Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
935 FXUS61 KBUF 211754 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 154 PM EDT Fri Aug 21 2026 .WHAT HAS CHANGED... Only minor changes with this forecast update. && .KEY MESSAGES... 1) Periodic showers and scattered thunderstorms this weekend into early next week. && .DISCUSSION... Key Message 1...Periodic showers and scattered thunderstorms this weekend into early next week. High pressure will maintain fair weather through tonight while drifting to our east. Our weather will turns unsettled this weekend, as an upper level trough digs southeastward across Ontario and eventually closes off over southern Ontario/southwestern Quebec later Sunday/Sunday night. An attendant elongated surface low will slowly push a warm front into our region Saturday, followed by a cold front Saturday night into Sunday morning. Dry weather is likely maintained through early Saturday afternoon, before the arrival of the warm front and associated moisture return. The warm front, increasing moisture and modest diurnally instability should be enough to set off some scattered convection from the Finger Lakes westward, with showers/storms becoming more numerous across the Southern Tier toward evening. Widespread showers and embedded thunderstorms will follow Saturday night through Sunday morning, as the cold front crosses our region and the upper trough approaches. PWAts during this time will peak around 1.5", which could lead to a few locally heavy downpours. Unfavorable timing of the front should keep the severe threat to a minimum. A cyclonic flow of progressively cooler air will overspread our region Sunday through Monday behind the front, with 850 mb temperatures will bottoming out in the +6C to +8C range later Sunday night into Monday. This regime will support additional scattered instability showers and a few storms Sunday through Monday, with these potentially turning a little more numerous as deeper wraparound moisture and shortwave impulses pivoting around the larger-scale closed upper low. The progressively cooler air should also allow for areas of lake enhanced/lake effect rain showers downwind of the lakes as the prevailing large-scale flow focusing most of these east of Lake Erie and ENE/E of Lake Ontario. Improving conditions are expected Monday night and Tuesday as the upper low ejects northeastward across Quebec and high pressure and drier air builds across our region. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Surface high pressure centered overhead this afternoon will continue to slide east across the Northeast through tonight and allow for widespread VFR conditions to prevail into Saturday morning. The only exception will be of KJHW where ample radiational cooling overnight will support patchy fog to develop across the river valleys of the Southern Tier. Meanwhile a surface low overhead of northern Wisconsin will continue to progress east across the Great Lakes, reaching northern Michigan by 12Z Saturday. A surface warm front will extend eastward and push into WNY after 18Z Saturday, supporting scattered showers and thunderstorms to develop across areas south of Lake Ontario. Within any shower/thunderstorm, localized MVFR to LIFR conditions will be possible along with gusty winds in excess of 35kt. A line of showers and embedded thunderstorms will then slide east across the area Saturday night into Sunday morning ahead of a passing cold front associated with the aforementioned surface low. Ceilings will lower to MVFR from west to east, and IFR across the western Southern Tier overnight. Outlook... Sunday through Monday...Periodic showers and isolated to scattered thunderstorms with associated MVFR/IFR...with mainly VFR expected outside of any precipitation. Monday night and Tuesday...Scattered showers and associated restrictions east of Lake Ontario diminishing...otherwise mainly VFR. Wednesday...Mainly VFR. && .MARINE... Surface high pressure will exit into New England tonight. A modest southeasterly to southerly flow will develop tonight and Saturday as the high exits and elongated low pressure pushes east across the central Great Lakes and Southern Ontario. This low will push a warm front and trailing cold front across the lower Great Lakes later Saturday through Sunday morning. While wind speeds during this time should remain below 20 knots, these boundaries will help generate periodic showers and scattered thunderstorms, a few of which could produce locally higher winds and waves. A cyclonic, west-southwesterly to westerly flow of cooler air will overspread the lower Great Lakes behind the front for Sunday and Monday. This may support some SCA-worthy conditions on both lakes with the chance for some waterspouts. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ DISCUSSION...TMA AVIATION...EAL MARINE...TMA