Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 040710 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 310 AM EDT TUE AUG 4 2015 .SYNOPSIS... A SLOW MOVING COLD FRONT WILL APPROACH OVERNIGHT THEN STALL ACROSS THE AREA TODAY. THE COLD FRONT MOVES OFFSHORE WEDNESDAY AS WEAK HIGH PRESSURE BUILDS INTO THE AREA. SEVERAL WAVES OF LOW PRESSURE MAY IMPACT THE AREA FOR THE END OF THE WEEK. HIGH PRESSURE BUILDS BACK IN FOR THE WEEKEND. && .NEAR TERM /UNTIL 9 AM THIS MORNING/...
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TWO RATHER DIFFUSE FRONTS APPROACHING FROM THE NW. THE FIRST FRONT IS FORCING CONVECTION AHEAD OF IT IS BEING MAINTAINED BY BOTH THERMODYNAMICS IN THE FORM OF HIGH CAPE AND DYNAMICS IN THE FORM OF A PRONOUNCED JET STREAK. INSTABILITY IS RATHER IMPRESSIVE. COMPARING LATEST KEWR ACARS SOUNDING WITH RAP SUPPORTS LI`S ON -2 C AND THE 60KT JET ENTRANCE WINDS. RAP SOUNDINGS INDICATES CONTINUED DESTABILIZATION THE NEXT FEW HOURS WITH AREAS TO THE EAST (CT AND LONG ISLAND) BECOMING VERY UNSTABLE. FOR EXAMPLE...KISP HAS 3000 J/KG OF CAPE AND -6 C ON THE LI`S. THUS AM FCSTING THE LINE THAT`S FORMING ALONG THE DELAWARE TO CONTINUE AND GROW. HAVE ADDED GUSTY WINDS AND HEAVY RAIN TO THE TSTM DESCRIPTORS. WILL HAVE TO WATCH THIS CLOSELY SEVERE AND QUICK SPIN UPS. HAVE INCREASED POPS FOR CT AND LONG ISLAND. EXPECT THE ACTIVITY IS EAST OF CT AND LONG ISLAND BY 930 AM. IT LOOKS LIKE MUCH OF THE ACTIVITY BEHIND THE EASTERN PA CLUSTER WILL WEAKEN - BUT CONFIDENCE IN THIS OCCURRING REMAINS LOW.
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&& .SHORT TERM /9 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE FRONT STALLS ACROSS THE AREA TODAY WITH A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS. VERY LITTLE APPRECIABLE DIFFERENCE WILL BE FELT WITH TEMPERATURES REMAINING ABOVE NORMAL AND SIMILAR HUMIDITY AS MONDAY. LATE TONIGHT THE UPPER TROUGH BUILDS FARTHER SOUTH AND EAST...FORCING THE ATTENDANT SURFACE FRONT FARTHER OFFSHORE WITH LOWER DEW POINTS ADVECTING INTO THE REGION. A SUBSEQUENT DECREASE IN HUMIDITY WILL BE FELT AS THIS OCCURS. THERE IS A HIGH RISK FOR THE DEVELOPMENT OF RIP CURRENTS AT THE OCEAN BEACHES TODAY. A RIP CURRENT STATEMENT IS IN EFFECT. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... COLD FRONT CONTINUES TO SLOWLY MOVE OFFSHORE WITH HIGH PRESSURE BUILDING INTO THE AREA ON WEDNESDAY. UPPER LEVEL TROUGH REMAINS OVER THE AREA INTO THURSDAY. UPPER LEVEL TROUGH DEPARTS THE AREA WEDNESDAY NIGHT INTO THURSDAY. MODELS HAVE COME INTO BETTER AGREEMENT WITH SURFACE LOW OVER THE MID- WEST TREKKING EAST WEDNESDAY NIGHT AND AFFECTING THE AREA MAINLY FROM THURSDAY NIGHT THROUGH AT LEAST FRIDAY NIGHT. HOWEVER...THERE IS STILL UNCERTAINTY ON WHERE IT TRACKS AND THEREFORE HOW MUCH RAIN WE DO RECEIVE. HOWEVER...IT DOES APPEAR MORE CERTAIN THAT A WIDESPREAD HEAVY RAIN EVENT IS IN STORE FOR THIS TIME PERIOD. ISENTROPIC LIFT OUT AHEAD OF THE APPROACHING LOW NOTED IN BOTH THE 12Z GFS AND 12Z ECMWF...MAINLY LATE THURSDAY NIGHT...SO THINKING THIS WILL BE MORE STRATIFORM RAIN. SURFACE LOW CONTINUES ITS APPROACH FRIDAY MORNING. MODELS DIFFER IN THE PLACEMENT OF THE LOW. THE 12Z ECMWF AND 12Z GFS AGREE WITH THE LOW BEING OVER THE NORTHERN MID-ATLANTIC STATES BY 06Z SATURDAY. THEREAFTER...MODELS DIFFER QUITE A BIT IN THEIR SOLUTIONS. 12Z ECMWF TREKS THE LOW NORTHEAST IN SIDE THE 40/70 BENCHMARK THROUGH THE DAY SATURDAY WHILE IT SLOWLY STRENGTHENS WHILE THE GFS WEAKENS THE LOW OVER THE OLD FRONTAL BOUNDARY OFFSHORE AND WEAKER WAVES OF LOW PRESSURE RIDING ALONG IT...WHILE THE 12Z CANADIAN IS AN OUTLIER BEING MORE PROGRESSIVE THAN THE OTHER MODELS. THEREFORE...SIDED MORE ALONG THE LINES OF THE GFS AND ECMWF AND KEEP CHANCE POPS IN THE AREA THROUGH THE DAY SATURDAY LOW PRESSURE PUSHES AWAY FROM THE AREA LATE SATURDAY NIGHT INTO SUNDAY AS WEAK HIGH PRESSURE BUILDS BACK INTO THE REGION FOR THE SECOND HALF OF THE WEEKEND WITH A RETURN TO DRY CONDITIONS. OUTSIDE OF FRIDAY...TEMPERATURES SHOULD BE SEASONABLE FOR THIS TIME OF YEAR. RAIN AND CLOUDS WILL KEEP TEMPERATURES DOWN ON FRIDAY...NOT MAKING IT OUT OF THE 70S REGION-WIDE. IN FACT...TEMPERATURES MAY PROVE TO BE A BIT LOWER THAN WHAT IS CURRENTLY FORECAST. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... A COLD FRONT CONTINUES TO SLOWLY APPROACH FROM THE WEST. ARE WATCHING AREAS OF CONVECTION OFF TO THE WEST. THESE STORMS SHOULD APPROACH THE NYC METRO AROUND 09Z. WILL CONTINUE TO KEEP TEMPOS IN TO ACCOUNT FOR THIS. HAVE LEFT OUT OF TERMINALS EAST OF NYC WITH LOWER CONFIDENCE OF ANY THUNDER REACHING THOSE TERMINALS. AMENDMENTS ARE LIKELY THIS MORNING TO ACCOUNT FOR CONVECTION TIMING. EXPECT S-SW WINDS OF 5-10 KT AT KNYC TERMINALS AND 5 KT OR LESS INLAND OVERNIGHT ALONG WITH MAINLY VFR CONDITIONS. SOME IFR CIGS ARE LIKELY FROM KISP AND POINTS EAST FOR LOW STRATUS. AFTER FRONTAL PASSAGE...WINDS SHIFT TO THE W-SW AND INCREASE TO 8-12 KT. GRADIENT TIGHTENS THIS AFTERNOON. LOCAL SEA BREEZES POSSIBLE AT COASTAL TERMINALS. SCT SHRA/TSRA POSSIBLE LATE IN THE AFTERNOON. .OUTLOOK FOR 06Z WED THROUGH SAT... .TUE NIGHT...SLGT CHC FOR TSTMS MAINLY CSTL TERMINALS IN THE EVENING. BECOMING VFR OVERNIGHT. SW FLOW BECOMING NW OVERNIGHT. .WED-THU...VFR. GENERALLY W FLOW. .FRI...MVFR OR LOWER IN RAIN. WINDS BECOMING NE. .SAT...MVFR OR LOWER POSSIBLE IN RAIN. NE WINDS. && .MARINE... FORECAST ON TRACK...NO UPDATES AT THIS TIME. WINDS OUT AHEAD OF THE FRONT WILL REMAIN STRONG INTO LATE TONIGHT BEFORE LIGHTENING WITH THE APPROACH OF THE FRONT. OCEAN SEAS BUILD DUE TO THE INCREASE IN THESE WINDS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT ON THE OCEAN WATERS THROUGH EARLY TUESDAY EVENING. OCEAN SEAS WILL BE SUBSIDING TUESDAY NIGHT...BUT 5 FT SEAS MAY LINGER ON THE EASTERN OCEAN UNTIL WEDNESDAY MORNING. WEAK HIGH PRESSURE PASSES OVER THE WATERS ON WEDNESDAY WITH SUB SCA CONDITIONS EXPECTED. SEVERAL WAVES OF LOW PRESSURE MAY PASS OVER THE WATERS FOR THE END OF THE WEEK. OCCASIONAL SCA CONDITIONS ARE POSSIBLE ON FRIDAY...ESPECIALLY ON THE OCEAN. WEAK HIGH PRESSURE PASSES OVER THE WATERS ON WEDNESDAY WITH SUB SCA CONDITIONS EXPECTED. LOW PRESSURE MAY PASS OVER OR NEAR THE WATERS FOR THE END OF THE WEEK INTO THE FIRST HALF OF THE WEEKEND. OCCASIONAL SCA CONDITIONS ARE POSSIBLE ON SATURDAY...ESPECIALLY ON THE OCEAN. && .HYDROLOGY... A TENTH TO A QUARTER INCH OF BASIN AVERAGE RAINFALL THIS MORNING. LOCALLY HIGHER AMOUNTS ARE POSSIBLE IN ANY HEAVIER THUNDERSTORMS. A WIDESPREAD SIGNIFICANT RAINFALL IS POSSIBLE LATE THURSDAY INTO FRIDAY. HOWEVER...UNCERTAINTY EXISTS IN WHERE AND WHEN THE HEAVIEST OF THE RAIN WILL FALL. ANTECEDENT DRY CONDITIONS SHOULD LIMIT FLOODING POTENTIAL. HOWEVER...ANY THUNDERSTORMS THAT DO DEVELOP WOULD HAVE THE POTENTIAL FOR LOCALIZED FLOODING. && .EQUIPMENT...
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TEWR TERMINAL DOPPLER RADAR REMAINS UNAVAILABLE.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...HIGH RIP CURRENT RISK FROM 6 AM EDT THIS MORNING THROUGH THIS EVENING FOR NYZ075-080-081-178-179. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...TONGUE NEAR TERM...TONGUE SHORT TERM...TONGUE LONG TERM...JP AVIATION...BC MARINE...TONGUE HYDROLOGY...TONGUE EQUIPMENT...

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