Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 121711 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 111 PM EDT SAT APR 12 2014 .SYNOPSIS... HIGH PRESSURE OVER THE REGION THIS AFTERNOON MOVES EAST TONIGHT. THE HIGH REMAINS OFF THE MID ATLANTIC COAST SUNDAY AND SUNDAY NIGHT. EARLY NEXT WEEK...A COLD FRONT APPROACHES SLOWLY FROM THE WEST...AS WAVES OF LOW PRESSURE DEVELOP ALONG IT. THE FRONT MOVES IN TUESDAY AND EXITS TO THE SOUTHEAST OF THE REGION TUESDAY NIGHT. THE FRONT STALLS TO THE SOUTH OF THE REGION AS HIGH PRESSURE TRIES TO BUILD IN FROM THE NORTH MID TO LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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TEMPERATURES WILL REMAIN A CHALLENGE THIS AFTERNOON AS WINDS SHIFT TO ONSHORE DIRECTIONS DUE TO SEABREEZE. THERE SHOULD BE NOTABLE DIFFERENCES IN TEMPS THIS AFTERNOON WITH WARMER READINGS ACROSS THE INTERIOR...AND MUCH COOLER TEMPS NEAR THE COAST. ASIDE FROM ONSHORE WIND COMPONENT...MORNING SOUNDING WOULD SUGGEST MAX TEMP IN THE LOWER 70S. ALREADY OBSERVING TEMPS RIGHT AROUND 70 IN NE NJ WITH WEST WIND. PLENTY OF SUNSHINE IS ANTICIPATED THIS AFTERNOON.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... HEIGHTS CONTINUE TO RISE ACROSS THE AREA TONIGHT INTO SUNDAY AS THE SURFACE HIGH OVER THE REGION MOVES OFF THE NORTHEAST COAST. MEANWHILE HIGH PRESSURE OFF THE MID ATLANTIC WILL BECOME THE DOMINATE HIGH AND REMAIN INTO SUNDAY. RISING DEW POINTS ACROSS THE AREA WITH LIGHT WIND MAYE RESULT IN SOME FOG TOWARD SUNDAY MORNING...MAINLY ALONG THE COAST. THE FOG WILL PERSIST INTO SUNDAY MORNING BEFORE DISSIPATING. A WEAK WAVE MOVING THROUGH THE UPPER RIDGE SUNDAY AFTERNOON WILL BRING AN INCREASE IN CLOUDINESS. AN INCREASING SOUTHERLY FLOW AROUND THE HIGH AND LOW PRESSURE APPROACHING FROM THE WEST SUNDAY WILL RESULT IN BREEZY CONDITIONS. COASTAL AREAS WILL REMAIN COOLER WITH THE FLOW OFF THE ATLANTIC WHILE INLAND AREAS WILL BE MUCH WARMER. LEANED TOWARD THE NAM GUIDANCE FOR LOWS TONIGHT AND HIGHS SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... OVERALL...IN THE MID TO UPPER LEVELS...MORE MERIDIONAL FLOW WITH RIDGING ACROSS THE EASTERN COAST LATE THIS WEEKEND INTO EARLY NEXT WEEK...IN RESPONSE TO TROUGHING IN CENTRAL U.S. THIS TROUGH WILL SLOWLY BE APPROACHING...EVENTUALLY MOVING INTO THE LOCAL REGION TUESDAY AS A STRONG UPPER LEVEL LOW PIVOTS INTO SOUTHEAST CANADA. IN OUR REGION...WITH A RIDGE OF HIGH PRESSURE BUILDING OFFSHORE...WARM AND MOIST AIR ADVECTION WILL CONTINUE SUNDAY NIGHT THROUGH EARLY NEXT WEEK. A GRADUALLY INCREASING TREND IN TEMPS AND DEWPOINTS WILL BE THE RESULT. WITH THE SECOND AND THIRD NIGHT OF ONSHORE FLOW...SUNDAY NIGHT AND MONDAY NIGHT...ENOUGH MOISTURE WILL BE ADVECTING INTO THE LOW LEVELS TO MAKE FOR PATCHY FOG AND AREAS OF FOG MONDAY NIGHT INTO TUESDAY...ESPECIALLY OVER THE COASTAL AREAS. THE CONTINUOUS MOISTURE AND WARMTH IS FED BY A DEVELOPING SOUTHERLY JET IN THE UPPER LEVELS. MODELS SHOW THE JET TAPPING INTO THE GULF OF MEXICO AND EMBEDDED STREAKS OF AROUND 130-150 KT. SOME UNCERTAINTY AS TO HOW MUCH OF THIS LOW LEVEL MOISTURE IS FOG VERSUS STRATUS FOR MONDAY NIGHT AND TUESDAY. ONE THING THAT IS MORE CERTAIN IS THE INCREASING CHANCES OF SHOWERS AS THE COLD FRONT DRAWS CLOSER TO THE REGION. WITH THE UPPER AND LOW LEVEL JETS FEEDING IN MOISTURE...THE HIGH PRECIPITABLE WATERS OF AROUND 1.25 TO 1.5 INCH...EXCEEDS 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. THERE WILL BE A POTENTIAL FOR HEAVY RAIN. SEE HYDRO SECTION FOR MORE DETAILS. THE BULK OF SHOWERS MOVES ACROSS TUESDAY...ENDING FROM WEST TO EAST LATE TUESDAY NIGHT. A MUCH COLDER AIR MASS RELATIVELY SPEAKING MOVES IN WITH CANADIAN HIGH PRESSURE FOR MID TO LATE NEXT WEEK. THERE IS SOME UNCERTAINTY WITH THE DISTANCE THE FRONT PUSHES OFFSHORE EARLY WEDNESDAY AND HOW DRY THE WEATHER WILL BE. ECMWF HAS HAD WIDE FLUCTUATIONS WITH THIS AND ASSOCIATED LOW ALONG THE FRONT WITH GFS AND CMC KEEPING HIGH PRESSURE STRONGER AND CLOSER TO THE AREA...PUSHING FRONT FARTHER SOUTH. HAVE KEPT A SLIGHT CHANCE OF POPS WEDNESDAY AND WEDNESDAY NIGHT...MOSTLY SOUTHERN PORTIONS OF THE FORECAST REGION TO ACCOUNT FOR THIS. WITH COLDER AIR AND TIMING...SOME OF THE LEFTOVER RAIN SHOWERS COULD MIX WITH SNOW SHOWERS LATE TUESDAY NIGHT AS WELL AS LATE WEDNESDAY NIGHT. THEREFORE...THE OVERALL SIGNALS STILL POINT TO A MOSTLY DRY PICTURE FOR MID TO LATE IN THE WEEK WITH TEMPERATURES BELOW NORMAL. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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HIGH PRESSURE BUILDS OVER THE TERMINALS THROUGH TODAY...AND MOVES OFFSHORE TONIGHT. VFR THRU 6Z...THEN MOST LIKELY VFR THRU 18Z. THERE IS A SUGGESTION IN SOME OF THE DATA THAT IFR STRATUS WILL DEVELOP FOR A A COUPLE HOURS SUN MRNG. THE TAFS LEAN TOWARDS VFR BECAUSE OF THE DRY AIRMASS IN PLACE. IN THE EXTENDED TAFS...IFR MAY DEVELOP BY 00Z MON...MAINLY S COASTS...WITH PERSISTENT FLOW OFF THE OCEAN. SOME VARIABILITY IN THE WINDS TIL THE SEA BREEZES SET IN. LIGHT NW FLOW BACKS TO THE W WITH GUSTS AS MIXING PRODUCES A CHANGE IN DIRECTION. LIGHT FLOW TNGT BECOMES SLY BY SUN MRNG...WITH SPEEDS INCREASING THRU THE TAF PERIOD. .OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY... .SUN...LOW CHC IFR BY 00Z. S WINDS AROUND 20KT. .SUN NGT-MON...PERIODS OF IFR/LIFR. S WINDS 15-25KT. .MON NGT-TUE...IFR LIKELY WITH RAIN AND FOG. LLWS POSSIBLE. .WED...VFR. .THU...VFR.
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&& .MARINE...
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SEAS REMAIN ELEVATED DUE TO S/SE SWELL. THESE PERSISTENT SEAS IN THE 4 TO 6 FOOT RANGE HAVE NOT BEEN CAPTURED WELL BY WAVE WATCH. EXTENDED AND EXPANDED THE SMALL CRAFT FOR HAZ SEAS EARLIER THROUGH 22Z...AND WILL REEVALUATE LATER ON. INCREASING DEW POINTS...INTO THE UPPER 40S AND LOWER 50S TONIGHT INTO SUNDAY WILL INCREASE THE LIKELIHOOD OF FOG DEVELOPING OVER THE OCEAN WATERS AND LONG ISLAND SOUND. OTHERWISE...WITH HIGH PRESSURE BUILDING OVER THE FORECAST WATERS TODAY AND TONIGHT TRANQUIL CONDITIONS ARE EXPECTED. THE HIGH MOVES EAST SUNDAY AS A SLOW MOVING FRONTAL APPROACHES. THE PRESSURE GRADIENT WILL INCREASE ACROSS THE WATERS SUNDAY...AND A SOUTHERLY FLOW WILL INCREASE IN RESPONSE. WIND AND GUSTS WILL LIKELY REMAIN BELOW SMALL CRAFT ADVISORY LEVELS...HOWEVER...WITH THE PERSISTENT SOUTHERLY FLOW SEAS ON THE OCEAN WATERS WILL LIKELY BUILD TO 5 TO 6 FT BY SUNDAY AFTERNOON. THE LONG TERM PERIOD IS FORECAST TO HAVE SCA CONDITIONS MUCH OF THE TIME COVERING SUNDAY NIGHT THROUGH MID NEXT WEEK. THE CONTINUED SOUTHERLY FETCH AND SWELL WILL ALLOW FOR AT LEAST 5 FT SEAS ON THE OCEAN DURING THIS PERIOD. EVEN BEHIND THE FRONT TUESDAY NIGHT AND WEDNESDAY...RESIDUAL SWELL WILL KEEP THE HIGHER SEAS IN PLACE. IN TERMS OF WINDS...SUNDAY NIGHT THROUGH MONDAY NIGHT COULD HAVE GUSTS LIMITED TO DUE TO INCREASING INVERSION BUT BY TUESDAY EVEN SUSTAINED WINDS REACH 25 KT ON THE OCEAN WITH GALES POSSIBLE DURING THE DAY AND ALSO AT NIGHT.
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&& .HYDROLOGY... DRY THROUGH MONDAY. NEXT WIDESPREAD RAIN EVENT IS TUESDAY THROUGH TUESDAY NIGHT. MODEL QPF RANGES MAINLY BETWEEN 1-2 INCHES FOR THAT TIMEFRAME. WITH PWATS FORECAST OF 1.25 TO 1.5 INCHES LATE MONDAY NIGHT THROUGH TUESDAY...HEAVY RAINFALL WILL BE POSSIBLE WHICH WOULD RESULT IN LOCALIZED AMOUNTS HIGHER THAN FORECAST...POSSIBLY UP TO 3 INCHES. PLEASE NOTE THAT MODEL TOTAL QPF RANGES COULD CHANGE WITH SUBSEQUENT MODEL RUNS. WITH THE UNCERTAINTY...DIFFICULT TO STATE THE EXACT POTENTIAL AND MAGNITUDE OF ANY POSSIBLE FLOODING FOR EXACT LOCATIONS BUT AT THIS POINT WITH THE LONG DURATION OF THIS RAINFALL...MINOR AND POOR DRAINAGE FLOODING INCLUDING MINOR FLOODING OF RIVERS AND STREAMS LOOKS TO BE THE MOST LIKELY THREATS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS EVENING FOR ANZ350-353. && $$ SYNOPSIS...JM/MET NEAR TERM...JM/MET/PW SHORT TERM...MET LONG TERM...JM AVIATION...JMC MARINE...JM/MET/PW HYDROLOGY...JM/MET

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