Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 312238 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 638 PM EDT FRI JUL 31 2015 .SYNOPSIS... HIGH PRESSURE TONIGHT WILL GIVE WAY TO A COLD FRONT ON SATURDAY. HIGH PRESSURE BUILDS OVER THE AREA ON SUNDAY AND THEN DEPARTS SUNDAY NIGHT. A SERIES OF FRONTAL BOUNDARIES WILL IMPACT THE AREA FOR THE START OF THE NEW WEEK WITH WEAK HIGH PRESSURE PREVAILING IN BETWEEN. LOW PRESSURE MAY IMPACT THE AREA LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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DECENT MIXING LATE THIS AFTERNOON AND EARLY EVENING WITH NW FLOW HAS ALLOWED DEW POINTS TO FALL INTO THE LOWER AND MIDDLE 50S. AT EWR...THE DEW POINT WAS 49 AT 22 UTC. THIS NW FLOW HAS BEEN STRONG ENOUGH TO HOLD THE SEA BREEZE FROM MAKING MUCH PROGRESS FROM THE SOUTH SHORE OF LONG ISLAND. WITH LOSS OF DAYTIME HEATING AND DIMINISHING WINDS THIS EVENING...DEW POINTS SHOULD RECOVER INTO THE LOWER 60S. HAVE UPDATED THE DATABASE TO REFLECT THIS TREND. DRY FORECAST TONIGHT WITH MAINLY CLEAR SKIES GIVING WAY TO PARTLY CLOUDY SKIES WITH THE UPPER TROUGH SETTLING OVER THE NORTHEAST. AT THE SFC...HIGH PRESSURE YIELDS TO A DEVELOPING TROUGH OVERNIGHT. TEMPS WILL REMAIN QUITE MILD OVERNIGHT. MOS BLEND WAS FOLLOWED AND A GENERAL RANGE FROM THE LOWER TO MIDDLE 70S NYC METRO TO THE LOWER 60S ACROSS THE INTERIOR IS EXPECTED.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
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MODELS REMAIN IN REASONABLE AGREEMENT AS THEY PROG UPPER LEVEL SHORTWAVE PIVOTING ACROSS THE NORTHEAST SATURDAY...PASSING TO THE EAST/NORTHEAST SATURDAY NIGHT. AT THE SFC...A COLD FRONT SLOWLY MOVES FROM WEST TO EAST ACROSS THE AREA DURING THE AFTERNOON HOURS. NAM SEEMS TO BE THE MOST AGGRESSIVE WITH REGARD TO CONVECTION AND COVERAGE COMPARED TO ECMWF/GFS AND CMC. LACK OF DEEP MOISTURE SHOULD CAP COVERAGE. HOWEVER...WEAK INSTABILITY IS NOTED ALONG WITH AMPLE SHEAR AND WEAK LIFT. AS SUCH...WILL MAINTAIN SLIGHT CHANCE POPS AT THIS TIME...AND BELIEVE SRN CT AND NEW ENGLAND WOULD BE THE FOCUS FOR HIGHEST COVERAGE BASED ON TIMING OF SHORTWAVE...COINCIDING WITH MAX HEATING. ANY SHOWERS/TSTMS DIMINISH AS THEY MOVE EAST SATURDAY NIGHT...SO A RETURN TO DRY WEATHER EXPECTED. TEMPS WILL BE QUITE WARM TO HOT...BUT HUMIDITY LEVELS WILL REMAIN RATHER LOW. DUE NOT EXPECT A TRUE SEA BREEZE AHEAD OF THE FRONT...AND MORE OF A WESTERLY FLOW WILL HELP BOOST TEMPS WELL INTO THE 80S...TO AROUND 90 IN SPOTS. THEN...TEMPS REMAIN RATHER WARM SATURDAY NIGHT BEHIND THE FRONTAL BOUNDARY. FOLLOWED A MOS BLEND...MET/MAV/ECS. THERE IS A MODERATE RISK OF RIP CURRENT DEVELOPMENT AT ATLANTIC OCEAN BEACHES ON SATURDAY.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/... SFC HIGH PRES BUILDS OVER THE TN VALLEY ON SUNDAY AND MOVES OFF THE MID-ATLANTIC COAST SUNDAY NIGHT. MEANWHILE...NEARLY ZONAL FLOW SETS UP ALOFT. THIS RESULTS IN A WEST-SOUTHWEST FLOW OVER THE AREA...AND WITH 850 MB TEMPS AROUND 14C...CAN EXPECT MAX TEMPS TO TOP OFF AROUND 90 DEGREES IN/AROUND NYC...AND IN THE MID TO UPPER 80S ELSEWHERE. HUMIDITY LEVELS LOOK TO BE FAIRLY LOW AWAY FROM THE COASTS...AS SFC DEW POINTS WILL RANGE FROM THE MID TO UPPER 50S EAST OF THE APPALACHIANS...IN/AROUND NYC...AND ACROSS THE INTERIOR...BUT IN THE LOW 60S ACROSS COASTAL CT AND EASTERN LONG ISLAND. AS HIGH PRES MOVES OFFSHORE SUNDAY NIGHT...A WARM FRONT WILL LIFT NORTH INTO THE NORTHEAST. MEANWHILE...A DEEP CLOSED H5 LOW OVER CENTRAL CANADA WILL DRIFT TO THE SOUTH AND EAST. THIS WILL PUSH A SERIES OF H5 TROUGHS/SHORTWAVES AND WEAK SFC COLD FRONTS ACROSS THE REGION MONDAY THROUGH TUESDAY. RIGHT NOW...NOT EXPECTING MUCH MORE THAN SLIGHT CHANCE TO CHANCE POPS FOR SHOWERS/TSTMS DURING THAT TIME. WITH MAINLY SOUTHERLY FLOW PREVAILING...HUMIDITY LEVELS WILL INCREASE AS SFC DEWPOINTS CLIMB THROUGH THE 60S AND APPROACH 70. AS A RESULT...LOCALLY HEAVY RAIN MAY BE POSSIBLE. SFC HIGH PRES BUILDS INTO THE AREA FOR WEDNESDAY. HOWEVER...A STRONGER H5 TROUGH/SHORTWAVE COMB WILL PASS NORTH OF THE LOCAL AREA. FOR NOW...THIS LOOKS TO BE TOO FAR NORTH TO IMPACT THE CWA...SO WILL CARRY A DRY FORECAST...BUT IT WILL HAVE TO BE WATCHED. NEXT CHANCE FOR WIDESPREAD RAIN COMES THURSDAY-FRIDAY AS LOW PRES PASSES THROUGH THE REGION. BOTH THE 12Z GFS AND THE 12Z ECMWF INDICATING POTENTIAL FOR HEAVY RAIN...BUT HEAVY RAIN AXIS IS ACROSS NORTHERN ZONES IN THE GFS AND SOUTH OF LONG ISLAND IN THE ECMWF. WILL CARRY CHANCE POPS AND WILL KEEP AN EYE ON HOW THIS DEVELOPS. HOT AND HUMID CONDS EXPECTED ON MONDAY WITH HIGHS IN THE UPPER 80S TO LOW 90S AND SFC DEW POINTS WELL IN THE 60S...THEN TEMPS AND HUMIDITY LEVELS BACK OFF A BIT ON TUESDAY AND WEDNESDAY. THURSDAY AND FRIDAY COULD BE NOTICEABLY COOLER...DEPENDING ON THE TRACK OF THE LOW. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... A WEAK SURFACE FRONT HANGS ACROSS THE REGION THROUGH SATURDAY. VFR. SEABREEZE FRONT...SOUTH OF KJFK...EXPECTED IT TO WORK NORTH THROUGH JFK BY 20Z. SW FLOW SHOULD PREDOMINATE AT KBDR/KGON. SSW SEABREEZE SHOULD MAKE IT INTO KISP BY 21Z. ELSEWHERE...WSW WINDS WITH GUSTS UP TO 20KT DIMINISHING THIS EVENING AND SETTLING TO THE WSW. W/SW FLOW STRENGTHENS SAT MORNING. 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: HIGH CONFIDENCE IN S SEABREEZE BETWEEN 20Z AND 21Z. KLGA FCSTER COMMENTS: WINDS WILL GENERALLY REMAIN LEFT OF 310 MAGNETIC THROUGH EARLY EVE. LOW PROB OF SEABREEZE (AFT 22-23Z). KEWR FCSTER COMMENTS: WINDS WILL GENERALLY REMAIN LEFT OF 310 MAGNETIC THROUGH EARLY EVE. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: SSW SEABREEZE EXPECTED BY 21-22Z. .OUTLOOK FOR 18Z SAT THROUGH WED... .SAT AFT...VFR. W WINDS OF 10 TO 15 KT WITH GUSTS TO 20 KT. SW WINDS LIKELY AT SOUTH COASTAL TERMINALS...WITH LOW PROB OF S SEABREEZE. LOW PROB AND SPARSE AFT SHRA/TSRA THREAT FOR NYC/NJ AND INTERIOR TERMINALS. .SAT NIGHT-SUN...VFR. SW/S FLOW...COASTAL SEABREEZE. .MON...GUSTY S FLOW. A CHC OF TSTMS. .MON NIGHT-TUE...CHC TSTMS. FROPA WITH S WINDS...SHIFTING TO THE W. .WED...VFR. W FLOW. && .MARINE... HIGH PRESSURE TONIGHT GIVES WAY TO A COLD FRONT ON SATURDAY. ACROSS THE OCEAN WATERS...WINDS WILL INCREASE DURING THE DAY SATURDAY AHEAD OF THE COLD FRONT FROM THE SW. SPEEDS LIKELY FALL SHORT OF SCA THRESHOLDS. HOWEVER...SEAS ACROSS THE WATERS EAST OF FIRE ISLAND LOOK TO BUILD CLOSE TO 5 FEET. AS SUCH...WILL POST A SCA FOR SATURDAY AND INTO SATURDAY EVENING AS SEAS SUBSIDE BEHIND THE FRONT. OTHERWISE...WINDS AND SEAS REMAINS RATHER TRANQUIL ACROSS THE NON OCEAN WATERS. A TIGHT SW GRADIENT MAY RESULT IN SCA CONDS ON THE OCEAN WATERS ON SUNDAY...THEN GENERALLY TRANQUIL CONDS ON TAP FOR MONDAY. A SERIES OF FRONTAL BOUNDARIES WILL MOVE ACROSS THE WATERS EARLY IN THE NEW WEEK...RESULTING IN OCNL SCA CONDS THROUGH THE MIDDLE OF NEXT WEEK. && .HYDROLOGY... NO SIGNIFICANT WIDESPREAD RAIN EXPECTED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM SATURDAY TO MIDNIGHT EDT SATURDAY NIGHT FOR ANZ350-353. && $$ SYNOPSIS...MPS/PW NEAR TERM...DS/PW SHORT TERM...DS/PW LONG TERM...MPS AVIATION...NV MARINE...MPS/PW HYDROLOGY...MPS/PW

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