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FXUS61 KOKX 042101
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
401 PM EST Mon Mar 4 2024

.SYNOPSIS...
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High pressure extending from the Canadian Maritimes into the Northeast will retreat out into the North Atlantic tonight, while an area of low pressure along the Mid Atlantic coast works northward and into the area on Tuesday. The low lifts north of the area Tuesday night. A second low pressure system approaches on Wednesday and passes to our southeast on Thursday. High pressure then briefly builds in during Friday ahead of another storm system next weekend. High pressure slowly builds back in on Monday.
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&& .NEAR TERM /THROUGH TUESDAY/...
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One of the more challenging aspects thus far this afternoon has been the varying amount of cloud cover across the region. Periods of sun have allowed temperatures top out around 60 at a few locations. Any partial clearing will be replaced by low clouds redeveloping and working in from the east this evening. The first in a series of southern branch systems will impact the area late tonight into Tuesday. Anomalously high PW values around 1.25" aided by a modest 40-50kt LLJ on the east side of a coastal low will bring rain into the area late tonight. A few showers and/or sprinkles are expected after midnight and will become more widespread closer to daybreak. The rain will be moderate at times, impacting western portions of the area first before working east in tandem with the LLJ as the morning progresses. By early Tuesday afternoon the coverage and intensity will diminish with perhaps some heavier pockets of rain (embedded showers) across far eastern LI/SE CT. Any lingering rain exits the area by around midnight. All in all looking for about half an inch of rain on average. This will more or less lay the foundation for wet antecedent conditions with subsequent rainfall events through the upcoming week. However, no flooding issues are expected with this event. Lows tonight will be on the warm side by about 10 degrees due to cloud cover and an easterly flow. Highs on Tuesday though will be limited to the upper 40s to around 50 with rain much of the day.
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&& .SHORT TERM /TUESDAY NIGHT/...
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Any lingering rain exits the area by around midnight as the low lifts to the north of the area. There will be brief respite in the rain before the next system follows quickly on its heels later Wednesday. Lows will again be in the lower 40s.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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An unsettled weather pattern continues during the long term period as a 500mb shortwave shifts through the TN Valley into the Mid- Atlantic Wednesday into Wednesday night. Associated surface low tracks through the Southeastern US during this time and emerges off the Mid-Atlantic coast early Thursday morning, passing to our southeast later in the day. Rain chances increase Wednesday morning with the approach of enhanced moisture convergence and lift along an inverted trough, then rain becomes likely for the entire forecast area during the afternoon. Rainfall continues through Wednesday night and may be heavy at times during this period as deep moisture (PWATS on the order of 3-4 standard deviations) combines with strong lift (llj/frontogenetic forcing + upper jet streak). See the hydrology section below for potential impacts. Rain will still be likely on Thursday, mainly east of NYC, although there is some uncertainty as some models lag moisture along with some lift from a trough aloft. Rain could potentially still be likely at least in the morning for the entire forecast area. Last chance of rain occurs before Thursday night in all but eastern areas, then dry late Thursday night through most of Friday night as high pressure noses down from the north. A complex low pressure system will be pushing in from the south and west this weekend with rain chances as early as late Friday night, but rain appears to be overall more likely Saturday afternoon through Sunday. Still a chance that thermal profiles would be cold enough well inland for a shot at a wintry mix at times, but with only marginally cold air to begin with and high pressure retreating instead of trying to build in, this looks to be mostly rain even for these areas. High pressure then follows for Monday with breezy, dry and cooler conditions.
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&& .AVIATION /21Z MONDAY THROUGH SATURDAY/...
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High pressure retreats to the northeast tonight, while another area of low pressure approaches from the south into Tuesday. Tricky forecast with respect to cloud cover. We have had some unexpected clearing east and lowering to the west with ceiling occasionally reaching MVFR. MVFR will fully overtake the area from east to west later this evening. Tempos have been added of the occasional MVFR. Winds are currently easterly around 10-15 kts, with some occasional gusts being reported at some TAF sites. Once cigs come down, its likely we stay down for the remainder of the evening and overnight. Widespread IFR or lower is expected tonight with rain moving into the region after 06z. LIFR is possible during the middle and end of tomorrow with the rainfall. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments will be likely to fine tune timing of lower cigs. Occasional gusts may continue early this evening. OUTLOOK FOR 21Z TUESDAY THROUGH SATURDAY... Tuesday: IFR/LIFR in Rain. Wednesday: MVFR or lower. Chance of rain in the morning, becoming likely in the afternoon into the night. E winds G15-20kt at night. Thursday: MVFR or lower in possible rain. NE-N winds G20-25kt. Friday: Mainly VFR. N wind gusts 15-20 kt possible. Saturday: MVFR possible with rain. E winds G20-25kt. 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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SCA in effect for the ocean waters Tuesday and Tuesday night. A strengthening easterly flow tonight into Tuesday will result in marginal SCA gusts and seas for the ocean waters. Seas are expected to build to 4 to 6 ft. Strongest winds will be during the morning hours with gusts up to 25 kt possible. Winds will then back off in the afternoon, veering around the the south as the low tracks primarily west of the waters. Marginal SCA conditions anticipated on the ocean during Wednesday. then all waters are expected to have advisory level conditions Wednesday night through Thursday afternoon as low pressure passes to the SE. Winds and seas diminish Thursday night with conditions falling below advisory thresholds on the non-ocean waters by Friday morning. Seas on the ocean will however remain elevated, partly due to swell, with 5+ ft seas lingering Friday through Saturday morning. An onshore flow increases Saturday afternoon ahead of the next storm system with advisory-level conditions on all waters Saturday night.
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&& .HYDROLOGY...
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No hydrologic impacts are expected with the system for late tonight into Tuesday. 1 to 2.50 inches of rain is expected Wednesday through Thursday with the higher amounts anticipated over Long Island and SE CT. The heaviest rainfall is expected to occur during the first half of Wednesday night, when it could could fall heavily at times. There will be the possibility of at least minor urban/poor drainage and small river/stream flooding Wednesday night into Thursday. The overall chance of flash flooding remains low at this point. If flash flooding were to occur, for now it appears that it would more likely occur east of NYC. Potentially 1 to 1.50 inches of rain could fall with the following storm system this weekend. Impacts with this event are still somewhat uncertain as it will partly depend on the amount of rain falling during the two rain events that will precede it.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 6 AM Tuesday to 6 AM EST Wednesday for ANZ350. Small Craft Advisory from 1 AM Tuesday to 6 AM EST Wednesday for ANZ353-355.
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&& $$ SYNOPSIS...JC/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...JC AVIATION...BR MARINE...JC/DW HYDROLOGY...JC/DW