SAN DIEGO -- Building high pressure will push temperatures across San Diego County upwards Friday through the weekend.
The first significant heat wave of the year is expected to send high temperatures throughout Southern California 5 to 15 degrees above average this weekend, according to the National Weather Service.
"The weather pattern through the upcoming weekend will feature abundant sunshine and much warmer conditions as a ridge of high pressure builds aloft from the Pacific," according to the weather service.
Predicted highs along the coast are 69 to 74 degrees Friday, 73 to 78 degrees Saturday and 69 to 74 degrees Sunday. In inland coastal areas, temperatures will rise from 77 to 82 degrees Friday to 81 to 86 degrees Saturday, then lower somewhat to 78 to 83 degrees Sunday.
In the forecast for the valleys are highs of 80 to 85 degrees Friday, 86 to 91 degrees Saturday and 85 to 90 on Sunday. Temperatures in the mountains are expected to increase from 71 to 78 degrees Friday to 78 to 85 degrees Saturday to 82 to 89 degrees Sunday.
In the deserts, temperatures are expected to soar past the 100-degree mark. Highs will rise from 87 to 92 degrees to around 97 on Saturday to between 100 and 105 degrees on Sunday.
"The heat will really be building across the deserts with triple digit readings forecast for the Coachella Valley/San Diego deserts beginning on Saturday and continuing through early next week, at least," according to the weather service.
Forecasters urged San Diegans to drink plenty of water, dress to accommodate hot weather, stay out of the sun between 10 a.m. and 4 p.m., close their blinds during the day and open windows at night. Also, help kids, the elderly and pets beat the heat.