Tuesday has been a hazy and hotter day for northern California with more unhealthy air quality. We've reached the peak of our heating for this week, and many changes are coming to our weather through next week. Tonight will be quiet and hazy as a ridge of high pressure remains in control of our region's weather. We'll have a clear sky except for the smoke from our area fires. Overnight lows will range from the 30s and 40s in the mountains to the 50s and 60s in the foothills and valley. Wednesday will be another sunny but hazy day, with more smoke in the mountains. Our cooling trend will begin, with highs in the mountains and foothills in the 70s and 80s, while the valley rises into the lower and mid 90s.
Two troughs of low pressure will collide with the West Coast over the next seven days, and they will drastically change our weather pattern. The first trough will be fairly shallow and will do little more than cool northern California to more seasonable levels, with some mountain breezes. After a brief break on Friday, a deeper and more energetic trough of low pressure will move over our region. It will bring breezes Saturday with stronger wind Sunday and lingering breezes next Monday. Light rain showers are possible for everyone, but more likely in the mountains. Next Tuesday will be quieter. Valley lows will range from the mid 50s to the mid 60s, while valley highs will fall from the 90s to the 70s before warming.