Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 171822 AFDOKX Area Forecast Discussion National Weather Service New York NY Issued by National Weather Service Mount Holly NJ 222 PM EDT Wed Apr 17 2024 .SYNOPSIS... A slow moving warm front approaches from the southwest today and moves through the area into Thursday. High pressure briefly builds in for Thursday night into Friday before a cold front passes through Friday night into Saturday morning. High pressure then follows from Saturday afternoon through early next week. A weak frontal system will impact the region mid week. && .NEAR TERM /THROUGH TONIGHT/...
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A high amplitude upper level ridge over southeastern Canada and western New England will continue to shift east today and and will start to deamplify over the Mid Atlantic this evening. As this occurs, a weakening stacked low over the Great Lakes region will eventually lift a surface warm front associated with this low will approach from the southwest today. The warm front will lead to isentropic lift in association with overrunning moisture thus bringing rain showers into the region during the late afternoon and evening. Instability will continue to be the challenge with the overall thunder potential but given that there has been some lightning upstream the forecast now includes a slight chance of some embedded thunderstorms. Confidence is low (15%) on the likelihood of widespread mention of thunder especially with a modest low level inversion keeping much of the area stable. The 12z suite of CAMs still indicated the potential for some short lived embedded heavier showers moving through southwestern portions of the forecast area overnight tonight within the New York City metro area. During the overnight expect the shower coverage to increase although decrease in intensity. As the WAA lift decreases, showers will transition from potentially heavy at times to more of a steady light rain. Temperatures are expected to be near normal for this time of year.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
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Shower coverage looks to lower Thursday as isentropic lift weakens over the area and high pressure building in from the northeast brings in a cooler and drier air mass in the lower levels. The high building in with the weak low to our south will mean a strengthening easterly flow develops across the area that starts to increase late tonight. It does not look to be overly windy, with sustained winds of 15 to 20 mph and gusts to 25 mph by Thursday morning. Winds start to decrease Thursday afternoon as the high continues to nose into the region, with the weak low well out to sea by this point. The easterly flow will also mean cooler than normal temperatures for Thursday, with highs only in the upper 40s to lower 50s. Mainly dry conditions from Thursday night (except perhaps some lingering showers for eastern areas) through Friday morning with high pressure over the region. The chances for showers increase Friday afternoon and Friday night as the associated cold front approaches and begins to move through late Friday night.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/... Little change in the long term and stuck fairly close to the previous forecast/NBM. A cold front approaches and passes through Friday night into Saturday morning. Moisture will deepen along with a chance of showers with its passage. High pressure then builds in behind the front with dry weather for Saturday afternoon. The high will continue to build into the region through the rest of the weekend and remain in control of the weather through Monday. High temperatures near normal on Saturday, but cooling off slightly for Sunday. Temperatures rebound a few degrees on Monday. A 500mb trough then shifts through the Great Lakes on Tuesday with an associated weak surface low and cold front. It appears that we should by dry through the day, but cannot rule out a shower for western zones by the end of the day. Rain chances increase Tuesday night into Wednesday. Temperatures remain in the lower and middle 60s. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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High pressure over the terminals weakens today as a warm front slowly approaches from the southwest. VFR through most of the day. Showers/rain become likely around 22z, however there is a chance that some light precip starts at early as 20z. Most of the precip though 23-00z should remain VFR, however can not rule out a brief period of MVFR conditions with the rain. MVFR conditions become more likely towards 00z, then dropping to IFR around 02-04z as the light rain become more steady. Winds should be generally easeterly thorugh the rest of the afternooon between 08-12kt with occasional gusts mixing to the surface up to 20kt. Wind direction will generally be between 080-120 for much of the TAF period. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of the onset of light rain and MVFR conditions late this afternoon may be off by 1-2 hrs. OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... Thu and Thu night: IFR conditions and possibly LIFR at times Thursday. Showers end with slowly improving conditions Thursday night. Winds will be from the east around 15kt with gusts 20-25kt, highest along the coast. Fri: VFR early, then MVFR late day and at night with a chance of showers. Sat: MVFR with showers ending in the morning, becoming VFR. Sun: 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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Winds and seas remain below SCA criteria throught this afternoon and early evening. However, easterly winds will increase tonight as strengthening high pressure builds in, and by late tonight will likely reach 25 kt on the ocean waters and the entrance to the harbor. A few hours later, all waters will see SCA wind gusts. A SCA is in effect for all waters from late tonight through the day on Thursday. Winds gusts diminish Thursday night as the high continues to build in over the area. Non ocean waters will likely drop below 25 kt early Thursday night. The ocean waters will likely have SCA gusts hang on for the first few hours of Thursday night before they also come down below 25 kt. Seas build to 4 to 7 ft on the ocean by Thursday morning into the afternoon, diminishing thereafter. However, they remain above or right around 5 ft Thursday night, so an extension to the SCA over the ocean may be needed for Thursday night and perhaps into Friday with a persistent, though slowly weakening easterly flow. Waves finally drop below 5 ft on the ocean by Friday night. High pressure building over the area waters Saturday through the first part of next week should keep conditions sub-advisory waters through at least Tuesday night. Conditions may build back to SCA levels for Wednesday with the next low pressure and associated cold front to approach.
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&& .HYDROLOGY... There is the potential for 0.25" to 0.75" of rainfall from late this afternoon through Thursday afternoon. Although a brief heavy showers is possible, no hydrologic impacts are expected with this event and thereafter through the first half of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Thursday for ANZ331- 332-335-340-345. Small Craft Advisory from 2 AM to 6 PM EDT Thursday for ANZ338- 350-353-355. && $$ SYNOPSIS...OKX NEAR TERM...99 SHORT TERM...OKX LONG TERM...OKX AVIATION...99/OKX MARINE...99/OKX HYDROLOGY...OKX

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