High temperatures will bring an extended period of hot weather to Southern California, prompting weather officials to issue a heat advisory.

With a high-pressure system moving into the region, KCAL News has issued a Next Weather Alert to warn communities of the potentially dangerous conditions on Wednesday and Thursday. The alert extends through the Inland Empire, LA Inland, OC Inland and valleys.

The National Weather Service said temperatures could be in the 90s from the coast. A heat advisory has been issued from 11 a.m. Wednesday through 9 p.m. Thursday for a portion of southwest California.

The heat will increase the risk of heated-related illnesses especially for vulnerable communities like young children, the elderly population and those without air conditioning. Weather officials warn people to take extra caution during peak hours. They recommend people stay hydrated, wear lighting clothing and limit outdoor physical activities.

Symptoms of heat-related illnesses include high body temperature, vomiting, dizziness, confusion and hot, red, dry or damp skin. Officials implore residents to call 911 if these symptoms appear. Heat stroke is a medical emergency.