Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 130246 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1046 PM EDT FRI SEP 12 2014 .SYNOPSIS... A FRONTAL WAVE OVER THE OHIO VALLEY WILL LINK UP WITH AN UPPER LEVEL DISTURBANCE ACROSS THE GREAT LAKES TONIGHT. THIS LOW WILL PASS TO NORTH LATE SATURDAY...SENDING A COLD FRONT THROUGH IN THE EVENING. AT THE SAME TIME...A WEAK COASTAL LOW WILL PASS TO THE SOUTH AND EAST OF LONG ISLAND. HIGH PRESSURE CONTROLS THE WEATHER SUNDAY THROUGH MONDAY FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE ON TUESDAY. COOL HIGH PRESSURE RETURNS AGAIN FOR WEDNESDAY INTO LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MINOR UPDATES TO REFLECT LATEST TEMP/DEWPOINT/SKY TRENDS. FORECAST IS ON TRACK. MODELS ARE IN GOOD AGREEMENT WITH TAKING A STRONG MID LEVEL SHORT WAVE TROF ACROSS THE GREAT LAKES TONIGHT AND THEN NE INTO CANADA ON SAT. THIS WILL ALLOW A FRONTAL WAVE OVER THE TN VALLEY TO LIFT NE...WHILE ANOTHER WEAK LOW DEVELOPS ALONG A COASTAL FRONT NEAR THE SE U.S. COAST. PRECEDING THIS DISTURBANCE TONIGHT WILL BE A TRANSIENT HIGH THAT PASSES TO THE NORTH AND MAINTAINS A SHALLOW DOME OF COOL AIR THAT WILL SET THE STAGE FOR A LIGHT TO MODERATE OVERRUNNING RAIN EVENT ON SAT. IN ADDITION...THIS WILL ALLOW FOR NE WINDS TONIGHT TO VEER TO THE E...FEEDING ATLANTIC MOISTURE INTO THE APPROACHING FRONTAL SYSTEM. CLOUDS WILL BE ON THE INCREASE LATE TONIGHT AS STRATUS DEVELOPS IN THE EASTERLY FLOW. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S INLAND...TO 55 TO 60 AT THE COAST. THIS IS SLIGHTLY BELOW NORMAL. STAYED CLOSE TO A MET/MAV MOS BLEND. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... HIGH PRESSURE BUILDS EAST ACROSS THE CANADIAN MARITIMES ON SAT...WHILE A FRONTAL SYSTEM WILL APPROACH FROM THE WEST. TWO AREAS OF LOW PRESSURE WILL BE FEATURED...ONE MOVING TO THE NORTH SAT NIGHT AND ANOTHER PASSING TO THE SE. THESE ARE WEAK SYSTEMS WITH THE MAIN IMPACTS BEING LIGHT TO MODERATE OVERRUNNING RAINS FROM THE LATE MORNING THROUGH THE EARLY EVENING HOURS. COLD FRONT WILL MOVE THROUGH SAT EVENING WITH A WIND SHIFT TO THE NW. ANOTHER SHOT OF DRY...COOL AUTUMN AIR WILL FOLLOW. HIGHS ON SAT WILL RANGE FROM THE UPPER 60S TO THE LOWER 70S...WITH LOWS IN THE UPPER 40S TO UPPER 50S. THESE READINGS ARE SEVERAL DEGREES BELOW NORMAL. THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC FACING BEACHES ON SAT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... CHANGES IN THE LONG TERM WITH THIS AFTERNOON`S UPDATE INCLUDE LOWER TEMPS AND FOCUS PCPN ON TUESDAY. LATEST NWP DATA REMAINS CONSISTENT WITH HIGH PRESSURE BUILDING IN ON SUNDAY AND MOVING OFFSHORE MONDAY AFTN. NEXT SHORTWAVE FROM WESTERN CANADA PASSES OVER ON TUESDAY WITH A SFC COLD FRONT. 12Z DETERMINISTIC EC IS MUCH MORE BULLISH WITH THE PCPN THAN THE GFS FOR TUESDAY, BUT IS ALSO ON AN UPWARD TREND FROM THE 00Z RUN. CMC GEM IS SORT OF IN THE MIDDLE. WITH ENSEMBLE GFS AND ECMWF MOS DATA SUPPORTING LIKELY POPS HAVE GONE WITH THIS FOR TUESDAY. HIGH PRESSURE RETURNS FOR WED-FRI. CMC AND GFS ARE COOLER THAN EC. WPC GUIDANCE IS TOO WARM...ESPECIALLY ON THURSDAY. HAVE GENERALLY LOWER TEMPS MOST PERIODS FROM PREVIOUS FORECASTS BASED ON ENSEMBLE AND BLENDED MOS. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... HIGH PRES WILL TRACK ACROSS SE CANADA TONIGHT. MEANWHILE...LOW PRES WILL DEVELOP NEAR THE EASTERN GREAT LAKES AND LIFT INTO SE CANADA ON SAT AS A WEAK COASTAL LOW PRES SYSTEM PASSES S OF LONG ISLAND. LATEST SAT IMAGERY INDICATING LOW CLOUDS AROUND 3K FT HAVE ALREADY DEVELOPED JUST NEAR KGON. SHOULD BE IN THERE SHORTLY AND HAVE NOW BACKED UP TIMING OF IT GETTING INTO KBDR/KISP TO 06Z WITH AN ELY FLOW EXPECTED OVERNIGHT. HAVE HIGHER CONFIDENCE THAT LOWER CLOUDS WILL BE IN SOONER RATHER THAN LATER EVEN AT WESTERN TERMINALS...SO HAVE MADE ADJUSTMENTS HERE AS WELL. TIMING COULD STILL BE OFF 1-2 HOURS AND WILL NEED TO BE MONITORED. VSBYS SHOULD REMAIN P6SM UNTIL RAIN MOVES IN SAT AFTN. THERE IS ALSO THE POSSIBILITY THAT CIGS DROP TO IFR LATE SAT AFTN BUT CONFIDENCE NOT HIGH ENOUGH TO GO THAT LOW ATTM. MODERATE TO HIGH CONFIDENCE IN WIND FORECAST. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .SAT NIGHT...RAIN ENDING WITH CONDS IMPROVING BACK TO VFR. N-NW WINDS 10-15G20KT. .SUN-MON...VFR. .TUE...CHC MVFR -SHRA .WED...VFR. && .MARINE... AS HIGH PRESSURE PASSES TO THE NORTH TONIGHT AND A FRONTAL WAVE TRACK OFF THE MID ATLANTIC COAST ON SAT...AN EASTERLY FLOW WILL DEVELOP AND STRENGTHEN OVERNIGHT INTO THE FIRST HALF OF SAT. AT THIS TIME...WINDS AND SEAS LOOK TO BE BELOW SCA CRITERIA WITH WINDS UP TO 4 FT ON THE OCEAN WATERS...AND GUSTS UP TO 20 KT ALL WATERS. A NW FLOW DEVELOPS BEHIND A COLD FRONTAL PASSAGE SAT NIGHT. WIND AND SEAS WILL REMAIN BELOW SMALL CRAFT LEVELS SUNDAY THROUGH TUESDAY. SOUTHWEST SWELLS FROM DISTANT TROPICAL CYCLONE EDOUARD COULD REACH THE REGION STARTING WEDNESDAY. ALSO ON WEDNESDAY NIGHT...NORTHERLY FLOW IN THE WAKE OF A COLD FRONT COULD WIND GUSTS APPROACH SCA LEVELS. && .HYDROLOGY... RAINFALL AMOUNTS ON SAT LOOK TO BE A 1/4 INCH OR LESS...THEN ON TUESDAY 1/4 TO 3/4 INCH IS POSSIBLE. NO HYDROLOGIC PROBLEMS ARE EXPECTED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...TONGUE/DW NEAR TERM...JC/DW SHORT TERM...DW LONG TERM...TONGUE AVIATION...24 MARINE...TONGUE/DW HYDROLOGY...TONGUE/DW

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