The National Weather Service has issued a Severe Thunderstorm Watch for much of Western New York and the Finger Lakes region, effective through 10 p.m. This development follows a day of rapidly building atmospheric instability, priming the region for a potentially dangerous evening of severe weather.
The watch includes 30 New York counties, ranging from Erie and Monroe to Seneca, Cayuga, Onondaga, and Yates, along with portions of northern Pennsylvania. In addition to the land-based alerts, several adjacent marine zones including Lake Erie, Lake Ontario, and the St. Lawrence River corridor are also under watch due to the expansive nature of the storm system.
Key Concerns: Wind, Hail, Tornadoes
Forecasters at the Storm Prediction Center and NWS Buffalo are warning that the greatest threats from these storms will include:
- Damaging straight-line winds in excess of 60 mph
- Large hail up to 1 inch in diameter
- Isolated tornadoes, particularly in discrete cells ahead of the main line
The primary risk window for the strongest storms extends from 4 p.m. to 9 p.m., though scattered storms are possible through the early evening. The atmosphere is highly sheared, which means any rotating thunderstorms that form could quickly become severe and capable of producing short-lived tornadoes.
According to NWS Buffalo, a cold front approaching from the Upper Great Lakes is the main trigger. Warm, moist air in place ahead of it is contributing to moderate to strong instability, and enhanced lift from an upper-level jet streak centered over southern Ontario is further fueling storm potential.
“Given the highly sheared environment… discrete organized cells out ahead of the front will have the potential to produce isolated tornadoes,” forecasters said in their afternoon update.
Where the Risk Is Highest
The highest risk for severe storms remains south and east of Buffalo and Rochester, especially across the Western Southern Tier, the Genesee Valley, and the western Finger Lakes. These areas will have the greatest combination of surface-based instability and minimal lake shadowing, which can suppress storm formation near the lake shores.
Storms may weaken slightly as they reach areas closer to Lake Ontario, but damaging wind gusts and localized hail are still possible through central and northern Finger Lakes counties, including Wayne, Cayuga, Seneca, and Onondaga.
Winds Already Picking Up Ahead of Front
Even before storms arrive, strong southwest surface winds are affecting the region. Sustained speeds of 30 to 35 mph are expected through the late afternoon, with isolated gusts near 40 mph, particularly in elevated and open areas of the Niagara Frontier and Genesee Valley.
Daytime high temperatures have surged well above seasonal norms, reaching into the upper 70s and low 80s across much of the region. This warm, humid air is one of the key ingredients driving today’s storm threat.
What to Expect After the Storms
Once the cold front passes, conditions will improve quickly from west to east. Showers and storms will taper off after 9–10 p.m., giving way to partial clearing overnight. Temperatures will drop sharply into the mid-30s, a stark contrast from the day’s summerlike warmth.
Wednesday will bring sunshine but cooler conditions, with highs only reaching the 50s across the Finger Lakes and Western NY.
Looking ahead, the weather will turn unsettled again late Thursday into Friday. A slow-moving storm system is expected to bring another round of widespread showers and possible thunderstorms, followed by more stable conditions heading into the weekend.
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