Thunderstorms possible in mountains, deserts in afternoon; heat builds for weekend

SAN DIEGO (FOX 5/KUSI) -- Listen for a rumble of thunder and look for flashes of lightning Thursday afternoon as mountains and deserts have good chances of getting isolated thunderstorms.

An influx of monsoonal moisture and a lot more instability are here, and it's creating a perfect recipe for thunderstorm development for late morning and early afternoon.

Any cell that develops could bring locally heavy rain, hail, gusty winds and thunder and lightning for mountain and desert communities.

Monsoonal moistures backs off as we head into the weekend, with thunderstorm chances looking better again for early next week.

The other weather headline will be the increasing heat that has prompted Excessive Heat Warnings yet again for desert areas this weekend and Heat Advisories for inland valleys and mountains.

High pressure building over the four corners region will expand to the west and jack up temperatures anywhere from five to 10 degrees above average this weekend.