A cooling and drying trend will occur across the region into the weekend and early next week. This will be accompanied by a building marine layer with clouds returning closer to the coastal areas each night and morning. An area of high pressure may strengthen by the end of next week, nudging temperatures back above average.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
High pressure continues to weaken over the region today with stronger onshore flow seen at current observations. This has allowed for a deepening marine layer, where some places along the coast saw low clouds and patchy fog earlier this morning. Looking toward the lunch hour, temperatures a relatively cooler with highs in the 70s to near 90 west of the mountains. Elevated westerly winds will also be felt across the mountains and deserts with wind gusts 20-40 MPH.
An area of low pressure off the west coast of British Columbia will continue to push southward today, eventually moving into the Pacific Northwest this weekend. This weather pattern will help bring in more cooler air and greater extent to the marine layer into far western valleys. We can expect to cool a few degrees each day with breezy westerly winds across the mountains and deserts each afternoon and evening. Temperatures will be near average by the weekend, with highs dipping below average by next Monday and Tuesday. High temperatures may stay below 90 degrees for areas west of the mountains with highs closer to 100 degrees over the Coachella Valley. Low temperatures will also begin to cool off through early next week as well with lows in the 50s and 60s along and west of the mountains and up in the high desert.
High pressure over the Southern Plains may expand further into the desert southwest by the end of next week. The placement and strength of this system is still uncertain, but many models are hinting that another subtle warm up may take place by this time. Nbm shows highs approaching 100 across inland valleys with 70s and 80s closer to the coast and across the mountains.
111800z, Coasts, Patchy low clouds based around 1000ft continue to stream up from the S-SE within a coastal eddy with low clouds just offshore at KSAN and along the beaches of Orange County late this morning. Low clouds to return after 02z Saturday with more uniform and expansive coverage. Bases initially around 800-1000ft MSL should lift to 1000-1400 feet MSL after 06z Saturday. CIGs expected to scatter out and pull back offshore/to the beaches by 16-17z Saturday.
Otherwise, SCT clouds above 15 kft and VFR conditions today and tonight, with cumulus clouds around 10 kft over mountains 19-00Z.
No hazardous marine conditions are expected through Tuesday.
Ca, Heat Advisory until 8 PM PDT this evening for Orange County Inland Areas-San Bernardino and Riverside County Valleys- The Inland Empire-San Diego County Coastal Areas-San Diego County Valleys.
Extreme Heat Warning until 8 PM PDT this evening for Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
