Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 140151 AFDOKX Area Forecast Discussion National Weather Service New York NY 951 PM EDT Fri Jul 13 2018 .SYNOPSIS... The center of a high pressure ridge will drift south of Long Island on Saturday. A weakening front crosses through the region on Sunday followed by brief high pressure into Monday. A stronger cold front will impact the area Tuesday into Wednesday with high pressure returning for the middle of the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Only minor updates this hour to reflect current temperature, dew point and wind trends. Otherwise the forecast remains on track. Diurnal cumulus have largely dissipated this evening with the loss of daytime heating. However, the dirty ridge building in should result in an increase in mid and high clouds overnight. A blend of the MET/MAV was used for temps, as the guidance was in good agreement. There remains a moderate risk for rip current development thru this eve on all ocean beaches. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Water vapor shows enough moisture to provide mid and high clouds during the day Sat. The position of the high and sea breeze component will keep sly component flow in. This will limit instability for most of the area. Combining this with subsidence across the area, the fcst for most of the day has been kept dry. A complex of tstms however is progged to develop from upstate NY into wrn Mass during the aftn, tracking sewd thru Sat ngt. This should result in some pcpn across the area, with the best chcs across wrn and interior areas before the convection tends to dissipate closer to the coast. For now, 30-40 pops have been carried in the fcst, with timing similar to the sref. There is an increase in elevated instability overnight, though the numbers per the NAM are generally blw 1000 J/kg, so the expectation attm is sct but non svr activity. The NBM was used for temps on Sat, with a blend of the MAV and MET used Sat ngt. There is a high risk for rip current development at all ocean beaches on Sat. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Lingering swells are likely to maintain at least a moderate rip current risk on Sunday. A shortwave trough and associated cold front will move off the New England on Sunday increasing the PoP chances. Under a southwest flow, dew points will rise into the low to mid 60s. However, upper level heights rise and there looks to be plenty of clouds around, so question remains as to how much the atmosphere destabilizes. SPC has included the majority of the CWA in a marginal risk, with gusty winds and heavy rainfall as the main threat. Heights will continue to rise behind the trough with ridging building over the region Sunday night into Monday. The flow looks to be progressive with the ridge likely to shift offshore Monday night as a a fast moving upper trough digs across the Great Lakes region into Tuesday. This upper trough swings through the area on Wednesday. The flow may remain progressive the end of next week with brief ridging on Thursday before another upper trough for the end of the week. The best chance for precipitation appears to be with a cold front associated with the shortwave Tuesday night into Wednesday. Southerly flow ahead of this cold front increases during the day on Tuesday, leading to PWAT values over 2 inches, so expect any storms to produce heavy rainfall. It appears the atmosphere dries out quickly once the front moves offshore Wednesday morning, so there is a possibility the second half of the day ends up dry. Lower chances for showers and thunderstorms exist on Friday, but this will be dependent on the timing of the shortwave and next frontal system. Temperatures will be above normal Sunday through Wednesday, before dropping a few degrees closer to normal values Thursday and Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... High pressure remains over the region into tonight and moves offshore Saturday. A cold front approaches Saturday night. Southerly winds will continue to diminish this evening and become light and variable tonight. SW winds increase through the day on Saturday with 10-15 kt expected in the afternoon. Gusts up to 20 kt possible at city terminals. VFR through the TAF period. There is a chance of a shower or thunderstorm after 00z Sunday, but for now have left out of the TAF due to uncertainty in timing and coverage. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night-Sunday night...Mainly VFR. Chance MVFR or lower in Showers and thunderstorms. .Monday-Monday night...Mainly VFR with a slight chance of afternoon/evening showers and thunderstorms mainly from NYC terminals on N/W. SW winds G15-20KT possible Monday afternoon. .Tuesday...MVFR or lower possible in showers and thunderstorms. SW winds G20-25KT possible along with LLWS east of the city in the afternoon and evening. .Wednesday...Showers/thunderstorms possible east early, then VFR. && .MARINE... Winds and seas will remain blw sca lvls thru Sat, then swell on the ocean will increase to near 5 ft Sat ngt. A sca my be required. Winds and seas Sun into Tue blw sca lvls, then wave heights could build to 5 ft on the ocean Tuesday night into Wednesday associated with a cold front. && .HYDROLOGY... No hydrologic impacts are anticipated thru Mon. Locally heavy rainfall is possible Tuesday afternoon and night with any convection. While it is still too far out, there is some potential for minor flooding towards the middle of next week. && .TIDES/COASTAL FLOODING... Astronomical tides are running high due to a combo of the new moon and incoming swells promoting tidal piling. High tides have passed for southern Nassau and the lower boroughs of NYC, so any remaining flooding will quickly recede. A coastal flood statement remains in effect for the western Long Island Sound, where minor flooding may be more spotty as water levels barely touch thresholds at forecast points. There is potential for similar minor coastal flooding in these same locations with the Saturday night high tide cycle. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...High Rip Current Risk from 6 AM EDT Saturday through Saturday evening for NYZ075-080-081-178-179. NJ...None. MARINE...None. && $$ SYNOPSIS...CB/12 NEAR TERM...12/MD SHORT TERM...12 LONG TERM...CB AVIATION...JC MARINE...CB/12 HYDROLOGY...CB/12 TIDES/COASTAL FLOODING... EQUIPMENT... is the U.S. government's official web portal to all federal, state and local government web resources and services.