There is a chance for isolated mountain thunderstorms this afternoon and evening. Valley highs will warm to the low 90s today and Tuesday but closer to 100 degrees by Wednesday.
Instability will be the highest this afternoon in northern Trinity and western Siskiyou County. We could see some isolated thunderstorms by the late afternoon, early evening. Once the sun sets, instability will quickly drop and mountain thunderstorm activity will collapse.
A weak delta breeze, combined with south winds the next couple of days will keep the valley floor in the low 90s, if not the upper 80s Tuesday. The ridge rebuilds and a northerly gradient will quickly warm the valley to or above 100 degrees Wednesday through the weekend.