180 FXUS61 KOKX 212136 AFDOKX Area Forecast Discussion National Weather Service New York NY 536 PM EDT Sat Aug 21 2021 .SYNOPSIS... Henri in the Atlantic will be moving northward tonight with impacts likely across parts of the local area starting as early as overnight tonight through Monday. A stretch of hot weather is possible for the middle of next week, followed by a cold frontal passage on Friday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... An upper level trough centered over southern Pennsylvania pulls moisture northward in the mid and upper levels from Henri tonight. This may prompt some shower activity for the first half of tonight. As Henri makes its way farther north tonight, heavier, steadier rain showers will make its way to Long Island and southeastern Connecticut around or just before daybreak Sunday morning. However, the heaviest of the rain will hold off until Sunday morning. North to northeast winds increase overnight, with gusts as high as 25 to 40 mph possible around sunrise Sunday morning. Please refer to the National Hurricane Center and Hurricane Local Statement for the official forecast track information. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... **HURRICANE CONDITIONS EXPECTED ACROSS PORTIONS OF LONG ISLAND AND SOUTHERN CONNECTICUT** Tropical storm or hurricane force winds are expected along the south shore, eastern Long Island and across southeast Connecticut, especially from mid morning onward, with the strongest winds across the Twin Forks and southeast coastal Connecticut. The current track from the National Hurricane Center takes Henri right near where the Twin Forks of Long Island meet. The heaviest of the rain is expected to be to the west of Henri as the system interacts with an upper level shortwave. Additionally, some higher amounts can be expected across some of the higher terrain well inland. The period of heaviest rain is between 8 am and 2 pm Sunday, where 2 to 4 inches or more may fall over much of Suffolk County. Storm surge inundation is also a concern and there is potential for life- threatening storm surge along the immediate shore of Long Island, Southern Connecticut, and the Western Sound. The timeline of impacts looks to be Sunday morning through Sunday evening, with the storm weakening as it moves northward. Additionally, heavy rain that may occur during times of high tide could exacerbate flooding along these areas, as there will be a combination of coastal and fresh water flooding. Finally, there is the potential for an isolated tornadoes to move through as Henri makes its approach and landfall. The Storm Prediction Center has placed southern Connecticut and eastern Long Island in a marginal risk for severe storms. Large helicity values are noted in the models, however surface based instability could the limiting factor and the reason that the possibility of tornadoes will not be more widespread. Henri will track northwest into southern New England overnight Sunday night, shifting the heavy rain into southwest Connecticut and the Lower Hudson Valley during this time frame. Please refer to the National Hurricane Center and Hurricane Local Statement for the official forecast track information. && .LONG TERM /MONDAY THROUGH SATURDAY/... Mon is still dependent on the exact exit plan associated with Henri. The sys itself will still have some tropical moisture to work with. The GFS shows pwats around 2 inches invof the low. Therefore, if the low is still lingering near the cwa, hvy rain will be possible in any shwrs and tstms that develop. Please continue to refer to the NHC for the official Henri track. Henri is expected to be done by Tue, and then the focus turns to the heat. H85 temps warm to around 18-19Z in the Tue-Thu period. The NBM looked a little low based on these numbers on Wed and Thu, so for those two days went with the MEX guidance for highs. There is still room for upward adjustment temp wise. Dewpoints are progged to be in the upr 60s to low 70s thru the period, yielding heat indices in the heat advy range for much of the area based on the 2-day criteria. 100 degree heat indices are also possible for some areas Wed and Thu. A cold front appears on track for late Fri with shwrs and tstms, then high pres builds in for Sat. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... Hurricane Henri approaches tonight and reaches the area on Sun. Showers increase in coverage and intensity tngt, although VFR to start early this eve. Heavier rain bands move in overnight into Sunday, with IFR. Light winds will continue to back gradually thru the ngt. Speeds will slowly increase, but significantly ramp up early Sun. Peak winds right now aft 16Z Sun. Direction and speed dependent on the exact track of Henri. Winds in the TAF are based on the official Hurricane Center data. ...Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... VIS will likely not be 3sm all ngt, but in bands of shwrs. Better chance for prolonged 3sm and lower VIS on Mon. .OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY... .Sun...IMPACTS EXPECTED FROM HURRICANE HENRI. .Mon...MVFR or lower at times with shwrs and tstms. .Tue...Mainly VFR but a chance for shwrs and tstms. .Wed-Thu...Mainly VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Dangerous conditions develop on the waters late tonight through Sunday due to Henri. Hurricane Warnings continue for the eastern waters, Tropical Storm Warnings for the western sound, western ocean, and the NY Harbor. Conditions should begin to improve Sunday night into Monday. Please refer to the National Hurricane Center for the official forecast track information. Waves are expected to build to anywhere from 10 to as much as 20 ft on the ocean waters by sunrise Sunday morning, with the highest waves across the eastern ocean zone. Waves across the central and eastern could build to 10 and 11 ft respectively. Up to 8 ft waves are possible in the Gardiner's Bay. Waves on the ocean diminish Sunday morning and early afternoon for the sound and will be below 5 ft on all waters except the eastern ocean zone by early Monday morning. Seas may remain abv 5 ft on the ocean Mon, Tue, and perhaps Wed. Winds may be close to sca lvls on all waters Mon depending on the position of Henri. All waters should be blw sca criteria for Thu and Fri. && .HYDROLOGY... A Flood Watch continues for the entire area tonight through Monday morning. Hydrologic impacts Sun-Mon will depend on the track and intensity of Henri. There is the potential of 3-6 inches of rainfall late tonight through Sunday night across Long Island and Connecticut and 2-4 inches further west. Locally higher amounts are possible. Flash flooding is possible, especially across Long Island and Connecticut. No hydrologic impacts are expected Tue-Thu. && .TIDES/COASTAL FLOODING... There is potential for life threatening storm surge from Henri across portions of the Long Island coast and southern Connecticut coast Sunday. Storm surge warnings are in effect. Dangerous rip currents are expected through Monday due to Tropical System Henri. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Storm Surge Warning for CTZ009>012. Hurricane Warning for CTZ006>008-010>012. Flood Watch through Monday morning for CTZ005>012. Tropical Storm Warning for CTZ005-009. NY...Storm Surge Warning for NYZ071-073-078-079-081-176-177. Hurricane Warning for NYZ078>081. Flood Watch through Monday morning for NYZ067>075-078>081- 176>179. Tropical Storm Warning for NYZ070>075-176>179. High Rip Current Risk through Monday evening for NYZ075-080- 081-178-179. Storm Surge Watch for NYZ080-179. NJ...Flood Watch through Monday morning for NJZ002-004-006-103>108. Tropical Storm Warning for NJZ006-104-106-108. MARINE...Hurricane Warning for ANZ331-332-340-345-350-353. Tropical Storm Warning for ANZ335-338-355. && $$ SYNOPSIS...DJ/JP NEAR TERM...JP SHORT TERM...JP LONG TERM...JMC AVIATION...JMC MARINE...JMC/JP HYDROLOGY...JMC/JP TIDES/COASTAL FLOODING...JP