279 FXUS61 KOKX 210558 AFDOKX Area Forecast Discussion National Weather Service New York NY 158 AM EDT Sat Aug 21 2021 .SYNOPSIS... A stationary front remains in the vicinity through Saturday. Henri in the Atlantic will be moving northward Saturday night with impacts likely across parts of the local area through Monday. A surface disturbance will be in the vicinity Monday night and Tuesday. A frontal boundary will remain to the north and west of the forecast area through the end of the week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Mid-upper level cloud cover continues to stream northward ahead of the developing tropical system. Given the continued cloud cover, expect low temperatures to be a few degrees above climatological normals tonight, generally in the low to mid 70s across the area. Winds will likely remain pretty light through the overnight hours into the morning. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Onshore flow develops in advance of T.C. Henri, with lingering cloud cover and a humid air mass across the area. Diurnal showers and isolated thunderstorms will be possible once again, particularly to the north and west of the city where the southeast flow will allow for an upslope component to aid in vertical motion. There will be a high risk of rip currents for Saturday. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... **HURRICANE CONDITIONS EXPECTED ACROSS PORTIONS OF LONG ISLAND AND SOUTHERN CONNECTICUT** The main focus continues to be with Henri which is beginning to make the northerly turn off southeast of Cape Hatteras. Please refer to the National Hurricane Center for the official forecast track information. Please refer to the Hurricane Local Statement for potential impacts. The latest forecast track takes the center of Henri across eastern Long Island and then towards southern Connecticut on Sunday. The ultimate track of Henri will determine where the strongest winds occur and the amount of rainfall. Tropical storm or hurricane force winds are expected along the south shore, eastern Long Island and across southeast Connecticut. Given the latest track, the heaviest rainfall looks to occur across Long Island and southern Connecticut, along and west of the center of the low. The cyclone may begin interacting with an upper level shortwave over the Middle Atlantic coast, which could enhance rainfall on the western side of the storm. 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. An upper level trough will be over the area Monday night and slowly track eastward, pushing off the coast by late Monday night into early Tuesday morning. This will mean a slight chance for showers Monday night. Not looking at anything widespread as an associated surface trough will be in nearly the same position as the upper trough, precluding any strengthening of the system. With the trough off shore for Tuesday into Wednesday morning, dry conditions will persist through then. A frontal boundary then remains to the north and west of the region through next Friday. There may be an upper level trough that approaches from the west on Wednesday, that could set off a shower or thunderstorm in the afternoon, but much of any activity should remain to the west. The best chances for any showers and thunderstorms comes towards the end of the week, as the cold front makes some progress toward the east. Temperatures will be warm on Tuesday. Ridging aloft with some height rises on Wednesday will mean continued warm conditions, leading to temperatures in the middle 80s to lower 90s on both days. With humid conditions in place (dew points in the upper 60s to lower 70s), heat index values across the forecast area could reach the middle to upper 90s. Slightly more clouds towards the end of the week will mean slightly lower temperature for Thursday and Friday. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... A weak frontal boundary will remains in the vicinity today. Tropical Cyclone Henri approaches tonight. Mainly VFR today with Conditions falling to MVFR tonight. Light and variable winds overnight become SE in the morning through the day tomorrow with speeds 10kt or less. Tonight, winds will become easterly and then northeasterly and increase to 10-15 kt. ...Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments may be needed for wind direction. .OUTLOOK FOR 06Z SATURDAY THROUGH WEDNESDAY... .Saturday night...VFR early, then MVFR or lower. Showers likely with a chance of thunderstorms. .Sunday...IMPACTS LIKELY FROM TROPICAL CYCLONE HENRI. .Monday...Mainly VFR. Chance of showers and slight chance of thunderstorms. .Tuesday...VFR. .Wednesday...VFR. Slight chance of thunderstorms in the afternoon. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Initially sub-SCA conditions through Saturday, before dangerous conditions develop on the waters late Saturday night through Sunday due to Henri. Hurricane Warnings have been issued for the eastern waters, Tropical Storm Warnings for the western sound and western ocean, and a Tropical Storm watch for 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. Seas will still be elevated for the eastern ocean zone Monday night, with 5 ft waves expected. However, waves will be diminishing and should fall below 5 ft after midnight. With a lack of a strong pressure gradient, winds and waves should remain below SCA criteria from Tuesday through Friday. && .HYDROLOGY... Hydrologic impacts Sun-Mon will depend on the track and intensity of Henri. There is the potential of 3-6 inches of rainfall late Saturday night through Sunday night across Long Island and Connecticut and 1-2 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. A storm surge watch is in effect. Dangerous rip currents are expected on Saturday and Sunday due to Tropical System Henri. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Storm Surge Warning for CTZ009>012. Hurricane Warning for CTZ006>008-010>012. Tropical Storm Warning for CTZ005-009. NY...Storm Surge Warning for NYZ071-073-078-079-081-176-177. Hurricane Warning for NYZ078>081. Tropical Storm Warning for NYZ070>075-176>179. High Rip Current Risk from 8 AM EDT this morning through this evening for NYZ075-080-081-178-179. Storm Surge Watch for NYZ080-179. NJ...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...MD/JP NEAR TERM...DJ SHORT TERM...DJ LONG TERM...JP/DS AVIATION...BC MARINE...MD/JP/DS HYDROLOGY...DS TIDES/COASTAL FLOODING...DS