The heat wave over San Diego County was forecast to continue into next week except at the highest mountain elevations, the National Weather Service said Saturday.
An excessive heat warning was issued from Saturday until 8 p.m. Tuesday for coastal areas, valleys, mountains and deserts.
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. The thunderstorm threat was higher than Friday along and west of the mountains, but the main threat continued to be lightning.
High temperatures along the coast Saturday were predicted to be in the upper 80s with overnight lows in the lower 70s. Highs in the valleys were expected to be 98 to 103, with lows in the mid-70s. Highs in the mountains were expected to be in the mid-90s with lows around 70 and highs in the deserts were predicted to be 104 to 109 with lows in the mid-80s.
The high 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, according to the NWS.
Some drying may occur Sunday with mid-level flow strengthening, allowing for increasing high temperatures and a lower threat of afternoon thunderstorms. This trend continues 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, the NWS 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