FXUS61 KBUF 231747 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 147 PM EDT Sun Aug 23 2026 .WHAT HAS CHANGED... Fine-tuned lake effect band placement for tonight as well as Monday night. && .KEY MESSAGES... 1.) Showers and thunderstorms today, with a few potentially strong to severe. 2.) Cool, upper level low to bring lake effect rain this afternoon through Tuesday night. Cool tonight through Monday night. && .DISCUSSION... Key Message 1...Showers and thunderstorms today, with a few potentially strong to severe. This early morning a surface low is near eastern Georgian Bay, with a cold front draped across WNY. A southerly flow ahead of the cold front will become more southwesterly behind the frontal passage for today. Aloft a closed and negatively tilted mid and upper level low is centered over the Central Great Lakes, with water vapor imagery displaying a shortwave trough diving towards Lake Superior. For today overall severe threat is marginal, with SPC outlining our entire region with a marginal risk. MUCAPE values range 500 to 1000 J/KG ahead of the cold front, with DCAPE values peaking around 1200 J/KG this early afternoon east of Lake Ontario. This front is expected to clear our eastern zones by mid afternoon. Flow through the lower levels is moderate with 0-6 km effect bulk shear values reaching 45 knots...which suggests any stronger storms building within a layer with increasing low level lapse rates of 6.5 to 7.0 C/Km could bring a few strong to damaging wind gusts...for which a marginal risk for severe storms is in effect, especially for our eastern zones. The increasing lapse rates with the approach of the cool upper level low could also yield large hail with any taller storms. Key Message 2...Cool, upper level low to bring lake effect rain this afternoon through Tuesday night. Cool tonight through Monday night. Behind the cold front, an early taste of fall tonight through Monday night as a cool upper level low rotates across our region. Temperatures at 850 hPa will plummet towards +7 to +8C across the warm eastern Great Lakes. This will generate a lake effect rain response with the cool air flowing over the very warm lakes. Initial moist cyclonic flow, combined with the approach of a shortwave trough from the Upper Great Lakes will bring both lake enhanced as well as upslope rain showers east of both eastern Great lakes. A southwest flow tonight will lift any organizing lake effect rain bands towards Buffalo and Watertown. Ahead of the closed low, a more southerly flow should push the band of rain off Lake Ontario up towards the Saint Lawrence Valley. Broken bands of lake effect rain will become disorganized through the day Monday with daytime heating and the passage of a trough. This trough could also spark a few thunderstorms through the day. Behind the trough a freshening westerly flow will bring organizing lake effect rain bands southward to areas south of Buffalo and towards the central Tug Hill Plateau. This rain will diminish Monday night off Lake Erie, and Tuesday and Tuesday night off Lake Ontario. In addition to the rain, there will be the potential for waterspouts along lake convergent boundaries with tall EL heights combined with the cool air associated with the upper level low over the warm lakes. Overnight lows will be some 5 to 8 degrees below normal tonight and Monday night, while high temperatures Monday will be some 10 to 15 degrees below late August normals. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Surface low pressure centered over the southern portions of the Ontario province, will continue to advect cool moist air across the region through the 18Z TAF period. As such wrap around, lake enhanced showers are currently scatteredacross WNY as of 1730Z, supporting VFR to MVFR ceilings. Meanwhile, the occluded front associated with the low is in progress of passing east across far eastern New York, supporting a line of showers and embedded thunder. Wrap around showers and thunderstorms will persist throughout this afternoon. Then with the loss of daytime instability, thunder will end shortly after sunset with just lake enhanced showers remaining east of both lakes. Given the cooler temperatures aloft, lake enhanced showers will continue through Monday. As such, a mix of MVFR and VFR ceilings will persist across both WNY and the eastern Lake Ontario region. Outlook... Monday night through Tuesday night...Lake effect rain, mainly east and southeast of the Lakes with associated restrictions diminishing off Lake Erie Monday night into Tuesday and off Lake Ontario Tuesday/Tuesday night. Otherwise mainly VFR. Wednesday...Mainly VFR. Thursday and Friday...Mainly VFR, except MVFR/IFR conditions possible from scattered showers and thunderstorms each afternoon. && .MARINE... Behind a cold front passage today, an upper level low will bring an early taste of autumn with a brisk west wind developing within a decently strong pressure gradient and moderate instability over the Lakes. While initial southerly flow Sunday should bring Small Craft Advisory (SCA) conditions to the lakes Sunday, the southwest flow under the upper level low Sunday night through Monday night, and then westerly flow Tuesday, will likely continue the choppy waters on the Lakes with SCA likely. In addition to the brisk winds, there will be the potential for waterspouts with the development of sizable lake-induced instability as cool air associated with cyclonic flow around the upper-level low crosses the warm lakes. The waterspout threat should continue through Tuesday. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Beach Hazards Statement through Tuesday evening for NYZ001>007. Beach Hazards Statement through late Monday night for NYZ010- 019-085. MARINE...Small Craft Advisory until 2 AM EDT Tuesday for LEZ040-041. Small Craft Advisory until 8 PM EDT Tuesday for LOZ042>045. && $$ DISCUSSION...Jaszka AVIATION...EAL MARINE...Jaszka/Thomas