STEERING FLOW WILL LEND TO AN URBAN/POOR DRAINAGE FLOOD POTENTIAL. TEMPS NEAR SEASONABLE IN MODERATING AIRMASS...LOWER 80S TO 85. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... DEEP UPPER TROUGH REMAINS TO THE EAST OF THE AREA FRIDAY NIGHT ALONG WITH A STRONG WESTERN ATLANTIC HIGH PRESSURE AREA. AS THE HIGH RETROGRADES WEST...IT WILL PUSH A FRONT TO THE WEST WITH IT. WITH THE BLOCKING PATTERN IN PLACE DUE TO THE UPPER LOW TO THE WEST...THE FRONT WILL SIT NEAR AND/OR OVER THE AREA THROUGH THE WEEKEND. A CONTINUOUS SOUTH-SOUTHWEST FLOW WILL ALSO HELP BRING SUFFICIENT MOISTURE INTO THE AREA. THE RIGHT ENTRANCE REGION OF AN UPPER JET ALSO SITS OVER THE REGION THROUGH THE WEEKEND. A COMBINATION OF THESE WILL KEEP UNSETTLED AND SHOWERY CONDITIONS OVER THE AREA. SOME OF THE SHOWERS/THUNDERSTORMS COULD PRODUCE MODERATE TO HEAVY RAINFALL. 12Z ECMWF IS A WETTER SOLUTION WITH THE FRONT SETTING UP ACROSS THE AREA WHILE THE GFS/NAM KEEPS IT TO THE SOUTH WHICH KEEPS THE AREA DRY THROUGH SUNDAY MORNING. WITH SO MUCH UNCERTAINTY REMAINING...DID NOT MAKE ANY MAJOR CHANGES TO THE POP GRIDS AND LEFT CHANCE FOR MUCH OF THE AREA SATURDAY AND SUNDAY. TEMPERATURES THROUGH THE WEEKEND WILL BE NEAR NORMAL...MAYBE SLIGHTLY BELOW NORMAL FOR HIGHS. WITH INCREASING DEW POINTS DUE TO THE MULTIPLE NIGHTS OF SOUTHERLY WIND...HAVE ADDED PATCHY FOG FOR SUNDAY AND MONDAY NIGHTS. A SURFACE LOW THEN DEVELOPS OVER THE SE IN RESPONSE TO THE DEEP UPPER TROUGH. THIS QUICKLY TRACKS NE OVER THE LOCAL AREA ON MONDAY. ECMWF FLATTENS THE UPPER LEVELS QUICKER ON MONDAY WHILE THE GFS LEAVES THE SURFACE LOW LINGERING ACROSS THE NORTHEAST WITH A WET SUNDAY AND MONDAY. AGAIN...WILL MAKE NO MAJOR CHANGES TO THE POP FORECAST. DRY WEATHER THEN EXPECTED TUES AND WED. TEMPS WILL BEGIN TO WARM MON-WED AS HEIGHTS RISE A FEW DEGREES WITH MORE BREAKS IN THE SUN THAN THE WEEKEND. LOWS WILL REMAIN NEAR NORMAL. && .AVIATION /12Z THURSDAY THROUGH MONDAY/...
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HIGH PRES WILL REMAIN OFFSHORE THRU FRI. ISOLD-SCT SHRA AND TSTMS LIKELY TO DEVELOP AFT 15-17Z...ESPECIALLY N AND W OF KNYC. THE PROB OF DIRECT IMPACTS AT A PARTICULAR TERMINAL TOO LOW TO INCLUDE IN THE TAFS...EXCEPT FOR KSWF WHERE SHRA HAVE BEEN RETAINED IN A TEMPO GROUP. SHRA/TSTMS DECREASE IN INTENSITY AND COVERAGE AFT 22Z. VFR OUTSIDE OF ANY PCPN. VRB WINDS BECOME SW THIS MRNG THEN VEER TO THE S AND INCREASE THRU THE DAY WITH A SEA BREEZE COMPONENT. SPEEDS LIGHTEN AGAIN TNGT AS THE SEA BREEZE INFLUENCE WEAKENS. 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: NO UNSCHEDULED AMENDMENTS EXPECTED. KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. .OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... .FRI...MAINLY VFR. ISOLD SHRA/TSTMS POSSIBLE IN THE AFTN/EVE. S FLOW. .SAT-SUN...AREAS OF MVFR OR LOWER. E FLOW SAT BECOMING S SUN. .MON...BECOMING VFR WITH WINDS SHIFTING TO THE W.
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&& .MARINE...
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WITH HIGH PRES OVER THE WATERS...CAN EXPECT SUB-SMALL CRAFT ADVISORY CONDS THROUGH FRIDAY. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THRU THE EXTENDED PERIOD.
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&& .HYDROLOGY... LOCALLY HEAVY DOWNPOURS IN SCATTERED TSTMS ON FRIDAY WILL PRESENT MAINLY A URBAN/POOR DRAINAGE FLOOD THREAT DUE TO AROUND 15 KT MOVEMENT...WITH A LOW AND LOCALIZED FLASH FLOOD THREAT WITH ANY TRAINING OF CELLS. AN INCREASINGLY MOIST AIR MASS WILL BE CONDUCIVE TO THE DEVELOPMENT OF HEAVY SHOWERS THIS WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...NV NEAR TERM...LN/NV SHORT TERM...NV LONG TERM...LN AVIATION...JMC MARINE...LN/NV HYDROLOGY...LN/NV

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