Area Forecast Discussion
Issued by NWS Upton, NY

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027 FXUS61 KOKX 050823 AFDOKX Area Forecast Discussion National Weather Service New York NY 423 AM EDT Sun May 5 2024 .SYNOPSIS...
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High pressure along the New England coast weakens locally as it shifts farther offshore today ahead of an approaching cold front from the west. The front eventually tracks through the region late Monday, stalling to our south. High pressure then briefly returns before the stalled boundary returns as a warm front Tuesday night. A series of low pressure centers then impact the weather from Wednesday through Saturday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A rather unsettled close to the weekend with rain, clouds, and cooler than typical conditions for early May. Stubborn amplified ridging aloft over the Eastern US begins to break down today as a shortwave swings east through the Great Lakes and into southeast Canada. A weak area of low pressure associated with a shortwave running into and over the ridge passes well to the northwest through the Upper Great Lakes. This will help push a frontal boundary toward the region, though will take plenty of time getting here. Ahead of it, surface high pressure centered near the Canadian Maritimes will maintain onshore flow as it begins to shift farther out into the western Atlantic. Bit of light rain around early this morning, mainly across the Lower Hudson Valley and SW CT, though a lull in this activity develops later this morning as a weak lift axis shifts north. More organized shower activity moves through the region this afternoon as the shortwave axis translates east over the shunted ridge. Timing for this rain looks to begin for western areas by lunchtime, spreading east into CT and Long Island by mid afternoon, then continuing intermittently into the evening before tapering from west to east overnight. QPF will be relatively light, generally ranging from a quarter to a half inch, and no hydro issues are anticipated. Look for areas of fog development tonight in the weak onshore flow and saturated low levels from the residual moisture. May be locally dense in spots, and will need to monitor this evening should any potential headlines be needed into the AM commute. With the rain, clouds, and return flow temperatures run 10 to 15 degrees below normal today, with afternoon highs in the 50s. These temperatures likely remain steady overnight, or even rise a few degrees toward Monday AM.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY/...
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Lingering showers should largely come to an end for eastern areas in the morning hours on Monday, with fog likely hanging around elsewhere before burning off by mid to late morning. Temperatures jump 20 degrees for some compared to Sunday as SW flow helps to advect in some milder air, rebounding into the 70s across the interior and areas away from maritime influence. Can`t rule out a few pop up showers in the afternoon ahead of the trailing cold front, but coverage appears limited on CAMs at this point with decreased moisture. The front finally moves through Monday night and stalls over the Mid-Atlantic on Tuesday. The boundary eventually lifts back north as a warm front, but before this, ridging returns, along with weak surface high pressure. This should set up the driest day of the week so far on Tuesday, with drier air working in. Another mild afternoon with downsloping helping the interior and areas away from the coast to warm into the mid to upper 70s. Night will remain mild, generally in the 50s, with lower 60s in the urban metro.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
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Models over the past 24 hours have trended farther south and slightly stronger regarding an area of low pressure tracking through the Great Lakes Region and heading towards us Tuesday night into Wednesday. There is therefore more confidence that an associated warm front advances through a good portion of the forecast area during Wednesday before a trailing cold front sinks south through here Wednesday night. Shower chances increase Tuesday night with the best chances occurring through the day Wednesday and generally higher across the northern zones, which will be closer to the low center. More instability is now anticipated - being in the warm sector. Thunderstorms will therefore be possible during Wednesday, and given potential shear profiles, steepening mid-level lapse rates with a bit of a cold pool aloft, and CAPE aloft, will need to monitor trends for the potential of strong wind gusts and small hail. NBM was used for high temps, which are now expected to reach the lower 80s for NE NJ and parts of the Lower Hudson Valley and city. Mainly 70s for most of the rest of the forecast area. The cold front stalls not too far to our south Wednesday night and remains to our south while another wave of low pressure from the Great Lakes Region approaches. Looks like an occlusion may occur as a weak secondary low forms along the stalled boundary to our south, resulting in a broad area of low pressure shifting through during late Thursday night into Friday. Potential remains for yet another wave of low pressure to pass nearby the area Friday night into Saturday. There will be at least some chance of showers for each period from Wednesday night through Saturday night. The highest chances appear to be Thursday afternoon into night, but might linger into Friday morning as well. NBM looked good for temperatures through the period.
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&& .AVIATION /08Z SUNDAY THROUGH THURSDAY/...
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High pressure weakens today as a frontal system slowly approaches from the west. Cigs lowering to IFR in the next hour or two, likely remaining IFR through the TAF period. A shower or two possible this morning without VSBY restrictions, but showers become more likely this afternoon, then remaining likely well into tonight. ESE-SE winds around 10kt or less through this evening, shifting more southerly late tonight. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of IFR onset may delayed by an hour or two. Chance that MVFR cigs develop for a few hours this afternoon. OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY... Sunday night: IFR with showers ending. Monday: IFR to MVFR in the morning, then MVFR, becoming VFR in the afternoon. A slight chance of showers, an isolated thunderstorm possible. Tuesday: VFR, becoming MVFR to IFR late at night. Wednesday: MVFR or lower with a chance of showers. Thunderstorms possible mainly in the afternoon. Thursday: Mainly MVFR. Showers likely, mainly in the afternoon. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE...
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Winds and seas are expected to remain below SCA conditions through Thursday, but ocean seas may rise to 5 ft Thursday night.
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&& .HYDROLOGY...
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There are currently no hydrologic concerns through this week.
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&& .TIDES/COASTAL FLOODING...
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Astronomical tides will increase with the approach of a new moon Tuesday night along with the threat of minor coastal flooding each night through this period and possibly including Wednesday night as well. Coastal flood statements may be needed for coastal Fairfield, southern Westchester, and southern Nassau counties tonight. Advisories may eventually be needed for these zones and Southern Queens Monday night, and even more so for Tuesday night. Statements may be needed during this period for other parts along western LI Sound as well as lower NY Harbor.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JC/DR NEAR TERM...DR SHORT TERM...DR LONG TERM...JC AVIATION...JC MARINE...JC/DR HYDROLOGY...JC/DR TIDES/COASTAL FLOODING...JC