Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 160010 CCA AFDOKX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE NEW YORK NY 810 PM EDT TUE APR 15 2014 .SYNOPSIS... A STRONG COLD FRONT WILL PASS OFFSHORE LATE THIS EVENING. HIGH PRESSURE THEN BUILDS IN FROM THE OHIO VALLEY ON WEDNESDAY. THE HIGH THEN LIFTS UP INTO THE CANADIAN MARITIMES WEDNESDAY NIGHT INTO THURSDAY AND UP INTO THE NORTH ATLANTIC ON FRIDAY. A LOW PRESSURE SYSTEM DEVELOPS ALONG A STALLED FRONT TO THE SOUTH FRIDAY NIGHT AND PASSES EAST OF THE REGION ON SATURDAY. HIGH PRESSURE RETURNS SUNDAY INTO MONDAY BEFORE SHIFTING OFFSHORE WITH THE APPROACH OF A COLD FRONT ON TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE COLD FRONT WAS INTO ERN LI AND CT AT 730 PM. BASED ON RADAR TIMING...IT IS TRACKING EASTWARD AT 18KT AND WILL BE OFF MONTAUK BY 930 PM. PRIOR TO THE FRONTAL PASSAGE...THERE WILL BE MULTIPLE BANDS OF SHOWERS WITH MODERATE TO HEAVY RAINFALL. OTHERWISE...POST- FRONTAL PCPN IN ASSOCIATION WITH AN AMPLIFYING UPPER TROUGH AND THE RRQ OF THE UPPER JET WILL CONTINUE THIS EVE. BY THE TIME THE EVENT IS OVER LATE TONIGHT INTO THE EARLY MORNING HOURS WED...MUCH OF THE REGION WILL HAVE SEEN 1 TO 2 INCHES OF RAINFALL. STRONG COLD ADVECTION WILL ALSO ALLOW FOR THE TRANSITION OVER TO SOME WET SNOW THIS EVENING. THE BEST CHANCE FOR THIS TO OCCUR WILL BE IN THE NW SUBURBS WHERE A COATING TO AN INCH OF SNOW WILL BE POSSIBLE. THE TIMING OF THE CHANGEOVER WILL BE CRITICAL AS TO THE AMOUNTS. SHOULD THIS TRANSITION OCCUR EARLIER THAN FORECAST... THERE COULD BE AS MUCH AS 2 TO 3 INCHES OF SNOWFALL. THE CHANGEOVER WILL FIRST HAPPEN ACROSS ORANGE COUNTY IN NEW YORK AND PASSAIC COUNTY NJ AROUND 8 PM. A COATING ACROSS EASTERN AREAS IS POSSIBLE. GUSTY SOUTH WIND EARLY WILL TURN AROUND TO THE NW THIS EVENING WITH GUSTS OF 40 TO 45 MPH. OVERNIGHT LOWS WILL BE IN THE MID 20S TO AROUND FREEZING. THUS... THE FREEZE WARNING HAS BEEN EXPANDED TO ALSO INCLUDE NYC...LONG ISLAND...AND COASTAL CT. THIS IS IN ADDITION TO MOST OF NE NJ AND ROCKLAND AND WESTCHESTER COUNTIES IN NEW YORK. GUIDANCE HAS BEEN TRENDING COLDER. BASED ON THE ANOMALOUSLY COLD AIR MASS...USED MODEL 2M TEMPS FOR LOWS...WHICH WAS SEVERAL DEGREES BELOW MOS GUIDANCE. LOWS WILL BE CLOSE TO RECORDS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE BUILDS EAST FROM THE OHIO VALLEY ON WED WITH AN ANOMALOUSLY COLD AIR MASS. HIGHS WILL BE IN THE MID AND UPPER 40S...WHICH IS SOME 10 TO 15 DEGREES BELOW NORMAL. GUSTY NW WINDS WILL LINGER INTO THE AFT...MAKING IT FEEL MORE LIKE THE MID AND UPPER 30S. WED NIGHT WILL FEATURE ANOTHER POSSIBLE RECORD COLD NIGHT WITH MOST LOCATIONS OUTSIDE OF THE NYC METRO DROPPING BELOW FREEZING. ANOTHER FREEZE IS POSSIBLE. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AT THE BEGINNING OF THE LONG TERM ON THURSDAY AND FRIDAY...THE REGION WILL BE ON THE WEST SIDE OF UPPER LEVEL RIDGING ACROSS THE WESTERN ATLANTIC WITH A TROUGH ACROSS THE CENTRAL STATES. AT THE SURFACE...HIGH PRESSURE OVER NEW ENGLAND THURSDAY SHIFTS INTO THE CANADIAN MARITIMES BY FRIDAY. THIS PATTERN SETS UP AN EAST TO NORTHEASTERLY FLOW IN THE LOW LEVELS. THIS ONSHORE FLOW SERVES TO KEEP TEMPERATURES ON THE COOL SIDE WITH READINGS IN THE UPPER 40S AND LOWER 50S ON THURSDAY AND LOWER AND MIDDLE 50S ON FRIDAY. INCREASING LOW LEVEL MOISTURE LATE THURSDAY NIGHT INTO FRIDAY MORNING COULD PROMOTE DRIZZLE OR LIGHT RAIN...MAINLY ACROSS SOUTHERN ZONES. HAVE INCLUDED SLIGHT CHANCE POPS DURING THIS TIME. THE TROUGH ACROSS THE CENTRAL STATES APPROACHES FRIDAY NIGHT INTO SATURDAY WITH A WAVE OF LOW PRESSURE DEVELOPING ALONG A STALLED FRONT OFFSHORE. MUCH OF THE GUIDANCE KEEPS THE LOW FAR ENOUGH OFFSHORE TO PREVENT A WIDESPREAD PRECIP EVENT. THE MODELS DIFFER ON THE AMPLITUDE...TIMING...AND PLACEMENT OF THE VORTICITY MAXIMA WITHIN THE UPPER TROUGH HOWEVER. AT THE VERY LEAST...SATURDAY WILL BE MOSTLY CLOUDY AND HAVE CONTINUED A CHANCE FOR SHOWERS WITH THE UPPER TROUGH PASSAGE. DUE TO CLOUDS AND PRECIPITATION...TEMPERATURES CONTINUE BELOW NORMAL IN THE 50S. A GENERAL ZONAL FLOW SETS UP ON SUNDAY AND CONTINUES INTO MONDAY. SURFACE HIGH PRESSURE BUILDS BACK IN DURING THIS TIME WITH DRY CONDITIONS. SLIGHTLY BELOW NORMAL TEMPERATURES WILL CONTINUE ON SUNDAY AND THEN WARMING TO NEAR NORMAL ON MONDAY. A SHORTWAVE AND ASSOCIATED COLD FRONT MAY APPROACH ON TUESDAY BRINGING A CHANCE FOR SHOWERS. HIGH UNCERTAINTY EXISTS AT THIS TIME SO HAVE ONLY INCLUDED CHANCE POPS. TEMPERATURES SHOULD BE NEAR NORMAL IN THE 60S. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... A COLD FRONT EXITS TO THE EAST EARLY THIS EVENING...FOLLOWED BY HIGH PRESSURE BUILDING OVER THE AREA INTO WEDNESDAY EVENING. CONDITIONS GRADUALLY IMPROVE FROM MVFR VARIABLE IFR TO VFR INTO THE OVERNIGHT HOURS. SHOULD SEE -SHRA TRANSITION OVER TO AT LEAST A RAIN/SNOW MIX AT ALL TERMINALS...AND OVER TO ALL -SN AT KSWF AND KHPN BEFORE ENDING. POTENTIAL FOR 1-2 INCH ACCUMULATION KSWF...AND LESS THAN 1 INCH KHPN. LOW PROBABILITY OF A COATING OF SLUSH ELSEWHERE. LLWS LINGERS AT KGON UNTIL COLD FRONT MOVES THROUGH...WHICH SHOULD BE RIGHT AROUND 1Z. BEHIND THE FRONT...WINDS OUT THE NW G20-30KT THROUGH THE NIGHT. COULD SEE ISOLATED 35-40KT GUSTS OVERNIGHT. WINDS GRADUALLY DIMINISH DURING THE DAY ON WEDNESDAY AS WINDS VEER TO THE NNW. WIND GUSTS SHOULD ABATE BY LATE AFTERNOON AS THE WINDS CONTINUE TO VEER TO THE N. 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: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX...ALL COULD BE OFF +/- 1-2 HOURS. KLGA FCSTER COMMENTS: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX...ALL COULD BE OFF +/- 1-2 HOURS. KEWR FCSTER COMMENTS: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX...ALL COULD BE OFF +/- 1-2 HOURS. KTEB FCSTER COMMENTS: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX...ALL COULD BE OFF +/- 1-2 HOURS. KHPN FCSTER COMMENTS: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX THEN CHANGE OVER TO ALL SNOW...ALL COULD BE OFF +/- 1-2 HOURS. KISP FCSTER COMMENTS: TIMING ON CHANGES IN CEILING/VISIBILITY/WIND SPEED-DIRECTION-GUST SPEED...AND ONSET OF RAIN-SNOW MIX...ALL COULD BE OFF +/- 1-2 HOURS. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT-THURSDAY...VFR. E WIND G AROUND 20KT POSSIBLE. .THURSDAY NIGHT-FRI NIGHT...VFR. .SATURDAY...PSBL MVFR CONDITIONS WITH LOW CHANCE OF -SHRA. W-NW WIND G25-30KT POSSIBLE. .SATURDAY NIGHT-SUNDAY...VFR && .MARINE... GALE WARNING IN EFFECT FOR ALL WATERS...PRIMARILY FOR THE NW FLOW TONIGHT BEHIND A STRONG COLD FRONTAL PASSAGE. GUSTS UP TO 40 KT POSSIBLE. HOWEVER...IN THE HOURS PRECEDING THE COLD FRONTAL PASSAGE EARLY THIS EVENING...THERE WILL ALSO BE MARGINAL GALE FORCE GUSTS IN THE SLY FLOW. MARGINAL SCA CONDITIONS ARE THEN POSSIBLE ON WED...MAINLY WITH LINGERING 5 FT SEAS. SCA WINDS AND SEAS LIKELY ON THURSDAY AS EASTERLY FLOW INCREASES. WINDS WILL TREND BELOW SCA LEVELS FRIDAY BUT SEAS ON OFFSHORE WATERS SHOULD STAY ABOVE SCA THROUGH FRIDAY NIGHT. WINDS AND SEAS WILL RELAX ON SATURDAY AS REGION WEAKER FLOW SETS UP OVER THE WATERS. SEAS AND WINDS COULD RETURN TO SCA LEVELS ON SUNDAY WITH INCREASED NORTHWESTERLY FLOW. && .HYDROLOGY... RAINFALL OF 1 1/2 TO 2 INCHES...MAINLY ALL LIQUID...EXPECTED FOR THE EVENT TOTAL THROUGH LATE TONIGHT. THERE IS THE POTENTIAL FOR LOCALLY HIGHER AMOUNTS IN ANY STRONG CONVECTION. LOW TO MODERATE POTENTIAL EXISTS FOR MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS. ALSO LOW POTENTIAL FOR FLASHY SMALL STREAMS ACROSS NORTHEASTERN NEW JERSEY INTO THE LOWER HUDSON VALLEY TO REACH MINOR FLOOD LEVELS WITH 1 HOUR FLASH FLOOD GUIDANCE AROUND 1 INCH. NOTE...MINOR FLOODING CONTINUES ALONG THE CONNECTICUT RIVER. ADDITIONAL HEAVY RAINFALL WILL LIKELY CAUSE WATER LEVELS TO CONTINUE TO RISE THROUGH THE WEEK...WITH POTENTIAL FOR MODERATE FLOOD LEVELS TO BE REACHED. MONITOR THE LATEST FLOOD WARNINGS FROM NWS TAUNTON MA. NO SIGNIFICANT PRECIPITATION IS EXPECTED FROM THURSDAY INTO EARLY NEXT WEEK. && .CLIMATE...
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RECORD LOWS FOR WEDNESDAY APRIL 16: EWR - 26 IN 1943 FORECAST LOW - 29 BDR - 29 IN 1981 FORECAST LOW - 29 NYC - 29 IN 1928 FORECAST LOW - 29 LGA - 31 IN 1943 FORECAST LOW - 30 JFK - 33 IN 1962 FORECAST LOW - 30 ISP - 32 IN 2008 FORECAST LOW - 30
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...FREEZE WARNING FROM 2 AM TO 10 AM EDT WEDNESDAY FOR CTZ009>012. NY...FREEZE WARNING FROM 2 AM TO 10 AM EDT WEDNESDAY FOR NYZ069>075- 078>081-176>179. NJ...FREEZE WARNING FROM 2 AM TO 10 AM EDT WEDNESDAY FOR NJZ004-006- 103>108. MARINE...GALE WARNING UNTIL 6 AM EDT WEDNESDAY FOR ANZ330-335-338-340- 345-350-353-355. && $$ SYNOPSIS...JMC/DW/DS NEAR TERM...JMC/DW SHORT TERM...DW LONG TERM...DS AVIATION...MALOIT MARINE...DW/DS HYDROLOGY...DW/DS CLIMATE...LN

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