Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 110830 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 330 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. && .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 AIRMASS 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 SHTRWV 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. LOOKS LIKE ANY CHANCE OF SNOW DIRECTLY ASSOCIATED WITH THIS LOW LOOKS LOW...HOWEVER...WITH THE ARCTIC FRONT AND DECREASING STABILITY DUE TO CYCLONIC FLOW ALOFT...SCT SNOW SHOWERS EXPECTED. WILL CAP POPS AT CHC FOR NOW. AN ANOMALOUSLY COLD AIR MASS THEN POURS IN BEHIND THE COLD FRONT FOR THE WEEKEND. ANOTHER SHORTWAVE ARRIVES ALONGSIDE THE CORE OF COLD AIR ALOFT DURING SAT/SAT EVENING. THE ATMOSPHERIC COLUMN DRIES...HOWEVER THERE IS STILL AT LEAST A CHANCE OF FLURRIES DURING THIS PERIOD. AS FOR TEMPS SAT AND SAT NIGHT...THE CALENDAR DAY HIGH TEMP ON SATURDAY WILL PROBABLY OCCUR DURING THE PRE-DAWN HOURS AS STRONG COLD ADVECTION DROPS TEMPS THROUGHOUT THE DAY. BY NOON...TEMPS ARE PROBABLY IN THE TEENS AREA-WIDE WITH WIND CHILL VALUES BELOW ZERO. RECORD TO NEAR-RECORD COLD TEMPS FOR SAT NIGHT IN SPITE OF GUSTY NW FLOW. BOTH GFS AND ECMWF SHOW 850MB TEMPS DROPPING TO -29C TO -30C DURING THE NIGHT BEFORE RISING A FEW DEGREES TOWARD DAYBREAK. BASED ON TEMPS THAT OCCURRED DURING A SIMILAR SYNOPTIC SETUP LAST FEBRUARY WITH WARMER TEMPS ALOFT...WENT SLIGHTLY BELOW THE LOW TEMPS THAT HAD OCCURRED...WHICH ARE CLOSE TO WHAT ECMWF MOS HAS BEEN SHOWING FOR THE PAST FEW RUNS. SEE THE CLIMATE SECTION BELOW FOR MORE DETAILS. THE COLD AIR COMBINED WITH WINDS WOULD PRODUCE WIND CHILLS THAT WOULD WARRANT AN ADVISORY DURING SAT NIGHT INTO SUNDAY MORNING...POSSIBLY EVEN A WARNING FOR SOME OF THE NORTHERN SUBURBS. REMAINING COLD BUT DRY ON SUNDAY AS HIGH PRESSURE BUILDS IN WITH HIGHS ONLY IN THE TEENS. MODELS THEN IN DISAGREEMENT WITH THE TIMING OF THE NEXT SYSTEM TO POTENTIALLY AFFECT THE REGION. HIGH PRESSURE SHIFTS OFFSHORE ON MONDAY WITH THE LIKELIHOOD THAT THE DAYTIME HOURS REMAIN DRY. A LONGWAVE TROUGH THEN SHIFTS THROUGH THE EASTERN HALF OF THE U.S. WITH ITS AXIS PROGGED TO MOVE THROUGH DURING TUESDAY 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 PCPN TYPE. HAVE CAPPED POPS AT 50 PERCENT FOR THE REST OF THE LONG TERM FORECAST FOR THE TIME BEING AND WENT WITH A GENERAL RAIN...SNOW OR MIX OF THE TWO AS PCPN TYPE. && .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. && .HYDROLOGY... LIQUID EQUIVALENT OF LESS THAN A TENTH OF AN INCH IS EXPECTED THRU FRI. && .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) / 19 LGA...........1 (1979) / 2.............15 (1979) / 19 JFK...........4 (1979) / 2.............17 (1979) / 19 ISP...........7 (2015) / 1.............26 (1987) / 18 EWR...........0 (1979) / 0.............15 (1979) / 19 BDR...........3 (2015*) / 0.............18 (1979) / 17 *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 NEAR TERM...JMC SHORT TERM...JMC LONG TERM...JC AVIATION...BC MARINE...JMC HYDROLOGY...JMC CLIMATE...

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