MOUNTAIN AREA — A High Wind Watch is going into effect for the Sierra Nevada from Yosemite National Park to the Tulare County line, according to the National Weather Service. The High Wind Watch above 4000 feet is slated from 10 p.m. Thursday evening, Dec. 1, until 10 p.m. Friday evening, Dec. 2.
Winds in excess of 40 miles per hour are possible with gusts as high as 70 miles per hour. These winds will be capable of toppling trees and power lines, says NWS. The strongest winds are expected between 4 a.m. Friday and Friday afternoon.
At last count, over 100 million trees in the Sierra Nevada are dead and pose a threat of toppling with high winds.
The foothill areas are not in the watch, say experts, though winds may be gusty and exceed 35 miles per hour at times.
A Mono Wind is a very strong and and damaging northeast wind that rushes down the rugged slopes of the Sierra Nevada. It starts with strong high pressure over the Great Basin in Nevada, and very cold air pools up alongside the eastern slopes of the Sierra. The jet stream pushes the cold air over the crest, where it rushes several thousand feet down the western facing slopes, with a potential of reaching 100 miles per hour or more.
Mono Winds are part of a family of winds that known in technical meteorological terms as katabatic winds. The term katabatic winds originates from the Greek Word katabatikos which means “going downhill,” says NWS.
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San Joaquin Valley Freeze Watch
A Freeze Watch is in effect for the San Joaquin Valley from late Friday evening, Dec. 2, through Saturday morning, Dec. 3, says NWS. Temperatures are expected to drop to the upper 20s for several hours over the rural areas of the valley after midnight, until a few hours after sunrise. The larger cities will see temperatures range from 30 to 34 degrees. A freeze has the potential to damage crops and harm pets and livestock. Homeowners should cover or bring in plants, check to make sure pets have adequate shelter and that pipes are covered.
This story was amended on Dec. 1 at 10:45 a.m. to reflect that freeze watch is delayed to Friday night through Saturday morning.