Hard freeze likely in Tri-Cities as temps fall. Mountain snow warning for drivers

The first freeze of the fall is forecast this week in the Tri-Cities, with lows taking a sharp drop into the 20s by the end of the week.

That means it’s time to dig out the winter coats, get your sprinkler system blown out and to consider bringing potted plants indoors and covering tender outdoor plants.

The National Weather Service expects the overnight lows, which have been in the 40s at the start of the week, to drop to 31 degrees Wednesday night and 30 Thursday night.

Friday and Saturday night temperatures are forecast to drop to 26 or 25 degrees, according to the weather service.

Highs are forecast to drop from the 60s to 55 on Tuesday then to 47 from Wednesday to Friday. Weekend highs are forecast to be as cool as 44.

The coldest night of the fall so far has been Oct. 13 with a temperature of 37 and the coldest day has been Sept. 21 with a high of 59.

Oct. 14 is the usual first day of the fall that the temperature in the Tri-Cities falls below freezing, based on averages, according to the weather service.

Usual temperatures for the start of this week in the Tri-Cities are highs of about 62 and lows of about 36.

Rain is likely Wednesday, followed by a slight chance of rain — or maybe even snow — on Friday into early Saturday morning.

Any precipitation is most likely to fall as snow early Saturday morning when the snow level is forecast to drop to 900 feet. Much of the Tri-Cities is at about 400 feet elevation.

Travel forecast

If you’re heading to the west side of Washington state on Interstate 90 or heading east from the Tri-Cities on Interstate 84, be prepared for snow.

The weather service forecasts about an 80% chance of at least 4 inches of snow on Snoqualmie Pass on I-90 in Western Washington Monday night through Wednesday afternoon. Parts of the east slopes of the Cascade Mountains are likely to get 5 to 10 inches of snow, according to the weather service.

Snow is also possible in the Blue Mountains, with about a 30% chance of at least 2 inches of snow on Interstate 84 near La Grande, Ore., Monday night through Wednesday afternoon. Parts of the Blue Mountains are likely to get 2 to 5 inches of snow.

This story was originally published October 23, 2023 at 11:58 AM.