San Diego weather

San Diego Weather: What to Expect During This Intense Heat Wave

According to NBC 7’s First Alert Forecast, scorching temps are expected to linger through Friday in San Diego County, with temps in the mid-90s sticking around the inland valleys

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San Diego’s almost-summer heat wave has arrived. Here’s what to expect this week as hot weather grips our region.

Excessive Heat Warning

The brunt of the heat wave hit San Diego County on Tuesday. The scorching temps weren't finished yet.

According to the National Weather Service, the heat would continue to blanket San Diego County through Wednesday and the rest of the week.

NBC 7 meteorologist Sheena Parveen said an excessive heat warning is in effect through Friday for San Diego County’s inland valleys and foothills. For the mountains, the excessive heat warning has been extended through Saturday and, in the deserts, the warning will last through Sunday.

Grueling temperatures will continue to swell in San Diego County, posing a threat to residents’ health and firefighting conditions.

"High temperatures will be 10 to 20 degrees above normal for this time of year," Parveen said Wednesday. "It will still be unseasonably hot as we head into the weekend."

Parveen said passing high clouds will linger Wednesday, which will make it feel a bit muggier in parts of San Diego County.

She said the forecast for the U.S. Open Championship -- which will take over the Torrey Pines Golf Course from June 17 to June 20 -- looks comfortable, with highs in the mid to upper-70s at the coastal, scenic golf course.

California Issues Flex Alert

The grueling heat wave is taxing California's energy grid, so the systems operator, (CAL ISO) asked residents to conserve electricity on Thursday from 5 p.m. to 10 p.m.

A flex alert is a voluntary call to conserve energy as demand reaches a peak, typically in the hot summer months. The CAISO monitors energy usage and as demand approaches available capacity, a flex alert is issued in order to prevent unplanned power outages. Track available capacity here.

Consumers should conserve electricity by turning off unnecessary lights, not using major appliances and setting air conditioner thermostats to 78 degrees or higher, especially in the late afternoon and early evening when the grid is most stressed, the ISO said.

More energy-saving tips can be found on the FlexAlert website.

The Worst of the Heat Wave

Local resident Larry Poole tried his best to dodge the 96-degree heat in Ramona Tuesday. He said that to him, 96 felt like "Somewhere near the surface of the Sun and Venus.”

Fortunately for Poole, he had his secret cooling weapons, a gallon of water and a cowboy hat.

Dagmar Midcap's Evening Forecast for June 15, 2021.

On Tuesday, Parveen said high temps between 95 and 105 degrees were expected in our inland valley, foothills, and mountains, while temps of up to 120 degrees (no, this is not a typo) could be seen in the deserts.

To that end, Parveen said near-record highs were expected Tuesday in areas like this:

  • Chula Vista (79 degrees expected, record high is 76 for this time of the year)
  • Ramona (99 degrees expected, record high is 94 for this time of the year)
  • El Cajon (95 degrees expected, record high is 92 for this time of the year)
  • Escondido (96 degrees expected, record high is 99 for this time of the year)

San Diegans could expect temps in the upper-70s at the coast Tuesday. The rest of the week will stay warm, in the 90s in San Diego’s inland valleys.

What Is a Heat Wave?

San Diego County knows heat waves all too well, but NBC 7 meteorologist Dagmar Midcap said it is a bit early in the year for a hot weather pattern of such intensity. She said it’s all leading toward a warming trend, and she breaks it down here.

We often hear about "heat waves" in San Diego County but what, exactly, defines this weather pattern? NBC 7 meteorologist Dagmar Midcap explains.

Midcap said a heat wave can be defined as unusually hot temperatures that last for at least two days. A heat wave builds slowly and can last for well over a week. It can happen with or without humidity.

With the region facing a drought, Cal Fire San Diego said it's bracing itself for this week's heat wave:

Firefighters are prepared for the potentially record-breaking heat expected in San Diego’s deserts. NBC 7’s Audra Stafford speaks to Cal Fire.

Cal Fire said the county has already seen a 26% increase in fires and the acres burned are 58% higher compared to this time last year.

Cal Fire recommends you stay hydrated and look out for each other.

“If you see folks profusely sweating, they have a rapid heart rate, they feel nauseous or dizzy and then the sweating stops, heat illness is actually taking effect and it can happen rather quickly,” Cal Fire spokesman Capt. Frank Lococo said.

Due to the excessive heat, Cal Fire has shut down popular hiking trails in the Cleveland National Forest (Cedar Creek Falls and Three Sisters Falls Trailhead), where they tend to have more rescues.

“Those tend to be the most difficult hikes in the county and tend to have more rescues, so those have been shut down through the weekend due to the excessive heat,” Lococo said.

Although Tuesday was the hottest day of the week, Cal Fire said that doesn’t mean the threat is over. The agency recommends people drink plenty of water. Also, do not mow your lawn in a heat wave like this because machines can create sparks, which can lead to fires.

It's been so dry in our region. How do extreme and moderate drought conditions impact San Diego County and other parts of California? NBC 7 meteorologist Sheena Parveen explains.

Safety Tips: How to Beat the Heat in San Diego County

San Diego County will open its Cool Zones for the 2021 summer season to both humans and service animals starting June 15. Here’s a list of local Cool Zones where you can find some respite from the heat.

Parveen also outlined some important heat safety tips here. This includes:

  • Drink lots of water
  • Take breaks from the sun/being outside
  • Check on the elderly
  • Wear lightweight, loose clothing
  • Never leave children or pets alone in cars – it get so in there, so quickly
Oof, it is HOT out there, San Diego. NBC 7 meteorologist Sheena Parveen shares safety tips on how to beat the heat during these heat waves in San Diego County.

"Please make sure your pets and livestock have cool water to drink and someplace to take shelter from the heat," Parveen said. "Remember: Never leave kids or pets in a hot car. Walk your pets in the morning and evening; pavement can be 40 to 60 degrees above the air temperatures. That's near 130 degrees and hot enough to fry an egg, let alone burn little paws!"

For those without air conditioning at home Tuesday, some turned to the Ramona Community Library branch, which was doubling as a county Cool Zone.

“We’ve seen quite a few more people today than we have been seeing in the last week or so,” said Ramona Community Library branch manager Colleen Baker.

San Diegans in East County were doing what they could to get relief from heat in the high 90s. NBC 7's Dana Griffin has more.

UV Index and Sunburns

During extreme heat like this – and when the sun angle gets higher, on or around summertime – the UV index also gets higher.

Parveen explains the UV index here, and how it’s much easier to get sunburns under these conditions.

How do UV rays change throughout the year and why is it possible to get a sunburn even when it's cloudy? NBC 7 Meteorologist Sheena Parveen has everything you need to know about the UV index.

Sunburn potential is at its peak in the summer because the sun’s rays are stronger, especially during the middle of the day. Parveen said those who are exposed to sun at that time could get a sunburn within 10 to 15 minutes, when the sun angle is at its strongest.

She said sunblock that is SPF 30+ or higher is the way to go.

Now, what about the heat index?

According to the National Weather Service, the heat index is also known as the apparent temperature – or what the temperature feels like to the human body when relative humidity is combined with the air temperature.

But, because the air in San Diego County is so dry, Parveen said our region isn’t in a place where heat index – factoring in relative high humidity – is much different than the actual temp in the air.

“We are in a Mediterranean climate, which is dry and hot in the summer,” she explained.

Summer came a week early. NBC 7's Artie Ojeda spoke to folks in the East County looking for relief.
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