High temperatures for inland areas will remain around 15 to 20 degrees above average into the weekend, with some record daily high temperatures continuing to be tied or broken, mainly for the mountains and deserts but occasionally for the inland valleys as well. The marine layer presence will continue, with some small day-to-day variations. Coastal low clouds not likely to spread as far inland on Friday and Saturday. Mid and high clouds will spread across the area for this weekend into early next week. High temperatures will lower only slightly during the weekend, with greater cooling spreading inland early next week as a low pressure system moves toward the California coast.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
The morning sounding shows the marine layer marginally shallower than yesterday, however the low clouds and fog had spread about as far inland. At this hour, the low clouds have cleared to the coast but will likely linger at the beaches into the afternoon due to the strength of the inversion. Temperatures this morning are near or a little lower than at this time yesterday, mainly in the low elevations west of the mountains.
Daytime high temperatures will gradually trend higher through Saturday as the high pressure ridge persists over the Southwest. High temperatures today will range from around 5 degrees above average near the coast to around 20 degrees above average in the mountains and high desert. It looks like Saturday will be the warmest day with high temperatures ranging from around 10-12 degrees above average near the coast to 20-25 degrees above average in the San Diego County mountains. Saturday high temperatures will range from the 70s to low 80s near the coast to the upper 80s to mid 90s for the Inland Empire, with the upper 90s to 103 for the lower deserts.
Onshore flow today will be strong enough to produce southwest winds gusting 30-40 mph in the favored areas of the deserts and desert mtn slopes this afternoon and evening. Onshore flow will be noticeably weaker for Thursday then strengthen somewhat again on Friday.
For Sunday through next Wednesday, Temperatures will trend lower and clouds will generally increase as a low pressure system approaches the CA coast from the west, displacing the high pressure ridge to the southeast into TX. Next Wednesday will likely be the coolest day, with daytime high temps in the 60s-70s west of the mtns and in the 80s in the low deserts.
A significant percentage of ensemble members (most from the European model) indicate the potential for precip next Tue/Wed as the low pressure system moves inland. At this time, the National Blend of Models indicate up to a 35 percent chance (mainly in the mtns) for at least 0.01 inch. Any rainfall will likely be confined to areas from the mtns westward. Uncertainty is still high due to the spread among the model solutions.
250930z, Low clouds based 800-1200 feet MSL and tops to 1500 feet will continue to fill coastal areas and western valleys this morning. Vis reduced 3-5SM mainly over higher coastal terrain and valleys. Scatter out to occur 16-18Z. Patchy and intermittent low clouds could linger along immediate coast thereafter. Low clouds with slightly lower bases will increase and spread inland after 02Z. Coverage a little less extensive. Cloud bases and vis should be a little lower tonight into Thursday morning.
Otherwise, mostly clear and VFR conditions will prevail today and tonight.
No hazardous marine conditions expected through Sunday.
Ca, None. PZ, None.
