Despite weak onshore flow knocking a few degrees off our highs today, it was still very warm across the county.

Even warmer temperatures are expected tomorrow along with high winds and very dry air.

High pressure will build over the Great Basin by tomorrow as the Pacific high off the West Coast nudges northeast. Offshore winds will pick up speed late tonight into Friday. 

A Red Flag Warning will be in effect for San Diego County inland valleys and mountains from 5 AM Thursday through 5 PM Friday. 

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All the ingredients will be there for a spark to lead to rapid brush fire growth. Expect northeast winds from 25 - 35 mph with gusts to 55 mph and single digit relative humidity values.

The strongest winds will start Thursday night for our mountains and inland valleys. A High Wind Warning will be in effect from 8 PM Thursday through 2 PM Friday. 

Expect east winds 25 - 40 mph with gusts up to 60 mph. Gusts to 75 mph through and below canyons are possible. The biggest threat during this time frame will be down trees and power lines that could lead to widespread power outages.

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Talking about temperatures, expect Santa Ana winds to bring back hot highs, west of the mountains. On the flip side, cooler temps will return to the mountains and desert.

THURSDAY MICROCLIMATE HIGHS:

  • Coastal highs near 90°, normal around 72°
  • Inland highs near 95°, normal around 80°
  • Mountain highs near 79°, normal around 67°
  • Desert highs near 89°, normal around 87°

A trough of low pressure will bring an end to warm and dry air for the coming weekend. Offshore winds will die down Friday afternoon as the trough approaches. By Saturday, the winds will be calmer, but the air will remain dry. 

Onshore flow on Sunday will add moisture back to our skies with passing clouds.

Temperatures will drop nearly 10° between Saturday and Sunday for most of the County. Cooler temperatures will continue through Monday.