Warmer through early next week with a shallower marine layer and periods of weak offshore flow. Warmest days are expected to be Sunday and Monday. Cooler conditions expected by the middle to end of next week. A cooler, windier, and potentially wetter pattern is expected to develop towards the end of next week with low confidence in details.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Evening update, Marine layer low clouds were quick to develop and spread inland this evening, already reaching the inland valleys of San Diego County and the far southern Inland Empire. Clouds will continue to fill in over Orange County, then begin to retreat back towards the coast early Friday morning as weak offshore flow develops. Otherwise clear with winds transitioning from westerly to northerly and locally breezy conditions developing along the coastal foothills Friday morning.
Previous discussion, The marine layer is expected to become shallower over the next few days, keeping any low clouds that do develop more confined to coastal areas through early next week. Patchy, potentially dense, fog may develop overnight and in the early mornings this weekend. An additional few degrees of warming is expected Friday for most locations from the coast to the deserts. The greatest warming will be for the valleys.
High pressure aloft over California will strengthen through the weekend. The high pressure combined with periods of weak north to northeast winds will result in warming conditions, especially for locations west of the mountains. The warmest days are expected to be Sunday and Monday when highs are expected to be 7 to 15 degrees, locally up to 20 degrees, above average with the biggest departure from normal expected in the inland valleys. Some cooling is expected for Tuesday, especially for the coast and valleys. Even with the cooling, highs on Tuesday will still be 5 to 12 degrees above average for inland areas.
An area of low pressure will develop off the US West Coast early next week and slowly move east through the week. This low pressure will eventually weaken the high pressure over California and displace it to our east. There remains uncertainty in the timing of the low pressure's forward progression. If the eastward progression slows, that would keep the high pressure and warmer temperatures over SoCal further into next week than currently thought. About 20 percent of ensemble cluster analysis solutions show the high still over the Arizona/California border on Wednesday, with the rest of the solutions showing the high further east. Ensemble cluster analysis for next Thursday is showing about 70 percent of model solutions keeping the incoming low offshore, with 20 percent showing the low over California, and 10 percent have the ridge axis still over the California/Arizona border. Individual ensemble members of both the GFS and ECMWF have trended mostly dry for Wednesday. It looks more likely that any measurable rainfall that occurs will fall during the end of next week. The eventual depth and strength of the incoming low will also have an influence on our wind, temperature, and potentially snow forecast. There is still plenty of uncertainty surrounding the details of this incoming system, so stay tuned!
070345z, Coasts/Valleys, Low clouds based 1000-1500 ft MSL has moved about 20 miles inland into San Diego Co and southern Orange County. Good chance for clouds to spread into parts of the Inland Empire, including 40% chance vcnty KONT and 15% chance vcnty KSBD. Low clouds begin to clear 15Z, lingering through about 18Z for southern San Diego and northern Orange counties. CIGs lower to 700- 1000 ft MSL as low clouds redevelop after Sat 01Z and move into coastal regions.
Mountains/Deserts, Mostly clear and VFR conditions expected through the TAF period.
No hazardous marine conditions are expected through Tuesday.
West-northwest swell with a period of 14 to 15 seconds will generate surf of 4 to 7 feet. Highest surf will be south of Del Mar this evening through Friday. Elevated surf combined with high tides could lead to minor tidal overflow. Check the Beach Hazards Statement for more details.
Ca, Beach Hazards Statement through late Friday night for San Diego County Coastal Areas.
Beach Hazards Statement through Friday afternoon for Orange County Coastal Areas.
PZ, None.
