Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 272319 AFDOKX Area Forecast Discussion National Weather Service New York NY 719 PM EDT WED JUL 27 2016 .SYNOPSIS... Weak high pressure tonight will give way to an approaching cold front Thursday. A wave of low pressure approaches and passes nearby Friday. This low moves east of the region Friday night. Weak high pressure briefly builds into the region for Saturday. Unsettled weather returns for the end of the weekend and start of next week with the passage of another low pressure system. Drier weather is expected for Tuesday and Wednesday as high pressure returns. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Mostly clear conditions early this evening with temperatures and dewpoints within a few degrees of forecast values. Only slight adjustments were made to better match observed trends. The forecast is on track. Aloft, upper trough moves across the upper Great Lakes region. A surface cold front accompany this features moves well to the north. Meanwhile, another weak frontal boundary remains to our south, with a series of weak lows along it. Weak high pressure remains offshore, and a light south flow prevails across the region. Dew points increase slightly, and as temperatures fall tonight under mostly clear skies, patchy fog formation is possible as boundary layer begins to saturate. Not quite sure of extent of any fog, but it is possible as hinted at by the models. Lows tonight will range from around 60 well inland, to the middle 70s in NYC metro. Followed a mos and model blend. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... Through this time period, upper trough axis extending south across the great lakes region/Ohio Valley and into the upper Mississippi Valley will move east, with embedded Vorts in the mid and upper level flow tracking east. Frontal boundary to the south remains Thursday, as a series of low pressure centers ride along it, the strongest of which approaches Thursday night and Friday. Better jet support Friday, and enhanced lift along with abundant moisture advecting east/northeast will allow for rain/possibly heavy Friday. Prior to that, isolated thunder per high resolution models develops along seabreeze boundary Thursday afternoon. Kept pops in slight chance range as coverage should be isolated, and this assumes ample moisture up the column materializes. One more warm to hot day is expected Thursday, with highs in the upper 80s to around 90 under partly sunny skies. With higher humidity levels, heat indices will run a degree or two above actual air temps. Temps will remain seasonably warm Thursday night, and not quite as much of a range is expected as clouds increase, and rain chances increase. With the passage of a wave of low pressure, possibly just to our south, temperatures on Friday will be cooler, upper 70s to around 80 thanks to clouds and rain. This has trended lower than previous forecast. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Low pressure moving across the region moves east Friday night, with just some left over showers and possibly a thunderstorm. Weak high pressure briefly returns on Saturday, with most of the forecast guidance keeping conditions dry. As a result, will keep conditions dry on Saturday. Unsettled weather returns Saturday night into Monday, as another shortwave and low pressure system moves across the region. Expect another round of showers and thunderstorms, with some storms producing locally heavy rainfall. High pressure builds back into the region early next week, providing dry conditions. Temperatures will remain seasonable Saturday through Wednesday with temperatures climbing into the 80s each day. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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Southerly flow will weaken tonight and become light and variable at outlying terminals and light SW at city terminals. Winds will become southerly at all terminals on Thursday increase to around 10 kt near the coast in the afternoon with seabreeze enhancement. Mainly VFR through the TAF period. There is a low probability of MVFR/IFR ceilings or visibilities late tonight at coastal terminals. Preference continues to be for VFR to prevail, but have added tempo MVFR visibility at KGON towards daybreak. A few showers and thunderstorms possible Thursday afternoon/evening, mainly NW of the city terminals, but probability is too low to include in TAFs at this time. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Low probability for MVFR/IFR ceilings or visibilities late tonight. KLGA TAF Comments: No unscheduled amendments expected. KEWR TAF Comments: No unscheduled amendments expected. KTEB TAF Comments: No unscheduled amendments expected. KHPN TAF Comments: MVFR/IFR visibilities possible around daybreak Thursday. KISP TAF Comments: Low probability for MVFR/IFR ceilings or visibilities late tonight. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... .Thursday Night into Friday Night...MVFR or lower possible in showers and thunderstorms, possibly widespread on Friday. Patchy fog. .Saturday...VFR. .Saturday Night into Monday...Iso-Sct showers and thunderstorms possible.
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&& .MARINE... Some gusts early this evening on the western ocean waters up to near 20 kt with otherwise lower winds for all other forecast waters. Ocean seas are below 2 ft. The forecast is on track. Conditions will remain below SCA. As a weak front approaches, and weak wave of low pressure moves by Thursday night and Friday, expect sub SCA conditions to continue across the area waters. A light pressure gradient over the area waters will result in sub- sca conditions this weekend and early next week. However, any thunderstorms that develop on the waters may produce brief SCA conditions. && .HYDROLOGY... There is potential for significant rainfall from late Thursday night into Friday night. Locally heavy rainfall is possible, which could cause flooding. Exact evolution of this potential storm remains unclear, so it remains too early for specifics. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BC/PW NEAR TERM...JM/PW SHORT TERM...PW LONG TERM...BC AVIATION...DS MARINE...BC/JM/PW HYDROLOGY...BC/PW is the U.S. government's official web portal to all federal, state and local government web resources and services.