Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 232241 AFDOKX Area Forecast Discussion National Weather Service New York NY 641 PM EDT Mon May 23 2022 .SYNOPSIS... High pressure slides offshore late Tuesday into Tuesday night and then remains offshore through the end of the week. A slow moving low pressure and frontal system will affect the area for the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Forecast is on track with only minor changes needed. Surface high pressure, centered near the Great Lakes, continues to build into the region as it slides east. Expecting to keep a decent amount of cloud cover tonight with increasing mid-level moisture as a shortwave passes nearby. CAMs try and introduce light rain for a period overnight as the disturbance tracks just to our south, though low-levels appear too dry to support much reaching the ground. Given this and limited moisture convergence, maintained a dry forecast overnight, though an isolated, spotty sprinkle is possible. After a sultry weekend, temperatures have returned to near seasonable levels for late May, and this continues into midweek. Forecast lows tonight will generally bottom out in the 50s, to near 60 around the metro.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... The weak flow regime continues on Tuesday as the region remains stuck between lower pressures over the Southeast, and the high to our north. Winds veer easterly/southeasterly early in the day as the center of surface high pressure slips off the coast of New England and the Canadian Maritimes. With the onshore flow and elevated mid- level moisture, expecting more clouds than sun, which should inhibit temperatures during the day. 850 temps fall from around 10C Monday, to 5-6C on Tuesday. Coupled with the clouds, onshore flow, and cooler air aloft, expecting maxTs to top out a few degrees cooler than Monday, generally around 70 for most. Dry conditions continue Tuesday night into Wed AM, with lows falling into the 50s. Didn`t stray far from NBM deterministic for this forecast. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Tranquil conditions expected through Wednesday night and possibly into Thursday as the center of high pressure off the New England coast slowly drifts east over the north Atlantic. Aloft, zonal flow transitions to a building ridge. Despite the building ridge an onshore flow thanks to a developing maritime air mass during this time frame will keep temperatures at or a few degrees below normal. Some uncertainty exists for Thursday morning with a weak low or inverted trough off the mid-Atlantic Coast that may drift northward Wednesday night into Thursday morning. Most deterministic models have this feature in one form or another, but whether this makes it into the area with some light precipitation, or perhaps low stratus and drizzle (GFS forecast soundings suggest a very dry layer at around 950-900 hPa) is still unknown. Capped POPs at slight chance for Thursday due to uncertainty. Thereafter, more significant uncertainty exists in the deterministic models with the advance eastward of a cold front from the mid-West on Thursday vs the potential for a low to cut-off over the Plains states along the frontal boundary as it moves slowly toward the region into the weekend. The frontal boundary will remain to the north and west during this scenario, with prolonged onshore flow, cooler than normal temperatures, and chances for precipitation from Friday through the weekend. The ECMWF and GFS ensembles show a few members with weak areas of low pressure at the surface that remain to the west into Saturday night, lending credence to the cutoff. So, will lean more towards the more pessimistic outcome for this time period, but a total washout is not expected at this time. Given the onshore flow, lowered temperatures a degree or two below NBM for Friday and Saturday, which end up around normal for this time of year. The cutoff could still be plaguing the area Monday, situated to the southeast over the mid-Atlantic. However, there is still a good deal of uncertainty this far out and stuck with NBM for this time frame. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... High pressure builds to the northwest of the terminals today, then north of the terminals tonight. VFR conditions through TAF period. N-NW winds with occasional gusts to 20 kt will continue til about 20-21z. Then, north winds 8 to 12 kt are expected through the remainder of the afternoon, before becoming light and variable tonight. There is a Low probability for late day sea breeze at JFK. Winds on Tuesday will be from the S-SE around 8-12kt. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Winds gusts may be occasional this afternoon. Low chance of afternoon seabreezes at JFK today. .OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY... .Tues...VFR. E/SE winds. .Wed-Wed Night...VFR. .Thu...MVFR or lower possible at times. Chance of showers. Slight chance of thunderstorms north and west of NYC. .Fri and Sat...MVFR or lower in possible showers. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ && .MARINE... Winds and waves are expected to remain below SCA criteria through Thursday night with a weak pressure gradient in place. Waves build on a prolonged southerly flow over the ocean waters, with 5 ft waves expected late Thursday night into Friday, which could remain elevated into Saturday. Winds will remain below 25 kt through Thursday night. Gusts to around 25 kt are possible on the ocean waters toward Friday afternoon given the approach of a frontal system or low pressure from the west. && .HYDROLOGY... A frontal system will likely bring rain to the area late this week, but there is too much uncertainty this far out in time in determining any hydrological impacts, if any. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JP/DR NEAR TERM...JP/DR SHORT TERM...DR LONG TERM...JP AVIATION...BC MARINE...JP/DR HYDROLOGY...JP/DR is the U.S. government's official web portal to all federal, state and local government web resources and services.