Northern California has heated quickly today and a lot more heat is coming our way. An Excessive Heat Warning went into effect at 2PM and it will remain in place through Saturday night. Do what you can to stay cool and safe! A strong ridge of high pressure is building over northern California at this time, and it will dominate our weather in the short term. Although we have a few clouds, they're not helping to cool us. We'll also have some northerly breezes which will warm us as well. Tonight will be mostly clear and quite mild with lows ranging from the 50s in the mountains to the 60s and 70s in the valley and foothills. Thursday will be mostly sunny and hotter with highs from the 90s in the mountains to around 110 in the valley.
Highs will stay very hot Thursday through Saturday, although minor cooling will probably occur by Saturday. The cooling trend will continue through early next week, and it should be more seasonable by next Tuesday and Wednesday. A trough of low pressure will form off the California coast early next week, and that onshore flow will serve us well, cooling us back to more seasonable June levels. Unfortunately we have no good chances of rain outside of perhaps a shower in the Siskiyou County mountains from now through the first few days of July, and no chances at all for the valley. Valley lows will start in the 70s, cooling to the 60s by next week. Valley highs will be near 110 tomorrow, cooling to seasonable 90s by next Wednesday.