Area Forecast Discussion
Issued by NWS Albany, NY

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536 FXUS61 KALY 242327 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 727 PM EDT Mon Jun 24 2024 .SYNOPSIS... As high pressure builds into the region, clouds will start to decrease across the region along with a diminishing wind for tonight. High pressure will allow for dry and sunny weather on Tuesday, with comfortable levels of humidity. Warm and more humid conditions are expected on Wednesday, along with some afternoon and evening thunderstorms. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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.UPDATE...As of 725 PM EDT, an upper-level low is now located near the coast of Maine and will continue to depart farther to the east tonight. Weak upper level ridging and surface high pressure then builds into the region by daybreak Tuesday. Showers have been quickly decreasing in coverage over the past hour or so but a few batches still remain, mainly for areas just south and east of the City of Albany. These showers may be enhanced by Mohawk-Hudson Convergence (MHC) with northerly winds down the Hudson Valley and northwesterly winds down the Mohawk Valley (per CSTAR research). These showers will continue to diminish over the next couple of hours with dry weather then expected the rest of the night with decreasing clouds. Some patchy fog will likely develop overnight, especially for areas that saw rain today and where winds trend light to calm. Previous Discussion: As of 345 PM EDT...A closed off upper level low is located over Vermont. With the cold pool overhead, 850 hpa temps have fallen to +8 C, which is much lower than recent days. At the surface, our region remains situated between a departing area of low pressure off the coast of New England and an area of high pressure over the Midwest. With a decent pressure gradient in place, there have been gusty west to northwest winds this afternoon. Some gusts have approached 30 mph at times. With the cyclonic flow in place and cool temps aloft, widespread stratocu clouds have developed across the region. In addition, some brief instability showers have been occurring across the region, especially for areas north and west of the Capital Region. These spotty showers will start to diminish this evening, as the upper level low continues to depart and the loss of daytime heating helps allows for more stable conditions within the lower portion of the troposphere. Overnight, clouds will be decreasing across the region, as some drier air works into the region and surface high pressure builds into the area. Skies will become mostly clear by the late night hours and winds will be decreasing as well. Some patchy fog could develop in some sheltered areas where the wind can go calm, but this will be fairly isolated. Otherwise, it will be a comfortable and quiet overnight, with temps down into the 50s to low 60s.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... High pressure will continue to allow for quiet weather through the day on Tuesday. Behind the departing upper level trough, heights and temps aloft will be rapidly rising on Tuesday. 850 hpa temps will reach +16 C by late Tuesday. Valley areas will be up into the mid to upper 80s for highs, with upper 70s to low 80s in the high terrain. Despite the warm temps, dewpoints will remain comfortable in the 50s thanks to the deep mixing and the low level flow out of the west. Skies will be fairly sunny through the day, but some clouds will start to increase for late in the day. On Tuesday night, temps will milder than Monday night, with lows in the 60s. Some passing clouds are expected and maybe a few light showers across northwestern areas as warm front starts approaching from the west. Our area will be within a warm sector for Wednesday. Upper level shortwave trough will be moving from the Great Lakes towards the Northeast on Wednesday with a surface cold front approaching from the west and some showers and thunderstorms look to develop across the area. With a warm and more humid air mass in place, there should be some instability to work with across the region. 12z NAM suggest SBCAPE values may exceed around 1000 J/kg on Wednesday. Decent deep-layer shear looks to be in place as well, so any storms that develop could become organized. SPC has a marginal to slight risk across the region, with the best threat for organized storms across southern areas, where there will be the best overlap of instability, shear and storm coverage. These storms could linger into Wed night as well depending on the exact timing of the cold front. Temps will be rather warm again on Wednesday with highs well into the 80s to low 90s. With dewpoints creeping higher, heat index values could approach advisory criteria in the mid Hudson Valley. Temps should fall into the mid 50s to mid 60s behind the front on Wednesday night, with some clearing expected late. && .LONG TERM /THURSDAY THROUGH MONDAY/...
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The long term period will begin with the 500 hPa trough axis shifting east and high pressure building into the Northeast behind a surface cold front. This will contribute to dry conditions and seasonable temperatures on Thursday and Friday. Ensemble guidance is in relatively good agreement with the evolution of a shortwave trough at 500 hPa that will progress eastward across the Great Lakes and Northeast on Saturday and Sunday. A warm front with the associated surface low is forecast to lift northeast through the CWA Saturday morning. Low level flow within the warm sector of the surface cyclone will advect tropical moisture into the CWA with NAEFS/ENS mean PWAT increasing to over 1.75" by Saturday evening (above the 90th percentile of KALB sounding climatology for late June/early July). The abundant moisture will support medium to high (50%-80%) chances for precipitation late Saturday afternoon through Sunday morning as the trough and surface cyclone move east of the forecast area. Based on the progressive nature of the system, the likelihood of flash flooding is currently very low (5% chance or less) despite the abundant moisture being advected into the region. While vertical wind shear greater than 30 knots will be supportive of organized convection, there is uncertainty with regards to how much destabilization will be able to occur within the warm sector of the surface cyclone. Therefore, the likelihood of strong/severe thunderstorms currently looks to be low (less than 15%). The system is expected to exit the area Sunday evening with drier conditions expected early next week.
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&& .AVIATION /23Z MONDAY THROUGH SATURDAY/...
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Through 00z/Wed...An upper level low will continue to depart the region tonight with surface high pressure building into the area for Tuesday. VFR conditions are in place at KALB/KGFL/KPOU with MVFR cigs at KPSF. Most of the shower activity has ended but will keep VCSH for a couple more hours at KPSF given radar trends. Clouds will gradually clear tonight keeping or trending all TAF sites to VFR conditions. Patchy fog may develop at KGFL/KPSF later tonight so included TEMPOs for IFR/MVFR vsbys, respectively, starting around 07z/Tue. VFR conditions then expected throughout the day Tuesday with just some developing fair weather cumulus and high cirrus. North to northwesterly wind around 10 kt will decrease to 5 kt or less tonight. A few gusts to around 20 kt may continue at KPSF for a couple more hours. Wind will become westerly on Tuesday at around 10 kt, except southwesterly at KGFL. Outlook... Tuesday Night: Low Operational Impact. Slight Chance of SHRA. Wednesday: High Operational Impact. Likely SHRA...TSRA. Wednesday Night: High Operational Impact. Likely SHRA...TSRA. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: Moderate Operational Impact. Breezy. Chance of SHRA...TSRA.
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&& .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis/Rathbun SHORT TERM...Frugis LONG TERM...Humphrey AVIATION...Rathbun