Today is expected to be the first of six straight days of 100-degree weather.
The temperatures in the Sacramento region are expected to stairstep a few degrees higher each day before reaching a high of 107 on Tuesday. The heat wave starts today at a predicted 102 degrees in Sacramento.
Because of the prolonged nature of the heat spell - and the possibility it could be accompanied by higher-than-normal humidity -- the National Weather Service has issued an "Excessive Heat Watch" for the Sacramento and San Joaquin valleys. The warning begins Sunday and continues through Wednesday.
The watch is issued to warn residents that the torrid temperatures and high humidity could create heat-related illnesses. The forecasters advise people to stay in air conditioned rooms, check on pets, livestock and relatives and keep hydrated.
The high temperatures are caused by strong high pressure over the desert Southwest where it will be even hotter. Today's high is expected to be 118 in Phoenix.
The high pressure in the Southwest is forecast to build into Northern California. Once the high pressure arrives with full force, temperatures will skyrocket.
The range of temperatures expected today through Tuesday: Redding, 105-110, Blue Canyon, 85-90, Sacramento, 102-107, Stockton, 102-107.
The detailed, 7-day forecast for the Sacramento region from the NWS:
Today: Sunny and hot, with a high near 102. Calm wind becoming west 5 to 7 mph in the afternoon.
Tonight: Clear, with a low around 65. West southwest wind 5 to 8 mph becoming south after midnight.
Saturday: Sunny and hot, with a high near 104. Light and variable wind becoming west 5 to 7 mph in the afternoon.
Saturday night: Clear, with a low around 70. West southwest wind 5 to 7 mph.
Sunday: Sunny and hot, with a high near 106. Light and variable wind becoming northwest around 6 mph in the afternoon.
Sunday night: Mostly clear, with a low around 68.
Monday: Sunny and hot, with a high near 106.
Monday night: Partly cloudy, with a low around 72.
Tuesday: Mostly sunny and hot, with a high near 107.
Tuesday night: Partly cloudy, with a low around 72.
Wednesday: Mostly sunny and hot, with a high near 102.
Wednesday night: Mostly clear, with a low around 67.
Independence Day: Sunny, with a high near 94.
Call The Bee's Bill Lindelof, (916) 321-1079. Follow him on Twitter @Lindelofnews.