Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 250259 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 959 PM EST TUE FEB 24 2015 .SYNOPSIS... LOW PRESSURE WILL PASS SOUTH AND EAST OF LONG ISLAND OVERNIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD FRONT MOVES ACROSS THE REGION ON WEDNESDAY. LOW PRES WILL PASS OFFSHORE ON THU. AN ARCTIC HIGH WILL THEN BUILD IN THRU THE WEEKEND. WINTRY WEATHER IS POSSIBLE SUN NGT INTO MON WITH A FRONTAL SYSTEM. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LOW PRESSURE WAS DEEPENING SLOWLY OFF THE SOUTHEAST COAST...AND PRESSURE FALL TRENDS HAVE THE LOW MOVING WELL TO THE SOUTHEAST OF LONG ISLAND OVERNIGHT. NORTHERN PRECIPITATION SHIELD AT 0230Z WAS JUST SOUTH OF THE TWIN FORKS WITH RETURNS OFF 30 DBZ. WITH THINKING THE LOW TRACKS A LITTLE FARTHER EAST HAVE REMOVED POPS ACROSS SOUTHWESTERN CONNECTICUT TO JUST EAST OF NYC KEEPING AREAS TO THE EAST AND NORTH DRY. HIGHEST ACCUMULATING SNOW OF 1 TO 2 INCHES...LIKELY ACROSS NEW LONDON...AND THE LONG ISLAND TWIN FORKS. SNOW RATIOS WILL BE HIGH...15 OR SLIGHTLY HIGHER TO 1...WITH IDEAL SNOW GROWTH LATE. WEAK WARM ADVECTION HAS ALLOWED FOR TEMPERATURES TO RISE A COUPLE OF DEGREES ACROSS LONG ISLAND AND INTO COASTAL CONNECTICUT. TEMPERATURES THEN DROP OFF AGAIN AFTER 07Z. SO RAISED OVERNIGHT LOWS ESPECIALLY ALONG THE COAST. UPPER LEVEL LOW TRACKS FROM CENTRAL CANADA INTO EASTERN CANADA. THIS WILL DRAG A DEEP H5 TROUGH WITH SEVERAL STRONG SHORTWAVES AND A SFC COLD FRONT INTO THE REGION LATE TONIGHT. MEANWHILE...LOW PRES OVER THE GULF COAST WILL MOVE OFF THE SOUTHEAST U.S. COAST AND TRACK INTO THE OPEN ATLANTIC WATERS. AS IT DEPARTS...A SECONDARY WEAK SFC LOW WILL FORM AROUND THE 40/70 BENCHMARK. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... COLD FRONT WORKS ITS WAY ACROSS THE REGION ON WEDNESDAY. WEST WINDS INCREASE TO 10-15 MPH WITH 20-25 MPH GUSTS...AND THE WESTERLY FLOW WILL ALLOW TEMPS TO RISE INTO THE LOW TO MID 30S...WHICH ARE STILL ABOUT 10 DEGREES BELOW NORMAL. HIGH PRES BUILDS INTO THE OH VALLEY...AND THEN INTO WESTERN NY/PA BEHIND THE DEPARTING FRONT. SKIES CLEAR OUT WEDNESDAY EVENING AS THE HIGH PASSES NORTH OF THE AREA. ANOTHER LOW WILL TRACK FRONT THE GULF COAST AND MOVE INTO THE OPEN ATLANTIC WATERS LATE WEDNESDAY NIGHT. CLOUDS ASSOCIATED WITH THE LOW WILL SPREAD INTO THE REGION AFTER MIDNIGHT WEDNESDAY NIGHT. LOWS WEDNESDAY NIGHT WILL DROP INTO THE LOWER TEENS ACROSS NYC/PORTIONS OF NE NJ/LONG ISLAND...AND INTO THE SINGLE DIGITS TO AROUND 10 FOR THE REST OF THE CWA. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THE SREF STILL GIVES THE AREA A 30-60 PCT CHC OF MEASURABLE SNOW ON THU. THIS IS ON THE PERIPHERY OF LOW PRES OFFSHORE AND NRN STREAM ENERGY STILL OVER THE CANADIAN ROCKIES. LITTLE TO NO QPF IN THE NAM AND GFS. AS A RESULT...KEPT POPS AT LOW CHC ON THE COAST AND SCHC INTERIOR. A 1040 MB ARCTIC HI THEN BUILDS IN THRU SAT NGT...THEN OFFSHORE EARLY SUN. THIS KEEPS FAIR WX AND SUB NORMAL TEMPS LOCKED IN. THE GUIDANCE HAS SHIFTED EVEN LWR WRT TEMPS FOR SUN...SO HIGHS MAY ONLY FLIRT WITH FREEZING. NEXT SYS STILL ON TRACK FOR SUN NGT INTO MON...BUT THE TREND IS FASTER WITH THE NRN STREAM AND AS A RESULT COLDER ACROSS THE CWA. WENT WITH A WINTRY MIX...BUT IF THE TREND HOLDS IT COULD BE ALL SNOW...PARTICULARLY INTERIOR. FURTHERMORE...IF THE NRN STREAM SYS SPEEDS UP SIGNIFICANTLY MORE...IT COULD SHUNT THE SRN STREAM MOISTURE OFFSHORE AND RESULT IN A DRY OR MAINLY DRY FCST. EITHER WAY...BY LATE MON AND MON NGT A BRIEF SHOT OF HI PRES...THEN THE NEXT SYS BRINGS MORE ICE AND SNOW POTENTIAL IN THE TUE TIME FRAME. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE WILL PASS WELL TO THE SOUTHEAST TONIGHT. A COLD FRONT WILL THEN MOVE ACROSS WED MORNING...FOLLOWED BY BUILDING HIGH PRESSURE LATER WEDNESDAY. AREA OF MODERATE TO LOCALLY HEAVY SNOW WAS RACING NE TOWARD KGON...AND CONDS THERE SHOULD QUICKLY DETERIORATE TO IFR/OCNL LIFR FROM ABOUT 04Z-08Z. THIS AREA SHOULD MISS THE OTHER TERMINALS. MVFR CIGS AT KHPN/KBDR AS OF 02Z SHOULD LIFT BY ABOUT 04Z AS LOW LEVEL FLOW TURNS SW. S WINDS 10-15 KT ALONG THE COAST WERE ALREADY BEGINNING TO SHIFT SW 10 KT OR LESS...AND SHOULD VEER W OVERNIGHT. AFTER COLD FROPA WED MORNING...EXPECT W WINDS 10-15 KT WITH GUSTS 20-25 KT FROM ABOUT 14Z-22Z...DIMINISHING TO AOB 10 KT WED EVENING. .OUTLOOK FOR 00Z THU THROUGH SUNDAY... .WED NIGHT...VFR. .THU...CHANCE OF LIGHT SNOW WITH MVFR CONDS. .FRI-SAT...VFR. .SUNDAY...VFR DAYTIME. CHANCE OF MIXED PCPN WITH MVFR CONDS AT NIGHT. && .MARINE... SOUTH FLOW AS HIGH PRESSURE DEPARTS ALLOWED FOR SEAS ON THE OCEAN WATERS TO BUILD TO AROUND 3 FT. WIND WILL DECREASE LATE TONIGHT AS THE HIGH MOVES NORTHEAST AND LOW PRESSURE PASSES TO THE SOUTH AND EAST. WIND MAY BECOME CALM FOR AWHILE THE SHIFT TO MORE WEST TO SOUTHWEST AS LOW PASSES. INCREASED SEAS ON THE OCEAN UNTIL AROUND 07Z...THEN SEAS LOOKED TO BE ON TRACK AFTER THAT. THE PRES GRADIENT WILL TIGHTEN ON WEDNESDAY...AND SMALL CRAFT ADVISORY CONDS WILL DEVELOP ON THE OCEAN WATERS. WILL ISSUE A SMALL CRAFT ADVISORY FOR THE OCEAN WATERS FOR WEDNESDAY FOR GUSTS TO 25 KT AND SEAS BUILDING TO AROUND 5 FT. SOME FREEZING SPRAY IS POSSIBLE FOR OCEAN WATERS AS WELL DURING THE DAY WEDNESDAY. WINDS AND SEAS DIMINISH THU...WITH CONDS BLW SCA LVLS THRU MON. && .HYDROLOGY... LIGHT SNOW WILL FALL OVER FAR EASTERN ZONES TONIGHT WITH UP TO A TENTH OF AN INCH LIQUID EQUIVALENT. OTHERWISE...MAINLY DRY WEATHER CAN BE EXPECTED UNTIL SUNDAY NIGHT AND MONDAY. ICE WILL CONTINUE TO DEVELOP ON LOCAL AREA RIVERS AND STREAMS AS TEMPS REMAIN WELL BELOW AVERAGE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR ANZ350-353-355. && $$ SYNOPSIS...JMC/MPS NEAR TERM...MET SHORT TERM...MPS LONG TERM...JMC AVIATION...GOODMAN MARINE...MET HYDROLOGY...JMC/MPS

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