LOS ANGELES (CNS / FOX 11) - Temperatures were on the rise Wednesday across the Southland as a mini heat wave brought the area of taste of summer that is expected to continue until early next week.
National Weather Service forecasters said high pressure will be building over the area and be in full force by Friday and Saturday, bringing temperatures well above normal.
The system will result "in daytime high temperatures around 10 degrees above what is normally the hottest time of the year,'' according to the NWS.
"Temperatures between 100 and 108 degrees will be common in the valleys and lower mountains of Los Angeles and Ventura counties Friday and Saturday with only modest relief at night.''
An excessive heat watch will be in effect from Friday morning through Saturday night in the Los Angeles County Mountains, Santa Mountain Mountains Recreational Area and the Santa Clarita, San Fernando and San Gabriel valleys.
Forecasters warned that triple-digit heat could present a danger to some residents, and demand for electricity could be high, creating the possibility of outages.
"Never, ever leave people or pets in enclosed vehicles, even for a short period of time,'' the NWS warned. "Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear light weight and loose-fitting clothing when possible and drink plenty of water.''
The Los Angeles County Department of Public Health issued a heat alert for Thursday through Saturday for the Santa Monica Mountains and the San Fernando, Santa Clarita and East San Gabriel valleys. A separate heat alert will be in effect Thursday and Friday for the Antelope Valley, and for Friday in the Los Angeles Basin.
A fire weather watch will be in effect Friday afternoon and evening in the Los Angeles County mountains and Angeles National Forest due to anticipated gusty winds and low humidity.
Temperatures are expected to gradually increase over the next few days, rising about four to five degrees by Saturday.
NWS officials noted, however, that there's not much chance of any heat records being broken.
"Friday through Sunday mark the 10-year anniversary of one of the hottest events on record for any month -- Woodland Hills hit 119 on July 22, 2006, the all-time high for any of our climate stations,'' according to the Weather Service.
Inland areas could see higher-than-normal temperatures as late as next Tuesday, although coastal areas should see some cooling beginning Sunday, forecasters said.