FXUS61 KBTV 222318 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 718 PM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... As of 254 PM EDT Saturday... No significant changes have been made to the forecast. The SPC Severe Weather Outlook for tomorrow shows the region in a Marginal Risk (Level 1 of 5) with the potential for isolated strong to severe thunderstorms. && .KEY MESSAGES... As of 254 PM EDT Saturday... 1. After a dry and seasonable afternoon, precipitation chances will increase across the region tonight through the start of the week. 2. Following a dry midweek period, the next chance for scattered showers and thunderstorms arrives in the late Thursday to Friday timeframe. && .DISCUSSION... As of 254 PM EDT Saturday... KEY MESSAGE 1: After a stretch of dry and seasonable weather the last few days, shower chances will return later tonight through the weekend. The main feature driving precipitation chances is a large upper level trough approaching from the Great Lakes. A frontal boundary associated with the parent low will move through tomorrow afternoon, driving the chances for scattered showers and thunderstorms through the afternoon. Model guidance shows modest instability tomorrow afternoon, with CAPE values of 500 J/kg or so depending on the location, although there is some uncertainty as to how much cloud cover lingers through the morning and inhibits afternoon heating. While it's not the most impressive environment, there should be enough instability, shear, and forcing to drive thunderstorm development tomorrow afternoon. SPC currently shows nearly all of the forecast area in a Marginal Risk for severe weather tomorrow, meaning that a few isolated strong to severe thunderstorms are possible, with possible hail and strong winds as the primary threats. The most likely time frame for thunderstorms will be from noon through about 7PM, so be sure to monitor the forecast if you have any outdoor plans. Storms looks to be progressive, limiting any hydro concerns at this time, especially given the dry weather the last few days. Current rainfall forecasts generally show about 0.25 to 0.50 inches of rain across the area, with lower amounts near the International Border and higher amounts possible within any thunderstorms. For the start of the week, the region will remain in broad cyclonic flow, will will allow for linger showers on Monday and Tuesday, especially across the higher terrain. This cyclonic flow will also lead to some lake effect showers off Lake Ontario, with increased shower chances expected across northern New York during this time period. Temperatures will be on the cool side, with highs only climbing into the 70s, with some locations in the Adirondacks struggling to climb out of the upper 60s. KEY MESSAGE 2: Long wave troughing appears to remain over the eastern US later next week, with the base of the trough to our west. As such, the pattern will be somewhat unsettled with chances for showers returning late in the week. The low pressure track is strongly favored to be well to our north into central or northern Quebec, so widespread heavy rain or strong wind is not on the table, and deep layer shear appears limited for severe storms at this time. Of the latest ensemble scenarios, ones with a bit more amplified trough than the mean upper level heights show 0-500 millibar shear probabilities exceeding 30 knots at a greater than 30% chance (rather than close to 0%). Probable hazards for this system would be fairly widespread, general thunderstorm potential associated with the system's cold front, which may be thermodynamically strong. Machine learning and other ensemble guidance does suggest seasonably high instability for late August could be present, with a slight preference for stronger variety thunderstorms as you go southward (roughly 5% chance of severe weather per GEFS). With a faster timing of an incoming cold front, this threat may be limited to Thursday, and a slower timing would suggest Friday would be a day to watch for thunderstorms, especially in Vermont. The latest guidance has trended perhaps a little more towards the later timing, consistent with an occluding low pressure system and associated slowing eastward progress of a cold front. For now, a slight chance of thunderstorms Thursday evening, and slight chance to chance Friday afternoon in most of the region, seems reasonable at this point. Given the amount of outdoor activities anticipated on Friday and large scale setup for thunderstorm potential, this will be a period to keep a close eye. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Through 00Z Monday...Conditions are mainly VFR, although some lower MVFR ceilings are encroaching on KRUT. As southeast low- level winds increase, that layer may scatter out at times. At least some mixing overnight will likely maintain 3-8 knot across the region, and it will help slowly bring in moisture that should result in lowering ceilings at KMPV and KEFK. It may also bring brief LLWS at KMSS, through 12z, but it's not noted at this time. After sunrise, rising condensation levels should bring those areas back to VFR ahead of the main region of lower ceilings associated with an occluding frontal boundary. This boundary will bring showers and a few embedded thunderstorms as well. The exact timing of precipitation is challenging with little consensus, and there could be waves of rain involved. Highest confidence is in southeast to south winds increasing to 8 to 11 knots sustained with a few gusts 15 to 20 knots. Thinking showers and storms will be most likely 15z-22z, but used PROB30s for most due to uncertainty with respect to timing. Storms could produce lightning, strong gusts, and heavy rain reducing ceilings and visibility. Behind the boundary, ceilings are likely to drop towards 1500-4000 ft agl, and winds will begin to shift south to southwesterly beyond 00z. Outlook... Sunday Night: VFR. Chance SHRA, Slight chance TSRA. Monday: VFR. Chance SHRA, Slight chance TSRA. Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Tuesday: MVFR/IFR conditions possible. Likely SHRA, Slight chance TSRA. Tuesday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Wednesday: Mainly VFR, with local IFR possible. Slight chance SHRA. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. Chance SHRA, Slight chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ WHAT HAS CHANGED...Kremer DISCUSSION...Kremer/Kutikoff AVIATION...Haynes