LOS ANGELES (CNS) – Temperatures will remain in the 100s in parts of the Southland today.

An excessive heat warning issued by the National Weather Service will be in effect from 11 a.m. until 8 p.m. today in the San Fernando, San Gabriel and Santa Clarita valleys, the Santa Monica Mountains Recreational Area, and the San Gabriel Mountains.

The NWS forecast a mix of sunny and partly cloudy skies in Los Angeles County today, and highs of 78 in Avalon; 79 at LAX; 83 in Long Beach; 87 in downtown L.A.; 98 in Burbank, San Gabriel and on Mount Wilson; 102 in Pasadena; and 106 in Woodland Hills, Saugus, Palmdale and Lancaster.

Partly cloudy skies were forecast for Orange County, along with highs of 75 in Newport Beach and Laguna Beach; 77 in San Clemente; 87 in Irvine and Mission Viejo; 88 in Anaheim;  and 90 in Yorba Linda and Fullerton.

Similar temperatures are expected Tuesday and Wednesday, followed by a slow cooling trend starting Thursday in some communities, Friday in others.