Brimacombe (Oshawa Ski Club) Snow Report

082 FXUS61 KBUF 230633 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 233 AM 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 /06Z SUNDAY THROUGH THURSDAY/... For the 06Z TAFS a surface low is wobbling eastward to the north of Lake Ontario, while slowly dragging a cold front across the TAF region. This will bring several rounds of showers and isolated thunder...initially this morning along the front, with more widespread showers and scattered thunderstorms in the late morning and early afternoon towards the east where limited daytime heating should yield enough instability to bring scattered coverage to storms. Early morning stratus IFR clouds across the Southern Tier are expected to lift with daytime heating. Expect largely MVFR to VFR ceiling heights through the early afternoon hours, with brief IFR/MVFR visibilities in any stronger downpours of rain. Behind the front, cool and moist cyclonic flow will bring rain showers and MVFR to IFR flight conditions to the TAF sites east of Lake Erie that will likely persist through the remainder of tonight. Much of the lower flight restrictions will be ceiling based. Additional plume of lake effect rain is expected off Lake Ontario, near KART later tonight. This plume may be better organized along the longer fetch of Lake Ontario such that IFR/MVFR visibilities will be possible for KART. Outlook... Monday...Periodic showers and isolated to scattered thunderstorms with associated MVFR/IFR, with mainly VFR expected outside of any precipitation. Monday night through Tuesday night...Lake effect rain, mainly east and southeast of the Lakes with associated restrictions diminishing off Lake Erie Monday night and Tuesday and off Lake Ontario Tuesday and Tuesday night. Otherwise mainly VFR. Wednesday...Mainly VFR. Thursday...Mainly VFR, except MVFR/IFR conditions possible from scattered showers and thunderstorms in the 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 from 8 AM EDT this morning through Tuesday evening for NYZ001>007. Beach Hazards Statement from 8 AM EDT this morning through late Monday night for NYZ010-019-085. MARINE...Small Craft Advisory from 8 AM this morning to 2 AM EDT Tuesday for LEZ040-041. Small Craft Advisory from 8 AM this morning to 8 PM EDT Tuesday for LOZ042>044. Small Craft Advisory until 8 PM EDT Tuesday for LOZ045. && $$ DISCUSSION...Thomas AVIATION...Thomas MARINE...Jaszka/Thomas