Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 011442 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1042 AM EDT FRI MAY 1 2015 .SYNOPSIS... HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST...THEN EVENTUALLY SHIFT TO THE SOUTHEAST STATES FOR THE WEEKEND...AND PASS TO THE EAST EARLY NEXT WEEK. A COLD FRONT WILL SLOWLY MOVE ACROSS TUESDAY AND TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE FOR THE REST OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SLIGHT RIDGING OCCURRING AS UPPER LEVEL LOW SLIDES TOWARDS THE CAROLINAS AS THE SURFACE LOW SLIGHTLY DEEPENS OFF THE CAROLINA COAST. THE PRESSURE GRADIENT IS LOWERING WITH TIME AND AS SUCH...SURFACE NORTHEAST FLOW IS ALSO DECREASING. PLENTY OF BREAKS IN THE OVERCAST OBSERVED AS OF 8-9 AM...BUT THINK THESE WILL WILL IN WITH DAYTIME HEATING/MIXING. WARMING TODAY WILL BE LIMITED DUE TO THE CLOUD COVER...WHICH WILL BE TOUGH TO BREAK UP CONSIDERING THE DECREASING PRESSURE GRADIENT AND THEREBY A LIGHTER NORTHEAST FLOW. BOTH 00Z MAV/MET MOS POINTED TO LOWER TEMPERATURES THAN YESTERDAY...BUT THE MAV SEEMS TO HAVE PERFORMED BETTER RECENTLY WITH RESPECT TO DAYTIME TEMPERATURES...SO THIS WAS USED FOR THE FORECAST AND INCREASED BY TWO. SEA BREEZES WILL LIKELY DEVELOP THIS AFTERNOON...BUT WILL HAVE MORE OF A SOUTHEAST COMPONENT AS WAS THE CASE YESTERDAY. THE DIURNAL WARMING WILL INCREASE THE INSTABILITY AND COMBINED WITH WEAK POSITIVE VORTICITY ADVECTION ALOFT...THERE COULD BE SOME SPRINKLES MAINLY NORTH/WEST OF NYC. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... THE UPPER LEVEL LOW AND SURFACE LOW TRACK FARTHER EAST INTO THE WESTERN ATLANTIC WITH HIGH PRESSURE BUILDING IN FROM THE WEST. ON SATURDAY...THE HIGH BEGINS TO WEAKEN AND BECOMES MORE BASED IN THE SOUTHEAST U.S. WITH A MID AFTERNOON TROUGH DEVELOPING ACROSS THE LOCAL REGION. FOR TONIGHT...THE PRESSURE GRADIENT DOES NOT CHANGE MUCH AND ALOFT...RIDGING BECOMES MORE APPARENT. THIS WILL LEAD TO SUBSIDENCE AND A DECREASE IN CLOUDS LATE. MIN TEMPS THEREFORE SHOULD FALL MORE COMPARED TO THE PREVIOUS NIGHT. THE COOLER MAV GUIDANCE WAS USED FOR THE MIN TEMP FORECAST A RESULT. EXPECTING DRY CONDITIONS WITH THE LOSS OF DIURNAL INSTABILITY. A MAV/MET/GMOS COMBINATION WAS USED FOR MAX TEMPS ON SATURDAY. AGAIN...THERE COULD BE AN ISOLATED SHOWER WITH DAYTIME TROUGH DEVELOPMENT...INSTABILITY WITH DIURNAL WARMING...AS WELL AS A PASSING VORT MAX WITH THE TROUGH AXIS ALOFT. THE LESS COVERAGE OF CLOUDS COMPARED TO THE PREVIOUS DAY WILL HELP MAKE SATURDAY A FEW DEGREES WARMER ALSO COMPARED TO THE PREVIOUS DAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... LONG TERM MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE H5 FLOW INTO EARLY NEXT WEEK...BUT BEGINS TO DIVERGE AS A CUTOFF LOW PRES SYSTEM IN THE PAC NW ON MON MOVES INLAND. THE GFS DROPS THE LOW SWD INTO CALIFORNIA WHILE THE EC TRACKS IT EWD INTO CANADA WHILE WEAKENING IT. THIS WILL IMPACT THE DOWNSTREAM PATTERN DURING THE LATTER PART OF THE WEEK. IN TERMS OF SENSIBLE WEATHER...A FAIRLY QUIET WEEK IS EXPECTED WITH THE EXCEPTION OF TUESDAY AND TUESDAY NIGHT AS A COLD FRONT SLOWLY WORKS ACROSS THE AREA. HAVE INCREASED POPS A BIT AS SEVERAL SOLNS ARE INDICATING SHOWERS...BUT ITS STILL A DAY 5 FORECAST SO MAINTAINED THE CHC CATEGORY. AFTER TAKING A LOOK AT STABILITY PARAMETERS IS ONLY LOOKS LIKE TSTMS ARE A POSSIBILITY FROM LATE TUE MORNING AND INTO THE AFTN. SO HAVE ADJUSTED WX ACCORDINGLY. A WEAK SHORTWAVE WILL ALSO MOVE ACROSS THE AREA ON SUN...BUT TIMING MAY NOT COINCIDE WITH PEAK HEATING. HAVE MAINTAINED SCHC POPS...FOR THE TIME BEING. ALSO HAVE REMOVED TSTMS DUE TO THE LACK OF INSTABILITY. THE OTHER THING WORTH NOTING IN THE LONG TERM IS THE POTENTIAL TO REACH THE 80 DEGREE MARK IN NYC SUN AND/OR MON. MON LOOKS LIKE THE BETTER CHANCE WITH HEIGHTS ALOFT AROUND 577DM. THE REMAINDER OF THE PERIOD LOOKS DRY WITH ABOVE NORMAL TEMPS WITH HIGH PRES IN CONTROL. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/...
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LOW PRESSURE PASSES WELL TO THE SOUTH TODAY. WEAK HIGH PRESSURE BUILDS. VFR PROBABLE. SCT TO BKN CLOUDS AT VARIOUS LEVELS WILL PREVAIL THROUGH THE DAY TODAY. CHC THAT CIGS LOWER TO 2000-3000FT FOR A COUPLE OF HOURS LATE THIS MORNING INTO EARLY AFTN. WINDS BCMG ESE-SE AROUND 10KT ON AVERAGE. 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: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. KLGA FCSTER COMMENTS: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. WIND SHIFT TO SE COULD BE OFF BY AN HOUR OR TWO. .KEWR FCSTER COMMENTS: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. KHPN FCSTER COMMENTS: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. KISP FCSTER COMMENTS: CIGS COULD LOWER 2000-3000FT FOR AN HOUR OR TWO BEFORE 18Z. .OUTLOOK FOR 12Z SAT THROUGH TUE... .SAT-MON NIGHT...VFR. .TUE...MVFR OR LOWER CONDS POSSIBLE WITH CHANCE OF SHOWERS/TSTMS.
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&& .MARINE... ATTM LOOKS MORE LIKELY THAT WIND GUSTS ON THE OCEAN WILL REMAIN BELOW SCA THRESHOLDS...SO HAVE CANCELED THE ADVY ON THE OCEAN W OF MORICHES INLET. QUIET CONDS EXPECTED THROUGH TUE. && .HYDROLOGY... THE NEXT WIDESPREAD CHANCE OF RAIN WILL BE TUE AFTERNOON/NIGHT WITH A COLD FRONTAL PASSAGE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JM NEAR TERM...GOODMAN/JM SHORT TERM...JM LONG TERM...24 AVIATION...JC/PW MARINE...24/JM HYDROLOGY...24/JM

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