The first day of summer is expected to be a scorcher, especially for San Diego County deserts and some mountains where an excessive heat warning will go into effect Thursday.
The National Weather Service issued the excessive heat warning for the deserts and eastern mountain slopes as temperatures are expected to reach up to 114 degrees in some areas.
The warning will go into effect at 11 a.m. Thursday and will expire at 8 p.m. Friday.
The day began with a thick layer of clouds along the coastline but the marine layer was expected to fade away by about 10 a.m., making way for plenty of sunshine, NBC 7 Weathercaster Brooke Landau said.
Temperatures near the coast will be in the mid-70s and in East County will be in the mid-80s. Mt. Laguna will be in the low 80s while Julian will reach the low 90s.
NBC 7 Meteorologist Dagmar Midcap said temperatures will be more mild inland and along the coast but are still expected to be warmer than what the region experienced last week.
"Do not leave children and/or pets in the car," Midcap said. Car interiors can reach lethal temperatures in just minutes.
Hot temperatures in the mountains are expected to continue through Saturday.
"The [heat] wave breaks as you head into Sunday with a bit of a cool down, but it’s still staying relatively warm for the middle of next work week for the mountains and the deserts," Midcap said.
There is a possibility the heat warning will be extended, Midcap added.
An excessive heat warning means that a prolonged period of hot temperatures is expected, and illnesses caused by the heat are likely if not taking proper precautions.
Residents should drink plenty of water, stay out of the sun and indoors with air-conditioning if possible. Try to limit outdoor activities to the morning and evening and wear light, loose-fitting clothing.