Monsoonal moisture and mountain thunderstorm chances in early September

SAN DIEGO (FOX5/KUSI)-- Humid and warm weather continues for the beginning of September as the monsoonal moisture brings daily thunderstorm chances to the mountains and deserts from San Diego to the Sierra Nevada. 

Some lightning strikes have sparked fires in Northern and Central California as surface heating and monsoonal moisture have triggered thunderstorms around mountains in the state over the past 24 hours.

Towering cumulus clouds over the mountains indicate that surface heating and monsoonal moisture, as well as some lifts, are providing fuel for thunderstorms.

A couple of cells have developed near Julian and are producing thunder, lightning, hail and moderate to heavy rain at times. Some roadways could be flooded with the heavier pockets of rain that roll through. 

The National Weather Service San Diego posted to its social media a Special Weather Statement for Julian, warning of wind gusts up to 40 mph and hail that could reach a half-inch in size. The statement was issued from 1:40 p.m. to 2:30 p.m.

Mountain and desert thunderstorms are expected again for Friday afternoon and possibly into the weekend.

An eye will be kept on the moisture from Tropical Storm Lorena off the coast of Baja Sur as it could enhance saturation in the region. If we do get some of the leftover moisture, it would make for another muggy weekend with more chances of thunderstorms to the east. Arizona and New Mexico could receive heavy rain and flash flooding because of the system.

Temperatures won't fluctuate much heading into the weekend, with upper 70s to low 80s expected for the coast, and in the upper 80s to low 90s for the valleys. 

The troughing pattern is expected to take shape by mid-next week, resulting in much cooler conditions and a return of our coastal marine layer.