And The Heat Goes On: Triple-Digit Heat to Persist in Pasadena Until Thursday

Punishing triple-digit heat continues to bear down on Southern California, with a fifth straight Flex Alert in effect Sunday urging residents to conserve electricity during peak hours.

Sunday’s high temperature in Pasadena was 107. Labor Day was predicted to hit 105. Due to the ongoing heatwave, Pasadena extended its cooling center at Robinson Park Recreation Center through Mon., Sept. 5, for community members needing relief from the heat. Residents are asked to wear a face mask at the Center.

Excessive heat warnings for Pasadena were extended until at least 8 p.m. Wednesday.

Overnight lows are not offering much relief either, staying in the 70s and even in the low 80s in some of the hotter areas.

“A prolonged period of very hot conditions with minimal coastal clouds is expected as high pressure aloft remains anchored over the West,” according to the National Weather Service. “Triple-digit heat will be common for many valley and mountain locations through early next week. Record-breaking heat will produce a very high risk of heat illness.”

“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,” the NWS urged. “Young children and pets should never be left unattended in vehicles under any circumstances.”

Forecasters also urged residents to be aware of the signs of heat stroke and to take precautions.

“Take extra precautions if you work or spend time outside,” according to the NWS. “When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke.

“Wear lightweight and loose-fitting clothing when possible. 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.”

The California Independent System Operator — which manages the state’s power grid — issued the statewide Flex Alert from 4 to 9 p.m. Residents are urged to take the following power-saving steps:

• setting thermostats to 78 degrees or higher;
• avoiding use of major appliances;
• turning off unnecessary lights; and
• avoid charging electric vehicles.

Residents are also advised to pre-cool their homes as much as possible and close blinds and drapes to keep interiors cool.

The alerts have worked thus far, with the state avoiding involuntary power cutoffs. Officials said Sunday, Monday and Tuesday in particular are shaping up to be the most difficult days of the heat wave. Tuesday’s peak demand is forecast to be 50,087 megawatts, just shy of the all-time record of 50,270 set in 2006.

According to Cal-ISO, electrical demand on Saturday was 45,829 megawatts, and the forecast for Sunday was about 45,000.

Triple-digit highs are expected to last through most of the week, with no significant cooling until Saturday.

Here is the forecast from the NWS:

Labor Day: Sunny and hot, with a high near 105. Heat index values as high as 108. Light and variable wind becoming southwest 5 to 10 mph in the afternoon.

Monday Night: Mostly clear, with a low around 80. Southwest wind 5 to 10 mph becoming east southeast after midnight.

Tuesday: Sunny and hot, with a high near 102. Heat index values as high as 105. East wind 5 to 10 mph becoming southwest in the afternoon.

Tuesday Night: Mostly clear, with a low around 75. South southwest wind around 5 mph becoming northeast after midnight.

Wednesday: Sunny and hot, with a high near 103.

Wednesday Night: Mostly clear, with a low around 74.

Thursday: Sunny and hot, with a high near 100.

Thursday Night: Partly cloudy, with a low around 79.

Friday: Mostly sunny and hot, with a high near 99.

Friday Night: Mostly cloudy, with a low around 70.

Saturday: A chance of showers and thunderstorms. Partly sunny, with a high near 88.

Saturday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70.

Sunday: A chance of showers and thunderstorms. Partly sunny, with a high near 87.