Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 030638 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 238 AM EDT WED JUN 3 2015 .SYNOPSIS... HIGH PRESSURE BUILDS DOWN FROM SOUTHEASTERN CANADA THROUGH WEDNESDAY...THEN BEGINS TO RETREAT TO THE NORTHEAST WEDNESDAY NIGHT. HIGH PRESSURE OVER THE GULF OF MAINE WILL MOVE OFFSHORE ON THURSDAY AS LOW PRESSURE WORKS ITS WAY UP ALONG THE COAST AND DEPARTS FRIDAY MORNING. A COLD FRONT APPROACHES FRIDAY AFTERNOON AND MOVES ACROSS THE REGION ON SATURDAY. HIGH PRESSURE BRIEFLY RETURNS ON SUNDAY...FOLLOWED BY ANOTHER FRONTAL SYSTEM FOR THE START OF THE NEW WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LIGHT RAIN OVER LONG ISLAND AT MIDNIGHT CONTINUES TO WEAKEN AS HIGH PRESSURE BUILDS TO THE NORTH. NORTHEAST FLOW CONTINUES WITH TEMPERATURES REMAINING NEARLY STEADY OVERNIGHT WITH MOSTLY CLOUDY CONDITIONS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... PERSISTENT ON SHORE FLOW WILL KEEP CLOUD COVER AT BEST PARTLY SUNNY WEDNESDAY...EVEN WITH SUBSIDENCE FROM N STREAM RIDGE PASSING OVER THE AREA. FOR HIGHS WEDNESDAY USED A BLEND OF MIXING DOWN FROM 925 TO 875 HPA WITH A BLEND OF ECS/MAV/MET GUIDANCE AND NAM 2-METER TEMPERATURES. HIGHS SHOULD BE AROUND 10 DEGREES BELOW NORMAL. AS AN INVERTED TROUGH APPROACHES UP THE MID ATLANTIC COAST LATE WEDNESDAY NIGHT...APPEARS COULD SEE SOME WEAK ISENTROPIC LIFT. THIS IS SUFFICIENT TO WARRANT A SLIGHT CHANCE OF LIGHT RAIN ACROSS S ZONES AFTER MIDNIGHT...ALONG WITH INCREASING CLOUD COVER FROM SW TO NE. FOR LOWS WEDNESDAY NIGHT A BLEND OF MET/ECS/MAV GUIDANCE AND NAM 2-METER TEMPERATURES WAS USED...WITH VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGH PRES OVER THE GULF OF MAINE WILL SLOWLY MOVE OUT TO SEA THURSDAY AND THURSDAY NIGHT. MEANWHILE...LOW PRES DEVELOPING OFF THE SOUTHEAST U.S. COAST ALONG A STALLED FRONTAL BOUNDARY WILL LIFT NORTH ALONG THE COAST. DEPENDING ON HOW STRONG THE HIGH IS AND EXACTLY WHERE IT IS PLACED WILL IMPACT HOW FAR NORTH SHOWERS WILL SPREAD INTO THE REGION. 12Z GFS HAS THE HIGH A BIT FARTHER TO THE NORTH AS COMPARED TO THE 12Z ECMWF...AND AS A RESULT...HAS OVERRUNNING PRECIPITATION SPREADING INTO THE CWA WHEREAS THE ECMWF HOLDS THE PRECIPITATION OFF UNTIL THURSDAY NIGHT/FRIDAY MORNING. WILL GO AHEAD AND CARRY LOW CHANCE POPS FOR SOUTHERN ZONES AND SLIGHT CHANCE POPS FOR NORTHERN AND EASTERN ZONES STARTING ON THURSDAY AND CONTINUING THROUGH FRIDAY MORNING WHEN THE LOW MOVES INTO THE OPEN ATLANTIC WATERS. THERE SHOULD BE A PERIOD OF DRY WEATHER AROUND MID-DAY FRIDAY. A COLD FRONT THEN APPROACHES WESTERN ZONES FRIDAY AFTERNOON AND SLOWLY WORKS ITS WAY ACROSS THE REGION THROUGH SATURDAY. SCT SHOWERS/TSTMS POSSIBLE FRIDAY AFTERNOON FOR WESTERN ZONES...AND THEN THERE WILL BE CHANCES FOR SHOWERS/TSTMS FRIDAY NIGHT/SATURDAY AS THE FRONT PASSES THROUGH THE REGION. DRY WEATHER ON TAP FOR SUNDAY AS HIGH PRES PASSES NORTH OF THE REGION. BY MONDAY...ANOTHER LOW PRESSURE SYSTEM WILL WORK ITS WAY ACROSS SOUTHERN CANADA...DRAGGING A COLD FRONT INTO THE REGION FOR THE START OF THE NEW WORK WEEK. UNSETTLED WEATHER POSSIBLE WITH ITS PASSAGE. WITH EASTERLY FLOW AND EXTENSIVE CLOUD COVER ON THURSDAY...NOT EXPECTING TEMPS TO CLIMB MUCH HIGHER THAN THE MID 60S...WHICH IS ABOUT 10 DEGREES BELOW NORMAL. TEMPS REBOUND A BIT ON FRIDAY...WARMING INTO THE UPPER 60S/LOW 70S...AND THEN TEMPS RETURN TO SEASONAL LEVELS FOR THE WEEKEND WITH HIGHS GENERALLY IN THE MID 70S. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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HI PRES WILL GRADUALLY BUILD IN FROM THE N TODAY. LAST OF THE RAIN HAS JUST MOVES THROUGH JFK AND IF IT HOLDS TOGETHER IS ESTIMATED TO REACH KISP BETWEEN 08Z AND 09Z. MORE DIFFICULT ASPECT OF THE FORECAST IS TIMING OF IMPROVING CONDS. GENERALLY HAVE VFR TO MVFR WITH ISOLD IFR AROUND. CONDS MAY VARY BETWEEN THESE CATEGORIES THROUGH 12Z-13Z. HAVE GONE A LITTLE MORE OPTIMISTIC BRINGING THINGS BACK TO VFR QUICKER THAN PREVIOUS TAFS THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. VFR THEN PREVAILS THROUGH THE EVENING. NE WINDS BLW 10KT OVERNIGHT. MODERATE TO HIGH CONFIDENCE IN WIND FORECAST...ALTHOUGH TIMING OF WINDS SHIFTING TO E THEN SE MAY BE +/- 1-2 HOURS. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .TONIGHT...MVFR IN PATCHY FOG POSSIBLE TONIGHT OUTSIDE OF NYC. .THU-THU NIGHT...VFR POSSIBLY DROPPING TO MVFR LATE THU NIGHT WITH AREAS OF RAIN DEVELOPING AT SRN TERMINALS. HOWEVER...MAY HOLD OFF UNTIL FRI. .FRI-FRI NIGHT...CHANCE OF RAIN WITH MVFR CONDITIONS IN THE MORNING. CHANCE OF TSTMS NEAR KSWF AFTN INTO EVE. MVFR OR LOWER POSSIBLE. .SAT...A CHANCE OF SHOWERS. A CHANCE OF TSTMS IN AFTN. MVFR OR LOWER POSSIBLE. .SAT NIGHT-SUN...VFR.
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&& .MARINE... SUB-SCA CONDITIONS WITH NE WINDS AND SEAS JUST BELOW CRITERIA OVERNIGHT. WINDS GRADUALLY WEAKEN AND VEER AROUND TO THE E/SE BY WED NIGHT. WINDS AND SEAS ARE FORECAST TO BUILD BACK TO SCA LEVELS WED NIGHT WITH A STRENGTHENING E FLOW...HOWEVER CONFIDENCE IN THIS IS NOT HIGH ENOUGH TO ISSUE AN SCA AT THIS TIME. ON THE NON OCEAN WATERS WINDS ARE FORECAST TO BE 10 KT OR LESS OVERNIGHT THROUGH WEDNESDAY NIGHT. SMALL CRAFT ADVISORY LEVEL WINDS/SEAS POSSIBLE ON THURSDAY FOR THE OCEAN WATERS WITH SUB-SCA CONDITIONS ELSEWHERE DUE TO A TIGHTENING EASTERLY GRADIENT BETWEEN HIGH PRES PASSING TO THE NORTH AND LOW PRES APPROACHING FROM THE SOUTH. TRANQUIL CONDITIONS EXPECTED FOR THE END OF THE WEEK AND OVER THE WEEKEND AS THE GRADIENT RELAXES. && .HYDROLOGY... LIGHT PRECIPITATION AMOUNTS...GENERALLY 1/4 INCH OR LESS...POSSIBLE FROM LATE WEDNESDAY NIGHT THROUGH SATURDAY. MORE WIDESPREAD PRECIPITATION IS THEN POSSIBLE STARTING ON MONDAY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$

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