The National Weather Service has issued an Excessive Heat Watch for the Mother Lode, the Northern San Joaquin Valley and the Yosemite Valley from Saturday afternoon through Wednesday afternoon.
High temperatures in the Yosemite Valley will be at or above 100 degrees Saturday, Sunday, and Monday.
High temperatures in the Mother Lode and the Northern San Joaquin Valley will range between 105 and 112 Sunday through Wednesday.
There is also an increasing threat of afternoon and evening thunderstorms over the Sierra Nevada, each day through Monday. The greatest chance of thunderstorms will be Tuesday through the Fourth of July, Thursday.
Thunderstorms could produce dangerous cloud to ground lightning, brief heavy rain, gusty winds and hail.
Children, the elderly and people with chronic ailments are the most susceptible to heat-related illness. Heat exhaustion, cramps or in extreme cases heat stroke can result from prolonged exposure to these conditions. Pets and livestock are also vulnerable to heat illness and should be cared for properly.