Area Forecast Discussion
Issued by NWS Upton, NY

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598 FXUS61 KOKX 131732 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1232 PM EST SAT FEB 13 2016 .SYNOPSIS... HIGH PRESSURE 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 /THROUGH TONIGHT/...
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TEMPS STILL IN THE TEENS ACROSS THE LOWER HUDSON VALLEY AND INTERIOR SW CT...AND LWR 20S ELSEWHERE. EXPECT TEMPERATURES TO CONTINUE TO FALL THRU THE AFTN TO 5-10 DEGREES ACROSS THE INTERIOR AND 10-15 ACROSS NYC METRO AND LONG ISLAND BY LATE AFTERNOON. POLAR LOW CONTINUES TO DESCEND INTO THE NORTHEAST THROUGH TONIGHT WITH A SHORT LIVED BUT DANGEROUS TO POTENTIALLY LIFE THREATENING ARCTIC INTRUSION TODAY INTO SUN. TEMPS SHOULD FALL INTO THE SINGLE DIGITS AND LOWER TEENS THIS AFTERNOON...WITH WIND CHILLS FALLING TO 5 TO 15 DEGREES BELOW ZERO. TEMPS DROP OF 6 TO 10 DEGREES IN 2 HOURS BEING NOTED ACROSS WESTERN NY EARLY THIS MORNING...INTO THE SINGLE DIGITS BELOW ZERO. HEART OF COLD ENTERS TONIGHT...WITH TEMPS LIKELY TO FALL TO AROUND ZERO FOR NYC/NJ METRO AND LONG ISLAND...AND 5 TO 10 BELOW ZERO ACROSS INTERIOR PORTIONS OF THE TRI-STATE LATE TONIGHT INTO EARLY SUN MORNING. COMBINED WITH MODERATELY STRONG WINDS...DANGEROUS TO POTENTIALLY LIFE THREATENING WIND CHILLS OF 20 TO 30 BELOW EXPECTED. WIND CHILL WARNINGS HAVE BEEN EXPANDED TO COASTAL AND SOUTHERN WESTCHESTER BASED ON EXPECTED TRAJECTORY OF COLD POOL. ADVISORIES CONTINUE ACROSS METRO NY/NJ AND COASTAL PLAIN WITH A BIT OF MODERATION IN TEMPS DUE TO URBANIZATION AND SURROUNDING BODIES OF WATER. WITH UPPER LOW APPROACHING IN THE AFT/EVE AND RESIDUAL LAKE STREAMER MOISTURE...SCT INSTABILITY CU AND ISO SNOW SHOWER/SCT FLURRY EXPECTED INTO EARLY EVENING. ACROSS TWIN FORKS OF LONG ISLAND...APPEARS SHOULD BE ENOUGH OF A FETCH OVER LONG ISLAND SOUND AND INSTABILITY FOR SCATTERED SNOW SHOWERS/FLURRIES THIS MORNING THROUGH THIS EVE. A LOCALIZED DUSTING AND REDUCED VSBY IS POSSIBLE WITH ANY SNOW SHOWER ACTIVITY. SNOW SHOWER/FLURRY ACTIVITY COMES TO AN END LATE THIS EVENING...WITH CLEARING SKIES ON BACKSIDE OF DEPARTING POLAR LOW. POTENTIAL FOR SUSTAINED WINDS INTO THE LOWER 30S AND A FEW GUSTS TO 50 MPH THIS AFT/EVE AS WINDS ALOFT PEAK ACROSS THE NJ/NYC METRO...COAST AND HIGHER ELEVATIONS. THE WIND HAZARD AND IMPACTS ARE COVERED IN THE WINTER WEATHER ADVISORY. WINDS WILL BE SLOW TO SUBSIDE TONIGHT WITH STRONG GRADIENT BETWEEN ARCTIC HIGH AND CANADIAN MARITIMES LOW.
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&& .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... POLAR LOW SLIDES OFFSHORE SUNDAY...WITH MODERATING ARCTIC HIGH PRESSURE BUILDING IN FROM THE WEST SUN INTO SUN NIGHT. SUNDAY SHOULD BE SUNNY...FRIGID...AND DRY WITH NW FLOW ALOFT AND ARCTIC HIGH PRESSURE BUILDING IN. AFTER A DANGEROUSLY COLD START TO THE DAY...DIMINISHING WINDS AND A MODERATING AIRMASS SHOULD ALLOW TEMPS TO MODERATE INTO THE TEENS...WITH WIND CHILLS FINALLY RISING ABOVE ZERO IN THE MID TO LATE AFTERNOON. HIGH PRESSURE MOVES ACROSS SUNDAY NIGHT...WITH STRONG RADIATIONAL COOLING CONDITIONS LIKELY FOR THE FIRST HALF OF THE NIGHT...BEFORE HIGH CLOUDS BEGIN TO MOVE IN. THIS SHOULD ALLOW FOR TEMPS TO FALL TO 5 TO POSSIBLY 10 BELOW ZERO ACROSS RURAL LOCALES LIKE THE PINE BARRENS OF LONG ISLAND AND INTERIOR VALLEYS OF CT WHERE A SOLID SNOWPACK EXISTS. TEMPS MAY BEGIN TO MODERATE LATE WITH INCREASING HIGH CLOUD COVER. ELSEWHERE TEMPS WILL LIKELY BOTTOM OUT IN THE SINGLE DIGITS ALONG THE COASTAL PLAIN...WHILE HOLDING STEADY INT HE MID TEENS FOR NYC METRO. && .LONG TERM /MONDAY THROUGH FRIDAY/... 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 ACROSS WESTERN NORTH AMERICA SENDS SEVERAL PIECES OF ENERGY INTO A DIGGING TROUGH ACROSS THE CENTRAL STATES. MODELS ARE COMING INTO BETTER GENERAL AGREEMENT WITH THIS TROUGH...BUT STILL SUBTLE DIFFERENCES IN PHASING OF ENERGIES REMAINS. THIS IS NOT SURPRISING AS THIS ENERGY IS EMANATING FROM THE NORTH PACIFIC AND IS COMING ASHORE LATE TODAY INTO EARLY SUNDAY. GENERAL AGREEMENT THAT 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 SUPPORTING SNOW. IT IS AFTER THIS TIME THAT UNCERTAINTY CONTINUES AS THE LOW INTENSIFIES AND TRACKS ALONG THE COAST OR JUST INLAND TUESDAY. DETERMINISTIC AND ENSEMBLE MODELS STILL SHOW 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. HAVE FOLLOWED A CONSENSUS FORECAST DUE TO THE REMAINING MODEL SPREAD ON THE TIMING/TRACK/INTENSITY OF THIS LOW...BUT HAVE INCREASED POPS TO CATEGORICAL MON NIGHT INTO TUE BASED ON SOME CONVERGENCE IN TIMING OF SOLUTIONS AND ENSEMBLE PROBABILITIES FOR GREATER THAN .05 INCHES QPF DURING THIS TIME. IN TERMS OF SENSIBLE WEATHER...A LIKELY SCENARIO AT THIS POINT IS 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. WILL ALSO HAVE TO MONITOR GROUND TEMPS SENSORS MONDAY NIGHT. IF GROUND TEMP WARM UP LAGS AIR TEMP WARMUP...THIS WOULD RESULT IN SERIOUS SURFACE ICING ISSUES. ON TUESDAY...RAIN...POSSIBLY HEAVY AT TIMES...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 /17Z SATURDAY THROUGH THURSDAY/...
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ARCTIC HIGH PRESSURE BUILDING TOWARDS THE REGION INTO SUNDAY AFTERNOON. VFR THROUGH THE TAF PERIOD. OCCASIONAL BKN DECK AROUND 3500-5000 FT THROUGH AROUND 22-23Z. CANNOT RULE OUT BRIEF ISOLATED -SHSN AT ANY GIVEN LOCATION. NW WINDS THROUGH THE TAF PERIOD...PRIMARILY TO THE RIGHT OF 300 TRUE/310 MAGNETIC...HOWEVER CANNOT RULE OUT WIND DIRECTION OCCASIONALLY BEING AT 300 TRUE. WINDS INCREASING TO 15-25G25-35KT...WITH PEAK GUSTS UP TO AROUND 40 KT...INTO THIS EVENING. WINDS SLOWLY DIMINISH THROUGH SUNDAY MORNING...WITH G15-20KT BY AROUND MIDDAY SUNDAY. .OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY... .SUNDAY AFTERNOON/NIGHT...VFR. .MONDAY...LIGHT SNOW LIKELY DEVELOPS FROM W TO E LATE MORNING/INTO THE AFTERNOON...WITH MVFR OR LOWER POSSIBLE. S WIND G15-20KT POSSIBLE. .MONDAY NIGHT...IFR OR LOWER DEVELOPING. A WINTRY MIX CHANGING TO RAIN AT S TERMINALS...AND SNOW CHANGING TO A WINTRY MIX AT NORTHERN TERMINALS. LLWS POSSIBLE. LOW CONFIDENCE FORECAST. .TUESDAY...ANY LINGERING WINTRY MIX N TERMINALS CHANGING TO ALL RAIN IN THE MORNING. RAIN TAPERING OFF LATE. IFR OR LOWER POSSIBLE. LLWS IN THE AM...THEN NW WINDS G20-25KT POSSIBLE IN THE AFTERNOON. .TUESDAY NIGHT...VFR. .WEDNESDAY...MOSTLY VFR. MVFR OR LOWER POSSIBLE IN ANY SPOTTY RAIN/SNOW SHOWER. W-NW WINDS G20-25KT POSSIBLE. .WEDNESDAY NIGHT-THURSDAY...VFR. NW WINDS G15-20KT POSSIBLE.
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&& .MARINE... STRONG NW WINDS TODAY IN THE WAKE OF AN ARCTIC FRONT. GALE WARNING IN EFFECT UNTIL 11Z SUNDAY FOR NY HARBOR AND WESTERN LONG ISLAND SOUND...AND UNTIL 15Z FOR THE OCEAN...EASTERN LONG ISLAND SOUND...AND LONG ISLAND BAYS. ISOLATED SNOW SHOWERS ARE POSSIBLE WITH BRIEF REDUCTIONS IN VSBY TODAY. A BRIEF SMALL CRAFT ADVISORY MAY BE NEEDED SUNDAY MORNING AFTER THE GALES END...BUT TRANQUIL CONDITIONS ON ALL WATERS EXPECTED BY SUNDAY AFTERNOON. 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) INTO SUNDAY...WITH HEAVY FREEZING SPRAY FORECAST TONIGHT 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... NO HYDROLOGIC IMPACTS THROUGH SUNDAY NIGHT. A DEVELOPING LOW PRESSURE SYSTEM MOVING NEAR OR ALONG THE COAST MONDAY NIGHT INTO TUESDAY HAS 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. && .TIDES/COASTAL FLOODING... POTENTIAL EXISTS FOR MINOR COASTAL IMPACTS WITH THE LATE MONDAY NIGHT/EARLY TUESDAY MORNING HIGH TIDE AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM MOVING UP THE COASTAL PLAIN. STILL QUITE A BIT OF UNCERTAINTY EXISTS ON THE EVOLUTION OF THIS SYSTEM. POSITIVE TIDAL DEPARTURES OF 2 TO 2 1/2 FT ARE NEEDED FOR MINOR FLOOD THRESHOLDS TO BE REACHED...AND 3 TO 3 1/2 FT FOR MODERATE THRESHOLDS. && .CLIMATE... WITH THE EXTREMELY COLD AIR MASS FORECAST TODAY 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 KENNEDY..........4 (1979) / 2 ISLIP............7 (2015) / 1 NEWARK...........0 (1979) / 0 BRIDGEPORT.......3 (2015*) / -2 STATION......RECORD LOW MAXIMUM/FORECAST HIGH FOR 2/14 CENTRAL PARK....17 (1979) / 14 LAGUARDIA.......15 (1979) / 15 KENNEDY.........17 (1979) / 16 ISLIP...........26 (1987) / 14 NEWARK..........15 (1979) / 15 BRIDGEPORT......18 (1979) / 14 *IN 1979 AS WELL && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR CTZ005>012. NY...WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR NYZ072>075- 078>081-176>179. WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR NYZ067>071. NJ...WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR NJZ004-006- 103>108. WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR NJZ002. MARINE...GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ330-340-345-350-353- 355. HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO NOON EST SUNDAY FOR ANZ330-335-340. FREEZING SPRAY ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330- 335-338-340. HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR ANZ338. GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ335-338. FREEZING SPRAY ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...JMC/NV NEAR TERM...JMC/NV SHORT TERM...NV LONG TERM...DS/NV AVIATION...MALOIT MARINE...JMC/MPS HYDROLOGY...DS/NV TIDES/COASTAL FLOODING... CLIMATE...

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