Excessive heat warning issued for Mendocino, Lake counties this weekend

The National Weather Service has issued an excessive heat warning for Mendocino and Lake counties this weekend as temperatures are expected to skyrocket across a large swath of Northern Californa.

The warning covers all of Lake County and the northeast corner of Mendocino County, in addition to much of the inland areas to the north. It begins Saturday afternoon and lasts through Monday evening, but temperatures will begin to shoot up Friday, according to the weather service.

Sonoma County is also expected to heat up this weekend, but temperatures won’t reach the threshold for a weather service warning, meteorologists said.

A high of 95 degrees is predicted for Clear Lake on Friday. Over the weekend, highs are expected to reach 103 degrees — about 15 degrees above normal — and notch down to 101 on Monday, according to the weather service.

The normal high temperatures for those dates in Clear Lake range from 87 to 88 degrees.

The heat is expected to stick around through the first half of next week and start to drop off Thursday, said meteorologist Scott Carroll.

The hot, dry weather could bring increased fire danger, but winds are expected to remain light, Carroll said.

The incoming heat wave is triggered by a high pressure system that’s centered over the Pacific Northwest. Forecasters initially warned of another sweltering weekend in Sonoma County, but have revised that prediction with the system expected to stay north of the area, said Bay Area meteorologist Drew Peterson.

“Looking at our forecast highs, they don’t look anything like what we were thinking three or four days ago,” Peterson said.

In Santa Rosa, the high temperature is expected to hover around 90 degrees on Saturday, dropping to the upper 80s on Sunday and the mid 80s on Monday, he said.

Santa Rosa’s normal high temperature is 84 degrees for those dates.

"We’re going to be somewhat above normal, but at this point the trend is moving away from those higher temperatures,“ Peterson said.

You can reach Staff Writer Matt Pera at matthew.pera@pressdemocrat.com. On Twitter @Matt__Pera.