Area Forecast Discussion
Issued by NWS Upton, NY

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885 FXUS61 KOKX 111002 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 502 AM EST THU FEB 11 2016 .SYNOPSIS... AN UPR LVL SYS WILL PASS THRU THE REGION TODAY. HIGH PRES WILL DRIFT ACROSS THE AREA ON FRI. AN ARCTIC COLD FRONT WILL APPROACH FRI NIGHT...AND PASS THROUGH LATE FRI NIGHT INTO SAT MORNING WHILE LOW PRES PASSES SE OF LONG ISLAND. STRONG HIGH PRES WILL THEN BUILD FROM THE W LATER SAT INTO SUNDAY NIGHT...THEN PASS E ON MON. A WARM FRONT WILL APPROACH MON AFTERNOON AND NIGHT...THEN LOW PRES WILL MOVE UP THE COASTAL PLAIN TUE INTO TUE NIGHT...AND PASS TO THE NE ON WED. && .NEAR TERM /THROUGH TONIGHT/... SNOW SHWRS TRACKING THRU THE CWA THIS MRNG PUTTING DOWN A COATING OF SNOW AND BRIEFLY REDUCING VIS TO A HALF MILE. THIS IS WITH A SHRTWV EMBEDDED IN THE FLOW. ANOTHER SHRTWV IS PROGGED TO COME THRU TODAY. THIS WILL WORK ON AN INCREASINGLY UNSTABLE AIR MASS WITH NEARLY DRY ADIABATIC LAPSE RATES IN THE H925-H5 LAYER. NAM EVEN SUGGESTS SBCAPE OVER 100 J/KG. WITH THIS SETUP EXPECT SNOW SHWRS AND SQUALLS TO DEVELOP BY THIS AFTN. INCREASING MID LVL WINDS WILL ALSO ALLOW FOR GUSTS IN THE 30S MPH. BRIEF PERIODS OF VERY HAZARDOUS TRAVEL POSSIBLE IN SNOW AND WIND. ALTHOUGH THIS FALLS BELOW ANY WRNG/ADVY CRITERIA...WILL INCLUDE THE THREAT IN THE HWO. LAPSE RATES EASE TNGT WITH SUBSIDENCE IN THE WAKE OF THE SHRTWV AND ANY DEPARTING CONVECTION. AS A RESULT WILL DRY THINGS OUT QUICKLY THIS EVE WITH CLEARING SKIES OVERNIGHT. && .SHORT TERM /FRIDAY/... FAIR WEATHER TO START WITH A SFC HI PRES RIDGE OVER THE AREA...THEN THE RIDGE IS WEAKENED BY LOW PRES PASSING OFFSHORE AND AN APPROACHING ARCTIC FRONT. THE DATA SEEMS TO BE TRENDING FASTER WITH APPROACHING UPR TROF AND CDFNT...SO WENT CLOSE TO THE 3Z SREF FOR TIMING ACROSS WRN ZONES. THE GFS PRODUCES SOME LGT SNOW ACROSS ERN AREAS ON THE PERIPHERY OF THE LOW. BUMPED UP THE DRY POPS IN THE SREF ACROSS ERN ZONES TOO SLGT CHC FOR THIS. ANY WWD TREND COULD BRING A DUSTING BY DARK ERN CT AND LI. A BLEND OF GUIDANCE WAS USED FOR TEMPS WITH READINGS OVER 10F BLW AVG. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... AN ARCTIC COLD FRONT APPROACHES FRIDAY NIGHT ALONG WITH A SHORTWAVE FROM THE NORTH. AT THE SAME TIME...SHORTWAVE ENERGY MOVES OFF THE MID ATLANTIC COAST. THE COMBINED ENERGY SHOULD INITIATE SFC CYCLOGENESIS ALONG A BAROCLINIC ZONE TO OUR SOUTH WITH THE LOW PASSING WELL SE OF THE 40N/70W BENCHMARK LATE AT NIGHT. CHANCE OF SNOW DIRECTLY ASSOCIATED WITH THIS LOW LOOKS HIGH ENOUGH TO RAISE POP TO LIKELY FOR ERN LONG ISLAND...WITH CHANCE POP ACROSS MOST OF SRN CT AND LONG ISLAND...WITH ONLY MINOR ACCUMS EXPECTED AS STRONGEST FORCING WITH THE LOW REMAINS WELL OFFSHORE. ELSEWHERE COULD SEE ISOLD-SCT SNOW SHOWERS WITH THE APPROACHING ARCTIC FRONT VIA DECREASING STABILITY AND CYCLONIC FLOW ALOFT. AN ANOMALOUSLY COLD AIR MASS THEN POURS IN BEHIND THE COLD FRONT FOR THE WEEKEND...WITH WINDS LIKELY APPROACHING ADVY CRITERIA IN NYC METRO...LONG ISLAND AND PERHAPS THE HIGHER ELEVATIONS INLAND. ANOTHER SHORTWAVE ARRIVES ALONGSIDE THE CORE OF COLD AIR ALOFT DURING SAT/SAT EVENING. THE ATMOSPHERIC COLUMN DRIES...HOWEVER THERE MAY STILL BE A CHANCE OF FLURRIES DURING THIS PERIOD. AS FOR TEMPS SAT AND SAT NIGHT...THE CALENDAR DAY HIGH TEMP ON SAT WILL PROBABLY OCCUR AT MIDNIGHT AS TEMPS COOL OFF OVERNIGHT AND THEN STAY DOWN THROUGH THE DAY VIA STRONG CAA. TEMPS MAY RECOVER A LITTLE ON SAT TO THE UPPER TEENS AND LOWER 20S...BUT STRONG NW WINDS DURING THIS TIME SHOULD KEEP WIND CHILLS AT OR BELOW ZERO THROUGH THE DAY. MODELS CONTINUE TO SHOW 850MB TEMPS DROPPING TO -30C DURING THE NIGHT BEFORE RISING A FEW DEGREES TOWARD DAYBREAK. BASED ON A SIMILAR SYNOPTIC SETUP LAST FEB WITH WARMER TEMPS ALOFT...WENT NEAR OR SLIGHTLY BELOW THE LOW TEMPS FCST BY ECMWF MOS...WITH LOWS CLOSE TO ZERO IN NYC AND ZERO TO 5 BELOW ELSEWHERE. THE COLD AIR COMBINED WITH WINDS WOULD PRODUCE WIND CHILLS THAT WOULD WARRANT AN ADVISORY DURING SAT NIGHT INTO SUNDAY MORNING...AND A WARNING FOR THE NORTHERN SUBURBS AND LONG ISLAND. REMAINING COLD BUT DRY SUNDAY/SUNDAY NIGHT AS HIGH PRESSURE BUILDS IN...WITH HIGHS ONLY IN THE TEENS...AND LOWS IN THE TEENS NYC METRO AND SINGLE DIGITS ELSEWHERE. MODELS THEN IN DISAGREEMENT WITH THE TIMING OF THE NEXT SYSTEM TO POTENTIALLY AFFECT THE REGION. HIGH PRESSURE SHIFTS OFFSHORE ON MON...WITH POSSIBILITY OF OVERRUNNING LIGHT SNOWFALL REACHING PARTS OF THE AREA BY LATE DAY. A LONGWAVE TROUGH THEN SHIFTS THROUGH THE EASTERN STATES...WITH ITS AXIS PROGGED TO MOVE THROUGH LATE TUE NIGHT. THIS THEN HELPS STRENGTHEN A SURFACE LOW MOVING UP THE VICINITY OF THE EASTERN SEABOARD. LOW CONFIDENCE IN THE EVOLUTION...TRACK AND TIMING OF THIS SYSTEM...AND CONSEQUENTLY PRECIP TYPE LATE MON NIGHT INTO TUE MORNING. WITH A LEADING WARM FRONT APPROACHING LATE MON NIGHT AND TEMPS WARMING ALOFT...THINK SNOW WILL TRANSITION TO MIXED PRECIP LATE MON NIGHT AND THEN RAIN DURING TUE MORNING. AFTER THAT...HEAVY RAIN LOOKS LIKE A GOOD BET TUE INTO TUE NIGHT AHEAD OF THE LOW. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... MAINLY VFR ACROSS THE TERMINALS. A WEAK TROUGH PASSING THROUGH THE REGION EARLY THIS MORNING HAS SET OFF SOME SNOW SHOWERS ACROSS THE REGION. EXPECT MVFR CONDITIONS IN ANY SNOW SHOWERS. THE PRESSURE GRADIENT TIGHTENS WITH WINDS/GUSTS INCREASING THROUGH 12Z...AND STRENGTHEN FURTHER BETWEEN 12Z AND 18Z. 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: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. KLGA FCSTER COMMENTS: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. KEWR FCSTER COMMENTS: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. KHPN FCSTER COMMENTS: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. KISP FCSTER COMMENTS: BRIEF PERIOD OF MVFR CONDITIONS POSSIBLE IN SNOW SHOWERS THROUGH 12Z. OCCASIONAL WIND GUSTS MAY BE SLIGHTLY HIGHER THAN FORECAST THIS AFTERNOON. .OUTLOOK FOR 06Z THURSDAY THROUGH MONDAY... .THURSDAY NIGHT...VFR. DIMINISHING NW WINDS. .FRIDAY...VFR. .SATURDAY...SUB-VFR POSSIBLE IN BRIEF -SHSN. NW WINDS AROUND 20 KT WITH GUSTS UP TO 30 KT. .SUNDAY-MONDAY...VFR. && .MARINE... WINDS WILL INCREASE OUT OF THE W TODAY WITH GALE COND EXPECTED. THE WRNG WAS THEREFORE EXPANDED TO ALL OF THE WATERS. THE WRNG REMAINS UP THRU TNGT...THEN WINDS DECREASE THRU THE DAY ON FRI. WINDS THEN INCREASE TO SCA LEVELS LATE FRI NIGHT AS LOW PRESSURE PASSES TO THE SE...AND GALES ARE LIKELY SAT INTO SAT NIGHT ON ALL WATERS AFTER AN ARCTIC COLD FRONTAL PASSAGE...CONTINUING INTO SUNDAY MORNING ON THE OCEAN. THE GALES COMBINED WITH SST IN THE LOWER 40S AND AIR TEMPS IN THE 20S ON SAT...SINGLE DIGITS SAT NIGHT AND TEENS ON SUNDAY WILL LEAD TO FREEZING SPRAY PROBLEMS... WITH MODERATE TO HEAVY ACCRETION POSSIBLE ESPECIALLY SAT NIGHT INTO SUNDAY MORNING. QUIET CONDS EVENTUALLY RETURN SUNDAY AFTERNOON/NIGHT AS HIGH PRESSURE BUILDS IN. && .HYDROLOGY... LIQUID EQUIVALENT OF LESS THAN A TENTH OF AN INCH IS EXPECTED THRU FRI...AND 1/10 INCH OR LESS FRI NIGHT INTO SAT MORNING. LOW PRESSURE MOVING UP THE COAST HAS POTENTIAL TO PRODUCE LIQUID EQUIVALENT QPF AT LEAST 1 TO 2 INCHES. PART OF THIS WILL FALL AS SNOW INITIALLY...BUT THEN RUNOFF VIA MELTING SNOW AND HEAVY RAIN TUE INTO TUE NIGHT COULD CAUSE AT LEAST URBAN AND SMALL STREAM FLOODING PROBLEMS. IT IS TOO EARLY TO SAY IF MAIN STEM RIVERS WOULD BE AFFECTED. && .CLIMATE... WITH THE EXTREMELY COLD AIR MASS FORECAST SATURDAY INTO SUNDAY...RECORD MINIMUMS AND RECORD LOW MAXIMUMS MAY BE REACHED. HERE ARE THE RECORDS AND FORECASTS... STATION......RECORD/FCST MINIMUM...RECORD LOW MAXIMUM/FCST HIGH FOR 2/14 FOR 2/14 NYC...........2 (1916) / 1.............17 (1979) / 17 LGA...........1 (1979) / 4.............15 (1979) / 18 JFK...........4 (1979) / 2.............17 (1979) / 19 ISP...........7 (2015) / -3.............26 (1987) / 15 EWR...........0 (1979) / 0.............15 (1979) / 18 BDR...........3 (2015*) / -3.............18 (1979) / 15 *IN 1979 AS WELL && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...GALE WARNING UNTIL 6 AM EST FRIDAY FOR ANZ330-335-338-340-345- 350-353-355. && $$ SYNOPSIS...JMC/GOODMAN NEAR TERM...JMC SHORT TERM...JMC LONG TERM...GOODMAN AVIATION...BC MARINE...JMC/GOODMAN HYDROLOGY...JMC/GOODMAN CLIMATE...

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