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,
, UPDATED AVIATION DISCUSSION,
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.
120000z, Coasts, Low clouds are beginning to reform over nearshore waters late this afternoon. Clouds should move ashore starting 01- 02z Sat with bases around 600-1000 ft MSL. Clouds slowly move 10-15 miles inland overnight, likely rising above 1000 ft MSL sometime Saturday morning. Minor vis reductions (1-5SM) expected along elevated coastal terrain and locally into western valleys. Clouds clear toward the coastline 16-18z with SKC expected for the afternoon.
Otherwise, FEW clouds above 15 kft and VFR conditions through Saturday afternoon.
West-northwest winds expected to gust up to 20 knots Saturday and Sunday afternoons over outer coastal waters. Otherwise, no hazardous marine conditions are expected through Wednesday.
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.
