Two disturbances to our south will be influencing the weather through Thursday. A cut off low just off the coast of California, and a high pressure system over the Four Corners, will feed moisture up from the South and allow for the development of thunderstorms across much of the viewing area. Cloud cover and spotty showers are already moving into Siskiyou County. Through Wednesday morning, the greatest threat for activity will be over Northern California and the Southern Klamath Basin.
A Red Flag Warning is now in place for Siskiyou County, the Klamath Basin, the Cascades and West Side. Showers and thunderstorms will be widespread Wednesday afternoon and evening. Not only will storms be slow moving, but hold a lot of moisture. This means they will be rain producers, and capable of dropping a lot of rain in a short amount of time. Precipitable water values are going to exceed 1.” This is an indication of VERY high moisture content in the air, especially for this region. Flash flooding will be a concern where strong thunderstorms form.
In addition to heavy rain, strong winds will become a threat. With very dry air at the surface, strong winds become typical when thunderstorms begin to dissipate. This is known as a gust front, or outflow wind/boundary. These outflow boundaries can actually lead to the development of new thunderstorms which is exactly what led to the large wildfires that sparked three weeks ago across Southern Oregon & Northern California. With cooler air aloft, hail is also likely through Thursday.
Meteorologist Alyssa Caroprese