Area Forecast Discussion
Issued by NWS Upton, NY

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782 FXUS61 KOKX 072049 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 349 PM EST SUN FEB 7 2016 .SYNOPSIS... INTENSIFYING LOW PRESSURE ALONG THE SOUTHEAST U.S. COAST WILL TRACK TO THE NORTH TONIGHT AND WILL PASS WELL SOUTH AND EAST OF LONG ISLAND ON MONDAY. THAT LOW THEN TRACKS INTO THE CANADIAN MARITIMES MONDAY NIGHT. AN UPR LVL SYS WILL THEN SPIN OVER THE REGION THRU THE END OF THE WEEK. AN ARCTIC AIRMASS OVERSPREADS THE AREA FOR THE WEEKEND. && .NEAR TERM /THROUGH MONDAY/... 12Z MODEL GUIDANCE ALL IN DECENT AGREEMENT...AND HAVE BROUGHT ABOUT AN INCREASE IN PRECIP ACROSS THE REGION. AS A RESULT...TRENDED HIGHER WITH QPF AND SNOWFALL...AND HAVE GONE AHEAD AND ISSUED WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES FOR MUCH OF THE CWA. HIGH PRES JUST SOUTH OF THE REGION CONTINUES TO MOVE OFFSHORE THIS EVENING. MEANWHILE...LOW PRES CONTINUES TO INTENSIFY OFF THE SOUTHEAST U.S. COAST...AND THAT LOW WILL PASS EAST OF CAPE HATTERAS AFTER MIDNIGHT...AND WILL CONTINUE ON AN E-NE TRACK FROM LATE TONIGHT THROUGH MONDAY. 1035 MB HIGH PRES BUILDS INTO EASTERN CANADA...AND ANOTHER LOW DIVES INTO THE GREAT LAKES AND OHIO VALLEY FROM LATE TONIGHT THROUGH MONDAY. THE 12Z NAM/GFS/ECMWF HAVE ALL COME IN WITH THE LOW A BIT FARTHER TO THE WEST...JUST ENOUGH TO SPREAD HEAVIER PRECIP INTO EASTERN AREAS. MODELS INDICATING HIGHER QPF AMOUNTS FOR THE REGION...AND WITH COLDER AIR IN PLACE...EXPECTING PRECIP TO FALL AS SNOW. THE HIGHEST QPF AMOUNTS WILL FALL OVER EASTERN LONG ISLAND AND SE CT...WHERE 4 TO 8 INCHES OF SNOW IS POSSIBLE. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THOSE AREAS. ELSEWHERE...SNOW WILL BE LIGHTER OVER THE REST OF THE CWA...AND EXPECTING A SHARP CUTOFF FROM WHERE SNOW FALLS AND WHERE IT DOES NOT. WENT AHEAD AND HOISTED WINTER WEATHER ADVISORIES FOR THE REST OF CT AND LONG ISLAND...AND FOR WESTCHESTER AND NYC AS WELL...AS SNOW ACCUMULATIONS OF 2 TO 4 INCHES IS POSSIBLE IN THOSE LOCATIONS THROUGHOUT THE PERIOD. WEST OF THAT LINE...ONLY ABOUT 1 TO 3 INCHES OF SNOW IS POSSIBLE FOR NE NJ AND THE REST OF THE LOWER HUDSON VALLEY...SO NO HEADLINES ISSUED FOR THOSE AREAS. WITH A TIGHT NE PRES GRADIENT DEVELOPING...CAN EXPECT STRONG WINDS OF 15-25 MPH WITH GUSTS OCCASIONALLY AS HIGH AS 35 MPH IN THE WARNING AREAS. NOT EXPECTING 3 HOURS OF 35 MPH WINDS AND/OR VSBYS LESS THAN 1/4 MILE...HENCE THE WINTER STORM WARNING AS OPPOSED TO A BLIZZARD WARNING. BUT BLIZZARD-LIKE CONDS POSSIBLE IN THE WARNING AREAS. WITH A HEAVY...WET SNOW EXPECTED...DOWNED TREES AND POWER LINES ARE POSSIBLE. ELSEWHERE...WINDS WILL NOT BE QUITE AS STRONG...BUT GUSTS TO 30 MPH POSSIBLE FOR COASTAL AREAS. LOWS TONIGHT WILL DROP INTO THE MID 20S TO LOW 30S. HIGHS ON MONDAY WILL TOP OFF IN THE LOW TO MID 30S. && .SHORT TERM /MONDAY NIGHT/... SNOW TAPERS OFF MONDAY EVENING. AS LOW PRES FROM THE OHIO VALLEY TRACKS EAST...A SECONDARY LOW LOOKS TO FORM OFF THE MID-ATLANTIC COAST. HARD TO SAY WHERE THE HEAVIEST PRECIP WILL SET UP...BUT LIGHT SNOW IS LIKELY THROUGH THE NIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... MODELS CONTINUE TO BE IN GOOD AGREEMENT WRT THE PATTERN THRU THE END OF THE WEEK. CYCLONIC FLOW ALOFT PLUS LLVL LAPSE RATES APPROACHING DRY ADIABATIC AT TIMES WILL PRODUCE PERIODS OF LGT SNOW. WET BULB ZERO HEIGHTS AOB 500FT THRU THE PERIOD SO ALL SNOW IS FCST. BREAKS IN THE CLOUDS WILL BE NEEDED FOR TEMPS TO REACH SUPERBLEND NUMBERS...SO DROPPED THEM DOWN A DEGREE FOR NOW. FOR SNOW ACCUMS...MAINLY LGT AMTS IN THE GRIDS ATTM. HOWEVER...THERE IS THE POTENTIAL FOR TWO PERIODS OF ENHANCED PCPN AS WEAK LOWS GET SPUN UP OFFSHORE IN THE TUE TIME FRAME AND WED TIME FRAME. IT IS TOO FAR OUT TO PINPOINT EXACTLY WHERE ANY HEAVIER BANDS SET UP...BUT THE POTENTIAL FOR AT LEAST A MDT SNOWFALL IN THE TUE-WED PERIOD IS THERE. A FIRST WAVE OF COLDER AIR COMES IN ON THU. VERY STEEP LLVL LAPSE RATES AGAIN SO ANY MOISTURE IN THE AREA SHOULD BE SQUEEZED OUT WITH MORE LGT SNOW. SNOW CHCS LESSEN ON FRI ATTM WITH THE MID LVL MOISTURE EXITING THE AREA. THE ARCTIC FRONT LOOKS TO BE FRI NGT SETTING THE STAGE FOR A FRIGID WEEKEND. PERHAPS SOME FLURRIES OR SNOW SHWRS SAT...THEN DRY ON SUN WITH A 1040S HI BUILDING IN FROM THE W. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... HIGH PRESSURE WEAKENS OVER THE AREA TODAY. MEANWHILE...LOW PRESSURE OFF THE SOUTHEAST COAST WILL TRACK TO THE NORTHEAST...PASSING SOUTHEAST OF LONG ISLAND ON MONDAY. VFR THROUGH 06Z OR SO. THEN MVFR TO IFR CONDITIONS LIKELY TO DEVELOP IN LIGHT SNOW FOR FOR NYC METRO AND EASTERN TERMINALS LATE TONIGHT INTO DAYBREAK MONDAY. MODERATE TO HIGH POTENTIAL FOR LIFR CONDITIONS ACROSS KISP AND KGON AFTER 12Z AND THROUGH 18 TO 20Z IN MODERATE TO HEAVY SNOW BANDING. LOW POTENTIAL FOR LIFR ACROSS NYC TERMINALS AND KBDR...AND ONLY SLIGHT POTENTIAL TO THE NW. NE/N WINDS OF AROUND 20 KT WITH GUSTS TO 30 KT DEVELOPING AFTER 06Z AND CONTINUING THROUGH 18 TO 20Z ACROSS NYC AND EASTERN TERMINALS...LOWER TO FOR INTERIOR TERMINALS. PEAK GUSTS TO 35 KT POSSIBLE ACROSS COASTAL TERMINALS...PARTICULARLY KISP/KGON. LIKELY SNOWFALL ACCUMULATIONS OF: LESS THAN 1 INCH FOR KSWF 1 TO 3 INCHES ACROSS KHPN/KEWR/KTEB 2 TO 4 INCHES FOR KLGA/KJFK/KBDR 4 TO 8 INCHES FOR KISP/KGON .OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY... .MON AFT...IFR OR LOWER LIKELY EAST/POSSIBLE WEST IN SNOW. NE-N WINDS G20-30KT WEST AND 30-35KT EAST POSSIBLE. .MON NIGHT-TUE NIGHT...MVFR OR LOWER LIKELY IN SNOW. N-NE WINDS G15-25KT POSSIBLE MON NIGHT-TUE. .WED-THU...SUB-VFR POSSIBLE IN -SN. W-NW WINDS G20-25KT POSSIBLE WED NIGHT-THU. .FRI...MAINLY VFR...BUT POTENTIAL FOR SCATTERED MVFR CONDS IN STRATO- CU AND FLURRIES. && .MARINE... HIGH PRES OVER THE WATERS DEPARTS THIS EVENING. LOW PRES OFF THE SOUTHEAST U.S. COAST WILL TRACK TO THE E-NE AND PASS WELL SOUTH OF LONG ISLAND LATE TONIGHT THROUGH MONDAY. A TIGHT PRES GRADIENT SETS UP ON THE WATERS WITH GALE FORCE WINDS ON THE OCEAN...EASTERN LI SOUND...AND EASTERN LI BAYS AND SMALL CRAFT ADVISORY LEVEL WINDS ON NY HARBOR...WESTERN LI SOUND...AND THE SOUTH SHORE BAYS. A FEW GUSTS TO STORM FORCE ARE POSSIBLE ON EASTERN OCEAN WATERS...BUT CONFIDENCE NOT HIGH ENOUGH TO UPGRADE TO A WARNING. WINDS DIMINISH FAIRLY QUICKLY MONDAY EVENING AS LOW PRES DEPARTS. SEAS ON THE OCEAN WILL REMAIN HIGH...AS IT WILL TAKE SOME TIME FOR THE SEAS TO SETTLE. HEADLINES FOR THE GALE WARNINGS AND SMALL CRAFT ADVISORIES LARGELY UNCHANGED. SCA COND ON THE OCEAN TUE-SAT. PERIODS OF SCA LVL WINDS LIKELY IN THE TUE-SAT PERIOD ELSEWHERE. && .HYDROLOGY... LIQUID EQUIVALENT QPF WILL RANGE FROM LESS THAN A TENTH OF AN INCH WEST OF THE HUDSON RIVER TO ALMOST AN INCH OVER SE CT AND FAR EASTERN LONG ISLAND. THE PRECIP WILL FALL AS SNOW...SO NO HYDROLOGIC PROBLEMS ANTICIPATED. MEASURABLE PCPN IS THEN LIKELY THRU AT LEAST THE MIDDLE OF NEXT WEEK. AMTS APPEAR TO BE GENERALLY LGT ATTM AND ALL IN THE FORM OF SNOW. && .TIDES/COASTAL FLOODING... POTENTIAL FOR MINOR TO LOCALLY MODERATE COASTAL IMPACTS MONDAY INTO WEDNESDAY WITH A NEW MOON ON MONDAY AND A SERIES OF LOW PRESSURES AFFECTING THE REGION. AN INTENSE LOW PRESSURE TRACKING SE OF THE REGION MONDAY WILL RESULT IN NE/N WINDS INCREASING TO POTENTIALLY GALE FORCE TONIGHT AND CONTINUING INTO MONDAY. BASED ON A TRACK OF INTENSIFYING LOW THAT SHOULD BE SE OF THE 40/70 LAT/LON BENCHMARK AND COLD AIR DAMMING SIGNATURE...WOULD EXPECT WINDS TO BE BACKED MORE TO THE N THAN NE. THIS SHOULD FAVOR THE LOWER SURGE GUIDANCE FOR THE MONDAY MORNING AND NIGHT HIGH TIDE CYCLES...WHICH WILL KEEP FLOODING MINOR AND LIMITED TO THE TYPICALLY VULNERABLE LOCALES. ISOLATED MODERATE FLOODING POSSIBLE ALONG THE MOST VULNERABLE SHORE BAYS OF NASSAU COUNTY. DUE TO THE LOWER ASTRONOMICAL TIDES ON MONDAY NIGHT...WATER LEVELS SHOULD BE A BIT LOWER...WITH MINOR FLOODING MAINLY LIMITED TO THE SOUTH SHORE BAYS OF LI/NY AND ALONG THE NORTH SHORE OF LI ADJACENT TO WESTERN LI SOUND. AS WE HEAD INTO TUESDAYS HIGH TIDE CYCLES...WINDS SHOULD VEER MORE TO THE NE AS ADDITIONAL WAVE/S OF LOW PRESSURE TRACK TO THE SOUTH OF THE REGION. THE SPRING ASTRONOMICAL TIDES AND MULTI-TIDAL CYCLE NATURE OF THE EVENT WILL FAVOR ADDITIONAL MINOR FLOODING...WITH POTENTIAL FOR WIDESPREAD MINOR TO MODERATE FLOODING IN THE SOUTH SHORE BAY AREAS TUESDAY. SURGE SHOULD DECREASE HEADING INTO WEDNESDAYS HIGH TIDE CYCLE...BUT LINGERING MINOR COASTAL FLOODING IS STILL POSSIBLE...PARTICULARLY INT HE SOUTH SHORE BAYS AREAS. HIGH SURF OF 6 TO 10 FT WILL ONCE AGAIN PRESENT A MODERATE TO HIGH THREAT FOR AREAS OF DUNE TOE EROSION ALONG THE ATLANTIC OCEAN BEACHES...AND A LOCALIZED POTENTIAL FOR OVERWASHES ON FIRE ISLAND. THIS IS BASED ON MODELED IMPACTS OF GALE CENTER FROM THE USGS COASTAL CHANGE HAZARDS PORTAL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WARNING FROM 3 AM TO 6 PM EST MONDAY FOR CTZ007- 008-011-012. WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM EST MONDAY FOR CTZ005-006-009-010. NY...WINTER STORM WARNING FROM 3 AM TO 6 PM EST MONDAY FOR NYZ078>081. WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM EST MONDAY FOR NYZ070>075-176>179. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST MONDAY FOR ANZ335-338-345. GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EST MONDAY FOR ANZ330-340-350-353-355. && $$ SYNOPSIS...JMC/MPS NEAR TERM...MPS SHORT TERM...MPS LONG TERM...JMC AVIATION...NV MARINE...JMC/MPS HYDROLOGY...JMC/MPS TIDES/COASTAL FLOODING...NV

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