The National Weather Service and the L.A. County Department of Public Health have both issued excessive heat warnings for the Santa Clarita Valley and many other Southern California locales Wednesday morning as temperatures build this week toward triple digits.

Temperatures will climb each day this week and become more uncomfortable from Thursday through Sunday for many local valleys, mountains and foothills, with daytime highs ranging from 100-107 degrees.

Overnight low temperatures will remain in the 70s to lower 80s across the warmest locations, especially in the foothills.

The heat wave results from high pressure building over the desert Southwest and expanding westward toward California today. The heat wave will become more widespread by Thursday and persist through the weekend.

The Health Department’s high heat alert specifies the Santa Clarita Valley on Friday and Saturday.

Along with the increasing temperatures, there will be some elevated moisture moving up from Mexico which could create added
humidity during this heat wave. As this happens it will be harder to cool off at night, with overnight temperatures remaining
in the mid-70s to lower 80s just above the valley floor.

The extended period of hot temperatures elevates the danger of brush fires.

The NWS reports it’s still too early to predict just how long this heat wave will last, but at this point temperatures in the mountains, deserts and valleys will remain well above normal through Sunday and possibly into early next week.

The very high temperatures may create a dangerous situation in which heat illnesses are possible. Temperatures inside vehicles, even if the windows are partially open, can quickly rise to life-threatening levels. ..

Never, ever, leave people or pets in enclosed vehicles, even for a short period of time.

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.

To reduce risk during outdoor work the occupational safety and health administration recommends scheduling frequent rest breaks
in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke
is an emergency, call 911.