“Temperatures will be 10 to 15 degrees above normal and will create heat-related issues this afternoon and evening… Thunderstorms will bring the potential for flash flooding in the mountains and the Antelope Valley.”
Additionally, high humidity shrouded the region, causing temperatures to feel even higher than they really are.
“Maximum temperatures will reach dangerous levels across much of Southern California again,” warned a NWS statement. “The peak of the heat event will continue on Thursday, though Friday will only be a few degrees cooler.”
Temperatures will fall slightly over the weekend “but will remain above normal” until early next week, it said.
Over the weekend, humidity levels will remain elevated “so even with slightly cooler temperatures it will not feel as though there is much of a difference,” warned an NWS advisory.
In the meantime, a flash flood watch will be in effect from 2 p.m. Thursday through Thursday evening in the Antelope Valley and the San Gabriel Mountains, both in Los Angeles and Ventura counties.
The NWS forecast partly cloudy skies Thursday and highs of 99 in Palmdale and 102 in Lancaster.
Friday’s temperatures are expected to be several degrees lower.
The high heat coupled with the elevated humidity is prompting health concerns. Forecasters said those at greatest risk of suffering heat-related ailments were infants, the elderly, the homeless, outdoor workers, people taking part in outdoor activities in the heat, and pets without access to shade.
They urged residents to drink plenty of water; wear light-colored and lightweight clothing; stay out of the midday sun; check on neighbors and the elderly to make sure they are not being overwhelmed by the heat; and never, ever leave children, the elderly, or pets in a vehicle parked in hot weather.
Also of concern is the availability of electricity in light of heavy air conditioning use. The Los Angeles Department of Water and Power said conserving energy is especially critical between 11 a.m. and 6 p.m., when use is traditionally the highest. They urged customers to:
- Set thermostats at 78 degrees or higher;
- Limit the use of major appliances during peak hours;
- Close drapes and blinds to reduce heat;
- Turn off lights and other equipment when not in use; and
- Unplug items like cell phone chargers, DVD players and microwave ovens that can use energy even when turned off.