Area Forecast Discussion
Issued by NWS Upton, NY

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795 FXUS61 KOKX 260534 AFDOKX Area Forecast Discussion National Weather Service New York NY 134 AM EDT Mon Sep 26 2016 .SYNOPSIS... High pressure will move off the coast on today as a cold front approaches from the west. The front passes across the region after midnight into early Tuesday morning accompanied by showers. The front will likely linger just offshore through the end of the week...resulting in a period of unsettled weather. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Clear (a couple of wisps of cirrus) with calm winds and radiational cooling. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... Latest NWP remains consistent with timing of FROPA and PCPN. After a sunny start to the day, high clouds will overspread the area from the west as a 500 millibar trough over the Northern Plains advances towards the area. Southerly winds will increase, especially along the south shore of Long Island, as the center of the high sets up over the Atlantic. Rain will end quickly from NW to SE during the early morning on Tuesday and may actually end by 12Z in the NY Metro. Have lowered PCPN totals back to around 1/2" based consensus, but locally an inch or so likely. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Models in good agreement with a deep closed low sitting over the Great Lakes/Southern Ontario on Tuesday. Then models coming into better agreement with the upper low slowly sinking se into the Ohio/Tennessee River Valley through the end of the week...and possibly meandering around through the weekend. This setup is pointing towards a more unsettled weather pattern for the mid to late week period. At the surface...a cold front associated with the stacked Great Lakes low approaches the region Monday Night...and crosses the region Tuesday. Continued good agreement in deep layered lift interacting with southern moisture (1 to 2 std PWAT) bringing a soaking rain during the late Monday night to Tuesday morning period. An isolated tstm is not out of the question Tue morning with some weak elevated instability and strong lift ahead of the cold front...but prob is quite low. Appears the cold front pushes far enough east late Tue/Tue eve for rain to taper off. Confidence is increasing in an unsettled mid to late week period based on ensemble/operational trend towards a less progressive and cutoff upper level scenario as described earlier. This will result in potential for additional waves of low pressure to develop along the cold front just offshore as well as broad low pressure to sit sw of the region...affecting the region with periods of rain mid to late week. Forecast has been further weighted towards the unsettled scenario. Temps on Tuesday will likely be above seasonable with offshore flow in wake of cold front and with any partial clearing. Thereafter...temps should be nears seasonable under a maritime airmass. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... VFR with high pressure in control through this afternoon. A cold front approaches from the west this evening. Light and variable winds early this morning become SE by late morning. Winds continue to veer to the south in the afternoon with speeds increasing to 10-15 kt with gusts up to 20 kt. The strongest winds are expected at city terminals and at KISP. S gusts 20-25 kt may continue at KJFK and KISP through this evening with S winds at other terminals around 10 kt. .Outlook for 06Z Tuesday through Friday... .MON NIGHT...Becoming IFR in SHRA .TUE...IFR in SHRA early morning, then becoming VFR from west to east mid to late morning. .WED...VFR. .THU and FRI...Potential IFR/MVFR CIGS with RA. NE Wind 15-20 KT. && .MARINE... Sub sca conds overnight. Southerly winds will increase Monday ahead of a cold front, but speeds will not reach 25 kt until Monday night. A small craft advisory will likely be required on the ocean as a result, and possible elsewhere. SCA conditions likely Tuesday morning on ocean waters...and possibly eastern nearshore waters...ahead of an approaching frontal system. Winds will fall below sca behind the front Tue afternoon...with ocean seas gradually following suit. Sub sca conditions likely return for Tues night into Wed...then potential for sca seas to develop once again with persistent easterly flow for remainder of the week. There is still a great deal of uncertainty regarding the specifics of the forecast during this time period. && .HYDROLOGY... Around an 1/2" from midnight into early Tuesday morning expected. locally 1" or so is possible. Additional bouts of rain are possible during the mid to late week. No hydrologic impacts are expected at this time for overnight into Tuesday morning other then the typical urban ponding. The PCPN later in the week may pose urban flood issue with the potential for a couple of inches of rain. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JMC NEAR TERM...Tongue SHORT TERM...Tongue LONG TERM...NV AVIATION...DS MARINE...JMC/NV HYDROLOGY...JMC/NV is the U.S. government's official web portal to all federal, state and local government web resources and services.