Strengthening high pressure over San Diego County was expected to continue the warming trend Thursday into Saturday with high temperatures on Saturday 5 to 10 degrees above average for inland areas, the National Weather Service said.
The heat for inland areas was expected to peak over the weekend, forecasters said. The marine layer could become much shallower by the weekend with night and morning low clouds much patchier and limited mostly to coastal areas, the NWS said.
Moisture from Hurricane Jova, forecast to remain well to the southwest of the area, may bring some high clouds from late Saturday into early next week with a slight chance for thunderstorms for the mountains Saturday afternoon. High pressure will weaken next week with a cooling trend for the early into the middle part of next week.
Along the coast Thursday, it was expected to be mostly sunny with high temperatures from 73 to 78 degrees, the NWS said. Inland areas were expected to be mostly sunny with highs from 79 to 82. It should be mostly sunny in the mountains with highs from 84 to 94. The deserts were predicted to be mostly sunny with highs from 103 to 106.
High pressure centered near El Paso was likely to move to a position over northwest Mexico on Sunday. This should continue the warming trend into Saturday with high temperatures on Saturday 5 to 10 degrees above average for inland areas.
An excessive heat warning has been issued for the lower deserts for the weekend. The heat risk could be near heat advisory thresholds for the valleys, inland coastal areas, and lower elevations of the mountains.
The marine layer was around 2,000 to 2,500 feet deep Thursday, but coastal low clouds have been slower to develop and move inland with the greatest coverage across the San Diego County coastal waters and central and northern coastal areas of San Diego County.
A greater decrease in marine layer depth was expected for Friday into Saturday with night and morning low clouds much patchier by the weekend and limited mostly to coastal areas, the NWS said.
Next week, a weak trough of low pressure was expected to develop near the California coast and should begin to suppress residual moisture from Hurricane Jova toward the south and west.
A cooling trend was expected for the early into the middle part of next week with high temperatures for the coast and valleys returning to around average on Tuesday and for the deserts returning to around average on Wednesday. The marine layer should slowly deepen with night and morning low clouds returning to portions of the valleys for Tuesday and Wednesday mornings.
