Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 011734 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 134 PM EDT WED APR 1 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD TO THE WEST AND THEN SOUTH OF THE AREA THROUGH TONIGHT. A WARM FRONT WILL PASS TO THE NORTH ON THURSDAY. A COLD FRONT WILL FOLLOW FROM THE NORTHWEST THURSDAY NIGHT...STALL NEARBY ON FRIDAY...THEN PASS THROUGH LATE FRIDAY NIGHT INTO SATURDAY MORNING. HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND. WEAK LOW PRESSURE WILL PASS TO THE NORTH LATE SUNDAY NIGHT INTO MONDAY. A SLOW MOVING FRONTAL SYSTEM THEN BEGIN TO APPROACH MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN UPDATE TO THE FORECAST DATABASE WILL BE TO THE DEWPOINTS...AS SFC DEWPOINTS ARE RUNNING ANYWHERE FROM 5-15 DEGREES BELOW FORECAST. NOT EXPECTING DEWPOINTS TO RISE MUCH UNTIL THIS EVENING...SO WILL GO AHEAD AND FOLLOW TRENDS BY GOING WITH LOWER DEWPOINTS AND NORTH WINDS AT 10-15 MPH THROUGH THE AFTERNOON. HIGH TEMPS TODAY SHOULD TOP OFF IN THE UPPER 40S TO AROUND 50...WHICH ARE AROUND 5 DEGREES BELOW AVG. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... THE DEEP LAYERED RIDGE CONTINUES TO BUILD IN TONIGHT...THEN ITS AXIS CROSSES THE AREA THURSDAY. ASSOCIATED SUBSIDENCE MORE THAN LIKELY WILL KEEP THINGS DRY. HOWEVER...PASSING SURFACE TO 850 HPA WARM FRONT THURSDAY MORNING COULD BRING A FEW -SHRA/SPRINKLES TO MAINLY NORTHERN ZONES. FOR NOW...APPEARS SUBSIDENCE UNDER THE BUILDING RIDGE WILL WIN OUT...BUT CANNOT 100 PERCENT RULE OUT ANY PRECIPITATION ACROSS NORTHERN ZONES THURSDAY MORNING. THE PASSAGE OF THE SURFACE AND 850 WARM FRONT THOUGH WILL BRING SOME CLOUDS IN LATE TONIGHT AND THURSDAY MORNING...OTHERWISE THERE SHOULD BE MINIMAL CLOUD COVER TONIGHT AND THURSDAY...UNTIL HIGH CLOUDS BUILD IN OVER MAINLY W ZONES LATE THURSDAY AFTERNOON AHEAD OF THE NEXT SYSTEM. SHOULD SEE AN INCREASE IN WINDS THURSDAY AFTERNOON. AREAS MAINLY W OF THE HUDSON AND ALL FAR N INTERIOR ZONES COULD SEE GUSTS UP TO 20-25 MPH WITH ISOLATED 30-35 MPH POSSIBLE. FARTHER S/E...MARINE LAYER COULD PREVENT 25-50KT LOW LEVEL JET (STRENGTH INCREASES FROM W TO E) FROM REACHING THE GROUND. FOR LOWS TONIGHT...USED A BLEND OF MAV/MET/ECS GUIDANCE WITH THE PREVIOUS FORECAST. THE AFOREMENTIONED WARM FRONT GENERATED CLOUDS LIKELY WILL BE THE LIMITING FACTOR ON THE LOWS...SO DID NOT SIGNIFICANTLY UNDERCUT GUIDANCE IN NORMALLY COLDER LOCATIONS. LOWS SHOULD BE AROUND NORMAL IN NYC TO AROUND 5-10 DEGREES BELOW NORMAL ELSEWHERE. A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 1000-875 HPA PER BUFKIT SOUNDINGS WAS USED FOR HIGHS ON THURSDAY. SW LOW LEVEL FLOW WILL RESULT IN A WIDE RANGE OF TEMPERATURES WITH ONLY THE MID-UPPER 40S OVER THE TWIN FORKS AND FAR SE CT TO THE LOWER TO MAYBE MID 60S OVER NE NJ/WESTERN PORTIONS OF THE LOWER HUDSON VALLEY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... CLOUDS WILL INCREASE THU NIGHT AHEAD OF AN APPROACHING COLD FRONT. CHANCE SHOWERS MAINLY AFTER MIDNIGHT AND MAINLY NW OF THE CITY...WITH STILL THE POTENTIAL FOR SOME ELEVATED THUNDER. SHOWERS THEN BECOME LIKELY FRI INTO FRI NIGHT AS THE FRONT STALLS NEARBY...PASSING THROUGH LATE FRI NIGHT INTO EARLY SAT MORNING ONLY AFTER AN AMPLIFYING UPPER TROUGH AND ASSOCIATED SURFACE LOW PRESSURE PASS THROUGH. MAINTAINED CHANCE THUNDER FROM PREVIOUS FORECASTS SINCE THERE SHOULD BE AT LEAST SOME ELEVATED INSTABILITY...POSSIBLY SFC-BASED FOR A TIME FRI AFTERNOON FROM NYC NORTH/WEST AS HIGHS THERE REACH THE LOWER 60S. FARTHER EAST... WITH MORE OF AN ONSHORE FLOW EXPECT HIGHS IN THE LOWER 50S ALONG IMMEDIATE SOUTH FACING SHORES...AND MID/UPPER 50S ACROSS INTERIOR SOUTHERN CT AND THE NORTH SHORE OF LONG ISLAND. THE ONSHORE FLOW SHOULD ALSO BRING INCREASING POTENTIAL FOR FOG AS HIGHER DEWPOINT AIR TRAVERSES COLD ATLANTIC WATERS. JUST A LINGERING CHANCE OF A SHOWER SAT MORNING AS THE COLD FRONT EXITS...THEN A GUSTY DRYING NW FLOW SHOULD HELP CLOUDS DIMINISH CLOUDS AND KEEP US DRY DURING THE AFTERNOON. HIGHS WILL BE IN THE LOWER/MID 50S...NEAR OR JUST BELOW AVG. MEDIUM RANGE GUIDANCE STILL SUGGESTS A COLD FRONT DROPPING DOWN CLOSE TO THE AREA ON SUNDAY...AND THEREAFTER HAVE SIDED WITH 31/21Z AND 00Z ECMWF IDEA OF A CLIPPER-TYPE LOW RIDING THE FRONT IN QUASI- ZONAL FLOW ALOFT...WITH CHANCE POP FOR SNOW/RAIN SHOWERS MAINLY FOR THE INTERIOR LATE SUNDAY NIGHT INTO MON. GUIDANCE ALSO MAINTAINS FAIRLY GOOD CONTINUITY ON THE IDEA OF A SLOW MOVING FRONTAL SYSTEM APPROACHING FROM THE WEST LATE MON NIGHT INTO TUE...WITH PROLONGED CHANCES FOR RAIN. TEMPS SHOULD CONTINUE NEAR TO SLIGHTLY BELOW AVG. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... HIGH PRESSURE BUILDS TONIGHT. THE HIGH TRACKS TO THE EAST AS A WARM FRONT MOVES THROUGH THURSDAY MORNING. NORTHWEST WINDS 10 TO 15 KTS ARE FORECAST THIS AFTERNOON. OCCASIONAL GUSTS 15 TO 20 KTS CAN BE EXPECTED. WINDS LIGHTEN TONIGHT AND BECOME SW BY MORNING. SPEEDS INCREASE AS THE MORNING PROGRESSES THURSDAY. VFR THRU THE TAF PERIOD. MAINLY CLEAR SKIES LATE THIS AFTERNOON AND TONIGHT. PASSING MID CLOUDS THURSDAY MORNING. 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: WINDS SHOULD REMAIN TO THE LEFT OF 310 MAGNETIC THROUGH 22-23Z. AMENDMENTS ARE POSSIBLE IF THE WINDS SHIFT BACK TO THE RIGHT OF 310 MAGNETIC. KLGA FCSTER COMMENTS: WINDS MAY SHIFT BACK TO THE LEFT OF 310 MAGNETIC BRIEFLY THIS AFTERNOON. AMENDMENTS ARE POSSIBLE FOR WIND DIRECTION FORECASTS. KEWR FCSTER COMMENTS: WINDS WILL REMAIN RIGHT AROUND 310 MAGNETIC THROUGH 22-23Z. AMENDMENTS ARE POSSIBLE IF THE WIND BACKS OR VEERS UNEXPECTEDLY. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. OCCASIONAL GUSTS ARE FORECAST THROUGH 22-23Z. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. OCCASIONAL GUSTS ARE FORECAST THROUGH 22-23Z. KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. OCCASIONAL GUSTS ARE FORECAST THROUGH 22-23Z...AND NW WINDS MAY BACK BRIEFLY. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THURSDAY AFTERNOON...VFR. S/SW WINDS 15 TO 25 KTS WITH GUSTS 30 KTS OR GREATER LOCALLY. .THURSDAY NIGHT...VFR...THEN MVFR POSSIBLE LATE IN DEVELOPING RAIN SHOWERS. .FRIDAY-FRIDAY NIGHT...MVFR OR LOWER IN RAIN SHOWERS. WIND FORECAST UNCERTAIN AS FRONT REMAINS NEARBY. .SATURDAY...SUB-VFR POSSIBLE IN SHOWERS EARLY...THEN VFR. GUSTY NW WINDS 20 TO 30 KTS. .SATURDAY NIGHT-SUNDAY...VFR. .SUNDAY NIGHT-MONDAY...MAINLY VFR...BUT CANNOT RULE OUT SUB VFR AT TIMES IN POSSIBLE SHOWERS. && .MARINE... PRES GRADIENT HAS WEAKENED OVER THE WATERS...AND CAN EXPECT N WINDS 10-15 KT ON ALL WATERS. WINDS SHOULD INCREASE THURSDAY NIGHT...WITH TIGHTENING PRESSURE GRADIENT AHEAD OF THE NEXT SYSTEM. FOR NOW DO BRING GUSTS UP TO 25-30KT ON ALL WATERS THURSDAY AFTERNOON. HOWEVER...CONFIDENCE IN THIS IS NOT HIGH ENOUGH TO WARRANT ISSUING AN SCA AT THIS TIME. THERE IS SOME POTENTIAL THAT A SUFFICIENT LOW LEVEL MARINE INVERSION COULD FORM TO PRECLUDE SCA WIND GUSTS...WITH THE BEST CHANCE FOR ANY 25-30 KT GUSTS ON THURSDAY AFTERNOON OVER NY HARBOR/W LONG ISLAND SOUND/COASTAL OCEAN WATERS W OF FIRE ISLAND INLET. A PROLONGED PD OF SCA CONDITIONS PROBABLY WILL BE SETTING UP FOR THE OCEAN WATERS BEGINNING THU AFTERNOON...FIRST VIA INCREASING SOUTHERLY FLOW THU AFTERNOON INTO FRI AHEAD OF A SLOW MOVING COLD FRONT. THE FLOW MAY WEAKEN AHEAD OF THE FRONT FRI NIGHT...BUT LEFTOVER SWELLS WILL STILL BE HAZARDOUS DURING THAT TIME. NW TO W WINDS AFTER COLD FRONTAL PASSAGE SHOULD REACH SCA CRITERIA ON ALL WATERS ON SAT...THEN CONTINUE ON THE OCEAN SAT NIGHT INTO SUNDAY. && .FIRE WEATHER... RELATIVE HUMIDITIES THURSDAY AFTERNOON FALL TO 30-35 PERCENT OVER AREAS MAINLY W OF THE HUDSON...AND WINDS THURSDAY AFTERNOON THERE LIKELY WILL GUST TO 20-25 MPH WITH PEAK GUSTS OF 30-35 MPH POSSIBLE. AT THE MINIMUM THESE CONDITIONS COULD PROMOTE RAPID GROWTH/SPREAD OF ANY FIRES WHICH OCCUR THURSDAY AFTERNOON. && .HYDROLOGY... THERE IS POTENTIAL FOR 3/4 TO 1 INCH OF RAIN FROM LATE THU NIGHT INTO EARLY SAT MORNING. RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANK FULL...BUT INCREASED RIVER/STREAM FLOW ACROSS THE LOWER HUDSON VALLEY AND SOUTHERN CONNECTICUT WILL CONTINUE ICE BREAKUP AND MOVEMENT INTO THIS WEEKEND. ISOLATED ICE JAMS ARE POSSIBLE...WHICH IF THEY OCCUR...COULD RESULT IN LOCALIZED FLOODING. SINCE ICE JAM FLOODING IS UNPREDICTABLE AND SUDDEN...INTERESTS ALONG ICE COVERED RIVERS SHOULD MONITOR NWS FORECASTS FOR THE LATEST INFORMATION. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...GOODMAN/MALOIT NEAR TERM...MPS SHORT TERM...MALOIT LONG TERM...GOODMAN AVIATION...PW MARINE...GOODMAN/MALOIT FIRE WEATHER... HYDROLOGY...GOODMAN/MALOIT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.