NWS extends San Diego’s excessive heat warning to Thursday
Forecasters say it also is possible that showers will reach coast on Tuesday
The intense heat wave that has led to rolling blackouts in San Diego County will last a day longer than expected and could produce thunderstorms and sprinkles at the coast on Tuesday.
The National Weather Service says that the excessive heat warning that is in place for all areas except for the coast will expire at 10 p.m. Thursday instead of 9 p.m. Wednesday.
The extended warning came as the California Independent System Operator, which operates the power grid, said that rolling power outages are likely unless customers statewide significantly cut electrical consumption through Wednesday. Parts of San Diego experienced outages on Friday and Saturday.
Forecasters had a bit of good news Sunday, noting that cool onshore winds prevented San Diego from rising above 78. Temperatures also were 3 to 6 degrees cooler across inland valleys and foothills, topping out in the 90s in most areas. The outliers were Campo, which got to 105, and Valley Center, which got to 103. Escondido hit 99 and Alpine got to 96.
Monday also will start off cool at the coast due to low clouds and fog. But a large, dawdling high pressure system will re-strengthen, lifting temperatures everywhere. San Diego is expected to hit 84, which is eight degrees above average. The valleys will get into the 90s and, in some areas, low 100s.
“We’re going to get an easterly wave on Tuesday, which means the winds could produce thunderstorms that move toward the coast,” said Miguel Miller, a weather service forecaster. “The coast would probably only get sprinkles.”
Summer heat waves typically last two to three days. The current system could last as long as five days.
Sunday’s sea surface temperatures reached 68 at Chula Vista and San Diego and 69 at Oceanside.
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