Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 171749 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 149 PM EDT WED SEP 17 2014 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE REGION THROUGH SATURDAY. LOW PRESSURE WILL THEN TRACK FROM THE GREAT LAKES THROUGH SOUTHEAST CANADA SATURDAY NIGHT AND SUNDAY WITH A COLD FRONT MOVING INTO THE AREA SUNDAY NIGHT AND POSSIBLY LINGERING THROUGH MONDAY. HIGH PRESSURE BUILDS BACK IN FOR TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE OVER THE AREA WITH STRONG SUBSIDENCE KEEPING ARE CLOUD FREE. MAYBE A FEW FAIR WEATHER CUMULUS POPPING UP THIS AFTERNOON OVER THE WESTERN ZONES AS SOME MOISTURE ADVECTS IN BELOW AN INVERSION NEAR 800-750 MB. RAISED DEW POINTS SEVERAL DEGREES INLAND AS DEW POINTS HAVE BEEN CLIMBING SLOWLY AS MOISTURE MOVES INTO THE REGION. WIND/THERMAL/MOISTURE PROFILES IN THE BOUNDARY LAYER SHOULD ALLOW FOR SEA BREEZES TO DEVELOP THIS AFTERNOON. A MAV/NAM MOS BLEND LOOKED GOOD FOR HIGH TEMPS. THERE IS A MODERATE RISK OF RIP CURRENT DEVELOPMENT AT THE ATLANTIC BEACHES ON TODAY. THIS MAY INCREASE TO A HIGH RISK LATE IN THE DAY DUE TO SWELLS FROM TROPICAL CYCLONE EDOUARD...SITUATED WELL OUT TO SEA. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... HIGH PRESSURE REMAINS THE DOMINANT FEATURE IN THE PATTERN DURING THIS PERIOD. AT THE SAME TIME...THE FLOW ALOFT AMPLIFIES WITH A MID LEVEL SHORTWAVE PASSING THROUGH DURING THURSDAY AFTERNOON/EVENING. SURFACE REFLECTION IN THE FORM OF A COLD FRONT/TROUGH PASSES THROUGH AT THE SAME TIME. LOOKS LIKE MOISTURE WILL BE TOO LIMITED FOR ANY CHANCE OF SHOWERS. 00Z GFS HAS EVEN BACKED OFF ON QPF OUTPUT WITH THE PASSAGE OF THESE FEATURES AS COMPARED TO ITS PREVIOUS FEW RUNS. WILL CONTINUE WITH A DRY FORECAST TONIGHT THRU THURS NIGHT. TEMPS THROUGH THE PERIOD ARE A MAV/NAM MOS BLEND...ALTHOUGH WEIGHTED MORE TOWARDS THE COOLER MAV GUIDANCE FOR HIGHS ON THURSDAY. LOW TEMPS ACROSS SOME THE NW SUBURBS DROP INTO THE LOWER 40S THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT WITH THE OVERALL H5 FLOW THROUGH THE LONG TERM...ALTHOUGH THERE ARE TIMING AND AMPLITUDE DIFFERENCES APPARENT THROUGH THE ENTIRE PERIOD. THE NORTHERN BRANCH OF THE JET STREAM WILL START OFF OVER SRN CANADA...BUT AS A CUTOFF LOW TRACKS INTO THE GULF OF ALASKA ON SAT...THE FLOW WILL AMPLIFY DOWNSTREAM RESULTING IN RIDGING OVER THE SW CANADA/PACNW AND A DIGGING TROUGH IN SE CANADA/THE GREAT LAKES REGION. THIS TROUGH WILL PERSIST OVER THE ERN US THROUGH EARLY NEXT WEEK. AT THE SFC...HIGH PRES OVER NORTHERN NEW ENGLAND FRI MORNING WILL TRACK OFFSHORE FRI NIGHT AND SAT. DRY WEATHER WILL PERSIST THROUGH THIS TIME. AS THE AFOREMENTIONED TROUGH DIGS OVER THE GREAT LAKES ON SAT...SFC LOW PRES WILL DEVELOP AND TRACK THROUGH SE CANADA SAT NIGHT AND SUN. THIS FEATURES WARM FRONT WILL PASS BY TO THE N ON SUN...FOLLOWED BY ITS COLD FRONT SUN NIGHT INTO MON MORNING. THE BIGGEST CHANGE WITH THIS SINCE YESTERDAY IS THE DECREASE IN THE AMOUNT OF RAINFALL FORECAST WITH IT. THEREFORE...HAVE LOWERED POPS A TAD. A BIG DIFFERENCE BETWEEN THE OPERATIONS GFS AND EC IS THAT THE 00Z EC HAS THE FRONT GETTING HUNG UP OVER THE AREA ON MON WITH A WAVE OF LOW PRES DEVELOPING ON IT. THE UPPER FLOW DOES BECOME PARALLEL TO THE FRONT IN BOTH MODELS AND THIS IS A POSSIBILITY BUT WOULD LIKE TO SEE THIS SOLN FOR A FEW MODEL RUNS BEFORE COMMITTING. HIGH PRES THEN BUILDS BACK IN FOR TUE. TEMPERATURES WILL VARY OVER THE PERIOD...FRI...MON NIGHT...TUE AND TUE NIGHT ALL BELOW NORMAL WHILE THE REMAINDER OF THE PERIOD WILL BE NEAR TO ABOVE NORMAL. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... HIGH PRESSURE THROUGH THE TAF PERIOD WILL KEEP VFR CONDITIONS IN PLACE. FEW-SCT CUMULUS DEVELOPMENT THROUGH REST OF TODAY MAINLY N/W OF CITY TERMINALS. SEA BREEZES WILL BE LIKELY WITH NORTH WINDS OF 5-10 KT BECOMING MORE SOUTHERLY. THERE IS SOME UNCERTAINTY OF A FEW HOURS WITH THIS TIMING. FOR EXAMPLE...RESIDUAL NORTHERLY FLOW COULD CAUSE SEA BREEZE TO HALT PROGRESS AND DELAY ENTERING OTHER TERMINALS AFTER KJFK. WINDS LIGHTEN AGAIN TONIGHT BEFORE INCREASING TO 5-10 KT FROM A GENERAL NORTHWEST DIRECTION EARLY THURSDAY. OVERALL...HIGH CONFIDENCE CATEGORY FORECAST AND MODERATE CONFIDENCE WITH WINDS. 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: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 1-2 HOURS. KLGA FCSTER COMMENTS: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 2-3 HOURS. KEWR FCSTER COMMENTS: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 2-3 HOURS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 2-3 HOURS. KHPN FCSTER COMMENTS: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 1-2 HOURS. KISP FCSTER COMMENTS: WIND DIRECTION COULD BECOME QUITE VARIABLE BEFORE THE SEA BREEZE...WHICH ITSELF COULD BE OFF BY 2-3 HOURS. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THURSDAY-SUNDAY...VFR. .SUNDAY NIGHT-MONDAY...CHANCE OF MVFR OR BELOW WITH POSSIBLE SHOWERS. && .MARINE... FORECAST WIND AND SEAS ON TRACK WITH NO CHANGES AT THIS TIME. WINDS WILL BE ON THE LIGHTER SIDE TODAY THROUGH EARLY THURSDAY EVENING WITH A WEAK PRESSURE GRADIENT OVER THE AREA. A COLD FRONT THEN MOVES THROUGH LATER IN THE NIGHT WITH WIND GUSTS APPROACHING 25 KT...BUT PROBABLY FALLING JUST SHORT OF IT. ASIDE FROM THIS...SEAS ON THE OCEAN WILL CONTINUE TO BUILD TODAY AND THURSDAY DUE TO SWELLS FROM EDOUARD. WAVEWATCH IS RUNNING ABOUT 2 FEET TOO HIGH...WITH THE NAH MODEL PERFORMING MUCH BETTER SO FAR. NAH BRIEFLY BUILDS SEAS UP TO 5 FT ON THE OCEAN LATE TONIGHT/EARLY THURS MORNING. SINCE IT IS A MARGINAL EVENT THAT WOULD APPEAR TO LAST FOR ONLY A SHORT TIME...WILL HOLD OFF ON ISSUING A SCA AT THIS TIME. A MODERATE NE FLOW FRI IS EXPECTED TO CAUSE MARGINAL SCA SEAS TO CONTINUE ON THE OCEAN WATERS FRI/FRI NIGHT. GUSTS WILL BE DIMINISHING FRI MORNING. SUB-ADVSY CONDS ARE THEN EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD. && .HYDROLOGY... NO RAINFALL IS EXPECTED THROUGH THE FIRST HALF OF THE WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JC/24 NEAR TERM...JC/24/MET SHORT TERM...JC LONG TERM...24 AVIATION...JM MARINE...JC/24 HYDROLOGY...JC/24

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