Mike Krueger

Northern California is experiencing a dramatic weather transition this week. A strong high-pressure ridge will peak mid-week before a powerful, unseasonably deep upper-level trough from the Gulf of Alaska plunges south. This will bring hot temperatures, a slight chance of mountain thunderstorms, and a rapid weekend cooldown with strong winds. Valley (Redding, Red Bluff, Chico) Wed-Thu: Sunny and hot, with highs approaching 100°. Moderate HeatRisk is expected.

Northern California is experiencing a distinct multi-day summer warming trend driven by an expansive upper-level ridge of high pressure, which will abruptly shift to a sharp cooling trend and breezy conditions by the weekend as a deep Gulf of Alaska trough digs into the Pacific Northwest. Overall Setup Early to Midweek (Tuesday – Thursday): A strong ridge of high pressure centered over the eastern Pacific and Southwest U.S. remains the dominant driver.

An expansive upper-level ridge of high pressure over the Pacific Northwest and Great Basin will dominate the first half of the week. This pattern compresses the air mass to drive a summer warming trend across the interior valleys and mountains. Simultaneously, it locks in a compressed, persistent marine layer along the immediate coastline. Relief from the heat arrives late in the week as an upper-level trough drops south, bringing a cooldown and a chance of rain by Friday.