895 FXUS61 KALY 060833 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 433 AM EDT Mon Sep 6 2021 .SYNOPSIS... There will be a chance for a few showers and an isolated thunderstorm today with a weak cold front, especially across the southern Adirondacks. Pleasant weather is expected Tuesday, but there will once again be a chance for showers and thunderstorms Wednesday with a few lingering showers possible for the end of the week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Areas of clearing across the region, along with near calm winds, has contributed to radiational cooling and development of areas of dense fog. The fog is mostly in and around river valleys and wet areas. Fog should lift and burn off within a couple of hours after sunrise. Isolated showers and storms tracking off Lake Ontario tracking east ahead of a weak cold front and that activity should brush northern Herkimer and Hamilton Counties this morning. New isolated to scattered shower and thunderstorm activity should develop off the Great Lakes midday and early afternoon. Then the showers and storms track across areas along and north of the Mohawk Valley and southern VT through the afternoon. There will be enough instability across northern areas with a little bit of shear for a marginal risk of severe thunderstorms in northern areas. Outside of the showers and storms, there should be intervals of sun and winds will become west and breezy in the afternoon. So, with some sun and some mixing with the winds, highs today in the mid 70s to near 80 with cooler in higher terrain. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... Clearing tonight and partly to mostly sunny Tuesday and dry. Highs Tuesday in the mid 70s to near 80 and upper 60s to lower 70s higher terrain. Clear much of Tuesday night, then some mid and high clouds possible by daybreak as warm advection strengthens. Upper energy in Canada will track north of the Great Lakes and lifts northeast into eastern Canada Wednesday night and beyond. The associated mean upper trough is slow to build east but the associated low level cold front should track through our region Wednesday afternoon and night. There is an increasing consensus from sources of guidance/ensembles that the timing of the front looks to be later Wednesday afternoon and through Thursday night. Boundary layer flow becomes southwest and increases through the day Wednesday and there is a fairly distinct wind shift to the west over our region Thursday evening and night. This suggests that there should be enough sun and enough winds mixing to the ground to warm many areas into the upper 70s to lower 80s with a little cooler in higher terrain. Instability is expected to be considerable with CAPEs potentially above 1000 j/kg with considerable shear. Some storms should be strong with small hail and gusty winds possible along with locally heavy rain and ponding of water on roadways. Will have to watch the trends, though, to determine what areas may have chances for severe thunderstorms and/or training of thunderstorms with potential standing water in low lying areas. Showers and storms will be slow to build east and some of the stronger storms will continue in our area during the evening, especially the Hudson Valley into western New England. By daybreak Thursday, there could still be some lingering showers, especially in western New England but just scattered to isolated elsewhere. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... In the wake of a surface cold front, an upper level trough will be moving from the Great Lakes towards the Northeast for Thursday into Friday. With the cyclonic flow and lower heights in place, a few showers are possible, especially in areas downwind of the eastern Great Lakes, as the cool temps aloft moving across the warmer lake waters will allow for some lake effect rain showers. Have gone with slight to low CHC POPs for Thursday through Friday, with the highest POPs in the western Adirondacks, as well as upslope favored areas of western New England. Despite the lower heights, good mixing should still yield high temps in valley areas around the lower to middle 70s, which is still seasonable for early-mid September. Overnight lows should be in the 50s, although some upper 40s are possible across the higher terrain. Over the weekend, the flow aloft will flatten out and become fairly zonal. Although dry weather is expected for Saturday, a weak disturbance passing within the westerly flow aloft could allow for a few showers on Sunday, mainly for northern areas. Temps will continue to be in the 70s for highs, with upper 40s to upper 50s at night. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... IR satellite imagery shows some clearing is moving towards the region, as band of bkn-ovc clouds over the region is departing off to the east. With the low T/TD spread, any clearing may allow for a period of MVFR/IFR fog/mist to develop prior to sunrise. KGFL has already seen some clearing and some fog has begun forming there. Elsewhere, it will take until later in the overnight for clouds to clear, but will include a TEMPO for any period of fog/mist until around daybreak, with surface winds remaining very light or calm. After sunrise, any fog/mist will dissipate, allowing for skies to become just sct around 4-6 kft. These clouds may gradually become bkn by the late morning for KGFL and possibly KALB/KPSF. A brief shower is possible for the late morning through mid- afternoon, mainly at KGFL, so will include a VCSH for that possibility. Otherwise, flying conditions will be VFR with southwest winds eventually become westerly by the mid to late afternoon hours. KALB/KPSF will see winds as strong as 10 to 15 kts with a few higher gusts as well, with lighter winds at KGFL/KPOU. Skies will be clearing out for Monday evening into Monday night. Dewpoints will be falling, so the threat for widespread fog looks likely less likely for Monday night, but can't rule out some brief patches near KGFL/KPSF for late in the overnight. Westerly winds around 5 to 8 kts on Monday evening will eventually become light to calm for all sites by later in the overnight. Outlook... Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA. Wednesday Night: High Operational Impact. Likely SHRA...TSRA. Thursday: Low Operational Impact. Slight Chance of SHRA. Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... There will be a chance for a few showers and an isolated thunderstorm today with a weak cold front, especially across the southern Adirondacks. Pleasant weather is expected Tuesday, but there will once again be a chance for showers and thunderstorms Wednesday with a few lingering showers possible for the end of the week. RH values will exceed 50 percent through Tuesday with 80 to 100 percent at night. Near calm winds this morning will become west by midday at near 15 mph with some gusts around 20 mph this afternoon. Winds diminish to less than 15 mph tonight. Winds should be west at less than 15 mph Tuesday. && .HYDROLOGY... Scattered showers and thunderstorms are expected today, mainly along and north of the Mohawk Valley to southern VT. Basin average amounts look fairly light, with rainfall amounts generally between 0.1-0.25" or less, except across the southern Adirondacks where up to a half inch is possible. As a result, this rainfall won't be enough for a significant response and area rivers and streams will continue to slowly fall. After a dry day on Tuesday, more showers and thunderstorms are possible for Wednesday. Thunderstorms could produce locally heavy rain Wednesday afternoon and night, resulting in ponding of water on roadways and standing water in low lying areas. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...NAS NEAR TERM...NAS SHORT TERM...NAS LONG TERM...Frugis AVIATION...Frugis FIRE WEATHER...NAS HYDROLOGY...NAS