National Weather Service
Area Forecast Discussion
Issued by NWS Upton, NY

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456 FXUS61 KOKX 241742 AFDOKX Area Forecast Discussion National Weather Service New York NY 142 PM EDT Wed Apr 24 2024 .SYNOPSIS... A frontal system moves across the region through early this evening. Strong high pressure then builds in tonight through Friday. The strong high remains over the area Friday night into Saturday and will shift to the south Saturday night as low pressure moves northeast across the upper Great Lakes into Canada and an associated warm front approaches. The front will lift through on Sunday but remain nearby to the east early next week. A cold front will approach on Tuesday. && .NEAR TERM /UNTIL 8 PM THIS EVENING/...
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Showers, with an embedded thunderstorm, is moving through northeast New Jersey as of 130 pm EDT in association with a cold front moving through. More showers and possible isolated thunderstorms over south central NY state will move through later this afternoon in association with a second cold front. Increased chances for precipitation south and east through mid afternoon with this first line of showers and added isolated thunderstorms to the forecast with this update. A warm front to the southwest, across southeastern Pennsylvania into southern New Jersey will move through the area early this morning, and any showers will briefly come to an end. However, with the surface low and cold front, along the US/Canada border at 08Z, moving toward the region showers will become possible until the front moves south of the area early this evening. Low level moisture will be limited with the cold front as lift and CAPE and instability increase. With the low levels dry, and an inverted V sounding, scattered showers could produce some brief gusty winds. And while a rumble of thunder can not be ruled out this afternoon as the capping is mixed out, have not included in the forecast as any thunderstorms will be rather isolated. CAMs continue to show widely scattered to isolated showers, and opted to use coverage terminology for the showers to indicate this.
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&& .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... High pressure builds into the region from the west/northwest this evening through Friday, as a high amplitude ridge builds to the west, as the upper trough remains from eastern Canada to off shore of the New England coast. A chilly airmass will remain over the region, and begin to modify Friday. Temperature will be around 10 degrees below normal tonight through Thursday night, and around 5 below normal for Friday. With light to near calm wind Thursday night, and clear conditions, temperatures are expected to once again fall to near or below freezing across the inland zones, and additional frost/freeze headlines may be needed. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Much of this time frame will feature an omega block over the eastern CONUS, with its western leg over the central states and multiple shortwaves lifting NE through the Plains states and upper Great Lakes, its eastern leg over the Canadian Maritimes and adjacent Atlantic, and an upper ridge over the East. The first of the shortwaves lifting through the Plains and Great Lakes will send a warm front toward the area Sat night that should then lift through on Sunday, with low chance for showers mainly inland. A warming trend will then follow, with temps well above normal especially from the NYC metro area north/west, with highs well into the lower/mid 70s on Sunday and either side of 80 on Mon. Most of Long Island and S CT should be cooler, with highs in the 60s, to near 70 on Mon, due to onshore flow and afternoon sea breezes, also some intrusion of cooler maritime air from the east depending on the position and intensity of low pressure developing well to the east over the Atlantic. The omega block should start to break down on Tue, with the upper ridge weakening and a cold front approaching from the west, bringing the chance for showers and possibly a tstm. Temps on Tue should continue to be on the mild side, with highs in the 60s across much of S CT/Long Island, and in the 70s across the NYC metro area north/west and interior S CT. Per NBM 50th/75th percentile forecasts, temps early next week have potential to be a few degrees warmer than fcst, possibly upper 70s to mid 80s on Mon, and mid 70s to lower 80s on Tue. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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A cold front moves across the terminals this afternoon. Strong high pressure will then build in tonight into Thursday. VFR. Isolated to scattered showers remain possible this afternoon with the cold front passage. A rumble of thunder is also possible. Coverage is still too limited to include in the TAF and have continued with a VCSH. The most likely timing for the NYC metro terminals looks to be 18-22z, and hour earlier NW and an hour later east. A stronger shower could produce a wind gust 30-35 kt and brief MVFR vsby. Winds will continue to veer to the W this afternoon and then become WNW-NW with the cold front passage. Wind speeds 10-15 kt with gusts 20-25 kt are possible, especially late afternoon and evening. Winds will continue veering to the N tonight and then NE early Thursday morning. Winds and gusts will diminish overnight with wind speeds around 10 kt or less by day break Thursday. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... A gusty shower or thunderstorm remains possible 18-22z. JFK may remain more S an hour or two longer than in TAF. Timing of wind shift to the WNW-NW may be off by 1-2 hours. Gusts could become occasional or end 1-3 hours earlier tonight. OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... Thursday Afternoon-Friday: VFR. Saturday: Mainly VFR. Low chance for showers with brief MVFR conditions Saturday night. Sunday-Monday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE... The Coastal Waters Forecast with wave component details becomes operational later today. Winds and gusts on the ocean waters were a few knots lower than forecast early this morning, and updated for current conditions and short term trends. Otherwise, no changes were made to winds and seas. An increasing, and gusty, southerly flow this morning will reach SCA levels on the ocean waters with building ocean seas also reaching advisory levels. With the passage of a cold front late this afternoon and into early this evening winds shift to the northwest, and with building high pressure, winds and gusts gradually diminish below advisory levels by late tonight. Ocean seas will remain elevated into Thursday morning, and then subside below 5 feet. A SCA remains in effect on the ocean waters, and was extended to 1000 AM EDT Thursday. With a weak pressure gradient later Thursday through Friday, with high pressure in control, winds and seas will remain below advisory levels across the forecast waters. Quiet this weekend into early next week with winds/seas below advisory criteria. S-SW flow up to 15 kt after a warm frontal passage could briefly push ocean seas up to 4 ft late day Sunday into Sunday evening. Fog may also become possible Sunday night as more humid air traverses colder waters. && .FIRE WEATHER... Relative humidity will be lowering to around 35 percent late this afternoon into early this evening behind a cold front, with west to northwest winds gusting as high as 25 MPH. With falling temperatures this evening relative humidity levels will then begin to increase. With the front there will be little to no wetting rain. Elevated fire spread conditions may briefly be present for NE NJ, portions of the lower Hudson Valley, New York City, and western Long Island. Minimum relative humidity will be in the upper teens to around 25 percent Thursday, however, winds will be under 10 MPH. && .HYDROLOGY... No hydrologic concerns through early next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Freeze Watch from late tonight through Thursday morning for CTZ005>008. NY...Freeze Watch from late tonight through Thursday morning for NYZ067>070. NJ...Freeze Watch from late tonight through Thursday morning for NJZ002-103. MARINE...Small Craft Advisory until 10 AM EDT Thursday for ANZ350-353- 355. && $$ SYNOPSIS...BG/MET NEAR TERM...JP/MET SHORT TERM...MET LONG TERM...BG AVIATION...DS MARINE...BG/MET FIRE WEATHER... HYDROLOGY...BG/MET