Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 041140 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 740 AM EDT WED MAY 4 2016 .SYNOPSIS... A SERIES OF LOW PRESSURE SYSTEMS WILL TRACK TO THE SOUTH OF LONG ISLAND THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL SLOWLY TRACK FROM NEAR THE MID ATLANTIC COAST THURSDAY NIGHT INTO SOUTHERN NEW ENGLAND BY SATURDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST SATURDAY NIGHT...THEN CROSSES THE AREA ON SUNDAY...FOLLOWED BY HIGH PRESSURE BUILDING IN TO THE SOUTH INTO TUESDAY. A WARM FRONT APPROACHES FROM THE SOUTHWEST ON TUESDAY AS WELL. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SW FLOW ALOFT...WITH ESE-NE LOW LEVEL FLOW THIS MORNING. UPDATED POPS TO REFLECT RAIN FALLING MAINLY WEST OF NYC THE NEXT COUPLE OF HOURS. A BRIEF BREAK LATE THIS MORNING AND THEN A 700-500 HPA SHORTWAVE CROSSES THE AREA THIS AFTN. THIS COUPLED WITH THE AREA BEING IN THE RIGHT REAR QUADRANT OF A 130+ KT 300 HPA JET AND SHOWALTER INDICES OF AROUND -2 TO 2 ACROSS MOST OF THE AREA THIS AFTERNOON. THIS...COUPLED WITH PRECIPITABLE WATERS AROUND 1 INCH WILL ALLOW FOR SOME MODERATE TO POSSIBLY LOCALLY HEAVY RAINFALL. ALSO HAVE THE POTENTIAL FOR ISOLATED ELEVATED THUNDER...HOWEVER IN COLLABORATION WITH SURROUNDING WFOS...CONFIDENCE IS NOT HIGH ENOUGH IN MORE THAN AN ISOLATED CELL OR TWO...SO HAVE LEFT A MENTION OF THUNDER OUT OF THE FORECAST. AS A RESULT...HAVE INCREASE POPS TO CATEGORICAL THIS AFTERNOON. FOR HIGHS TODAY...A BLEND OF MAV/MET/ECS GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 950 HPA PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD BE AROUND 10-15 DEGREES BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... THE AFOREMENTIONED SHORTWAVE AND UPPER JET STREAK BOTH EXITS TO THE NNE THIS EVENING BRINGING SIGNIFICANT RAINFALL TO AN END FROM SW TO NE. WILL BE LEFT AGAIN WITH PATCHY DRIZZLE AND SPOTTY LIGHT RAIN. ALSO EXPECT PATCHY FOG TO DEVELOP LATE TONIGHT AS WELL. LOWS TONIGHT WERE BASED ON A BLEND OF MAV/ECS/MET GUIDANCE AND NAM 2-METER TEMPERATURES...AND SHOULD BE NEAR TO SLIGHTLY BELOW NORMAL. THERE IS A BIT MORE UNCERTAINTY WITH WHETHER THURSDAY WILL BE MAINLY GRAY AND DAMP...OR WILL THE AFTERNOON FEATURE ANOTHER ROUND OF MORE SIGNIFICANT RAINFALL DUE TO THE PASSAGE OF ANOTHER 700-500 HPA SHORTWAVE. THE ANSWER WILL BE DETERMINED BY THE EXACT TRACK/TIMING/ORIENTATION/STRENGTH OF A DEVELOPING CUTOFF LOW PROGGED TO TRACK FROM E TN/KY/FAR W NC/VA THURSDAY MORNING TO THE CAROLINA COAST BY THURSDAY EVENING. THE ISSUE IS...THE MODELS DIFFER IN THE EXACT TRACK/TIMING/ORIENTATION AND STRENGTH OF THIS CUTOFF...AND THIS IMPACTS THE TIMING/PLACEMENT OF A 700-500 HPA SHORTWAVE ROTATING AROUND IT. THE ECMWF GIVES THE AREA MORE OF A DIRECT IMPACT...THE GFS/CMC-REG MORE OF A MISS THAN A HIT AND THE NAM IS IN BETWEEN. GIVEN THE UNCERTAINTY...POPS HAVE BEEN LIMITED TO CHANCE FOR NOW. FOR HIGHS ON THURSDAY A BLEND OF ECS/MET/MAV GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 975-950 HPA PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD AGAIN BE AROUND 10-15 DEGREES BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH THE H5 PATTERN ACROSS NOAM THROUGH THE WEEKEND. A HIGHLY AMPLIFIED BLOCKY PATTERN STARTS OFF THE PERIOD WITH CUTOFF LOW PRES SYSTEMS OVER EACH U.S. COAST...WITH RIDGING OVER THE PLAINS AS WELL AS THE CENTRAL ATLANTIC. THE RIDGE OVER THE MIDDLE OF THE CONUS BREAKS DOWN AS IT TRIES TO MOVE EWD WITH A SPLIT FLOW BECOMING ESTABLISHED OUT WEST OVER THE WEEKEND. AN UNSETTLED PATTERN WITH BELOW NORMAL TEMPS WILL PREVAIL THROUGH THE END OF THE WEEK WITH THE AFOREMENTIONED CUTOFF OVER THE MID ATLANTIC COAST THU NIGHT...GRADUALLY LIFTING N WHILE WEAKENING FRI AND EVENTUALLY CONSOLIDATING WITH A TROUGH DIGGING OUT OF CENTRAL CANADA. AS ONE WAVE OF LOW PRES DEPARTS THU NIGHT...THERE SHOULD STILL BE WEAK LIFT AND PLENTY OF LOW LEVEL MOISTURE AROUND FOR LIGHT RAIN/DRIZZLE...SO HAVE MAINTAINED THIS IN THE FORECAST. MEANWHILE...ANOTHER AREA OF LOW PRES DEVELOPS OVER THE CAROLINAS AND SLOWLY TRACKS UP THE EAST COAST ON FRI. THIS SHOULD BRING ANOTHER ROUND OF RAINFALL TO THE AREA AND DUE TO INCREASED CONFIDENCE IN RAINFALL ON FRI...HAVE INCREASED POPS TO LIKELY. TRACK AND STRENGTH DISCREPANCIES REMAIN WHICH WILL IMPACT THE WIND FORECAST AND SUBSEQUENTLY...TIDAL PILING. SEE TIDES SECTION BELOW FOR MORE INFORMATION ON COASTAL FLOODING LATE THIS WEEK. DUE TO THE DOWNSTREAM BLOCK OVER THE ATLANTIC...THE SYSTEM WILL BE SLOW TO MOVE OUT...ALTHOUGH AN UPSTREAM KICKER DIVING OUT OF CANADA ON SAT SHOULD HELP. LOW CHC/SCHC POPS SAT DUE TO COOL POOL ALOFT FOLLOWED BY A COLD FRONT TRACKING THROUGH LATE SAT NIGHT INTO SUN. RIDGING THEN RETURNS FOR THE REMAINDER OF THE WEEKEND AND INTO NEXT WEEK WITH NEAR TO ABOVE NORMAL TEMPERATURES. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... A SERIES OF WEAK LOWS WILL MOVE ALONG A STATIONARY FRONT SOUTHEAST OF THE REGION THROUGH THE TAF PERIOD. CONDITIONS CURRENTLY RANGE FROM IFR ACROSS THE WESTERN TERMINALS TO VFR ACROSS THE EASTERN TERMINALS. TERMINALS THAT ARE NOW VFR...ARE EXPECTED TO FALL TO MVFR BY MID TO LATE MORNING. EXPECT CONDITIONS TO REMAIN EITHER MVFR OR IFR...AND POSSIBLY FLUCTUATE BETWEEN THE TWO THROUGHOUT THE DAY. LOW CONFIDENCE ON ANY TIMING OF FLIGHT CATEGORY CHANGES. GENERALLY LOOKING AT PATCHY DRIZZLE OR LIGHT RAIN THIS MORNING UNTIL THE BETTER CHANCES OF RAIN MOVE IN DURING THE MID TO LATE MORNING HOURS. LIGHT AND VARIABLE WINDS THIS MORNING BECOME EASTERLY AND INCREASE TO NEAR 10 KT WITH SOME GUSTS 15-20 KT THIS AFTERNOON. WIND SPEEDS INCREASE JUST A BIT OVERNIGHT. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.WEATHER.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. KLGA FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. KEWR FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. KHPN FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. KISP FCSTER COMMENTS: AMENDMENTS LIKELY TODAY FOR CHANGING FLIGHT CATEGORIES. WINDS GUSTS MAY BE OCCASIONAL THIS AFTERNOON. .OUTLOOK FOR 12Z THU THROUGH SUNDAY... .THURSDAY THROUGH SUNDAY MORNING...PERIODS OF RAIN/FOG/LOW CLOUDS WITH MVFR OR LOWER CONDITIONS. NE WINDS G20 KT POSSIBLE WED EVENING AND ALSO AT TIMES THU AND FRI. .SUNDAY AFTERNOON/NIGHT...COLD FRONTAL PASSAGE SHOULD FINALLY BRING AN END TO DISMAL CONDITIONS...WITH CONDITIONS IMPROVING TO VFR AND NW WINDS. GUSTS TO NEAR 20KT POSSIBLE. && .MARINE... SMALL CRAFT CONDITIONS WILL CONTINUE ON THE COASTAL OCEAN WATERS THROUGH THURSDAY...WITH GUSTS OF 25-30 KT AND SEAS OF 4-6 FT. ON THE NON-OCEAN WATERS...GUSTS SHOULD PEAK AT 20 KT TODAY...THEN COULD REACH 25 KT TONIGHT...AND POSSIBLY AGAIN ON THURSDAY. AT THIS TIME...CONFIDENCE IN 25 KT GUSTS ON THE NON-OCEAN WATERS TONIGHT AND THURSDAY IS NOT HIGH ENOUGH TO ISSUE A SMALL CRAFT ADVISORY THERE. MARGINAL WIND GUSTS ARE POSSIBLE ON THE OCEAN WATERS AS LOW PRES APPROACHES FROM THE S ON FRI AND AGAIN ON SUNDAY BEHIND A COLD FRONT. OTHERWISE...THE LOW WILL BE CHURNING UP SEAS ON THE OCEAN AS IT SLOWLY LIFTS UP THE MID ATLANTIC COAST WITH ADVISORY LEVELS INTO SAT. SUB-ADVISORY CONDITIONS SHOULD RETURN BY MIDNIGHT SUN ALTHOUGH SEAS COULD BUILD AGAIN ON THE OCEAN LATE SUN. SUB- ADVISORY LEVELS ARE EXPECTED THROUGH THE PERIOD ON THE NON-OCEAN WATERS...ALTHOUGH GUSTS COULD GET CLOSE SUN AFTERNOON. && .HYDROLOGY... AROUND 1/4-1/2 INCH OF RAINFALL IS FORECAST THROUGH TONIGHT...WITH LOCALLY HIGHER AMOUNTS OF AN INCH OR MORE POSSIBLE IN AREAS EXPERIENCING STRONG CONVECTION. AREAS THAT DO RECEIVE LOCALLY HEAVY RAINFALL COULD EXPERIENCE PONDING OF WATER ON ROADWAYS...AND A VERY LOW CHANCE OF LOCALIZED MINOR FLOODING. ADDITIONAL MAINLY LIGHT TO MODERATE RAINFALL IS POSSIBLY AGAIN THURSDAY...WITH A LOW CHANCE OF LOCALLY HEAVY RAINFALL POSSIBLE. FOR NOW EXPECT AMOUNTS TO REMAIN BELOW 1/2 INCH ON THURSDAY. A QUARTER TO A HALF INCH OF RAINFALL IS POSSIBLE THU NIGHT AND FRI. ADDITIONAL RAINFALL OF LESS THAN AN INCH IS EXPECTED WITH A COLD FRONTAL PASSAGE OVER THE WEEKEND. NO HYDROLOGIC ISSUES EXPECTED. && .TIDES/COASTAL FLOODING... THE HIGHEST SPRING TIDE OF THE YEAR IS APPROACHING WITH THE NEW MOON ON FRIDAY. THE THREAT FOR MINOR COASTAL FLOODING WILL INCREASE DURING THE EVENING HIGH TIDES THROUGH FRIDAY...AND LIKELY CONTINUE INTO THIS WEEKEND. PERIODIC NE FLOW IS EXPECTED THROUGH LATE WEEK AS A SERIES OF LOW PRESSURE WAVES TRACKS TO THE SOUTH OF THE REGION. THE TIMING AND STRENGTH OF THESE WAVES WILL PREDICATE POTENTIAL FOR MODERATE COASTAL FLOODING...BUT THE THREAT IS THERE PARTICULARLY FOR THE SOUTH SHORE BAYS OF LONG ISLAND/QUEENS. 15 TO 20 KT E/ENE WINDS TODAY WILL RESULT IN MINOR COASTAL FLOODING ALONG VULNERABLE LOCALES OF THE SOUTH SHORE BAYS OF WESTERN LONG ISLAND/NYC WHERE TIDAL DEPARTURES OF 1 TO 1.5 FT ARE FORECAST...SO A COASTAL FLOOD ADVISORY HAS BEEN ISSUED THERE FOR THIS EVENINGS HIGH TIDE. COASTAL FLOOD BENCHMARKS LIKELY WILL JUST BEING REACHED ACROSS WESTERN LONG ISLAND SOUND AND NY HARBOR...EXCEPT FOR THE MANHATTAN/N QUEENS/BRONX COASTS...DURING THIS EVENINGS HIGH TIDE. TIDAL DEPARTURES OF AROUND 1/2 TO 1 FT ARE LIKELY IN THOSE TWO AREAS. FARTHER EAST ACROSS E LONG ISLAND SOUND AND THE EASTERN BAYS OF LONG ISLAND...IT APPEARS DEPARTURES WILL RUN AT LEAST A FEW TENTHS OF A FT BELOW LEVELS NEEDED TO REACH MINOR COASTAL FLOOD BENCHMARKS THIS EVENING. FOR THURSDAY EVENINGS HIGH TIDE...ASTRONOMICAL TIDES WILL BE AROUND 1/4-1/2 FT HIGHER THAN THIS EVENING...WHILE TIDAL DEPARTURES SHOULD REMAIN AROUND THE SAME LEVELS AS THIS EVENING. THIS SHOULD RESULT IN MORE WIDESPREAD MINOR COASTAL FLOODING ACROSS MOST COASTAL AREAS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT THIS EVENING FOR NYZ075-080-178-179. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ350-353- 355. && $$

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