A sweltering heat wave across the U.S. Southwest will send San Diego County's temperatures soaring into dangerous territory for most of the county this week.
All parts of the county except the coast will see temperatures climb to about 10 to 15 degrees above average for this time of the year, which has prompted an excessive heat warning for most of the county, according to NBC 7 Meteorologist Sheena Parveen.
"This is dangerous heat," Parveen said. "You really want to avoid long hours outside. Make sure you stay hydrated, stay cool. This is going to last for the rest of the week and it's still going to be hot as we head into the weekend."
Extreme heat
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Warnings and advisories
While the heat wave is expected to last through the weekend, Wednesday through Friday are expected to be the hottest days of the week. The excessive heat warning will go into effect 11 a.m. Wednesday to 8 p.m. Friday from the inland areas to the deserts. A lesser heat advisory is in effect for the coast.
"The only area not under an [heat warning] as of now is going to be the coast but the coast is still going to be unseasonably hot," Parveen said. "If you're not right there on the sand on the beach, you could be pushing the mid- to low-90s."
Temperatures are expected to be close to 105 degrees inland, 108 degrees in the foothils and 102 degrees in the mountains. The deserts are expecting high temperatures near 118 degrees.
The heat wave is affecting most of the southwest this week, prompting excessive heat warnings for most of Southern California, a large swath of Arizona and part of Nevada.
"Labor Day weekend normally marks the unofficial end to summer but [this time] not so much," Parveen said.
How to stay cool
An excessive heat warning means extreme temperatures could cause heat-related illness. Forecasters recommend people avoid long hours outside and stay hydrated. Use cool zones if necessary and never leave pets or children unattended in hot vehicles.
Those recommendations are even more important during this heat wave as there will be little relief overnight, Parveen said. Temperatures are expected to stay in the 70s and above across the county.
🧊 Tap the link below for a list of places to cool off in San Diego County
Fire weather potential
One benefit to this stretch of weather: we are not expecting Santa Ana winds, Parveen said. There is still an elevated fire threat, though, because temperatures will be so hot and humidity will be low.
Overgrowth from heavy rains earlier this year has left behind dry brush that can easily burn if a wildfire sparks.
Fire danger will be elevated Thursday through Saturday, NBC 7 meteorologist Greg Bledsoe said.
"Fortunately, we're not expecting much wind, but still, with the heat and the dry conditions out there, the lack of humidity, we will have some serious fire danger. And then for the weekend, monsoonal moisture returns with a slight chance for thunderstorms on Sunday and the far eastern parts of the county might feel a little more humid, keep temperatures down a little bit," Bledsoe said.
On Tuesday, local fire departments, Cal Fire and law enforcement held a planning session at the San Diego County Office of Emergency Services to prepare for this week's extreme heat and the rest of the fire season. A training exercise is scheduled for Friday to make sure they're all on the same page if a fire does break out.
We will be aggressively fighting the fire. We will be aggressively protecting the structures," San Diego County OES Executive Director Chris Heiser said. "SDG&E will be working with us to protect their infrastructure. Everything that's available will be brought to bear, but your part of it is you need to evacuate when we tell you to."
Click here for the steps you should take to prepare for a wildfire, including having an emergency bag packed with water, non-perishable food, medicine and important papers. It is also important to have one or two evacuation routes prepared out of your neighborhood.
Heat could affect power
California may also need to take measures to mitigate strain on the power grid. Cal ISO issued a Heat Bulletin over the weekend that said the agency does not expect shortfalls but extreme heat causes an increase risk of power outages.
If the risk of a rolling power outage is observed, Cal ISO can issue a a Flex Alert, which is a call to voluntarily reduce energy consumption.
To avoid strain to the energy grid, San Diego Gas & Electric recommends:
- Setting your thermostat to 78 degrees
- Keeping the shades closed while you're out of the house and keep them down until after sunset
- Avoid using major appliances during peak hours of 4 to 8 p.m.
After Flex Alerts, grid managers have several options before rotating power outages, such as tapping backup generators, buying more power from other states and using so-called demand response programs, where people are paid to use less energy.
