San Diego County deserts under extreme heat warning

San Diego County’s desert regions are dealing with dangerous heat conditions this week. An extreme heat warning took effect Tuesday and runs through 8 p.m. Thursday, July 10. The National Weather Service describes the conditions as dangerously hot, with temperatures potentially reaching as high as 117 degrees Fahrenheit during peak afternoon hours. Overnight temperatures offer little relief, with lows expected to stay in the 80s throughout the warning period.

The heat stems from a large area of high pressure parked over the southwestern United States. That system is pulling temperatures well above normal across multiple states. Forecasters expect it to begin shifting toward the Midwest on Friday, which should trigger a gradual cooldown for San Diego County by the weekend.

Mountain areas face a moderate heat advisory

While desert regions deal with the most extreme conditions, San Diego County’s mountain areas are also under a heat advisory. That advisory runs from 10 a.m. Wednesday through 8 p.m. Thursday. Mountain communities can expect high temperatures climbing into the 90s over the next two days. Although considerably cooler than the desert heat, those temperatures still pose a risk for anyone spending extended time outdoors without adequate water and shade.

The coastal areas of San Diego County are experiencing a very different situation. Cloudy, cool conditions along the coast stand in sharp contrast to the extreme heat just a short drive inland. That marine layer is keeping coastal communities comfortable while the interior bakes under the high-pressure system.

Relief arrives Friday but more heat is possible next week

The pattern begins to shift on Friday. Forecasters expect temperatures to drop heading into the weekend, offering a brief respite for residents in desert and mountain areas. However, the break may be short-lived.

FOX 5 meteorologist Heather Lake warned that more high pressure could return by next week, bringing another round of elevated temperatures across a broad portion of the country. She noted the pattern could take over much of the continental United States once it develops.

Residents in San Diego County desert and mountain areas should limit outdoor activity during peak afternoon hours, stay hydrated and check on vulnerable neighbors, children and pets throughout the warning period.

Source: FOX 5 San Diego / National Weather Service