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,
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.
171800z, Easterly winds will continue to weaken through the afternoon, with easterly winds 20-35 kts continuing for coastal slopes and portions of the valleys this afternoon. Winds weaken further and become confined to coastal slopes after 06z Sun.
Otherwise, VFR conditions expected with SCT-BKN high clouds through today. High clouds scatter out across the area tonight.
Isolated northeast gusts could exceed 20 knots through this afternoon. Otherwise, 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 with local sets to 7 feet (along south and southwest-facing beaches) through at least next 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, Heat Advisory until 8 PM PDT this evening for Orange County Coastal Areas-Orange County Inland Areas-San Diego County Coastal Areas.
High Wind Warning until 8 PM PDT this evening for San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Valleys.
High Wind Warning until midnight PDT tonight for Riverside County Mountains-San Diego County Mountains-San Gorgonio Pass near Banning.
PZ, None.
