Gradual cooling trend through the middle of the upcoming week. For Tuesday and Wednesday, increased high cloud cover is likely along with a 15 to 25 percent chance of light precipitation as moisture from Tropical Cyclone Karina potentially gets pulled northward. This tropical system is forecast to remain well to our south. Gradual warming for the latter half of next week. Night and morning low clouds will be more widespread for the upcoming week, reaching into the western valleys at times.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
While high temperatures today will remain 3 to 7, locally up to 12 degrees above average they're forecast to be 3 to 5 degrees cooler than yesterday. That cooling trend will continue through Tuesday or Wednesday for most locations. By Wednesday, high temperatures are expected to be 3 to 7 degrees below average for this time of year. Additionally, marine layer low clouds and areas of fog will become more prevalent along the coast and in the western valleys at times.
Moisture from Tropical Cyclone Karina may be pulled into Southern California by mid-week. There is high confidence this will increase high cloud coverage across the area, with lesser confidence in chances of light rain. Current forecast has pulled rainfall chances back for much of Wednesday, leaving the highest chances on Tuesday at 15-25 percent. Model guidance still is yet to align on the amount of moisture that moves into our area. The EC continues to trend drier than the GFS/Canadian. How the tropical cyclone tracks will ultimately be the biggest influence in moisture influx, with a more westerly track being drier for us and a more easterly track being wetter. Current forecast closely follows the NBM.
Thursday into next weekend, the upper level high begins to shift back westward, bringing warming and the potential return of monsoon moisture. High temperatures return to near average by Friday.
291800z, Coast, Low clouds based around 600ft MSL remain situated along the beaches and offshore of south-central San Diego County this morning, and will likely continue into the early afternoon. Low clouds are expected to redevelop after 06z Sunday, likely becoming more widespread overnight compared to what has been seen in recent days. 80% chance of CIGs across coastal San Diego County (KSAN and KCRQ) by 09-11z, with a ~30% chance of CIGs reaching coastal Orange County (KSNA) for 12-16z. Bases are expected to be around 600-1000 ft MSL. Any clouds that move inland will scatter back to the beaches/offshore by 16-17z.
Elsewhere, Widespread gusts to 15-25 kts in the mountains and deserts this afternoon/evening, locally up to 35 kts within mountain passes. Gusts weaken after 03z Sunday.
Gusts around 20 knots expected each afternoon through Monday in the vicinity of San Clemente Island. Otherwise, no hazardous marine conditions are expected through Thursday.
A 3-foot swell from the south-southwest (200 degrees) at 15-17 seconds will persist into Sunday. This will bring localized elevated surf of 3-5 feet with sets to 6 feet, along with a high rip current risk to southwest-facing beaches, mostly in north San Diego County and Orange County. A new pulse of southerly swell (180-190 degrees) from Tropical Storm Karina will keep surf elevated at 3-6 feet for Monday through Wednesday.
Ca, Heat Advisory until 8 PM PDT this evening for Orange County Coastal Areas-San Diego County Coastal Areas.
Extreme Heat Warning until 8 PM PDT this evening for Coachella Valley-Orange County Inland Areas-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Deserts-San Diego County Mountains-San Diego County Valleys- San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.
PZ, None.
