Searing temperatures are expected in San Diego County this week, prompting the National Weather Service to elevate an excessive heat watch to a warning.

Temperatures are expected to jump about five degrees between Monday and Tuesday, but the peak of the heatwave is expected mid-week, NBC 7 Meteorologist Sheena Parveen said.

"Just wait until the middle of the week; there's going to be a big warm-up," Parveen said.

Dangerous heat is expected Wednesday, when temperatures are expected to soar into the mid-110s in the deserts and into the mid-90s for inland areas, Parveen said. Along the coast, expect temperatures in the mid-80s.

During that time, an excessive heat warning will go into effect for Southern California deserts, including Borrego Springs, and an excessive heat warning will go into effect for the inland valleys. Both will remain in effect from 11 a.m. Wednesday to 9 p.m. Thursday.

An overall warming trend is expected over the next several days. Here are your forecast high temperatures for Monday, Tuesday, and Wednesday. Remember to partake in heat safety if you are going to be outdoors! ☀️#cawx pic.twitter.com/NxXJgmZpfQ — NWS San Diego (@NWSSanDiego) August 12, 2019

There will be little cool-down overnight. Temperatures in the deserts will likely stay un the 80s.

A heat watch is issued when dangerous heat is expected. Prolonged hot temperatures could lead to heat illness and, in some cases, heat stroke.

The NWS says people should stay in air-conditioned rooms, stay out of the sun, check on relatives and neighbors and never leave pets or children in cars.

San Diego County provides dozens of "cool zones" where residents can get out of the sun and into an air-conditioned room. For a list of locations, visit here.

The county is offering dozens of locations across the county where residents can keep cool amid high heat. NBC 7's Audra Stafford has some tips to avoid heat illness.