Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 241651 AFDOKX Area Forecast Discussion National Weather Service New York NY 1251 PM EDT SUN JUL 24 2016 .SYNOPSIS...
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High pressure builds in from the west this afternoon and moves offshore tonight. A cold front approaches on Monday and moves through the region Monday night. High pressure returns on Tuesday and moves offshore Wednesday into Thursday. A slow moving frontal system approaches the region Friday, possibly affecting the region through the weekend.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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No significant changes will be made to this forecast package. Will update hourly grids based on latest surface obs and satellite trends. High pressure builds in from the west this afternoon with an airmass that is not as hot as the one on Saturday. Highs will top off in the low to mid 90s across NYC and NE NJ, and in the upper 80s to around 90 elsewhere. With dewpoints ranging from the upper 50s to lower 60s for most areas, heat indices will be in the lower 90s. For NYC...heat index will stay below 95, so Heat Advisory will not be issued based on consecutive days with a heat index of 95 or higher. Light winds continue to give way to afternoon seabreezes. Winds turn S at 10-15 MPH, possibly gusting 20-25 MPH in NYC. There is a moderate risk for rip currents at Atlantic Ocean beaches this afternoon and evening.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... High pressure moves offshore this evening. SW flow develops, and with increasing humidity levels, it will be warm and muggy tonight with lows in the mid to upper 70s in/around NYC and in the upper 60s to low 70s elsewhere. With the increase in low level moisture, can expect patchy fog as well. The hottest airmass of the seas builds into the region on Monday. Surface dewpoints will climb into the lower 70s. With highs in the upper 90s across NYC and most of NE NJ, the heat index will range from 105-110. An Excessive Heat Watch remains in effect for those areas. For the Lower Hudson Valley, Long Island, and southern CT, highs will top off in the low to mid 90s, and the heat index will range from 100-105. A Heat Advisory has been issued for those areas. A cold front approaches during the day Monday. Scattered showers and thunderstorms will develop over far NW zones and spread east during the afternoon and evening. MUCAPE values will range from 2000-3000 J/kg. Inverted-V forecast sounding indicate potential for gusty and potentially damaging winds. PWATs will be over 2", and heavy rainfall is possible as well. Cold front moves offshore late Monday night and showers and thunderstorms will taper off. High pressure builds in from the west on Tuesday with slightly cooler and less humid conditions. Highs will top off in the low to mid 90s in/around NYC and in the upper 80s to low 90s elsewhere. Dewpoints will be in the low 60s. Heat indices will be in the low to mid 90s. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Models in fairly good agreement with the region lying between a closed low over Northern Ontario/Quebec and heat ridge across the southern US for mid week. This low will eventually pivot northeastward on Friday...but be replaced by a trough digging into the Great Lakes this weekend. The result will be an active upper flow through the region...with a series of weak shortwaves/vorts moving through during the period. At the surface...weak high pressure moves offshore Wed into Thu, with a slow moving cold front approaching the region from the NW Fri. Very warm conditions will continue for the mid to late week...with high generally about 5 degrees above seasonable...well into the 80s to lower 90s. As moisture gradually increases and shortwave energy increases aloft...increasing potential for diurnal shra/tstm activity away from the coast Thu and moreso Fri. Uncertainty on how far south this front makes it heading into the weekend as troughing digs into the Great Lakes. SW upper flow ahead of the trough will also have potential for a southern frontal system to track close to the region. Overall low confidence on sensible weather details for the weekend...but potentially unsettled with seasonable warm temps and humid conditions. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... High pressure builds into the area today and offshore tonight. VFR expected through this evening. Light northerly winds back to a more westerly direction by late morning and early this afternoon. Sea breezes crosses in the afternoon for coastal terminals...possibly to 12 kt at KJFK in the late aft. Southerly sea breeze development expected for KLGA and KHPN late this afternoon. For KEWR and KTEB westerly gusts into the mid teens possible this afternoon...likely impeding any sea breeze development until late in the day. Winds subside and return to the s/sw this evening. Sparse shra/tsra coverage possible late tonight into Monday morning. 5-6sm br/hz development possible towards daybreak Monday. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .Monday-Monday Night...5-6sm hz possible during the day. MVFR or lower possible in any scattered shra/tsra. Tsra timing and coverage uncertainty at this point. SW winds becoming gusty to 15-20 kt for NJ and interior terminals in the afternoon...meanwhile afternoon southerly sea breeze for coastal terminals. .Tuesday-Wednesday...VFR. .Thursday...Mainly VFR, except MVFR or lower possible in isolate late day/evening thunderstorms for interior terminals. && .MARINE...
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High pressure builds in from the west this afternoon and then moves offshore tonight. A light W-NW flow will give way to afternoon sea breezes, turning winds S 5-10 KT. For ocean waters, S winds will range from 10-20 KT. Winds diminish tonight. Patchy fog develops tonight as humidity levels rise. A cold front approaches on Monday. Scattered showers and thunderstorms will develop in the afternoon and continue into Monday night. High pressure returns for Tuesday. Winds and seas will overall remain below SCA criteria during the period, and then will continue through Thursday with a weak pressure gradient as the high builds east.
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&& .HYDROLOGY... No rain is forecast through Monday morning. There is the potential for 1/4 to 1/2 inch of rainfall, with locally higher amounts, possibly 1 inch or more, in showers and thunderstorms Monday and Monday night. Dry weather returns for Tuesday and Wednesday. There is the potential for additional showers and thunderstorms, mainly across the interior and during the afternoons and evenings Thursday and more so Friday. This threat may continue into the weekend. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Heat Advisory from 11 AM to 6 PM EDT Monday for CTZ005>012. NY...Heat Advisory from 11 AM to 6 PM EDT Monday for NYZ067>071- 078>081-177-179. Excessive Heat Watch from Monday morning through Monday afternoon for NYZ072>075-176-178. NJ...Heat Advisory from 11 AM to 6 PM EDT Monday for NJZ002. Excessive Heat Watch from Monday morning through Monday afternoon for NJZ004-006-103>108. MARINE...None. && $$ SYNOPSIS...MPS/NV NEAR TERM...MPS/PW SHORT TERM...MPS LONG TERM...NV AVIATION...BC/NV MARINE...MPS/NV/PW HYDROLOGY...MPS/NV

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