120 FXUS61 KBTV 041705 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 105 PM EDT Wed Sep 4 2019 .SYNOPSIS... A cold front will cross the area today along with scattered showers and a few thunderstorms, a few of which may trend briefly strong across eastern and southern portions of Vermont. Behind the front, high pressure brings seasonably cool and dry weather to the region for Thursday into Friday. The next chance for a few showers occurs by this coming weekend, but coverage should be relatively sparse with many dry hours expected on both days. && .NEAR TERM /THROUGH THURSDAY/... As of 1259 PM EDT Wednesday...SPC has placed Rutland and Windsor Counties into SVR Thunderstorm Watch #634 until 01z. Our southern cwa will be on the northern edge of the better instability/moisture with continued favorable deep layer shear. Thinking the best chance for svr will be across our southern Rutland/Windsor counties thru 20 or 21z, before better instability shifts east and drier air aloft mixes to the sfc. Water vapor shows deep dry layer moving across northern NY, which has started to mix to the sfc, with sfc dwpts dropping 3 to 7 degrees in 1 hour. This trend will continue to advance eastward, behind sfc trof. Given wind profiles, primary threat would be isolated damaging winds, mainly south of a Rutland to Lebanon line. Prior discussion... Most active weather over the next 5 days occurs today with the approach and passage of a seasonably strong late summer cold front. As discussed over the past few nights, dynamical forcing aloft is quite robust, but BL instability will be more on the marginal side given temperatures in the upper 60s into the 70s and ample mid-level debris cloudiness. Based off the timing of the pre- frontal trough, the best threat for any stronger storms will lie across eastern/southern VT, especially along and south/east of a Ticonderoga-KMPV-K1V4 line in the early to mid afternoon hours. As such have included strong/gusty wind potential in these areas accordingly but widespread/organized severe weather is not expected. Further north and west, trough and associated low level convergence arrives early enough (morning hours) that stronger activity is not expected. The actual surface front then clears east by later this afternoon/early evening with any lingering showers ending as winds veer west/northwesterly and slowly abate. Then mostly clear to partly cloudy overnight tonight as surface high pressure across the Great Lakes builds eastward. Low temperatures to bottom out in the 40s to around 50 with some patchy late night fog across the Dacks/SLV where low level wind fields trend lightest. An outstanding early September day is then expected for Thursday as aforementioned high builds atop the area along with mostly sunny skies and light winds. High temperatures to run on the seasonably cool side by about 5 degrees with late afternoon readings topping out in the mid 60s to lower 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... As of 310 PM EDT Tuesday...Clouds will begin to move in from the northwest Thursday night as shortwave energy digs into the Great Lakes Region. Still expecting a chilly night overall with Canadian high pressure cresting to our north, but the clouds will temper the degree of radiational cooling somewhat. Have stayed relatively close to MOS guidance with this setup, forecasting overnight lows in the mid 40s to around 50...with a few of the typical colder hollows in the northern Adirondacks and NEK dipping into the upper 30s. Clouds will increase during the day Friday as the shortwave moves to the eastern Great Lakes. Most of the shower activity associated with the wave will stay to our west through Friday, so have kept with a dry forecast. High temperatures will be in the upper 60s to low 70s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 310 PM EDT Tuesday...Upper-level shortwave will move through Friday night, resulting in lowering and thickening of clouds and some isolated light showers. At the same time, Dorian is forecast to lift northeastward over the western Atlantic while staying well off the New England Coast (please see the NHC for up-to-date latest track). A deepening longwave trough over Ontario/Quebec Saturday will push Dorian northeastward and out to sea late Saturday, further raising confidence that the storm will not impact the North Country. A weakening Canadian low will send a cold front through the BTV forecast area Saturday night. Still looking like moisture transport ahead of the system will be minimal given the continentally sourced air moving in, so have kept PoPs generally under 30 percent. Behind the front, a shot of cooler air will arrive...with 850 mb temps dropping to near 0 deg C. Sunday night will see the coldest temperatures (lows in the upper 30s to mid 40s) before a gradual warming trend commences going into midweek. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... Through 12Z Thursday...SCT to BKN mainly VFR cigs expected through 00Z, after which skies trend SCT to SKC. Cold front to push through the area later this morning into this afternoon with scattered showers and a few thunderstorms. Highest coverage expected this morning into mid-afternoon, especially from KSLK eastward. Brief IFR vsbys and MVFR cigs possible with heavier showers/storms, a few of which could be strong at KMPV and KRUT and points east/south this afternoon. Winds generally south to southwest and gusty into the 20-30 kt range at selected terminals through 18Z ahead of the front. Winds then veer to westerly, then northwesterly in the 16-23Z time frame and slowly abate thereafter into the overnight hours as the front clears east. Some late night patchy MVFR/IFR BR and/or FG possible at KMSS/KSLK after 07Z. Outlook... Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. Slight chance SHRA. Saturday: VFR. Slight chance SHRA. Saturday Night: Mainly MVFR, with local IFR possible. Slight chance SHRA. Sunday: Mainly VFR, with local IFR possible. Slight chance SHRA. && .MARINE... As of 911 AM EDT Wednesday...A Lake Wind Advisory remains in effect this aftn for gusty south winds. Winds should peak with sustained values generally in the 25 to 35 knot range creating significant wave heights of 2 to 5 feet. Winds will veer to west/northwesterly and slowly abate by late this afternoon and evening as wave heights subside. Additionally, showers and a few thunderstorms are expected this aftn. A few of the storms may become strong across the southern portions of the lake. As such, boaters and others with recreational interests on the lake should plan accordingly and seek safe harbor quickly should threatening weather approach. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG/Taber SHORT TERM...Duell LONG TERM...Duell AVIATION...JMG MARINE...JMG/Taber