Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 250538 CCA AFDOKX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE NEW YORK NY 1235 AM EST TUE NOV 25 2014 .SYNOPSIS... A COLD FRONT MOVES ACROSS THE REGION OVERNIGHT AS LOW PRESSURE TRACKS THROUGH SOUTHEASTERN CANADA. HIGH PRESSURE BUILDS IN TUESDAY AND MOVES NORTHEAST TUESDAY NIGHT. LOW PRESSURE ALONG THE SOUTHEAST COAST TUESDAY NIGHT...DEEPENS AND TRACKS NORTHEAST... PASSING SOUTHEAST OF LONG ISLAND WEDNESDAY NIGHT...AND THEN UP INTO THE CANADIAN MARITIMES THURSDAY. HIGH PRESSURE GRADUALLY BUILDS IN THURSDAY NIGHT THROUGH FRIDAY AND THEN MOVES OFFSHORE FOR THE WEEKEND. A COLD FRONT APPROACHES ON SUNDAY...MOVING ACROSS SUNDAY NIGHT. ANOTHER HIGH FROM THE NORTH BUILDS IN BEHIND THE FRONT FOR EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... PATCHY DENSE FOG HAS MOVED INTO THE SOUTH SHORE OF SUFFOLK COUNTY...WILL ADDRESS WITH A SPECIAL WEATHER STATEMENT. THE FOG SHOULD DISSIPATE WITH THE COLD FRONTAL PASSAGE 8-9Z. A COLD FRONT CROSSES THE REGION OVERNIGHT THROUGH AROUND 09Z...AND HIGH PRESSURE BEGINS TO BUILD IN FROM THE SOUTHWEST. THE AIR MASS IS NOT THAT COLD BEHIND THE FRONT AND WILL REMAIN ABOVE NORMAL OVERNIGHT...IN THE UPPER 40S TO LOWER AND MID 50S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... BROAD UPPER TROUGH REMAINS WEST OF THE AREA TUESDAY AND TUESDAY NIGHT AS A SHORTWAVE MOVES OUT OF THE PACIFIC NORTHWEST AND INTO THE MID SECTION OF NATION. MEANWHILE A SOUTHERN STREAM SHORTWAVE MOVES OUT OF SOUTHERN TEXAS AND ACROSS THE GULF COAST STATES TO THE SOUTHEAST COAST BY WEDNESDAY MORNING. AT THE SURFACE HIGH PRESSURE BUILDS OVER THE AREA TUESDAY AND MOVES NORTHEAST TUESDAY NIGHT. THE COMBINATION OF THE UPPER SHORTWAVES DEVELOP LOW PRESSURE OVER THE GULF OF MEXICO AND CENTRAL PLAINS TUESDAY. TUESDAY NIGHT THE SOUTHERN STREAM LOW MOVES OFF THE SOUTHEAST COAST AND DEEPENS WHILE THE CENTRAL PLAINS LOW LAGS...NOT QUITE PHASING WITH THE SOUTHERN STREAM BY WEDNESDAY MORNING. PRECIPITATION WILL BE MOVING IN AFTER 06Z WEDNESDAY WITH ONLY SLIGHT AND CHANCE POP UNTIL TOWARD 12Z. THE PRECIPITATION BEGINS AS RAIN AS THE AREA WILL STILL BE WARM. AS THE LOW PUSHES NORTH TOWARD 12Z AND PRECIPITATION BREAKS OUT INLAND...IN THE COLDER AIR...THERE WILL BE A MIX OF RAIN AND SNOW. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THERE IS INCREASING LIKELIHOOD OF A SIGNIFICANT WINTER STORM TO IMPACT THE TRI-STATE AREA WEDNESDAY INTO WEDNESDAY NIGHT. THIS WOULD HAVE MAJOR IMPACTS ON HOLIDAY TRAVEL. MODELS REMAIN IN GOOD AGREEMENT WITH TAKING A FULL LATITUDE UPPER TROUGH INTO THE EASTERN U.S. AND FORMING A COASTAL LOW ALONG THE SE COAST TUE NIGHT. THIS LOW WILL THEN DEEPEN WHILE TRACKING NE ON WED TO JUST EAST OF THE SOUTHERN NEW ENGLAND COAST WED NIGHT. THIS SCENARIO WITH A MARGINALLY COLD AIRMASS AND SIGNIFICANT PRECIPITATION INCREASES THE LIKELIHOOD FOR HEAVY WET SNOW ACROSS THE INTERIOR...AND MIXTURE OF RAIN AND SNOW AT THE COAST WED AND WED NIGHT. THUS...A WINTER STORM WATCH REMAINS UP FOR INTERIOR LOCATIONS OF NE NJ...THE LOWER HUDSON VALLEY...AND CONNECTICUT. NO CHANGES WERE MADE TO THE WATCH CONFIGURATION. MODELS HAVE TRENDED SLIGHTLY COOLER WITH THERMAL PROFILES...WITH THE 12Z GFS REMAINING THE MOST CONSISTENT IN TAKING THE DEEPENING COASTAL LOW ACROSS THE BENCHMARK...40N...70W WED NIGHT. THE 12Z NAM WRF IS JUST EAST...WHICH EXPLAINS THE COLDER PROFILES AND A PRIMARILY SNOW EVENT EVEN AT THE COAST. THE 12Z ECMWF HAS TRENDED EAST LIKE THE SREF THE LAST 24H...BUT REMAINS JUST INSIDE THE BENCHMARK AND IS ABOUT 6H SLOWER THAN GFS AND NAM. WITH NO POLAR HIGH TO THE NORTH...THE EVENT WILL BE STRONGLY DEPENDENT OF DYNAMICS IN A MARGINALLY COLD AIRMASS. WET BULB TEMPS EVEN ALONG THE COAST ARE 1 TO 2 DEG C FROM 1500 FT TO THE SFC...AND NEARLY ISOTHERMAL ALOFT AND SLIGHTLY COOLER THAN 0 DEG C. THUS...THIS FORECAST IS HIGHLY DEPENDENT ON STORM TRACK AND WHERE BANDING...OR STRONG FRONTOGENETIC FORCING SETS UP. IT WILL NOT TAKE TOO MUCH TO GO FROM ALL SNOW AND VICE VERSA...SO THIS IS WHERE THERE IS SIGNIFICANT UNCERTAINTY IN THE FORECAST. HOWEVER...INTERIOR LOCATIONS CONFIDENCE OF A PRIMARILY SNOW EVENT IS MUCH HIGHER THAN THE P-TYPE FORECAST AT THE COAST. SNOWFALL AMOUNTS WILL RANGE FROM 6 TO 10 INCHES IN THE WATCH AREA...TO AS LITTLE AS 1 TO 2 INCHES ACROSS THE EASTERN FORKS OF LONG ISLAND. RAIN WILL CHANGE TO ALL SNOW ACROSS THE INTERIOR BY NOONTIME...AND MIX WITH OR CHANGE TO SNOW DURING THE AFTERNOON HOURS AT THE COAST. AS FOR TEMPS DURING THE PERIOD...USED A BLEND OF THE NAM/GFS 2M TEMPS/DEW POINTS. MOS IS LIKELY TOO WARM. FOR P-TYPE...WITH MOST OF THERMAL PROFILE BELOW FREEZING...EXCEPT THE LOWEST 1500 FT AT THE COAST...USED THE WET BULB IN THIS LAYER. SNOW TAPERS OFF WED NIGHT WITH A GUSTY NW FLOW ON THE BACKSIDE OF THE STORM. TEMPS REMAINING 5 TO 8 DEGREES BELOW NORMAL INTO THANKSGIVING DAY WITH HIGHS AROUND 40. STARTING AT THE UPPER LEVELS...JET STREAM SOUTH OF THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT WILL BE AMPLIFIED. THE JET WILL EVENTUALLY LIFT NORTH DURING THE WEEKEND...REMAINING NEAR THE AREA. THE JET REMAINS NEAR THE REGION AND IS PRIMARILY ZONAL FROM THE WEEKEND INTO EARLY NEXT WEEK. LOOKING AT THE MID LEVELS...THE TROUGH AXIS MOVES ACROSS THURSDAY NIGHT. THE TROUGH SHIFTS EAST OF THE REGION FRIDAY AND A PRIMARY ZONAL FLOW ESTABLISHES THEREAFTER THROUGH EARLY NEXT WEEK. AT THE SURFACE...A HIGH PRESSURE RIDGE STARTS TO BUILD IN FROM THE WEST THURSDAY NIGHT AND FRIDAY. THE RIDGE AXIS MOVES ACROSS FRIDAY NIGHT AND THEN HIGH PRESSURE SLIDES OFFSHORE THIS WEEKEND. A COLD FRONT APPROACHES SUNDAY...PUSHING THROUGH THE REGION SUNDAY NIGHT. THIS WILL BE ASSOCIATED WITH A CLIPPER SYSTEM PASSING THROUGH SOUTHEAST CANADA. ANOTHER HIGH PRESSURE FROM THE NORTH WILL BE BUILDING IN NEXT MONDAY. IN TERMS OF WEATHER...THE ONLY CHANCES FOR PRECIPITATION WILL BE SUNDAY AND SUNDAY NIGHT IN ASSOCIATION WITH THE APPROACHING COLD FRONT. THERE ARE LARGE UNCERTAINTIES THAT FAR OUT...SO LEFT A SLIGHT CHANCE FOR THE WHOLE DAY SUNDAY AND ALL OF SUNDAY NIGHT. DEPENDING ON THE TIMING...SOME PRECIP COULD BE IN THE FORM OF SNOW SHOWERS EARLY SUNDAY OR LATE SUNDAY NIGHT...MORE SO FOR THE INTERIOR. OTHERWISE...JUST A SLIGHT CHANCE OF RAIN SHOWERS. THE LIQUID PRECIP TOTALS ARE CONVEYED TO BE A FEW HUNDREDTHS OF AN INCH OR LESS. IN TERMS OF TEMPERATURES...DAYTIME HIGHS ARE FORECAST TO BE BELOW NORMAL FRIDAY THROUGH NEXT MONDAY AND NIGHTTIME LOWS ARE FORECAST TO BE BELOW NORMAL THURSDAY NIGHT AND FRIDAY NIGHT AND NEAR NORMAL FOR THE NIGHTS DURING THE WEEKEND. NORMAL HIGHS LATE NOVEMBER ARE GENERALLY IN THE UPPER 40S TO NEAR 50 WHILE NORMAL LOWS FOR THE SAME TIME PERIOD ARE GENERALLY IN THE MID TO UPPER 30S. COLDEST DAY LOOKS TO BE FRIDAY WITH FORECAST HIGHS ONLY IN THE LOW TO MID 30S FOR MUCH OF THE REGION. && .AVIATION /05Z TUESDAY THROUGH SATURDAY/... A COLD FRONT OVER WILL TRACK ACROSS THE AREA EARLY THIS MORNING...FOLLOWED BY WEAK HIGH PRESSURE BUILDING IN DURING THE DAY. LOW PRESSURE WILL THEN TRACK UP THE SOUTHEASTERN COAST TONIGHT. LIFR/VLIFR CONDITIONS FROM KISP EASTWARD. THIS AREA EXTENDS SOUTHWESTWARD TO OFF THE CENTRAL NJ COAST. IT IS SLOWLY WORKING NORTHWARD...BUT OBSCURED ON SATELLITE BY HIGH/MID CLOUDS. THERE IS A POTENTIAL THAT THESE LOW CEILINGS COULD REACH KJFK AND POSSIBLY KLGA BEFORE THE FRONT ARRIVES. STILL THE HIGHEST PROB IS VFR SO HAVE MAINTAINED ONLY SCT008 IN THE TAFS. REMAINDER OF TERMINALS VFR AHEAD OF COLD FRONT. VFR AFTER THE FRONT AND THROUGH THE REMAINDER OF THE TAF PERIOD. SSW WINDS SHIFT TO THE W BEHIND THE FRONT. W WINDS CONTINUES TODAY THEN WINDS LIGHTEN TONIGHT. .OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY... HIGH IMPACT EVENT WEDNESDAY INTO WEDNESDAY NIGHT... .TUESDAY NIGHT...VFR. .WEDNESDAY-WEDNESDAY NIGHT...RA/RASN IN THE MORNING CHANGES TO SNOW IN THE AFTERNOON. BASED ON THE CURRENT EXPECTED TRACK...4-8 INCHES POSSIBLE AT THE CITY TERMINALS. N WINDS 10-15 KT AM...INCREASING TO 15-20 KT IN THE EVENING WITH GUSTS 25-30 KT. .THURSDAY-THRUSDAY NIGHT...BECOMING VFR. LINGERING SNOW SHOWERS POSSIBLE EARLY. WNW-NW WINDS G15-20 KT. .FRIDAY-FRIDAY NIGHT...VFR. NW WINDS G20 KT POSSIBLE DURING THE DAY. .SATURDAY...VFR. W-SW WINDS G15-20KT POSSIBLE. && .MARINE...
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PATCHY FOG WITH VISIBILITIES LESS THAN 1 MILE HAVE MOVED BACK INTO THE SOUTH SHORE BAYS AND EASTERN COASTAL OCEAN WATERS. THIS SHOULD LAST UNTIL COLD FRONTAL PASSAGE. WILL ADDRESS WITH A MARINE WEATHER STATEMENT. A STRONG AND GUSTY SOUTHERLY FLOW REMAINS ACROSS THE WATERS EARLY THIS MORNING AHEAD OF AN APPROACHING COLD FRONT...WITH SMALL CRAFT CONDITIONS ACROSS ALL THE FORECAST WATERS. AFTER 08Z WINDS AND GUSTS DIMINISH AS THE COLD FRONT CROSSES THE WATERS AND WINDS ALOFT ALSO DIMINISH. THERE WILL BE A LULL IN THE GUSTS ACROSS THE WATERS AROUND MID MORNING. THEN IN THE COOLER AIR GUSTS WILL INCREASE ON THE OCEAN WATERS TO SMALL CRAFT ONCE AGAIN. IN ADDITION SEAS ON THE OCEAN REMAIN AT SMALL CRAFT INTO TUESDAY EVENING...BECOMING MARGINAL DURING THE EVENING. FOR NOW WILL HAVE A SMALL CRAFT ADVISORY ON THE OCEAN THROUGH TUESDAY...AND ON THE REMAINDER OF THE WATERS UNTIL 06Z TONIGHT. A COASTAL LOW BRINGS A CHANCE OF GALE CONDITIONS TO THE COASTAL OCEAN WATERS WEDNESDAY AND WEDNESDAY NIGHT. A GALE WATCH HAS BEEN ISSUED FOR THESE LOCATIONS. SMALL CRAFT CONDITIONS ARE LIKELY ON THE REMAINDER OF THE WATERS DURING THIS TIME FRAME...WITH A LOW CHANCE OF GALES. CONDITIONS SUBSIDE TO SUB-SMALL CRAFT CONDITIONS ON THE NON-OCEAN ZONES THURSDAY WITH LINGERING HIGH SEAS ON THE OCEAN WATERS. SCA CONDITIONS ARE FORECAST FOR MAINLY THE OCEAN THURSDAY NIGHT AND FRIDAY. ON FRIDAY...THIS WILL BE MAINLY FOR WINDS WITH A STEEP ENOUGH PRESSURE GRADIENT BETWEEN THE HIGH TO THE WEST TO LOW PRESSURE WELL INTO THE NORTH ATLANTIC. A BRIEF LULL WITH SUB SCA CONDITIONS IS FORECAST FRIDAY NIGHT AND SATURDAY AS THE RIDGE AXIS MOVES ACROSS AND JUST OFFSHORE. HOWEVER...THE PRESSURE GRADIENT WILL INCREASE AS HIGH PRESSURE MOVES FARTHER OFFSHORE WITH SCA CONDITIONS FORECAST LATE SATURDAY AFTERNOON THROUGH SUNDAY...AGAIN MOSTLY ON THE OCEAN.
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&& .HYDROLOGY...
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NO SIGNIFICANT PRECIPITATION THROUGH LATE TUESDAY EVENING. THERE IS THE POTENTIAL FOR AROUND 0.75 TO 1.5 INCHES OF QPF TO FALL FROM LATE TUESDAY NIGHT INTO EARLY THURSDAY MORNING. THE HIGHEST QPF AMOUNTS AREA CURRENTLY EXPECTED OVER EASTERN CT/LONG ISLAND AND THE LOWEST OVER FAR WESTERN PORTIONS OF THE TRI-STATE. OVER THE INTERIOR MOST OF THIS WILL FALL IN THE FORM OF SNOW...SO LITTLE IF ANY IMMEDIATE HYDROLOGIC IMPACT IS EXPECTED THERE. FARTHER TO THE S/E...BASICALLY ALONG AND E OF I-95...THERE WILL BE A A MIX OF RAIN AND SNOW. THIS COULD CAUSE MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS. NO SIGNIFICANT WIDESPREAD PRECIPITATION EXPECTED THURSDAY AFTERNOON THROUGH MONDAY.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR CTZ005>008. NY...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR NYZ067>070. NJ...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR NJZ002-004-103-105. MARINE...GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR ANZ350-353-355. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...MET/DW NEAR TERM...MPS/MET SHORT TERM...MET LONG TERM...JM/DW AVIATION...JMC/MALOIT MARINE...MPS/MET/DW HYDROLOGY...MET/DW

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