Weakening Santa Ana winds today, with chances of light precipitation mainly for the mountains tonight into Friday. Dry over the weekend with warm conditions and weak Santa Ana winds. Pattern change expected next week, with chances of widespread precipitation.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
At 12 PM, breezy easterly winds continued on mountain foothills and below the San Gorgonio Pass with only a few isolated locations seeing gusts over 35 mph. High clouds were streaming east to west across the area due to an upper level closed low west of northern Baja. The low is expected to slowly move northeast maintaining fairly widespread high cloud coverage and bringing a slight chance of showers to the mountains and High Desert into Friday. Any rainfall accumulations will be light with the probability of rainfall totals exceeding 0.10" over 24 hours is 5 to 15 percent, highest in the San Bernardino mountains. Dry conditions will return for the weekend.
Substantial cooling is expected between today and Friday. Highs on Friday near the coast are expected to be 10 to 15 degrees cooler than today with highs further inland expected to be 5 to 10 degrees cooler than today. The cool down will be brief, with warmer conditions expected for the weekend. By Sunday, highs for inland locations will be back to 10 to 15 degrees above average. Along with the warm conditions, weak Santa Ana winds are expected for coastal mountain foothills and below passes. A change in the overall upper level pattern is expected for next week. The effects will be felt as early as Monday, with temperatures expected to be 3 to 5 degrees cooler than Sunday. Further cooling is expected through next week.
A broad troughing pattern is expected to prevail over the West Coast next week. This pattern will bring cooler conditions, the return of onshore flow, and chances of widespread precipitation. About 30 percent of global ensemble clusters have the low in position to bring us precipitation on Tuesday, with more guidance showing wetter solutions for Wednesday and Thursday. Most of the individual ensemble members are indicating mostly light rainfall amounts, with only a few members showing moderate amounts. There remains quite a bit of uncertainty in the details, especially when it comes to the timing of any precipitation. Please continue to monitor the forecast in coming days for more information.
051815z. Coast/Valleys, Low clouds based 1000-2000ft MSL will develop after 06z Fri and attempt to move inland, with periods of MVFR CIGs at coastal TAF sites. The low clouds are expected to be patchy, which may result in periods of scattering out and conditions briefly returning to VFR. VIS generally should be above 5SM everywhere except where clouds intersect terrain. Low clouds should move out of inland areas or scatter out by 16z Fri.
High clouds AOA 15,000ft MSL continuing to stream over the area, moving out by 12-18z Fri. Easterly winds will continue to weaken through 21z today, falling below 20 mph for nearly everywhere. Slight chance of -SHRA mainly over mountains and deserts after 00Z, with cloud bases as low as 8000 feet MSL.
A building northwesterly swell (280 degrees) at 15-16 seconds may bring seas of 6-9 feet in the outer waters near/around San Clemente Island Friday and Saturday. This may also lead to localized steep, rough conditions near the entrance to the San Diego Bay/Zuniga Shoal. Otherwise, no hazardous marine conditions are expected through Monday.
Increasing long-period (15-16 second) swell from the west-northwest (280 degrees) will bring elevated to high surf of 5-8 feet with locally higher sets to 10 feet late Friday into Saturday. Impacts will be greatest at west facing beaches, especially across southern San Diego County, and there will be a high risk for rip currents. Further information can be found in the High Surf Advisory. This may also lead to minor tidal overflow for low-lying beach areas during high tide late Friday into early Saturday.
Ca, High Surf Advisory from 10 AM Friday to 6 AM PST Sunday for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
