Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 280627 AFDOKX Area Forecast Discussion National Weather Service New York NY 227 AM EDT THU JUL 28 2016 .SYNOPSIS... Weak high pressure overnight 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 THIS MORNING/... Mostly clear conditions remain late tonight with temperatures and dewpoints still within a few degrees of forecast values. Only slight adjustments were made to better match observed trends, notably with dewpoints. These have increased a few degrees along the coast over the last few hours. The forecast overall remains on track. Aloft, the 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 overnight 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 with their light moisture conveyed in the QPF fields between 06Z and 12Z. Lows tonight will range from the lower 60s well inland, to the middle 70s in NYC metro. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM 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 /06Z THURSDAY THROUGH MONDAY/...
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Light southerly flow at city terminals overnight with light and variable winds at outlying terminals. Winds will become southerly at most terminals daytime Thursday, and increase to around or just over 10 kt near the coast in the afternoon with sea breeze enhancement. Exceptions to the rule will be KLGA, with an ENE morning sound breeze, and KEWR/KTEB, where SE sea breezes close to 10 kt expected mid to late afternoon. Low clouds/fog beginning to develop off the NJ coast should spread northward, and could impact KJFK/KISP with IFR cigs up to around daybreak. KGON could also be impacted as well, but confidence not as high attm. Cannot totally rule out an isold shower or tstm this afternoon, mainly near sea breeze boundaries on Long Island. KISP could experience brief vicinity impact. .OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY... .Late Thu Night into Fri Night...IFR likely in showers/tstms. Rain heavy at times. Tstms could produce strong winds in the morning NYC metro terminals and KISP. .Saturday...VFR. .Saturday Night into Monday...Iso-sct showers/tstms possible.
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&& .MARINE... The forecast remains on track. Conditions will remain below SCA with a weak pressure gradient in place. 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...Goodman MARINE...BC/JM/PW HYDROLOGY...BC/PW

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