As August begins this weekend, a very serious fire weather threat will develop east of the Cascade crest due to strong westerly winds and low humidity.
Forecasters at the Storm Prediction Center have highlighted much of central and eastern Washington with a rare "Extremely Critical" fire weather designation Saturday. Significant fire growth is likely, and any new fires that develop could spread very rapidly.
Local National Weather Service forecasters have issued Red Flag Warnings for all of the state east of the Cascades, and have dubbed this a "Particularly Dangerous Situation" (PDS) on Saturday afternoon into early evening. This includes Chelan and Douglas counties, as well as Okanogan County, the Kittitas Valley and all points east. A "Particularly Dangerous Situation" is a extreme risk designation used by the NWS very rarely.
With large, uncontained fires already underway, rapid and erratic spread along with sudden torching of trees and long-range spotting from flying embers can create an uncontrolled and chaotic situation where both firefighting and evacuating an area on short notice can become dangerous.
The culprit is stronger onshore, or westerly, wind flow off the Pacific Ocean associated with a cold front. This front will bring more clouds, cooler temperatures, and a chance of rain showers to Western Washington on Saturday into early Sunday.
These winds will not be able to bring much moisture or clouds east of the crest of the Cascades, but instead the air flow will warm and dry as winds descend on the eastern slopes. The wind will also speed up with gusts over 50 mph possible.
If you live in central or eastern Washington, or are traveling east of the Cascades to start August Saturday, make sure to have a way to get emergency weather information like a cell phone with Wireless "Emergency Alerts" turned on. Know more than one evacuation route from your location and be prepared to leave with little to no advance warning if fire approaches suddenly.
Also, every family should have one or more "go bags" with important items, medications, and documents that can be grabbed and carried away on a moment's notice, should a "go now" evacuation order be issued.
Learn more about having a "go bag" from KIRO 7 Pinpoint Meteorologist Robert Van Winkle here.
Winds will subside Saturday night into Sunday and the extreme threat will end, with fire danger remaining high beyond.
Stay with KIRO 7 and KIRO7.com for the latest.