Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 061728 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 128 PM EDT MON JUL 6 2015 .SYNOPSIS... A DIFFUSE WARM FRONT GRADUALLY MOVES NORTH INTO THE REGION THROUGH TUESDAY. A COLD FRONT APPROACHES FROM THE WEST TUESDAY NIGHT...THEN TRACKS ACROSS THE AREA WEDNESDAY INTO WEDNESDAY NIGHT. THE FRONT STALLS JUST TO THE SOUTH ON THURSDAY AS A WEAK WAVE OF LOW PRESSURE MOVES ALONG IT. HIGH PRESSURE BUILDS LATE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO SIGNIFICANT CHANGES TO FCST FOR THE EARLY AFTERNOON UPDATE. DEW POINTS HAVE RISEN FASTER THAN FORECAST INTO THE MID TO UPPER 60S. CIRRUS HAS THICKENED UP A BIT MORE AS WELL. TEMPERATURES REMAIN ON TRACK. RATHER COMPLEX PATTERN WITH WEAKENING UPPER LOW OVER EASTERN OHIO AND WELL DEFINED VORT MAX NEAR KNOXVILLE TN. THERE`S ALSO A LOWER LEVEL VORT MAX OR PSEUDO MCV AHEAD OF THIS FEATURE NEAR LYNCHBURG VA AS OF 16Z. THESE FEATURES REMAIN SOUTHWEST OF OUR REGION INTO THIS EVENING. TIMING OF THE MCV LIKE FEATURE WOULD BE LATE EVENING. INSTABILITY IN LATEST NWP IS LIMITED WITH SFC BASED LI`S AROUND 0 OVER WESTERN SECTION. WILL THUS CONTINUE WITH THE DRY FCST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... CONTINUE WITH CHANCE TO SLIGHT CHANCE POPS OVER WESTERN SECTIONS OF THE FORECAST AREA TONIGHT IN RESPONSE TO THE APPROACH OF THE TROF AND MOIST SW FLOW AND PERHAPS REMNANTS OF THE MCV. FORCING AHEAD OF 700-500 HPA SHORTWAVE THAT MOVES INTO THE REGION LATE TUESDAY WARRANTS LIKELY POPS OVER THE NW 1/3 OF THE CWA AND CHANCE POPS ELSEWHERE. NOTING FORECAST SFC BASED CAPES OF 500-1500 J/KG (HIGHEST IN GFS) - SLIGHTLY LOWER OVER E LONG ISLAND/FAR SE CT...SHOWALTER INDICES FORECAST TO BE MAINLY 0 TO 2 INDICATING LOW LEVEL INSTABILITY AS WELL WARRANTS A CHANCE OF THUNDER AS WELL. HOWEVER WITH BULK 0-6 KM SHEAR OF ONLY 20-25 KT...RISK OF STRONG TO SEVERE STORMS IS FAIRLY LOW BUT CANNOT 100 PERCENT BE RULED OUT. HIGHS SHOULD BE A FEW DEGREES ABOVE NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A TROUGH OF LOW PRESSURE LIFTS TO THE NORTH TUESDAY NIGHT AND WEDNESDAY AS SFC COLD FRONT APPROACHES FROM THE WEST. THIS FRONT WILL BE NEARLY PARALLEL TO UPPER STEERING FLOW...SO IT WILL BE SLOW TO MOVE THROUGH ON WEDNESDAY. MODEL TIMING IS SIMILAR WITH FRONTAL PROGRESSION EAST. ANY LEFTOVER SHOWERS/TSTMS TUESDAY NIGHT DEPART OR WEAKEN. MOS TEMPS ARE CLOSE...AND SEASONABLY WARM READINGS ARE EXPECTED. THE COLD FRONT REMAINS OVER THE AREA LATE WEDNESDAY...AND PROBABLY CLEARS THE EASTERN ZONES BY MIDNIGHT. WILL MAINTAIN HIGH CHANCE COVERAGE FOR NOW...WITH SCATTERED SHOWERS/TSTMS WEDNESDAY. HEAVY RAIN IS POSSIBLE WITH THIS SLOW MOVING ACTIVITY...WITH PW OVER 2 INCHES ALONG THE FRONT. THE CONCERN FOR HEAVY RAIN AND TRAINING OF CELLS COULD LEAD TO AT LEAST MINOR URBAN/SMALL STREAM FLOODING. MOST MODEL SOLUTIONS FORECAST THE FRONT TO SETTLE TO THE SOUTH THURSDAY...WITH SOME TIMING DIFFERENCES NOTED WITH A WAVE OF LOW PRESSURE RIDING ALONG IT. BELIEVE THE LOW PASSES TO THE SOUTH BY THURSDAY OR THURSDAY NIGHT...WITH WEAK HIGH PRESSURE BUILDING IN BEHIND IT. WILL MAINTAIN LOW CHANCES FOR SHOWERS THURSDAY INTO FRIDAY...WITH A DRY FORECAST THEREAFTER...OR UNTIL POSSIBLY LATER SUNDAY AS NEXT FRONT APPROACHES. TEMPS SHOULD AVERAGE RIGHT AROUND NORMAL LEVELS THROUGH THE PERIOD. BLENDED FORECAST DATABASE WITH NEW GRIDDED MOS AND WPC GUIDANCE. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY. A WARM FRONT APPROACHES FROM THE SOUTHWEST TONIGHT. VFR INTO EARLY THIS EVENING. WITH 2ND NIGHT OF ONSHORE FLOW AND A FAVORABLE S-SE WIND DIRECTION AHEAD OF THE APPROACHING WARM FRONT...MVFR CONDS SHOULD DEVELOP AROUND 03Z. CONDS THEN LOWER TO IFR MAINLY AFTER MIDNIGHT. LIFR CONTINUES TO BE EXPECTED AFTER 06Z AT KGON/KISP/KBDR AND CANNOT RULE IT OUT FOR KJFK. WINDS THROUGHOUT MUCH OF THE TAF PERIOD WILL BE OUT OF THE SE...GENERALLY 10 KT OR LESS. 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: WIND DIRECTION MAY VARY BETWEEN 150 AND 180 TRUE THROUGH THE AFTERNOON. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KLGA FCSTER COMMENTS: AN OCCASIONAL GUST TO AROUND 20 KT POSSIBLE THIS AFTERNOON. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KEWR FCSTER COMMENTS: WIND DIRECTION MAY VARY BETWEEN 150 AND 180 TRUE THROUGH THE AFTERNOON. TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KTEB FCSTER COMMENTS: TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KHPN FCSTER COMMENTS: TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. KISP FCSTER COMMENTS: TIMING OF CHANGES IN FLIGHT CATEGORY TONIGHT MAY BE OFF BY +/- 1-2 HOURS. .OUTLOOK FOR 18Z TUE THROUGH SAT... .TUE AFTN...CHANCE OF TSTMS WITH MVFR OR LOWER CONDITIONS AT TIMES... ESPECIALLY FROM NYC METRO NORTH/WEST. .TUE NIGHT...MVFR/IFR CONDS POSSIBLE IN FOG. .WED...SCT SHRA/TSTMS WITH MVFR OR LOWER CONDITIONS AT TIMES. .THU-FRI...CHANCE OF SHOWERS WITH MVFR OR LOWER CONDITIONS AT TIMES. .SAT...VFR. && .MARINE... A RELAXED PRESSURE GRADIENT OVER THE REGION WILL KEEP WINDS 10 KT OR LESS THROUGH TUESDAY...WITH THE EXCEPTION OF 10-15 KT WINDS WITH OCCASIONAL GUSTS TO 20 KT IN THE NY BIGHT REGION TUESDAY AFTERNOON DUE TO THE SEA BREEZE. SEAS WILL REMAIN BELOW SCA LEVELS THROUGH TUESDAY AS WELL. PATCHY FOG COULD IMPACT THE WATERS LATE TONIGHT AND TUESDAY MORNING...BRING VISIBILITIES TO 1 TO 3 NM...AND POSSIBLY BELOW 1 NM AT TIMES. SOUTHERLY FLOW PERSISTS AHEAD OF A SLOW MOVING COLD FRONT TUESDAY NIGHT AND WEDNESDAY. THEN AS THE FRONT PASSES NEARBY AND STALLS...WINDS SHOULD LIGHTEN AS THEY SHIFT TO THE NW BRIEFLY. WITH A WEAK PRESSURE GRADIENT IN PLACE...THE WINDS MAY SHIFT BACK AROUND TO THE S/SW THURSDAY. AS A WAVE OF LOW PRESSURE MOVES ALONG THE FRONT LATER THURSDAY AND THURSDAY NIGHT...RELATIVELY LIGHT WINDS MAY BECOME VARIABLE...DEPENDING ON THE EXACT TRACK OF THIS LOW. OVERALL...SUB SCA CONDITIONS ARE ANTICIPATED FOR THE MID TO LATE WEEK PERIOD. OCEAN SEA FORECASTS WERE BASED ON FORECAST DATABASE AND NEW WAVE WATCH OUTPUT...WHICH SEEMED QUITE REASONABLE. WIND CLIMATOLOGY WAS THE BASIS FOR SEA/WAVE FORECAST FOR THE NON OCEAN WATERS SURROUNDING LONG ISLAND. && .HYDROLOGY... GENERALLY AROUND 1/4 INCH OR LESS OF RAIN IS EXPECTED LATE TONIGHT AND TUESDAY. WITH HIGHEST AMOUNTS GENERALLY W OF THE HUDSON RIVER. HOWEVER...WITH PRECIPITABLE WATERS FORECAST TO BE BETWEEN 1.75-2 INCHES...THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH ANY STRONGER CONVECTION. LOCALIZED MINOR FLOODING OF URBAN AND POOR DRAINAGE AREAS WOULD BE POSSIBLE IF THIS WERE TO OCCUR. HEAVY DOWNPOURS WITH SLOW MOVING SHOWERS/THUNDERSTORMS ARE POSSIBLE WEDNESDAY INTO WEDNESDAY EVENING. AS SUCH...AT LEAST LOCALIZED URBAN AND POOR DRAINAGE FLOODING...WITH A LOW CHANCE OF FLASH FLOODING...IS A POSSIBILITY WEDNESDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO FROM FAIRFIELD AND NASSAU COUNTIES ON WEST...INCLUDING NYC. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/PW NEAR TERM...TONGUE SHORT TERM...MALOIT LONG TERM...PW AVIATION...DS MARINE...MALOIT/PW HYDROLOGY...MALOIT/PW

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