Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 122108 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 408 PM EST FRI FEB 12 2016 .SYNOPSIS... AN ARCTIC COLD FRONT APPROACHES FROM THE NORTHWEST THIS EVENING...THEN CROSSES THE TRI-STATE LATE LATE TONIGHT AND SATURDAY MORNING...AS A COASTAL LOW TRACKS WELL TO THE SOUTHEAST. ARCTIC HIGH PRESSURE THEN BUILDS IN THROUGH SUNDAY NIGHT BEFORE SLIDING OFFSHORE ON MONDAY. A LOW PRESSURE SYSTEM DEVELOPS ACROSS THE SOUTHEAST MONDAY NIGHT AND TRACKS UP THE EASTERN SEABOARD TUESDAY INTO TUESDAY NIGHT. A COLD FRONT MOVES THROUGH WEDNESDAY FOLLOWED BY HIGH PRESSURE FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MOST GUIDANCE SUGGESTS THAT AS THE 700-500 HPA TROUGH AXIS APPROACHES TONIGHT...IT SHOULD BE ABLE TO PULL ENOUGH MOISTURE NW FROM THE COASTAL LOW WELL OFFSHORE TO BRING THE CHANCE OF SOME LIGHT SNOW TO THE REGION TONIGHT...WITH LIGHT SNOW LIKELY OVER THE S FORK OF LONG ISLAND. THERE IS ALSO A LOW CHANCE FOR SNOW SQUALLS RIGHT AHEAD OF THE ARCTIC FRONT. EXPECT GENERALLY A DUSTING TO LESS THAN 1 INCH OF SNOW AT MOST LOCATIONS...THOUGH THE SOUTH FORK COULD SEE AN INCH MAYBE TWO. THE MAIN THREAT FROM ANY SNOW SQUALL WOULD BE A RAPID REDUCTION IN VISIBILITY AND GUSTY WINDS WITH ITS PASSAGE. AFTER A RELATIVELY TRANQUIL EVENING...WIND INCREASE AHEAD OF THEN...BEHIND THE ARCTIC FRONT. LOWS WILL OCCUR VERY LATE TONIGHT/EARLY SUNDAY MORNING...BEHIND/WITH THE ARCTIC FRONT. BLENDED NAM 2-M TEMPERATURES WITH MET/ECS/MAV GUIDANCE FOR LOWS. VALUES SHOULD BE AROUND 10-15 DEGREES BELOW NORMAL. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... ARCTIC AIR POURS IN TO THE REGION SATURDAY/SATURDAY NIGHT...WITH 850 TEMPERATURES PLUNGING TO 25-30 BELOW LATE SATURDAY NIGHT (DEPENDING ON MODEL OF CHOICE). EXPECT HIGHS TO OCCUR SATURDAY MORNING...MAINLY IN THE 10S...THEN TEMPERATURES SLOWLY FALL DURING THE DAY. WILL SEE A MORE RAPID DROP OFF SATURDAY EVENING WITH LOSS OF SOLAR HEATING AND STRONGEST LOW LEVEL COLD ADVECTION. WINDS INCREASE OUT OF THE NW 15-30 MPH WITH GUSTS TO 35-45 MPH BY MID SATURDAY MORNING...AND REMAIN ABOUT THAT STRONG INTO SATURDAY EVENING. THIS IS JUST BELOW ADVISORY CRITERIA...CANNOT NOT RULE OUT A FEW GUSTS TO 40KT/SUSTAINED WINDS OF 27KT. REGARDLESS...WIND ISSUES WILL BE ADDRESSED IN THE WSW PRODUCT. WINDS DO DIMINISH LATE SATURDAY NIGHT TO 10-25 MPH WITH GUSTS OF 30-40 MPH. LOWS SATURDAY NIGHT GENERALLY FROM NEAR 0 ACROSS LONG ISLAND/NYC METRO TO 5-10 BELOW ACROSS NORTHERN INTERIOR ZONES. LOWS BASED ON BLEND OF NAM/GFS/ECMWF 2-METER TEMPERATURES AND MOS GUIDANCE - WEIGHED TOWARDS COLDER NAM VALUES...NOTING GENERALLY UNDER FORECAST OF EXTREME COLD BY MOST GUIDANCE. AS FOR WIND CHILLS...SHOULD FALL BELOW ZERO SATURDAY MORNING...TO AROUND 10-15 BELOW BY SATURDAY EVENING...THEN TO ADVISORY (15-24 BELOW)/WARNING (25-30 BELOW) LEVELS LATE SATURDAY NIGHT INTO SUNDAY MORNING. DID CONVERT MOST OF THE WIND CHILL WATCH TO AN ADVISORY...WITH THE EXCEPTION OF S NEW LONDON WHERE 25 BELOW WIND CHILLS WERE MOST LIKELY. SUNDAY SHOULD BE DRY WITH NW FLOW ALOFT. HIGHS SHOULD BE AROUND 25 DEGREES BELOW NORMAL...CONSISTENT WITH A BLEND OF MAV/MET/ECS GUIDANCE...NAM/ECMWF 2-METER TEMPERATURES...AND A MIX DOWN FROM 925 HPA PER BUFKIT SOUNDINGS. WITH DIMINISHING WINDS...WIND CHILLS IN THE AFTERNOON SHOULD RANGE FROM 5 BELOW TO 5 ABOVE ZERO. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... SUNDAY NIGHT...BRUNT OF THE ARCTIC MASS WILL HAVE MODIFIED BY SUNDAY NIGHT AS 850 HPA TEMPS WARM TO AROUND -10C. HOWEVER...THE SURFACE HIGH SETTLES RIGHT OVER THE TRI-STATE WHICH WILL ALLOW FOR GOOD RADIATIONAL COOLING CONDITIONS AS WINDS WILL BE LIGHT. THE ONLY POTENTIAL DRAWBACK IS FROM SOME HIGH CLOUDS WHICH MAY BEGIN TO STREAM OVERHEAD AS A 500 HPA SHORTWAVE LIFTS ACROSS THE GREAT LAKES REGION. LOW TEMPERATURES WILL RANGE FROM THE LOW SINGLE DIGITS INLAND TO THE UPPER SINGLE DIGITS AND LOWER TEENS CLOSER TO THE COAST. WIND CHILLS WILL BE CLOSE TO ACTUAL AIR TEMPERATURE WITH LIGHT WINDS. MONDAY THROUGH TUESDAY...HIGH PRESSURE WILL MOVE OFFSHORE ON MONDAY ALLOWING FOR A RETURN FLOW TO SET UP WITH LOW LEVEL WARM ADVECTION COMMENCING DURING THE DAY. ALOFT...AMPLIFYING RIDGING ON ACROSS WESTERN NORTH AMERICA SENDS SEVERAL PIECES OF ENERGY INTO A DIGGING TROUGH ACROSS THE CENTRAL STATES. THIS IS WHERE UNCERTAINTY IN THE FORECAST GREATLY INCREASES AND MODELS DIVERGE IN THE HANDLING OF THIS ENERGY. THIS IS NOT SURPRISING AS THIS ENERGY IS EMANATING FROM THE NORTH PACIFIC. IT WILL NOT BE UNTIL SUNDAY MORNING THAT THIS ENERGY MOVES OVER LAND WITH BETTER SAMPLING. LOW PRESSURE WILL DEVELOP ACROSS THE SOUTHEAST LATE MONDAY INTO MONDAY NIGHT AS THIS ENERGY AMPLIFIES THE MIDDLE AND UPPER LEVEL TROUGH. WARM ADVECTION AND INCREASING MOISTURE AHEAD OF THIS LOW SHOULD ALLOW FOR PRECIPITATION TO BREAK OUT MONDAY AFTERNOON AND EVENING...WITH THERMAL PROFILES MAINLY SUPPORTING SNOW. IT IS AFTER THIS TIME THAT UNCERTAINTY GREATLY INCREASES AS THE LOW INTENSIFIES AND TRACKS ALONG THE COAST OR JUST INLAND TUESDAY. DETERMINISTIC AND ENSEMBLE MODELS SHOW QUITE A LARGE SPREAD WITH THE TRACK AND INTENSITY OF THIS LOW PRESSURE MONDAY NIGHT INTO TUESDAY. THIS WILL ULTIMATELY DETERMINE EXACT THERMAL PROFILES AND HOW MUCH PRECIPITATION WE END UP SEEING ACROSS THE AREA. THE SIGNALS ARE THERE FOR A RAPIDLY INTENSIFYING LOW TO MOVE FROM THE MIDDLE ATLANTIC REGION TUESDAY MORNING TO NORTHERN NEW ENGLAND AND SE CANADA BY TUESDAY NIGHT. THE 12Z GFS TAKES THE LOW ACROSS LONG ISLAND AND CONNECTICUT WHILE ITS ENSEMBLE MEAN IS A LITTLE FURTHER WEST...MOVING IT ACROSS NEW YORK CITY AND UP THE LOWER HUDSON VALLEY. THE 12Z ECMWF APPEARS TO BE ON THE WESTERN EDGE OF THE GUIDANCE WITH THE LOW TRACKING ACROSS CENTRAL PA. THIS WOULD PUT THE ENTIRE AREA IN THE WARM SECTOR. THE 12Z ECMWF IS ALSO ONE OF THE MOST AMPLIFIED OF THE GUIDANCE AS IT SHOWS THE ENERGY AT 500 HPA CUTTING OFF...WHICH THE OTHER MODELS DO NOT INDICATE AS THE SYSTEM IS QUITE PROGRESSIVE. THE 12Z CMC IS FURTHER EAST AND FASTER...WITH THE LOW MOVING ACROSS EASTERN LONG ISLAND/SE CT. THERE IS ALSO LARGE SPREAD IN THE ENSEMBLES SHOWING VARIETY OF THESE SOLUTIONS MENTIONED ABOVE. HAVE FOLLOWED A CONSENSUS FORECAST DUE TO THIS UNCERTAINTY. HAVE ALSO CONTINUED WITH LIKELY POPS FOR THIS TIME PERIOD. THIS BRINGS SNOW CHANGING TO RAIN AT THE COAST MONDAY NIGHT...WITH A WINTRY MIX CHANGING TO RAIN INLAND LATE MONDAY NIGHT INTO TUESDAY. TEMPERATURES MAY TAKE A LITTLE LONGER TO WARM ABOVE FREEZING INLAND...SO A PERIOD OF FREEZING RAIN IS POSSIBLE MONDAY NIGHT...BEFORE CHANGING TO RAIN TUESDAY MORNING. RAIN...POSSIBLY HEAVY AT TIMES...IS EXPECTED ON TUESDAY WITH TEMPERATURES WELL INTO THE 40S. TIMING AND AMOUNTS REMAIN UNCERTAIN AT THIS TIME...BUT A GENERAL RANGE OF 1 TO 3 INCHES OF TOTAL QPF IS FORECAST IN THE CONSENSUS OF THE MODELS. SEE HYDRO SECTION FOR MORE INFORMATION. IT COULD ALSO BECOME QUITE BREEZY TUESDAY...BUT THIS AGAIN WILL ULTIMATELY BE DETERMINED BY THE EXACT TRACK AND INTENSITY AS THE LOW MOVES ACROSS THE AREA. MUCH OF THE PRECIPITATION SHOULD END TUESDAY NIGHT AS THE LOW MOVES WELL NE OF THE AREA. WEDNESDAY THROUGH THE END OF THE WEEK....A TRAILING SHORTWAVE MAY SWING THROUGH ON WEDNESDAY...SO HAVE LEFT POPS IN THE LOW CHANCE RANGE. A COLD FRONT ALSO MOVES THROUGH ON WEDNESDAY. TEMPERATURES WILL BE NEAR NORMAL IN THE LOWER 40S. TEMPERATURES SHOULD FALL BACK BELOW NORMAL LEVELS THURSDAY AS HIGH PRESSURE BUILDS OVER THE REGION. THE HIGH IS CURRENTLY PROGGED TO MOVE OFFSHORE FRIDAY AS ANOTHER FRONTAL SYSTEM APPROACHES. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... WEAK HIGH PRESSURE INTO THIS EVENING. A COLD FRONT MOVES THROUGH LATE TONIGHT. VFR INTO THIS EVENING. SW WINDS AROUND 10KT. OUTLOOK FOR THIS OVERNIGHT...SCT SHSN COULD POTENTIALLY LEAVE A COATING OF SNOW ON THE RUNWAYS. ...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: NO UNSCHEDULED AMENDMENTS EXPECTED. KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KEWR FCSTER COMMENTS: OCCASIONAL GUSTS AROUND 15KT POSSIBLE UNTIL 22- 23Z. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. .OUTLOOK FOR 18Z SAT THROUGH WEDNESDAY... .SAT...VFR. NW GUSTS AROUND 35KT. .SUN...VFR. NW GUSTS 20-25KT IN THE MORNING. .MON...VFR AM. CHANCE AFTERNOON SNOW WITH SUB-VFR. .MON NIGHT...IFR CONDITIONS LIKELY. SNOW CHANGING TO RAIN BY LATE EVENING NYC METROS/KISP...AND AROUND/SHORTLY AFTER MIDNIGHT KHPN/KBDR/KGON...AND COLD GROUND COULD MAKE FOR A BRIEF PERIOD OF FREEZING RAIN ON RUNWAYS DESPITE AIR TEMPS RISING ABOVE FREEZING. SNOW MIXING WITH OR CHANGING TO FREEZING RAIN AFTER MIDNIGHT AT KSWF. SE GUSTS AROUND 25KT LATE. .TUE...RAIN LIKELY WITH IFR CONDITIONS. SE-S WINDS G30-35KT AND LLWS. .WED...MOSTLY VFR. CHANCE RAIN/SNOW SHOWER AND BRIEF SUB-VFR. && .MARINE... SUB-SCA CONDITIONS ON MOST WATERS THIS EVENING...THEN SCA CONDITIONS DEVELOP ON THE COASTAL OCEAN WATERS OVERNIGHT...SO HAVE ISSUED AN SCA THERE. THERE ALSO COULD POSSIBLY BE SCA GUSTS LATE ON THE E SOUND/BAYS OF LONG ISLAND...BUT CONFIDENCE IN THIS IS NOT HIGH ENOUGH FOR A HEADLINE AT THIS TIME. GALE CONDITIONS DEVELOP RAPIDLY SATURDAY AND LAST THROUGH SATURDAY NIGHT ON ALL WATERS. GALES WILL LINGER INTO SUNDAY MORNING OVER THE COASTAL OCEAN WATERS AND EASTERN SOUND/BAYS. AS A RESULT HAVE CONVERTED THE EXISTING GALE WATCH TO A GALE WARNING FOR THE NON-OCEAN WATERS...AND SYNCHED UP WITH EXISTING ONE ON THE OCEAN TO COVER SATURDAY/SATURDAY NIGHT. THE GALE WARNING WAS EXTENDED FOR THE COASTAL OCEAN WATERS AND EASTERN SOUND/BAYS THROUGH SUNDAY MORNING. A SCA WILL BE NEEDED ONCE GALE CONDITIONS HAVE ENDED ON ALL WATERS FOR A PERIOD OF TIME ON SUNDAY. THE COMBINATION OF GALES AND COLD TEMPERATURES WILL PRODUCE AT LEAST MODERATE FREEZING SPRAY ON ALL BUT THE SOUTH SHORE BAYS (FORECAST WAVES ARE TOO LOW FOR SIGNIFICANT SPRAY THERE) SATURDAY INTO SUNDAY...WITH HEAVY FREEZING SPRAY FORECAST SATURDAY NIGHT ON THE SOUND/NY HARBOR/E BAYS...AND INTO SUNDAY MORNING FOR THE EASTERN SOUND/BAYS. SUB-SCA CONDITIONS FORECAST SUNDAY NIGHT THROUGH MONDAY AS HIGH PRESSURE MOVES OVER THE WATERS. THEN...DEVELOPING LOW PRESSURE ACROSS THE SE TRACKS UP THE EASTERN SEABOARD MONDAY NIGHT INTO TUESDAY. THIS WILL INCREASE SEAS WELL ABOVE SCA LEVELS ON TUESDAY AND BRING THE LIKELIHOOD OF SCA WINDS ACROSS ALL WATERS. THERE IS ALSO A CHANCE FOR GALE FORCE GUSTS...AT LEAST ON THE OCEAN...ON TUESDAY. THE LOW MOVES WELL NE OF THE WATERS TUESDAY NIGHT INTO WEDNESDAY WITH...BUT CONDITIONS SHOULD AT LEAST REMAIN ABOVE SCA LEVELS THROUGH WEDNESDAY. && .HYDROLOGY... LESS THAN A TENTH OF AN INCH OF LIQUID EQUIVALENT QPF IS FORECAST THROUGH SATURDAY. IT SHOULD BE DRY SATURDAY NIGHT AND SUNDAY. A DEVELOPING LOW PRESSURE SYSTEM MOVING NEAR OR ALONG THE COAST MONDAY NIGHT INTO TUESDAY HAD THE POTENTIAL TO PRODUCE 1 TO 3 INCHES OF LIQUID EQUIVALENT PRECIPITATION. SOME OF THIS WILL FALL AS FROZEN PRECIPITATION MONDAY NIGHT...BUT THEN RUNOFF VIA MELTING SNOW AND HEAVY RAIN TUESDAY COULD CAUSE AT LEAST URBAN AND SMALL STREAM FLOODING PROBLEMS. IT IS TOO EARLY TO SAY IF MAIN STEM RIVERS WOULD BE AFFECTED DUE TO UNCERTAINTY IN WHERE THE HEAVIEST RAINFALL WILL OCCUR AS WELL AS THE EXACT TRACK AND INTENSITY OF THE LOW PRESSURE. && .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/FORECAST MINIMUM FOR 2/14 CENTRAL PARK.....2 (1916) / 0 LAGUARDIA........1 (1979) / 1 JF KENNEDY.......4 (1979) / 2 ISLIP............7 (2015) / 1 NEWARK...........0 (1979) / 0 BRIDGEPORT.......3 (2015*) / -1 STATION......RECORD LOW MAXIMUM/FORECAST HIGH FOR 2/14 CENTRAL PARK....17 (1979) / 14 LAGUARDIA.......15 (1979) / 15 JF KENNEDY......17 (1979) / 16 ISLIP...........26 (1987) / 14 NEWARK..........15 (1979) / 14 BRIDGEPORT......18 (1979) / 14 *IN 1979 AS WELL && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WIND CHILL ADVISORY FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR CTZ009>011. WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR CTZ005>008-012. NY...WIND CHILL ADVISORY FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NYZ071>075-078>081-176>179. WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NYZ067>070. NJ...WIND CHILL ADVISORY FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NJZ004-006-103>108. WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NJZ002. MARINE...GALE WARNING FROM 6 AM SATURDAY TO NOON EST SUNDAY FOR ANZ330- 340-345-350-353-355. HEAVY FREEZING SPRAY WARNING FROM 6 PM SATURDAY TO NOON EST SUNDAY FOR ANZ330-335-340. FREEZING SPRAY ADVISORY FROM 4 AM TO 6 PM EST SATURDAY FOR ANZ330-335-338-340. HEAVY FREEZING SPRAY WARNING FROM 6 PM SATURDAY TO 6 AM EST SUNDAY FOR ANZ338. GALE WARNING FROM 6 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ335- 338. SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 AM EST SATURDAY FOR ANZ350-353-355. FREEZING SPRAY ADVISORY FROM 4 AM SATURDAY TO 6 PM EST SUNDAY FOR ANZ350-353-355. && $$ SYNOPSIS...MALOIT/DS NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...DS AVIATION...JC MARINE...MALOIT/DS HYDROLOGY...MALOIT/DS CLIMATE...

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