Weekend weather: Big cool down to last into next week

A large low-pressure system is moving out of the Gulf of Alaska and bringing a major cool down with showers starting Thursday morning.

Mostly cloudy skies are expected Thursday with gusty southwest winds to 23 mph.

The change in weather is creating instability in the atmosphere that could trigger some thunderstorm within shower clouds likely to spread across the region.

The low-pressure system is expected to migrate southward along the coast into Oregon and become stalled to the south of the Inland Northwest.

But it will create an ongoing risk of showers.

National Weather Service forecasters said the chances of showers are 40 percent today dropping to 20 to 30 percent on Friday through Sunday.

Highs could drop by 18 to 20 degrees Thursday after temperatures went to near 90 degrees on Wednesday.

The high Thursday in Spokane may reach 73 and then drop into the 60s through early next week.