Temperatures in valley and mountain areas of the Southland again will reach dangerous "excessive heat'' levels today, fall marginally during the week and rise anew next weekend, National Weather Service forecasters said.
Highs will climb into triple digits thanks to a hot air mass resulting from a ridge of high pressure over the Southwestern United States, and high humidity levels will make it feel even hotter, according to the weather service.
"Heat index values, which take into account the air temperature and humidity, are expected to reach 105 degrees in many valley locations in Los Angeles and Ventura counties ... and to around 100 degrees in the lower mountain elevations,'' according to an NWS advisory.
"The combination of very hot temperatures and moderate humidity will combine to create a dangerous situation in which heat illnesses are possible,'' it said.
An excessive heat warning, issued by the NWS to indicate health-threatening conditions resulting from high heat and humidity, will be in effect from 11 a.m. to 8 p.m. in the San Gabriel, San Fernando, and Santa Clarita valleys, the L.A. County portion of both the San Gabriel and Santa Monica mountains, and several areas of Ventura and Santa Barbara counties.
The weather service urged area residents to take precautions to avoid heat-related illnesses, including: schedule any outdoor work for early morning
or evening; wear light, loose-fitting clothing; and drink plenty of water. Anyone overcome by the heat should be moved into the shade, and 911 should be
called.
The NWS forecast highs today 79 at LAX; 80 in Avalon; 81 in Newport Beach; 92 in downtown L.A.; 93 in Anaheim; 94 in Long Beach; 99 in San Gabriel; 100 in Burbank; 102 in Pasadena; 105 in Palmdale; 106 in Saugus and Lancaster;
and 108 in Woodland Hills. Highs are expected to fall by a few degrees on
Tuesday and again on Wednesday.
On Sunday, the mercury hit 98 in Sandberg in the Antelope Valley, beating the record of 95 for an August 12 set in 2002, according to the NWS.
"There will be some cooling both Tuesday and Wednesday, but maximum temperatures will remain above normal and further warming is now forecast for
next weekend,'' according to an NWS advisory this morning.
Along with the heat, there is a chance of thunderstorms in mountain areas and the Antelope Valley this afternoon and evening, according to the NWS.
"Any thunderstorms that develop would be capable of producing brief, heavy rain, gusty winds, dangerous cloud-to-ground lightning and possible small hail,'' the agency said in an advisory.
