Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 140926 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 426 AM EST SUN FEB 14 2016 .SYNOPSIS...
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HIGH PRESSURE BUILDS OVER THE AREA ON TODAY AND OFFSHORE TONIGHT. THE HIGH CONTINUES TO MOVE EAST AWAY INTO THE ATLANTIC MONDAY AS A LOW PRESSURE SYSTEM DEVELOPS TO THE WEST. THIS LOW TRAVELS NEAR OR TO THE WEST OF THE REGION TUESDAY AND INTO THE CANADIAN MARITIMES TUESDAY NIGHT. A CLIPPER LOW MOVES IN FOR WEDNESDAY INTO WEDNESDAY NIGHT. THEN...CANADIAN HIGH PRESSURE RETURNS FOR THURSDAY AND FRIDAY. FOR FRIDAY NIGHT INTO SATURDAY NEXT WEEK...ANOTHER LOW APPROACHES FROM THE NORTH AND WEST.
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&& .NEAR TERM /THROUGH TONIGHT/...
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POLAR LOW SLIDES EAST ON NEW ENGLAND THIS MORNING...WITH MODERATING ARCTIC HIGH PRESSURE BUILDING IN FROM THE WEST TODAY INTO TONIGHT. COLDEST AIR AS OF 4 AM IS SITTING ACROSS CONNECTICUT THIS MORNING WITH LOWS GENERALLY 5 TO 10 DEGREES BELOW ZERO...AND WIND CHILLS AROUND 20 TO 30 DEGREES BELOW ZERO. THIS IS COINCIDENT WITH THE AXIS OF THE -30C 850 HPA CORE. 1 BELOW ZERO AT NWS NEW YORK ON BROOKHAVEN LABS AS OF 3AM...AND 3 DEGREES AT CENTRAL PARK. TEMPS SHOULD DROP ANOTHER 2 TO 3 DEGREES BY DAYBREAK. TODAY WILL 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 BY LATE DAY/EARLY EVE. WIND CHILL W/A WILL BE ALLOWED TO EXPIRE AT NOON WITH DECREASING WINDS MODERATING APPARENT TEMPS ABOVE -15 DEGREES. HIGH PRESSURE MOVES ACROSS TONIGHT...WITH STRONG RADIATIONAL COOLING CONDS 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 EASTERN LOCALES LIKE THE PINE BARRENS OF LI AND INTERIOR VALLEYS OF CT WHERE A SOLID SNOWPACK EXISTS. 0 TO 5 BELOW ZERO ACROSS INTERIOR VALLEYS OF LOWER HUDSON VALLEY. ELSEWHERE TEMPS WILL LIKELY BOTTOM OUT IN THE SINGLE DIGITS ALONG THE COASTAL PLAIN...WHILE HOLDING STEADY IN THE MID TEENS FOR NYC METRO. TEMPS THEN COULD RISE LATE TONIGHT AND TOWARDS DAYBREAK WITH INCREASING HIGH CLOUDS.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY/...
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MODELS IN GENERAL AGREEMENT WITH SEVERAL PIECES OF PAC ENERGY HELPING TO AMPLIFY A CENTRAL US TROUGH TODAY INTO MONDAY...WHICH SLIDES INTO THE OHIO/TENNESSEE VALLEYS MONDAY NIGHT...AND THEN SWINGS UP THE COAST ON TUESDAY. DETERMINISTIC MODELS AND ENSEMBLES STILL EXHIBITING SOME MODEL SPREAD AND JUMPINESS ON TIMING AND AMPLITUDE OF THIS SHORTWAVE ENERGY AS IT COMES UP THE COAST. SBU SENSITIVITY TRACKING THIS MODEL SPREAD TO THE PAC ENERGY COMING ONSHORE THIS MORNING. THIS MODEL SPREAD IN SHORTWAVE EVOLUTION IS STILL MANIFESTING DIFFERENCES IN TIMING AND TRACK OF LOW PRESSURE. 00Z GFS/UKMET/CAN AND 00Z GEFS/03Z SREF ARE CLUSTERED ON A TRACK OF LOW PRESSURE FROM THE DEEP SOUTH MONDAY MORNING...TO TENNESSEE RIVER VALLEY MONDAY NIGHT AND THEN AN INLAND TRACK UP INTO CENTRAL PA/NY ON TUESDAY. NAM/ECMWF TRACKS LOW PRESSURE RIGHT ALONG THE COAST AND SLIGHTLY SLOWER. THIS IS A SIGNIFICANT EASTWARD SHIFT FOR THE ECMWF FROM 12- 24 HRS AGO AND WESTWARD SHIFT FOR THE GFS. AGAIN...NOT INSTILLING CONFIDENCE. 12Z GEFS/21ZSREF/12Z CMC ENSEMBLE MEANS WERE PRETTY WELL CLUSTERED WITH A MEAN LOW TRACK ALONG THE EAST SIDE OF THE APPALACHIANS ON TUESDAY. MUCH OF THE SPREAD WAS ON THE W/SW SIDE OF THE LOW...WHICH MAY SIGNAL A FURTHER WEST TRACK SIMILAR TO THE DETERMINISTIC CLUSTERING AND PERHAPS A BIT SLOWER. THIS HAS BORNE OUT WITH THE 00Z SREF AND GEFS ENSEMBLE MEANS FURTHER WEST. BASED ON THIS...WILL LEAN TOWARDS THE BETTER CLUSTERED LOW TRACK NEAR THE APPALACHIANS. IN TERMS OF SENSIBLE WEATHER...A LIKELY SCENARIO AT THIS POINT CONTINUES TO BE LIGHT SNOW DEVELOPMENT MONDAY MORN/AFT FROM SW TO NE FOR THE ENTIRE AREA WITH WARM ADVECTION IN DEEP SW FLOW ALOFT OVER THE MODERATING ARCTIC AIRMASS. AS WAA INCREASES...EXPECTATION FOR PRECIP TO CHANGE TO WINTRY MIX AND THEN LIQUID MONDAY EVENING FROM S TO N. ALONG THE CITY/COAST...TRANSITION FROM SNOW TO RAIN SHOULD BE FAIRLY QUICK IN THE EVENING WITH STRENGTHENING ONSHORE FLOW. GENERALLY AN INCH OR TWO OF SNOW ALONG THE COAST...BUT POTENTIAL FOR ROAD ICING EXISTS A COUPLE OF HOURS AFTER TRANSITION TO RAIN AS AIR TEMPS MAY WARM ABOVE FREEZING QUICKER THAN GROUNDS TEMPS. INCREASING POTENTIAL FOR ICING AWAY FROM SOUTH COASTS. ACROSS INTERIOR PORTIONS OF NE NJ...LOWER HUDSON VALLEY...AND SW CT...A GENERAL 2 TO 4 INCHES OF SNOW POSSIBLE THROUGH MON EVENING AND THEN SEVERAL HOURS OF FREEZING RAIN POSSIBLE MONDAY NIGHT BEFORE LOW LEVEL WAA FINALLY SCOUR LOW- LEVEL COLD AIR MASS BY EARLY TUESDAY MORNING. WITH PRECEDING ARCTIC AIRMASS...GROUND TEMP WARM UP WILL LIKELY LAG AIR TEMP WARMUP...WHICH COULD RESULT IN SERIOUS ROAD ICING ISSUES. WILL ADDRESS THREAT IN HWO. ON TUESDAY...RAIN...POSSIBLY HEAVY AT TIMES...WITH TEMPERATURES WELL INTO THE 40S TO 50S AS WARM CONVEYOR BELT OVERRIDES THE REGION IF INLAND TRACK VERIFIES. A GENERAL RANGE OF 1 TO 2 1/2 INCHES OF TOTAL QPF IS FORECAST IN THE CONSENSUS OF THE MODELS. SEE HYDRO SECTION FOR MORE INFORMATION. CONSENSUS LOW TRACK WOULD ALSO RESULT IN WINDY CONDITIONS ALONG THE COAST WITH 60 TO 65 KT JET AT 950 HPA MOVING OVER THE REGION. WINDS OF 25 TO 30 MPH WITH GUSTS TO 40 MPH WOULD BE LIKELY...WITH POTENTIAL FOR WIND ADVISORY CONDITIONS OF SUSTAINED WINDS IN THE LOWER 30S AND GUSTS TO 50 MPH. LLJ/DEEP MOISTURE AXIS MOVES EAST TUESDAY EVENING WITH DRYING CONDS.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
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FOR THE REST OF THE FORECAST TUESDAY NIGHT AND WEDNESDAY...LINGERING RAIN AND SNOW SHOWERS POSSIBLE AS MAIN LOW MOVES INTO THE CANADIAN MARITIMES AND ANOTHER SHORTWAVE MOVES THROUGH ALOFT WITH ITS PVA. DRIER CONDITIONS WILL BECOME MORE PREVALENT WEDNESDAY NIGHT ALTHOUGH THERE COULD BE A FEW SNOW SHOWERS REMAINING WEDNESDAY NIGHT. ANOTHER ROUND OF COLD AIR ADVECTION OCCURS WEDNESDAY NIGHT BEHIND THE SHORTWAVE. STRONG CANADIAN HIGH PRESSURE MOVES IN THURSDAY THROUGH EARLY FRIDAY WITH DRY WEATHER. ANOTHER LOW AND ANOTHER CHANCE OF PRECIPITATION ARRIVES FRIDAY INTO SATURDAY OF NEXT WEEK.
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&& .AVIATION /09Z SUNDAY THROUGH THURSDAY/...
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NO SIGNIFICANT CHANGES MADE TO PREVIOUS TAF PACKAGE. ARCTIC HIGH PRES CONTINUES TO BUILD INTO THE REGION THROUGH THIS EVENING. VFR THROUGH THE TAF PERIOD. GUSTY NW WINDS WILL CONTINUE TO DIMINISH INTO THIS AFTERNOON. NW WINDS 15-20 KT WITH 20-30 KT GUSTS WILL DIMINISH TO 10-15 KT WITH GUSTS UP TO 20 KT BY 18Z. GUSTS SHOULD END AT ALL BUT KNYC TERMINALS BY THEN. WINDS WILL DIMINISH TO LESS THAN 10 KT BY LATE AFTERNOON/EARLY EVENING. WIND DIRECTION WILL BE MAINLY AT OR JUST RIGHT OF 310 MAGNETIC. .OUTLOOK FOR 09Z MONDAY THROUGH THURSDAY... .SUNDAY NIGHT...VFR. LIGHT WINDS. .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...
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WINDS DIMINISHING ON THE WATERS...BUT GALES WILL CONTINUE ON THE OCEAN AND E LI SOUND THROUGH 15Z THIS MORNING. ON NY HARBOR/W LI SOUND/LI BAYS...EXPECTING SMALL CRAFT ADVISORY CONDS THROUGH AFTERNOON WITH WIND GUSTS TO 25 KT. TRANQUIL CONDS EXPECTED BY THIS EVENING. FREEZING SPRAY WILL ALSO CONTINUE THROUGH THIS MORNING. SUB SCA CONDITIONS MONDAY WILL BE FOLLOWED BY SCA TO GALE CONDITIONS MONDAY NIGHT INTO TUESDAY. GALES TREND TO SCA WINDS LATER TUESDAY AND TUESDAY NIGHT. THE WINDS TREND BELOW SCA THEREAFTER BUT SCA OCEAN SEAS REMAIN.
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&& .HYDROLOGY...
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A GENERAL 1 TO 2 1/2 INCHES OF LIQUID EQUIVALENT IS FORECAST WITH LOCALLY HIGHER AMOUNTS MONDAY THROUGH TUESDAY NIGHT. THIS WILL BE MOSTLY BE IN THE FORM OF RAIN. THIS TYPE OF RAINFALL WILL BRING POTENTIAL FOR URBAN AND POOR DRAINAGE FLOODING. LI AND EASTERN CT ALSO HAVE MORE IN THE WAY OF SNOWPACK AND SNOW CLOGGED DRAINAGES TO ADD TO POOR DRAINAGE FLOOD POTENTIAL. WITH INITIALLY FROZEN GROUND...SIGNIFICANT RISES ARE LIKELY WITH POTENTIAL MINOR FLOODING ALONG FLASHY SMALL STREAMS ACROSS NE NJ/LOWER HUDSON VALLEY IF HIGH END OF RAINFALL AMOUNTS ARE REALIZED. MMEFS AND STEVENS FAS ARE NOT SHOWING ANY AREAS GOING INTO FLOOD AS OF YET.
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&& .TIDES/COASTAL FLOODING...
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POTENTIAL EXISTS FOR MINOR COASTAL FLOOD IMPACTS WITH THE LATE MONDAY NIGHT/EARLY TUESDAY MORNING AND POSSIBLY TUE AFT HIGH TIDE CYCLES AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM MOVING UP THE COASTAL PLAIN. STILL QUITE A BIT OF UNCERTAINTY EXISTS ON THE TIMING AND TRACK OF THIS SYSTEM. POSITIVE TIDAL DEPARTURES OF 2 TO 2 1/2 FT ARE NEEDED FOR MINOR FLOOD THRESHOLDS TO BE REACHED IN THE MORNING...AND 2 1/2 TO 3 FT IN THE AFTERNOON.
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&& .CLIMATE...
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WITH THE EXTREMELY COLD AIR MASS...RECORD MINIMUMS AND RECORD LOW MAXIMUMS MAY BE REACHED. HERE ARE THE RECORDS AND FORECASTS... STATION......RECORD LOW(YEAR)/FCST LOW BY MIDNIGHT FOR 2/13 LAGUARDIA.........8 (2016) / 8 ISLIP.............4 (2016) / 4 STATION......RECORD LOW(YEAR)/4AM TEMP FOR 2/14 CENTRAL PARK.....2 (1916) / 3 LAGUARDIA........1 (1979) / 5 KENNEDY..........4 (1979) / 5 ISLIP............7 (2015) / 3 NEWARK...........0 (1979) / 5 BRIDGEPORT.......3 (2015*) / -4 STATION......RECORD LOW MAXIMUM(YEAR)/FCST HIGH FOR 2/14 CENTRAL PARK....17 (1979) / 15 LAGUARDIA.......15 (1979) / 16 KENNEDY.........17 (1979) / 17 ISLIP...........26 (1987) / 13 NEWARK..........15 (1979) / 15 BRIDGEPORT......18 (1979) / 13 *IN 1979 AS WELL
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...WIND CHILL WARNING UNTIL NOON EST TODAY FOR CTZ005>012. NY...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR NYZ072>075- 078>081-176>179. WIND CHILL WARNING UNTIL NOON EST TODAY FOR NYZ067>071. NJ...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR NJZ004-006- 103>108. WIND CHILL WARNING UNTIL NOON EST TODAY FOR NJZ002. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ335- 338-340-345. HEAVY FREEZING SPRAY WARNING UNTIL NOON EST TODAY FOR ANZ330- 335-340. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ338. GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ANZ330-350-353- 355. FREEZING SPRAY ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350- 353-355.
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&& $$ SYNOPSIS...NV NEAR TERM...NV SHORT TERM...NV LONG TERM...JM AVIATION...MPS MARINE...MPS HYDROLOGY...NV TIDES/COASTAL FLOODING...NV CLIMATE...NV

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