A plume of humid tropical air is expected to clash with the slowly advancing leading edge of a cooler, drier Canadian system over the Berkshires late Wednesday, setting the stage for potentially heavy thunderstorms.

Some of those storms could cause torrential downpours and gusty winds, according to meteorologist Hugh Johnson at the National Weather Service in Albany, N.Y. Though pop-up showers could develop at any time, the highest risk of severe weather is expected Wednesday night into Thursday morning.

Slow-moving thunderstorms are expected to be a problem during that period, Johnson predicted. Several microbursts -- intense storms with strong winds that can bring down trees and power lines within several minutes -- could develop, he added.

After the Canadian air mass pushes through around daybreak Thursday, drier, pleasant conditions are expected right through the weekend, an ideal scenario for the many outdoor activities planned for the Berkshires. Seasonable highs around 80 and overnight lows in the 50s will be accompanied by mostly clear skies and calm winds.

Next week, look for a trend toward above-normal temperatures and increasing chances of thunderstorms, especially on Tuesday, although no all-day washouts are expected by long-range forecasters.

For June so far, National Weather Service records at Pittsfield Municipal Airport reflect temperatures and rainfall very close to normal, with no unusually hot days and only two heavy thunderstorms in portions of the county.

The outlook for the first week of July calls for above-normal temperatures and rainfall throughout the Northeast, according to the government’s Climate Prediction Center in College Park, Md.

To contact Clarence Fanto: cfanto@yahoo.com or (413) 637-2551. On Twitter: @BE_cfanto