Area Forecast Discussion
Issued by NWS Upton, NY

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985 FXUS61 KOKX 230604 AFDOKX Area Forecast Discussion National Weather Service New York NY 204 AM EDT Thu May 23 2024 .SYNOPSIS... A cold front approaches overnight and slowly moves through the area Thursday and Thursday night, moving offshore sometime early Friday morning. Weak high pressure builds on Friday. A weak low passes through the area late Saturday into early Sunday. A deep low pressure system tracks through the Great Lakes and into Canada late Sunday through Tuesday with the system`s warm front passing north Monday and its associated cold front moving through Tuesday into Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... With cell moving out of Orange County, and becoming stratified, and CAMs not indicating any farther development until early Thursday morning, updated probabilities. A mid-level low, embedded in the broader upper level trough over the western US, lifts north of the Great Lakes tonight. The associated surface low will also pass well to our north and west, but will send a cold front towards our area. Ahead of the front, a S/SW flow has brought in a warm and humid airmass with 850mb temps around 16 to 18C and surface dewpoints in the low to mid 60s for most. Moisture will continue to increase ahead of the front tonight, with guidance showing pwats peaking around 1.60 inches tonight into early Thursday. These pwat values are over the 90% moving average for the 12z 05/23 sounding at OKX per the SPC Sounding Climatology Page. The next best chance / likelihood for showers and thunderstorms will be as the cold front starts to slowly move through the area Thursday morning. Given the environment, with MLCAPE values around 1000-1500 J/kg and 0-6 km shear increasing to around 35-40 kt, some storms could become strong to marginally severe. The SPC continues to outline the area in a "marginal" risk of severe weather, with large hail and damaging winds being the main threat. Given the high pwats, any thunderstorms could also produce heavy downpours. At this time, there are no flooding concerns. Given the activity in the morning, it will be difficult to destabilize again for the afternoon and reinitiate convection. We will likely see just a few lingering showers as the front continues to sag through the area. However, if we end up seeing less or no activity in the morning, the stronger showers/ thunderstorms could be in the afternoon. For this reason, have left chance of thunder through the day Thursday. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... With the front slowly sagging south, a chance of showers and thunderstorms continue through Thursday night, mainly for the southern half of the area. The front likely finally passes south early Friday morning. With plenty of clouds around, above normal low temperatures are expected. If the front moves through northern locations a bit quicker and they get under some clearing, some of these locations could drop lower than the upper 50s. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A cold front exits Friday morning with any lingering precip quickly exiting with the front. The cold front will not help cool things down much, with afternoon temperatures still expected to reach the mid-80s to mid-70s. The front will, however, help dry us out, reducing any chances for showers or thunderstorms. Sunny to mostly sunny conditions are expected on Friday. Zonal flow will remain aloft through the weekend with above normal temperatures and occasional shortwaves. Moisture will increase late Saturday with a returning southerly flow. Shower chances will increase with it late Saturday into Saturday night with slighter better chances for a few thunderstorms in the western interior developing along a passing warm front. Rain chances increase early Monday into Monday night then linger in the forecast through Wednesday. A Great Lakes low will lead to a stalled boundary that will pass as a warm front on Monday, then bring a cold front Tuesday or Wednesday as it tracks into Canada and/or New England. The warm front will bring us into the warm sector of the system and bring a chance for thunderstorms across the area late Monday into early Tuesday. The pressure gradient front the low passing to the north may lead to breezy conditions late Monday into early Tuesday. Guidance varies somewhat on the timing and location of this system so have kept chance POPs throughout Tuesday and Wednesday. Temperatures will be closer to seasonal Monday through mid-week aided by an approaching and deepening trough. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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A cold front approaches tonight into Thursday pushing through Thursday night. Outside of showers and thunderstorms for Thursday morning into the early afternoon hours, conditions are expected to be VFR, including eastern terminals where MVFR or lower conditions tonight now appear to be unlikely. S to SSW winds tonight under 10 kt shift briefly shift to the WSW to W around 14Z Thursday (western terminals) and 17Z Thursday(eastern terminals) as a pre- frontal trough moves through. Winds shift back to the S to SW in the afternoon before the passage of the cold front between 06Z Friday or thereafter. Any gusts will be associated with thunderstorms, generally up to 20 kt. However, stronger thunderstorms will be associated with gusts of 30 to 40 kt, of which there is a low chance of this happening. Showers and thunderstorms associated with the pre-frontal trough from west to east 13Z-17Z for western terminals and 15Z-19Z for eastern terminals. Brief MVFR conditions possible with these showers and thunderstorms. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No unscheduled AMD expected through 10Z. Amendments may be needed towards the Thu morning push if thunderstorm activity arrives earlier than expected. OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY... Thursday night: VFR expected. Low chance of MVFR or lower. Friday: VFR. Saturday: Chance of afternoon/evening showers and possibly a tstm, with MVFR cond possible. Sunday: Mainly VFR. Monday: Chance of showers and possibly a tstm, with MVFR cond possible. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE... Winds and waves will generally remain below SCA criteria through Thursday night, with wind gusts potentially briefly reaching 25 kt this evening. A cold front approaches late tonight and slowly moves through the area on Thursday. Some showers and thunderstorms ahead and along the front are possible tonight through Thursday night, with the highest chances being Thursday morning/early afternoon. Sub-SCA conditions are then expected through Monday night. && .HYDROLOGY... Thunderstorms are possible Thursday, with potential for heavy downpours mainly during Thursday morning/early afternoon. At this time, no hydrologic impacts are expected through the middle of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BR/JT NEAR TERM...JE/MET/JT SHORT TERM...JT LONG TERM...BR AVIATION...JP MARINE...BR/JT HYDROLOGY...BR/JT