Beachgoers begin to pack Ocean Beach Pier beach as early as 9 a.m. Photo by Chris Stone
Beachgoers pack Ocean Beach Pier beach as early as 9 a.m. Photo by Chris Stone

An excessive heat warning remains until 8 p.m. Tuesday for coastal areas, valleys, mountains amid record-high temperatures in San Diego and Chula Vista, according to the National Weather Service.

On Saturday, San Diego’s high temperature of 95 broke the 1998 record high of 92, while Chula Vista’s high of 96 broke the 1955 record high of 94.

San Diego County’s heat wave is expected to continue into the week, except at the highest mountain elevations, the NWS said.

Isolated thunderstorms may develop in the afternoons over the mountains and drift west into the valleys and coastal areas as Tropical Storm Javier lifts north off the Baja coast through Sunday, forecasters said, but the main threat continued to be lightning.

The highs were expected to weaken after the middle of next week. Slow cooling may spread inland then, with high temperatures returning to around average by the end of next week, the NWS said.

Some drying may occur Sunday with mid-level flow strengthening, allowing for increasing high temperatures and a lower threat of afternoon thunderstorms. This trend was forecast to continue into Monday, which is expected to be the hottest day of the week for most areas.

The east flow was predicted to weaken substantially on Tuesday, allowing the sea breeze to offer some cooling for the coastal areas and western valleys, though the mountains and deserts won’t see much change.

Another burst of east winds may cause areas west of the mountains to heat up a bit again Wednesday while remaining areas won’t change much.

The excessive heat warning may need to be extended into Wednesday for some areas west of the mountains, NWS officials said.

The ridge should finally weaken Thursday and Friday for significant cooling with temperatures gradually returning to near normal.

No hazardous marine weather was expected through Wednesday, but a pair of south swells should bring elevated surf and a high risk of rip currents to the beaches through the holiday weekend.

City News Service contributed to this article.