Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
533 FXUS61 KBTV 120724 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 324 AM EDT Wed Aug 12 2026 .WHAT HAS CHANGED... As of 309 AM EDT Wednesday... No Significant changes were made. Isolated to scattered showers with a few embedded thunderstorms are expected today. && .KEY MESSAGES... As of 309 AM EDT Wednesday... 1. Isolated to scattered showers are expected this afternoon with a few thunderstorms mixed in. Chances increase Thursday as a wave moves through with lingering showers Friday. 2. Tranquil weather on Saturday, then beneficial rain likely spreads in from the west Sunday afternoon and exits on Monday. Becoming seasonably warm and dry early next week. && .DISCUSSION... As of 309 AM EDT Wednesday... KEY MESSAGE 1: Maintained yesterday`s forecast change of including some showers and very isolated convection today. Best chances of thunderstorms lie in the St Lawrence Valley where the CAPE gradient will be sharpest with around 500J/kg to work with. Otherwise, temperatures will be similar to yesterday with highs in the mid/upper 70s to low 80s today and Thursday. Shower and thunderstorm chances increase Thursday as low pressure moving through southern Canada pushes a boundary through the region. Around 500 J/kg of CAPE is projected to be in the region coincident with the weakening boundary with the strongest forcing towards the Canadian border(CAMs are highlighting potential for a bullseye of 1000+J/kg at max heating which may strafe our northern zones in Vermont - lower likelihood, but potentially impactful scenario where a couple stronger storms would be possible). Another trough is anticipated to move through Friday in broad northwest flow. Showers are mostly expected, but could see a few rumbles in southern Vermont where timing will play a roll in convective chances. Should the trough slow, surface instability will likely build enough for more showers and storms, but current timing of this wave supports mainly showers as the wave exists early afternoon. Some breezy conditions should be anticipated with this trough, especially on Lake Champlain and the peaks where gusts could approach or exceed 30 mph. Gusts 15 to 25 mph are probable at lower elevations away from Lake Champlain. KEY MESSAGE 2: A mid-level ridge over the southeastern US will build northward a bit on Saturday, leaving us in northwesterly flow with dry air and no precipitation chances. This ridge will breakdown on Sunday, allowing a weak wave of low pressure originating in the foothills of the Colorado Rockies to zip eastward and bring us some overrunning/warm frontal type of rain. There is a slight chance of thunder indicated at this time Sunday night in much of Vermont, which would only be a factor if the low pressure system trended stronger and/or tracked farther north, such that our region got into the system`s warm sector. Otherwise, a steady soaking rain looks favored, with current consensus timing from Sunday afternoon through Monday morning. Probabilities of event total rainfall exceeding 0.5" currently ranges from about 20% to 40%, tapering off generally towards the north. among the latest global ensemble scenarios, some solutions are a little slower to bring rain to an end on Monday with higher probabilities of rain into Monday evening than what the current forecast suggests. Given the uncertainties, the 10-30% chance of showers Monday afternoon looks reasonable at this time; some of this precipitation could be orographic, post-frontal showers. Following this system it appears a ridge of high pressure may build in, which would provide us with generally quiet weather for Tuesday. There are weak signals for perhaps a terrain-driven shower in the Adirondacks or off of a lake breeze interface, which would make sense given a typical summertime heating scenario with lack of other forcing mechanisms for precipitation. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... Through 06Z Thursday...Dense fog will certainly be the main aviation impact over the next six hours, particularly at fog-prone sites. At SLK, intervals of fog have already begun. Would expect the typically frequent LIFR conditions through about 12Z, with crossover temperatures already met prior to 06Z. Mid-level clouds currently are moving through northern Vermont which could delay fog formation at EFK and MPV, but don`t think it will linger all night based on satellite trends. Otherwise, isolated to scattered showers with a few thunderstorms are anticipated for much of the 18Z through 06Z timeframe, with perhaps a greater likelihood of a direct hit at our northern terminals (especially MSS, and perhaps PBG and BTV) based on the latest guidance. Chances are too low to indicate in the TAFs at this time. Winds aside from a thunderstorm or stronger shower will be light; during the daytime, generally expect west/northwest winds, except terrain driven in the Champlain Valley (SE at PBG, N-NW at BTV). Outlook... Thursday: VFR. Likely SHRA, Chance TSRA. Thursday Night: VFR. Chance SHRA. Friday: VFR. Chance SHRA. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Slight chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ WHAT HAS CHANGED...Boyd DISCUSSION...Kutikoff/Boyd AVIATION...Kutikoff