Although northern California is only slightly hotter than average for the first week of July at this time, potentially dangerous heat is only a few days away. Excessive Heat Warnings and Heat Advisories will go into effect Friday. We've had quiet, hot and fairly seasonable weather for northern California this afternoon as temperatures rose back into the 90s and 100s. Tonight will be mostly clear to clear, calm and mild with lows ranging from the 50s in the mountains to the 60s and lower 70s in the valley and foothills. Thursday will be mostly sunny to sunny once again, but most everyone will begin the next round of hotter weather. Highs will range from the 80s and 90s in the foothills and mountains to the lower 100s in the valley.
The strong ridge over most of the western United States will only get stronger on Friday and this weekend, and that will allow temperatures to continue to soar in our area. Most of northern California outside of the immediate coast will be under Excessive Heat Warnings beginning Friday and they will continue through Monday night. The mountains can expect 90s and lower 100s for highs, the foothills will be well into the 100s by this weekend, and the valley will have highs from 107 to 113 degrees Saturday and Sunday, with 115 degrees possible in a few areas. The overnight hours will not bring much relief, with lows in the 70s and lower 80s in a few unlucky locations. Only minor cooling is expected through early next week.