Warm and dry conditions with periods of weak Santa Ana winds this week. Above average temperatures expected into next week, with the most significant departure from normal expected today through Thursday. Mostly clear skies are expected through at least Thursday, with low clouds and fog returning to coastal areas as early as Friday or Saturday morning.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Temperatures at 1 PM were running 3 to 8 degrees warmer than 1 PM yesterday for most locations expect the mountains where they were running up to 11 degrees warmer than yesterday. A few additional degrees of warming is expected for inland areas Wednesday and Thursday, with some cooling at the coast. The surface high pressure over the Great Basin will remain in place through Friday, continuing periods of weak Santa Ana winds. Strongest winds will remain confined to coastal mountain slopes, foothills, and below passes with gusts 25 to 35 mph. The airmass getting pushed into Southern California from the Great Basin is quite dry, with minimum afternoon relative humidity for inland areas falling to 10 to 20% each afternoon through Thursday, bringing periods of elevated fire weather conditions.
Skies are expected to remain mostly clear through Thursday. Chances of low clouds and fog returning to the coast begin to increase Friday with higher chances over the weekend. High resolution guidance is showing the development of a coastal eddy Thursday night into Friday, which would increase the chances of low clouds and fog returning to coastal areas. The first night or two that marine layer low clouds and fog return, the fog has the potential to be dense especially as ridging aloft remains over the area.
Highs for the weekend into early next week will remain above average, but not quite as warm as this week. Highs along the coast through Monday will be about 5 degrees above average and 8 to 12 degrees above average for inland areas. For the early to middle part of next week there starts to become some uncertainty in the upper level pattern. By next Tuesday, 65% of ensemble clusters are showing the ridge continuing over the West Coast, with 20% showing the ridge weakening due to an incoming trough, and 15% showing the ridge present but over the Eastern Pacific.
092100z, Beautiful clear skies with VFR conditions will continue through the TAF period at all sites. Breezy northeast winds in the foothills and locally into the adjacent valleys with gusts up to 25- 30 kts will be possible through 18Z Wednesday with winds beginning to trend down after 20Z.
No hazardous marine conditions are anticipated through Sunday.
Ca, None. PZ, None.
