000
FXUS61 KOKX 171505
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1005 AM EST Sun Dec 17 2023

.SYNOPSIS...
Strong low pressure approaches from the south today and passes
through during Monday. In the wake of the exiting low, high pressure
builds in from the west through Wednesday, remaining in place
through late week.

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.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Bands of light rain have been moving into and through portions of the region this morning. Despite the shallow low level moisture drizzle has not been observed, and are now mentioning light rain. Shallow moisture deepens through the day with ESE winds. Isentropic lift was producing light rain. Mild conditions today with highs in the mid 50s, which is about 10 degrees above normal.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
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Low pressure approaches from the south tonight as it deepens. Models are still trying to resolve where the center of this storm will be be by the time it gets near us - depicting a broad storm center with two separate circulations. There`s at least agreement that the northern circulation will likely pass through the western half of the forecast area Monday morning, with the southern circulation moving through the eastern half of the forecast area Monday afternoon as it tries to merge with the other. This will maintain the likelihood of rain into Monday afternoon for most spots. Rainfall could be heavy at times after early this evening into Monday with anomalously high moisture for this time of year. It will combine with strong lift from a low level jet and upward forcing in the vicinity of both circulations. With elevated instability, isolated thunder is still a possibility tonight through early Monday afternoon. CAMs reflectivity forecast continue to show this convective potential. No changes to the flood watch - see the hydrology section below for more details. As for strong winds, 925mb winds are still progged at 60-85kt along with 55-70kt at 950mb over coastal sections late tonight into Monday morning. Still looks like the low level inversion will be neutral to weak, so thinking there`s potential for 60-70% of the 925mb winds to mix down to the surface, especially in the heavier downpours. High wind watches have now been upgraded to warnings. Wind advisories remain unchanged from the previous forecast and are posted through Monday morning. There remains a chance of advisory-level gusts Monday afternoon with deeper mixing on a SW-W wind flow, but this probably won`t last too long and didn`t have have enough confidence to expand the advisory in time. Also did not have the confidence to expand advisories westward based on progged track of the aforementioned northern circulation by most models. NBM probabilities of advisory and warning thresholds being met continue to rise over the past few days, although feel that the warning threshold probabilities are too low. Mild for Monday with highs near 60 - approaching records for the date in some areas. Winds subside Monday night, but remaining on the breezy side. There will be a chance of showers after midnight as a closed 500mb low approaches from the west and another low pressure center is generated offshore.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/... As surface low pressure exits well to the north, the parent upper trough axis pivots through the area on Tuesday. While there will be little remaining moisture, cyclonic curvature and frictional effects in the lower levels may lead to a few lingering rain or snow showers into the afternoon. Noticeably colder conditions settle in as a blustery NW flow helps to advect in a colder air mass and adds to the chill. Though highs get into the low to mid 40s Tuesday afternoon, apparent temps likely remain in the 30s for much of the day. Relaxing pressure gradient into midweek will allow winds to subside by Wednesday, and a much drier regime develops in the system`s wake as a strengthening surface high builds east. Ridging remains in place through late week, maintaining dry, tranquil conditions, with temperatures pretty close to normals. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/...
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HIGH IMPACT AVIATION EVENT TONIGHT INTO MONDAY... Deepening low pressure tracks up the East Coast through Monday. Mostly MVFR conditions across the area terminals with IFR conditions across KHPN, KWF and KBDR. Ceilings could vary between MVFR and VFR at the coastal terminals at times with MVFR to IFR across inland terminals through this afternoon. Widespread IFR tonight, possibly LIFR, with steady rain developing toward 00Z Mon. Easterly flow increases to around 10 to 12 kt by late morning with gusts up to 20 kt. Winds steadily ramp up tonight after 03Z Mon, with strongest winds after 06Z Mon. SE winds increasing to 20-30kt G35-55kt, strongest along the coast. Slow improvement late Mon AM through the afternoon, with winds gradually lowering and becoming S/SW. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... The afternoon haze potential forecast at KEWR is YELLOW, which implies slant range visibility 4-6SM outside of cloud. IFR cigs possible into early afternoon with drizzle or mist. Gusts today may be more occasional than frequent. Isolated 50+ kt gusts late tonight into Monday morning, especially at KJFK and KLGA. OUTLOOK FOR 15Z MONDAY THROUGH THURSDAY... Monday: IFR, possibly LIFR in rain early. Isolated thunderstorm possible in the morning. LLWS through the morning. SE winds 20-30kt gusting 35-50 kt before 15Z, strongest along the coast, becoming S then SW to W diminishing late Monday afternoon and night. Tuesday: Chance of flurries mainly north and west of the NYC terminals early, then a few rain or snow showers possible along the coast during the afternoon. MVFR, possibly IFR, especially in any snow showers. WNW G20-25kt in the afternoon. Wednesday through Thursday: VFR. 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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No changes to winds and seas, and hazards at this time. Marginal SCA conditions continue on the ocean water today. Winds and seas then ramp up tonight into Monday. The Storm Watch has been converted to a Storm Warning for all waters, covering tonight through Monday morning. Best chance of storm force winds will be late tonight through the first half of Monday morning. Thereafter, gales should prevail in the afternoon. Ocean seas peaking roughly in the 16-21 ft range with 5-10 waves on Long Island Sound. Winds should fall below 25kt by the end of Monday night, however seas will remain elevated above 5 ft on the ocean. In the wake of exiting low pressure, NW flow on Tuesday may continue to produce gusts upwards of 25 kt on most waters, before subsiding Tuesday night. High pressure allows more tranquil winds mid to late week, though ocean seas will remain elevated, at or above 5 ft through Friday.
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&& .HYDROLOGY... A total of 2 to 4 inches of rainfall is expected through Monday afternoon, with most of this falling from late evening tonight through Monday morning. Locally higher amounts are possible, and the greater amounts are expected to fall generally north and west of NYC. Widespread minor urban/poor drainage/river flooding can be expected with localized to scattered flash flooding possible. Moderate river flooding is becoming more probable for small rivers and streams in NE NJ and the Lower Hudson Valley, and there`s even at least a chance that major flooding occurs over the typically quick-responding rivers in NE NJ. Otherwise, no hydrologic issues expected mid to late next week. && .TIDES/COASTAL FLOODING... Coastal flood warnings issued for southern Queens, southern and eastern portions of LI and coastal CT as widespread moderate coastal flooding is likely with the daytime high tide cycle on Monday. There is potential for locally major flood thresholds to be reaches for southern Queens, SW LI and twin forks, if windshift occurs near or after the time of high tide. Elsewhere minor to moderate coastal flood potential is increasing, where coastal flood watches have been issued. This includes the tidally affected rivers, particularly Hudson and Hackensack rivers, where the surge is favored to be forced upstream by the strong southerly flow. Peak surge of 3 1/2 to 5 ft will likely be between high tidal cycles Monday morning. A later timing of windshift closer to the early Monday afternoon time of high tide will be critical to the potential for major flood thresholds to be reached or exceeded. There is still spread in exact storm track and intensity as it moves up the coast. A track more to the west and/or slower would place the area more squarely under the strongest winds and increase the threat for locally major coastal flooding for the most vulnerable southern Queens, SW and E LI portions of the area. A more easterly and/or farther east track would lessen the threat. More clarity on these scenarios likely over the next 24 hrs. In addition, heavy rainfall and/or runoff coinciding with the Sunday Night and Monday afternoon high tides will exacerbate street and property flooding issues along the coast and tidally affected rivers. Along the ocean beachfront, potential exists for 12+ ft breakers Sunday overnight into Monday, which combined with elevated water levels, will likely result in widespread dune erosion and scattered overwashes. Finally, minor coastal flooding possible with tonight`s high tide mainly for southern Queens, SW LI and coastal Westchester and SW CT. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Flood Watch from 5 PM EST this afternoon through Monday afternoon for CTZ005>007-009>011. Wind Advisory from midnight tonight to noon EST Monday for CTZ005>007. High Wind Warning from midnight tonight to noon EST Monday for CTZ008>012. Coastal Flood Warning from 10 PM this evening to 6 PM EST Monday for CTZ009>012. NY...Flood Watch from 5 PM EST this afternoon through Monday afternoon for NYZ067>075-176-178. Wind Advisory from midnight tonight to noon EST Monday for NYZ071>074. High Wind Warning from midnight tonight to noon EST Monday for NYZ075-078>081-176>179. Coastal Flood Warning from 10 PM this evening to 6 PM EST Monday for NYZ071. Coastal Flood Watch from 9 PM EST this evening through Monday afternoon for NYZ074-075. Coastal Flood Watch from this evening through Monday afternoon for NYZ073-078-176-177. Coastal Flood Warning from 11 PM this evening to 6 PM EST Monday for NYZ079-081. Coastal Flood Warning from 9 PM this evening to 6 PM EST Monday for NYZ080-178-179. NJ...Flood Watch from 5 PM EST this afternoon through Monday afternoon for NJZ002-004-006-103>108. Wind Advisory from midnight tonight to noon EST Monday for NJZ006. Coastal Flood Watch from 9 PM EST this evening through Monday afternoon for NJZ006-104-106-108. MARINE...Storm Warning from 6 PM this evening to 1 PM EST Monday for ANZ331-332-335-338-340-345-350-353-355. Small Craft Advisory until 6 PM EST this evening for ANZ350- 353-355.
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