HARLINGEN — Read it and weep — and definitely sweat.

Late spring in the Rio Grande Valley is showing a brutal side, with dangerous temperatures as high as 108 to 111 degrees forecast for the region Friday through Monday.

A heat advisory issued Thursday afternoon is likely to be repeated daily, National Weather Service forecasters in Brownsville say.

The mid-summer weather conditions are due to a combination of an upper-level ridge over northern Mexico and Deep South Texas and the remnant humidity left in the wake of the tropical disturbance called Invest 91L.

The atmospheric result will be very high temperatures and heat indices which will lock in for the next several days.

“It will be pretty strong but we also have the humidity to factor in,” said Matthew Brady, a meteorologist with the NWS Brownsville office. “We’re expecting with that ridge for temperatures to climb to an excess of 100 degrees for most locations over the next few days.

“When you factor in the humidity, we’re going to have heat indices that are going to climb above 110 and even 115 degrees this week,” Brady added, referring to the “feels-like” temperature. “We may even have some close to 117 to 118 on Friday and Saturday.”

The humidity was dragged up from the tropics by Invest 91L, which flirted with becoming a named tropical storm, but eventually scooted past the Rio Grande Valley. The tropical disturbance dumped its heaviest rain farther up the Texas gulf coast before reaching Louisiana, where tornado and flash flood warnings were issued yesterday.

“We will lose some of that humidity, especially out west over the next few days,” Brady said. “But it will still linger, especially in the Lower to Mid-Valley and along the coast, and that will keep our moisture levels high enough that, in combination with the temperatures, it will create the excessive heat that we’re expecting for this next week.”

Power demand

Power companies in the Valley are watching the weather, but as of now aren’t anticipating any strain on the region’s electrical grid.

“Yes, it will be a crazy weather forecast for South Texas,” said Luis Reyes, spokesperson for Magic Valley Electric Cooperative in Mercedes. “As of right now, ERCOT (Electric Reliability Council of Texas) has not issued any emergency alerts about grid conditions. We will see a rise in energy demand over the next few days, but ERCOT is forecasting normal conditions on the grid.”

Reyes said ERCOT expects power usage to hit record levels in the state this summer. “If temperatures continue to rise over the summer, we may see abnormal conditions on the grid,” he added.

At AEP Texas, spokesperson Eladio Jaimez said the company also was ready to meet demand.

“We’re in good shape,” he said. “We always have energy-saving tips on our website, www.aeptexas.com, that we refer our customers to when they call, but we feel comfortable where we’re at and we just follow ERCOT’s lead when it comes to anything that has to do with the grid.”

Both Jaimez and Reyes urge customers to download each company’s mobile app for the latest updates on outages or to report an outage. “It makes it easier for customers to report these outages and that means it’s quicker for us to get to the problem,” Jaimez said.

Both the AEP Texas and Magic Valley mobile apps are free and available at the Apple Store for iPhones and Google Play for Android phones. Customers must have their account number to sign up.

Four-day siege

Valley residents need to prepare to confront the unusually hot weather — normal high temperatures in early June are 93 degrees — at least for the near future.

And summer doesn’t even start until June 21.

“Right now it looks like we’re going to have a temporary break starting early next week, Monday into Tuesday,” said the weather service’s Brady. “There’s actually a weak frontal boundary expected to approach from the north. It looks like it could potentially slide through and give us a slight break from the heat that we’re expecting, perhaps getting back toward normal levels.”

Until that occurs, Brady says people performing any outdoor activities should do so early in the day or late in the day.

“Wear light clothing, light-colored clothing, stay hydrated and also avoid alcohol,” he said. “Also, if you’re out in the sun at all, remember to wear sunscreen because it could take 15 minutes or less for skin to burn.

“And if you’re also going out and about, and you have a child with you, please look in the back seat before leaving the car,” he added. “Even going to work or going to the store. We call it ‘Look Before you Lock.’”