High heat, monsoonal moisture headed to Southern California

Southern California may see more high humidity and thunderstorms before July is over.

The National Weather Service says a strong ridge of high pressure expanding westward over the Southwest will drive temperatures up Wednesday through Friday and draw monsoonal moisture into the region.

Forecasters say the combination may cause some areas to approach excessive-heat levels.

Thunderstorms are likely to develop over the mountains, interior valleys and deserts, but forecasters say some coast and coastal valley areas could also see storms. The storms will carry the risk of lightning and flash floods.

Despite being a typically dry month, this July has been marked by rainfall that has set records. Flash flooding earlier this month washed out a bridge on Interstate 10 near the California-Arizona border, disrupting travel on the major route.