Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 312142 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 542 PM EDT TUE MAR 31 2015 .SYNOPSIS... LOW PRESSURE PASSES SOUTH OF LONG ISLAND TONIGHT. HIGH PRESSURE BUILDS TO THE SOUTH FROM WEDNESDAY INTO THURSDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST THURSDAY NIGHT AND FRIDAY...THEN PASS THROUGH LATE FRIDAY NIGHT INTO SATURDAY MORNING. ANOTHER COLD FRONT FOLLOWS ON SUNDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LOW PRESSURE OVER THE PENNSYLVANIA/MARYLAND BORDER WILL CONTINUE TO SLIDE SOUTHEAST...PASSING SOUTH OF THE REGION THIS EVENING. PRECIPITATION CONTINUES TO FALL ACROSS ALL BUT FAR EASTER PORTIONS OF THE FORECAST AREA...AND WILL CONTINUE TO SLIDE EASTWARD THROUGH THE EVENING AND INTO THE FIRST PART OF THE OVERNIGHT. THE PTYPE HAS LARGELY BEEN RAIN WITH POCKETS OF SNOW MIXED IN. STARTING TO SEE PREDOMINATELY SNOW ACROSS INTERIOR LOWER HUDSON VALLEY. TEMPERATURES ARE STILL ABOVE FREEZING AREAWIDE...IN THE MIDDLE AND UPPER 30S WHERE PRECIPITATION IS FALLING. HOWEVER...SOME COLDER AIR IS EXPECTED TO MOVE INTO THE REGION FROM NORTHWEST TO SOUTHEAST LATER THIS EVENING. AS THIS COLDER AIR MOVES INTO THE REGION...THE MIXED PRECIPITATION WILL BEGIN TO MIX WITH AND CHANGE OVER TO SNOW. THE BEST CHANCES FOR ALL SNOW WILL BE ACROSS THE HIGHER ELEVATIONS OF NJ AND THE LOWER HUDSON VALLEY. THERE COULD BE SOME LIGHT ACCUMULATIONS IN THE HIGHER ELEVATIONS. CLOSER TO THE COAST...LITTLE TO NO ACCUMULATION IS EXPECTED. PRECIPITATION SHOULD TAPER OFF AFTER MIDNIGHT WITH CLEARING SKIES FROM WEST-EAST. LOWS SHOULD RANGE FROM THE LOWER 30S IN THE VICINITY OF NYC...TO 25-30 MOST ELSEWHERE...TO SOME LOWER 20S IN THE VALLEYS WELL NORTH/WEST OF THE CITY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE BUILDS INTO THE REGION FOR WEDNESDAY AND WEDNESDAY NIGHT. EXPECT DRY WEATHER THROUGH THE SHORT TERM PERIOD. THERE COULD BE SOME INCREASED CLOUD COVER LATE WEDNESDAY MORNING AND AFTERNOON AS A WEAKENING UPPER TROUGH MOVES ACROSS THE AREA. HIGHS SHOULD BE MOSTLY IN THE LOW TO MID 40S... WHICH IS 5-10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGH PRESSURE CENTER WILL BE SITUATED JUST OFF THE MID-ATLANTIC COAST THURSDAY MORNING. A RETURN SW FLOW THEN SETS UP. THESE SW WINDS OFF THE COLD WATERS FOR EASTERN ZONES WILL LIMIT MIXING...BUT WITH HIGH PRESSURE SUBSIDENCE WEAKENING...WESTERN ZONES ARE FORECAST TO MIX UP TO AROUND 900MB. BASED ON THE AFTN FCST TEMP AT THIS LEVEL...HAVE GONE ABOVE GUIDANCE FOR HIGH TEMPS ACROSS THESE AREAS NOT AFFECTED BY THE OCEAN/SOUND INFLUENCES. LOOKS LIKE THE SW FLOW IN THE BOUNDARY LAYER SHOULD BE STRONG ENOUGH TO PRECLUDE A SEA BREEZE PUSHING THROUGH NE NJ...SO EXPECTING HIGHS UP TO THE MID 60S HERE. CLOUDS THEN THICKEN THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. CHC SHOWERS MAINLY AFTER MIDNIGHT AND MAINLY NW OF THE CITY. BASED ON FCST MUCAPES AND MID LEVEL LAPSE RATES...INCLUDED THE MENTION OF THUNDER. SHOWERS THEN BECOME LIKELY DURING FRIDAY WITH THE LIKELIHOOD LASTING INTO FRIDAY NIGHT AS THE COLD FRONT APPROACHES AND PASSES THROUGH. ENOUGH INSTABILITY PRESENT FOR A CHC OF THUNDER. CLOUDS/RAIN AND LIMITED MIXING...AS WELL AS A WIND FLOW OFF THE WATERS FOR SOME AREAS...SHOULD PREVENT TEMPERATURES FROM SOARING. STILL...LOOKS LIKE HIGHS RANGE FROM THE MID 50S TO LOW 60S. JUST A LINGERING CHANCE OF A SHOWER SATURDAY MORNING AS THE COLD FRONT EXITS...THEN A GUSTY DRYING NW FLOW SHOULD HELP CLOUDS DIMINISH CLOUDS AND KEEP US DRY DURING THE AFTERNOON. HIGHS A FEW DEGREES BELOW NORMAL. FOR SUNDAY...A COLD FRONT TRIES TO DROP DOWN FROM THE NORTH...BUT MODELS ARE TRENDING WEAKER WITH THE FRONT AS THE FLOW ALOFT WILL BE FAIRLY ZONAL. THE FRONT POTENTIALLY WASHES OUT OR BECOMES STATIONARY IN THE VICINITY AT SOME POINT LATE SUNDAY OR SUNDAY NIGHT. WILL MAINTAIN A DRY FORECAST FOR SUNDAY...BUT WILL GO WITH SLIGHT CHC POPS FOR SUNDAY NIGHT. PCPN TYPE PRIMARILY RAIN...BUT THE NORTHERNMOST ZONES PROBABLY SEE A MIX OR RAIN AND SNOW LATE AT NIGHT INTO EARLY MONDAY MORNING. SLIGHT CHC POPS REMAIN FOR MONDAY WITH THE STALLED BOUNDARY IN THE VICINITY. MODELS THEN SHOW OVERRUNNING MOISTURE PUSHING EAST ALONG THE STALLED BOUNDARY AND INTO THE TRI STATE AREA FOR MONDAY NIGHT THROUGH WEDNESDAY. WILL CARRY CHC POPS THROUGH THE PERIOD. THERMAL PROFILES SUPPORT RAIN...EXCEPT THERE COULD BE A MIX OF RAIN AND SNOW FOR THE NORTHERNMOST ZONES LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/...
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LOW PRES MOVES ACROSS THE REGION THIS EVENING AND DEPARTS TONIGHT. HIGH PRES BUILDS INTO THE REGION ON WEDNESDAY. MVFR/IFR CONDS IN -RA/SN ACROSS THE TERMINALS. COULD BE A CHANGEOVER TO SNOW ACROSS CITY TERMINALS BETWEEN 23Z AND 02Z WITH A BAND OF HEAVIER PRECIP. LITTLE TO NO ACCUMULATION EXPECTED. BETTER CHANCE FOR A PERIOD OF SNOW WITH A LIGHT ACCUM WILL BE ACROSS NORTHERN TERMINALS (KSWF/KHPN/KBDR)...AND POSSIBLY KISP/KGON LATER THIS EVENING. N/NE WINDS 10 KT OR LESS...INCREASING AFTER 00Z...AND SHIFTING TO THE NW AT 15 KT WITH 20-25 KT GUSTS FROM JUST AFTER MIDNIGHT THROUGH DAYBREAK WEDNESDAY. HIGH PRES BUILDS INTO THE REGION WEDNESDAY WITH VFR CONDS AND NW FLOW. ...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: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. KLGA FCSTER COMMENTS: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. POTENTIAL FOR A BRIEF PERIOD OF IFR CONDS IN ALL SNOW BETWEEN 23Z AND 02Z. KEWR FCSTER COMMENTS: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. POTENTIAL FOR A BRIEF PERIOD OF IFR CONDS IN ALL SNOW BETWEEN 23Z AND 02Z. KTEB FCSTER COMMENTS: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. POTENTIAL FOR A BRIEF PERIOD OF IFR CONDS IN ALL SNOW BETWEEN 23Z AND 02Z. KHPN FCSTER COMMENTS: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. MODERATE POTENTIAL FOR A PERIOD OF IFR CONDS IN ALL SNOW BETWEEN 23Z AND 02Z. KISP FCSTER COMMENTS: AMDS POSSIBLE FOR POTENTIAL FLIGHT CATEGORY CHANGES. POTENTIAL FOR A PERIOD OF IFR CONDS IN ALL SNOW BETWEEN 00Z AND 03Z. .OUTLOOK FOR 21Z WEDNESDAY THROUGH SUNDAY... .WEDNESDAY-THURSDAY...VFR. .THURSDAY NIGHT-FRIDAY NIGHT...MVFR IN RAIN SHOWERS. .SATURDAY...SUB-VFR POSSIBLE IN SHOWERS EARLY...THEN VFR LATE. .SUNDAY...MAINLY VFR.
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&& .MARINE... CONDITIONS HAVE BEEN SLOW TO INCREASE TO SMALL CRAFT LEVELS. WINDS AND SEAS ARE EXPECTED TO INCREASE TO MARGINAL LEVELS OVERNIGHT AS LOW PRESSURE PASSES OVER OR JUST SOUTH OF THE AREA WATERS. DOES NOT MAKE SENSE TO DROP THE SMALL CRAFT FOR JUST A FEW HOURS...SO WILL KEEP THE SMALL CRAFT UP FOR THE OCEAN WATERS THROUGH TONIGHT...THEN ON THE EASTERN TWO OCEAN ZONES THROUGH 18Z WEDNESDAY. SUB-SCA CONDITIONS ARE THEN EXPECTED FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA. WINDS PICK UP ON THURSDAY WITH A RETURN SW FLOW. LOOKS LIKE THERE WILL BE A PROLONGED PERIOD OF SCA CONDS ON THE OCEAN WATERS WITH EITHER WINDS OR SEAS...OR A COMBINATION OF THE TWO. THIS WOULD START THURSDAY AFTERNOON AND LAST THROUGH SATURDAY NIGHT AS A SWELL LINGERS. EVEN ON SUNDAY...A COLD FRONT PASSAGE COULD BRING GUSTS UP TO 25 KT DURING THE AFTERNOON ON THE OCEAN WATERS. AS FOR THE OTHER WATERS. IT APPEARS THAT MOST IF NOT ALL OF THE LONG TERM WILL FEATURE PRIMARILY SUB-SCA CONDS WITH THE EXCEPTION OF THURSDAY AFTERNOON/EARLY EVENING WHERE A SCA MIGHT BE NECESSARY FOR SOME SPOTS. && .HYDROLOGY... QPF OF 2 TO 4 TENTHS OF AN INCH EXPECTED THROUGH TONIGHT...WITH SOME OF THIS IN THE FORM OF SNOW...ESPECIALLY INLAND. THERE IS THE POTENTIAL FOR AROUND A HALF INCH OF RAIN FROM LATE THURSDAY NIGHT THROUGH EARLY SATURDAY MORNING. RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANK FULL...BUT INCREASED RIVER/STREAM FLOW ACROSS THE LOWER HUDSON VALLEY AND SOUTHERN CONNECTICUT WILL CONTINUE ICE BREAKUP AND MOVEMENT INTO THIS WEEKEND. ISOLATED ICE JAMS ARE POSSIBLE...WHICH IF THEY OCCUR...COULD RESULT IN LOCALIZED FLOODING. SINCE ICE JAM FLOODING IS UNPREDICTABLE AND SUDDEN...INTERESTS ALONG ICE COVERED RIVERS SHOULD MONITOR NWS FORECASTS FOR THE LATEST INFORMATION. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ355. SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR ANZ350-353. && $$ SYNOPSIS...BC/JC NEAR TERM...DS SHORT TERM...BC LONG TERM...JC AVIATION...NV MARINE...BC/JC HYDROLOGY...BC/JC

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