LOS ANGELES (AP) — Southern California could see record-breaking high temperatures this weekend while the rest of the country shivers.

The National Weather Service says a warming trend is beginning Thursday.

Saturday and Sunday could see highs of 90 or above in Los Angeles and surrounding cities — about 20 degrees above normal for the period.

Coastal and valley areas will see mid-80s to low 90s.

Sunday is expected to be so hot that organizers of the annual LA Marathon moved up the start time by a half-hour to 6:55 a.m. Runners also will have access to ice, cold towels, misting stations and even “cooling buses.”

A ridge of high pressure is blamed for the hot spell. Forecasters say it should be slightly cooler on Monday but highs will still be well above normal.

(© Copyright 2015 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)