San Diego County will be cooler than normal through Sunday

A weak low-pressure system will make San Diego County cooler than normal through Sunday. But high pressure will return Monday, slowly ushering in another round of unseasonably warm and dry conditions, the National Weather Service said.

San Diego’s daytime high is expected to reach 63 Friday and Saturday and 65 Sunday. The seasonal average is 67. The marine layer along much of the county’s coast could be 4,000 feet deep Friday and Saturday. Persistent fog is not expected.

The surf will be in the 2-to-4 foot range, creating moderate rip currents. Sea surface temperatures are in the 59-to-61 degree range.

Forecasters say that an enormous winter storm that will hit much of the eastern half of the U.S. starting on Friday could affect flights in and out of San Diego International Airport.