Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 170911 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 411 AM EST WED DEC 17 2014 .SYNOPSIS... LOW PRESSURE MOVES NORTHEAST TODAY...TOWARD THE CANADIAN MARITIMES TONIGHT AND THURSDAY. HIGH PRESSURE WILL BUILD INTO NEW ENGLAND AT THE END OF THE WEEK AND SLOWLY DEPART OVER THE WEEKEND AS LOW PRESSURE TRACKS ACROSS THE SOUTHERN U.S. THIS LOW WILL TRACK FROM THE SOUTHEAST COAST TO THE MID ATLANTIC COAST EARLY NEXT WEEK BEFORE CONTINUING ON A NORTHEAST TRACK. MEANWHILE A STRONGER LOW PRESSURE SYSTEM WILL APPROACH FOR THE MIDDLE OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPPER LEVEL SHORTWAVE PIVOTS NORTHEASTWARD THIS MORNING AROUND CLOSED LOW OVER THE GREAT LAKES REGION THIS MORNING. THE LOW SLOWLY MOVES EAST TOWARD THE AREA TODAY. THIS CLOSED LOW MOVES TO NY STATE BY LATE IN THE DAY. AT THE SURFACE...LOW PRESSURE APPROACHING CAPE COD THIS MORNING WILL TRACK TOWARD THE GULF OF MAINE BY AFTERNOON. PARENT LOW NEAR LAKE ONTARIO WEAKENS AS SECONDARY COASTAL LOW DEEPENS BY LATE IN THE DAY. MAIN AREA OF RAIN PULLS AWAY THIS MORNING AHEAD OF THE FRONT/UPPER SHORTWAVE AND COASTAL LOW. THEREAFTER...CANNOT RULE OUT A FEW SHOWERS DUE TO INSTABILITY AND APPROACHING PVA LATER ON. WESTERLY WINDS INCREASE TODAY AND WILL BE GUSTY BY AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS BEHIND THE LOW. AS FOR HIGH TEMPS TODAY...ANY COLD AIR ADVECTION WILL ARRIVE TOO LATE TO PREVENT TEMPS FROM REACHING THE UPPER 40S TO AROUND 50. READINGS WILL BE QUITE MILD THIS MORNING...AND A SLIGHT RISE IS EXPECTED BEFORE TEMPERATURES DROP LATER ON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... ALOFT...CLOSED UPPER LOW MOVES ACROSS SOUTHERN NEW ENGLAND TONIGHT...WITH ASSOCIATED PVA MOVING THROUGH BEFORE MIDNIGHT. THIS LOW PIVOTS TOWARD THE CANADIAN MARITIMES...WITH CYCLONIC FLOW THROUGH THURSDAY FOR OUR REGION. SURFACE LOW PRESSURE CONTINUES TO DEEPEN THROUGH THE PERIOD AS IT SLOWLY MOVES TOWARD THE CANADIAN MARITIMES. HIGH PRESSURE BUILDS WELL TO THE WEST. FOR TONIGHT...ANY LINGERING RAIN SHOWERS WILL TRANSITION TO SNOW SHOWERS OR FLURRIES AS COLDER AIR ARRIVES. FEEL MOISTURE IS DEEP ENOUGH EARLY TONIGHT FOR ANY PRECIP TO BE IN THE FORM OF SNOW...FROM WEST TO EAST. AS THE STACKED LOW LIFTS NORTHEAST LATE TONIGHT AND THROUGH THURSDAY...DEEPENING NW FLOW SHOULD PRECLUDE ADDITIONAL SNOW SHOWER ACTIVITY. MOISTURE LOOKS TO BE RATHER SHALLOW PER TIME HEIGHTS OF ECMWF/GFS AND NAM. WITH COLDER AIR MOVING IN...GUSTY NW WINDS IN A TIGHT PRESSURE GRADIENT CAN BE EXPECTED LATER TONIGHT AND THROUGH THE DAY THURSDAY. MIXED LAYER DEEP ENOUGH FOR STRONGER GUSTS OF 20 TO 30 MPH DURING THE DAY THURSDAY. AS FOR TEMPERATURES...CLOSER TO NORMAL READINGS ARE FORECAST. EXPECT LOWS TONIGHT TO RANGE FROM THE UPPER 20S INLAND TO THE LOWER TO MID 30S NEAR THE COAST. ON THURSDAY...HIGH TEMPS SHOULD RISE TO THE LOWER TO MID 40S. MOS NUMBERS ARE FAIRLY CLOSE...BUT LEANED TOWARD THE COOLER GUIDANCE WHERE APPROPRIATE. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT WITH THE H5 FLOW ACROSS NOAM INTO THE WEEKEND...BUT START TO DIVERGE ON SUNDAY WITH TIMING AND AMPLITUDE DIFFERENCES APPARENT BY EARLY NEXT WEEK. ANOMALOUS UPPER RIDGE NEAR JAMES BAY IN SOUTHERN CANADA WILL TRACK EWD ACROSS NRN NEW ENGLAND WHILE WEAKENING. THIS WILL RESULT IN DRY AND SEASONABLE WEATHER FROM THU NIGHT THROUGH SAT. A SHORTWAVE TROUGH WILL MOVE ACROSS THE AREA LATE SAT NIGHT INTO SUN WITH SOME LIGHT PCPN EXPECTED. MAINLY SNOW INLAND AND RAIN AT THE COAST. GFS IS UP TO ITS OLD TRICKS OF DEPARTING THE RIDGE TOO QUICKLY...SO LEANED HEAVILY TOWARDS THE EC SOLN WITH THIS FEATURE AND THEN BACKED OFF A BIT WITH LOW PRES TRACKING UP THE COAST FROM THE SE FOR EARLY NEXT WEEK. THE GFS UPPER FLOW IS PROBABLY TOO FLAT AND TAKING IT TOO FAR OUT TO SEA...BUT ALSO THINK THE 00Z EC IS TOO FAR W. SO HAVE COMPROMISED THIS PART OF THE FORECAST WITH A 60/40 12ZEC/00ZGFS BLEND. THIS RESULTS IN LOW POPS MON NIGHT INTO TUE. THEN...THERE IS GOOD AGREEMENT AMONGST THE GUIDANCE THAT A STRONGER AREA OF LOW PRES WILL IMPACT THE AREA FOR THE MIDDLE OF THE WEEK...ALTHOUGH TIMING REMAINS UNCERTAIN AND THEREFORE IMPACTS AS WELL. HOWEVER IT DOES LOOK LIKE MOSTLY A LIQUID EVENT AT THIS TIME. TEMPS THROUGH THE REMAINDER OF THE PERIOD LOOK TO BE NEAR NORMAL LEVELS. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE DEEPENS INTO GULF OF MAINE AND CANADIAN MARITIMES THROUGH THURSDAY AS HIGH PRESSURE TO THE WEST...EVENTUALLY SLOWLY BUILDING INTO THE AREA. MAINLY IFR/LIFR IN FOG AND LEFTOVER RAIN INTO THIS MORNING WITH IMPROVEMENT TO MVFR AND EVENTUALLY VFR BY LATE MORNING/EARLY AFTERNOON. VFR THEN STAYS THROUGH REST OF TAF PERIOD BUT MVFR WILL BE POSSIBLE AT TIMES. WINDS WILL BE NW LESS THAN 10 KT...INCREASING TO AROUND 15KT WITH GUSTS AROUND 25KT TODAY. WINDS STAY UP NEAR THE COAST TONIGHT AND GRADUALLY SUBSIDE ELSEWHERE. ...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: UNCERTAINTY OF +/- 2 HRS WITH END TIME OF IFR AND MVFR. KLGA FCSTER COMMENTS: UNCERTAINTY OF +/- 2 HRS WITH END TIME OF LIFR/IFR AND MVFR. KEWR FCSTER COMMENTS: UNCERTAINTY OF +/- 2 HRS WITH END TIME OF IFR AND MVFR. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: UNCERTAINTY OF +/- 2 HRS WITH END TIME OF IFR AND MVFR. KHPN FCSTER COMMENTS: UNCERTAINTY OF +/- 3 HRS WITH END TIME OF LIFR/IFR AND MVFR. KISP FCSTER COMMENTS: UNCERTAINTY OF +/- 3 HRS WITH END TIME OF LIFR/IFR AND MVFR. .OUTLOOK FOR 09Z THU THROUGH SAT... .WED NIGHT...VFR. W 10-15KT. GUSTS 20-25KT NEAR COAST. .THU...VFR. NW 10-15KT. GUSTS 20-25KT. .FRI-SAT...VFR. .SUN...SUB-VFR IN RAIN AND/OR SNOW. && .MARINE... WESTERLY WINDS THIS MORNING WILL INCREASE AS LOW PRESSURE PULLS AWAY FROM THE WATERS. THE LOW DEEPENS AS IT TRACKS TOWARD THE CANADIAN MARITIMES TONIGHT AND THURSDAY. WINDS WILL INCREASE TO SMALL CRAFT ADVISORY LEVELS...OR GUSTS TO 25 KTS LATER THIS MORNING FOR THE OCEAN WATERS...AND LATE THIS AFTERNOON FOR THE WATERS SURROUNDING LONG ISLAND. THESE INCREASINGLY STRONG AND GUSTY WINDS CONTINUE TONIGHT AND THURSDAY AS THE WINDS SHIFT TOWARD THE NORTHWEST. AN OCCASIONAL GUST TO 35 KTS IS NOT OUT OF THE QUESTION...MAINLY ACROSS THE OCEAN ZONES. CONFIDENCE IN THIS HAPPENING...OR FREQUENT GUSTS TO 35 KTS...IS QUITE LOW...SO WILL NOT CONSIDER GALE WARNINGS AT THIS TIME. SEAS BUILD TODAY AND TONIGHT AS THE WESTERLY WINDS INCREASE. WAVE WATCH III OUTPUT LOOKED REASONABLE...AND WAS BLENDED WITH PREVIOUS FORECAST. SCA CONDS MAY LINGER ON THE OCEAN WATERS INTO THU NIGHT. SUB-ADVSY CONDS ARE THEN EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD AS HIGH PRES BUILDS ACROSS THE AREA WITH A WEAK PRES GRADIENT. && .HYDROLOGY... AS THE RAIN TAPERS OFF TO A FEW SHOWERS THIS MORNING...NO SIGNIFICANT PRECIPITATION IS EXPECTED TODAY THROUGH THURSDAY. DRY THROUGH SAT WITH LIGHT QPF AMOUNTS EXPECTED SAT NIGHT INTO SUN. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM EST THURSDAY FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...24/PW NEAR TERM...PW SHORT TERM...PW LONG TERM...24 AVIATION...JM MARINE...24/PW HYDROLOGY...24/PW

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