UPDATE: Temperature soars then drops as storm brings heavy rain

High stream flows flood a low laying flood plain. Blackburn News stock photo.

A new record high temperature was reached, unofficially, in Sarnia early Saturday.

The mercury at Chris Hadfield Airport soared to 11.7 C, 53 F, at 6 a.m. before dropping off to 2 C, 36 F, by 11 a.m. as gusty winds shifted from south to north. The previous record high for Sarnia for January 11 was 11.1 C set in 1975.

Area conservation authorities issued flood watches Friday with a large low-pressure system approaching Sarnia-Lambton.

Environment Canada’s rainfall warning remained in effect.

Meteorologist Peter Kimbell said 50 millimetres, two inches of rain, is likely with most of it falling Saturday.

“This evening it begins in earnest and the bulk of it will likely be Saturday,” said Kimbell. “10 to 20 millimetres tonight, the risk of a thunderstorm, and tomorrow rain at times heavy, 30 to 40 millimetres tomorrow for a total of 50 maybe even more in some areas.”

Kimbell said up to 75 millimetres, three inches, is possible in isolated thunderstorms Friday night into early Saturday morning.

There’s also the slight possibility of some freezing rain Saturday night.

Both the St. Clair region and Ausable Bayfield conservation authorities issued bulletins. Ausable Bayfield said there’s the potential for significant flooding this weekend with “some of the highest stream flows observed across the watershed in nearly a decade.”

Some road closures are anticipated in St. Clair Township and residents along the Lake St. Clair shoreline may experience wind-driven high water levels and wave action with the potential for erosion.

Residents are urged to avoid watercourses and flooded areas.