Warm conditions with weak to locally moderate Santa Ana winds today. Cooler conditions expected Sunday through the upcoming week. For the middle to end of the week westerly winds are expected to increase over the mountains and deserts. Increasing chances for rain from the coast to the mountains for Wednesday and Thursday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
Santa Ana winds have weakened since their peak yesterday. Over the past 12 hours the top 3 wind gusts were 73 mph at Hellhole Canyon, 71 mph at Rancho Heights, and 70 mph at Freemont Canyon. Lingering gusts in the 35 to 55 mph range can be expected through the afternoon mostly in places prone to easterly winds. Winds will become more confined to wind prone locations into the evening and overnight hours. Above average temperatures can be expected west of the mountains today, with below average temperatures in the deserts. Highs Sunday will run 3 to 7 degrees cooler for the coast and 2 to 4 degrees warmer for inland locations. That cooling will spread inland through Tuesday. By Tuesday, most locations will see below average temperatures.
Model guidance is in good agreement that a closed low will dig south along the West Coast Monday and Tuesday, before swinging east into Southern California Tuesday night or Wednesday. In addition to cooler conditions, this low will bring an increase in westerly winds and rain chances. Winds may begin to increase Tuesday afternoon, peaking Wednesday or Thursday over the mountains and into the deserts.
Rain chances are in the forecast as early Tuesday evening for some locations, but the most likely time for precipitation looks to be this Wednesday and Thursday. Right now, mainly light to moderate precipitation is expected. On Thursday as the low moves directly over Southern California it will bring it's associated vorticity with it, increasing the instability of the atmosphere. This introduces a 10 to 15 percent chance of thunderstorms in the coastal basin. If thunderstorms develop, locally heavy rain will occur. Most places in and west of the mountains have a 50 to 70% chance of rainfall totals exceeding 0.50", with the San Bernardino Mountains having a higher chance and area deserts a lesser chance. The place with the highest chances of seeing 1" or more of rain is the San Bernardino Mountains. Overall, confidence in rain occurring is high with moderate confidence in the details.
180600z, Easterly offshore winds have largely subsided at the surface, though elevated easterly winds remain possible near the in the mountains and at 4000-8000ft into the early overnight hours.
Otherwise, VFR conditions expected with SCT-BKN high clouds AOA 10,000ft MSL through this evening. High clouds scatter out across the area tonight, with SKC thereafter.
No hazardous marine conditions are expected through Wednesday.
Elevated surf will continue this weekend into mid-next week with multiple south swells moving in through this period. Surf increases slightly Sunday, with surf 3 to 6 feet and local sets to 7 feet along south and southwest-facing beaches through at least Wednesday.
While surf and rip currents will be elevated, daily high tides will not be particularly high, and the threat of coastal flooding is minimal.
Ca, High Wind Warning until midnight PDT tonight for Riverside County Mountains-San Diego County Mountains-San Gorgonio Pass near Banning.
PZ, None.
