Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
404 FXUS61 KBTV 122337 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 737 PM EDT Wed Aug 12 2026 .WHAT HAS CHANGED... As of 228 PM EDT Wednesday... No significant changes we made to the forecast. && .KEY MESSAGES... As of 228 PM EDT Wednesday... 1. Isolated to scattered showers and thunderstorms expected this afternoon, and Thursday afternoon as a pair of shortwaves move through the region. Conditions turn drier and quieter by Friday and Saturday. 2. Showers return for late Sunday and the beginning of next week. && .DISCUSSION... As of 228 PM EDT Wednesday... KEY MESSAGE 1: Isolated to scattered showers and thunderstorms are beginning to move through the area this afternoon as a shortwave axis centered over western Ontario slowly pivots east. Upper level northwesterly zonal flow is set up across New England on the periphery of a stagnant ridge over the Plains and Intermountain West. Marginal instability around 1000J/kg is analyzed by on mesoanalysis providing the fuel for showers and storms today. Additionally, effective bulk shear to around 35-40 knots may lead to some locally gusty winds up to 30 MPH under any thunderstorms. However, given the marginal instability, weaker mid level lapse rates, and an apparent cap around 700mb based on satellite cloud presentations will keep any severe threat low through this evening. Best chances for any stronger storms will be across the St. Lawrence Valley where the best CAPE gradient is. A few training storms will be possible with storm motion paralleling the mean flow. However, deep moisture will be lacking with PWs only to around an inch. Thus, any risk of flooding will be slim. While a few isolated showers may continue through the overnight hours, any thunderstorm activity is expected to wane beyond sunset. Another shortwave is expected to move through tomorrow, with better aligned forcing for our region. Increasing diurnal instability around 1000-1500J/kg focused around the International Border with similar shear profiles will bring better chances for thunderstorms to the region tomorrow afternoon, though a few showers may be possible in the mid to late morning with little capping inversion present. Instability will highest in northern Vermont, though showers and thunderstorms anywhere across the northern portions of the CWA will be possible tomorrow. PWs will slightly increase tomorrow to near an inch and a quarter, with parallel motion and training cells. However, again, deep warm cloud depths will be thin with a low risk for any flooding concerns. Troughing will slide east with surface high pressure building in by Friday. More calm and quieter conditions are expected through Saturday. Temperatures will be relatively seasonable in the mid to upper 70s. A radiational cooling night is increasingly likely Friday night with lows potentially dipping to the upper 40s to low to mid 50s. A few pocket low 40s may be possible in the decoupled protected valleys of the Adirondacks and eastern Greens. KEY MESSAGE 2: An area of low pressure enters the region for late in the weekend and early next week, bringing another round of showers to the region. The track of the low will determine the exact impacts. Right now, a track slightly south is favored, bringing a period of steady rain. However, some ensemble members bring the low just far enough north to push the warm sector into at least southern areas. This would cause some severe potential, so the threat will be watched. GEFS/EPS/CMCE combined probabilities of receiving more than an inch of rain are under 10 percent, and probabilities of a half inch are from 10-30 percent. Overall, not much of a flood threat is expected. Behind the system, temperatures should trend seasonably cool with a couple additional chances of showers. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Through 00Z Friday...Earlier scattered shower/tstorm activity has largley passed but a couple of lingering showers is likely through 09z. If any -tsra, it would likely be at KMSS.These showers and storms will cause brief visibility reductions, with a period of MVFR or IFR visibility occurring during the storms. Patchy fog development will occur later in the night. It is expected to reach MPV and SLK, and there is a chance (~30 percent) that it forms at EFK. Areas that see rainfall today will see locally higher probabilities of fog formation. The fog should lift by 13Z and VFR conditions are expected through the rest of the morning. Winds will generally be under 5-10 KT, except during storms where erratic gusts up to 30 KT are possible. Outlook... Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Chance SHRA. Sunday Night: Mainly MVFR, with areas VFR possible. Chance SHRA, Slight chance TSRA. Monday: Mainly VFR, with areas MVFR possible. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ WHAT HAS CHANGED...Danzig DISCUSSION...Myskowski/Danzig AVIATION...SLW