A gradual cooling trend begins today and will continue through Tuesday/Wednesday, bringing temperatures around 5 degrees above average for midweek. The upper level ridge will shift west again towards Las Vegas and restrengthen in the latter half of the week. There is increasing confidence that this setup could provide the hottest temperatures of the Summer thus far.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
High pressure continues to dominate aloft but has shifted just far enough east to bring some monsoonal moisture over the area through the afternoon. Light rain has been observed from the San Diego coast into the San Diego mountains with accumulations less than 0.1 inches. Rain and storm chances will continue through this afternoon with the highest chances in the mountains and the San Diego deserts. Conditions will dry out by this evening, leaving chances for rain below 5% through the end of the week.
High temperatures will stay slightly cooler through Wednesday as the upper level ridge stays a little east. Heat is expected to return Thursday through the end of the week as high pressure aloft builds and expands west once again. High temperatures will warm to be 10-15 degrees above the seasonal average by Friday and into the weekend.
270000z. Coast/Valleys, FEW-BKN mid-level clouds over inland areas this afternoon, decreasing into the evening. Low clouds based 1100-1400 ft MSL start developing onshore within 15-20 miles of the coast after 03z (after 07z in OC), remaining patchy until around 10z when coverage increases and fills in gaps. VIS reduced along elevated coastal terrain and locally in elevated valleys up to 20 miles inland. Low clouds mostly scatter 16-17z. 30% chance that brief cigs possible at the immediate coast after 21z as low clouds begin redeveloping early. Otherwise, VFR conditions prevail Monday afternoon.
Mountains/Deserts, VFR prevails with FEW-BKN mid-level clouds around 10-15k ft MSL passing through today. A few stray showers are possible over the mountains and into the adjacent deserts until around 02z this evening.
Calm conditions into the early half of next week with waves 3 to 5 feet and afternoon wind gusts near 15 kts or less through Tuesday. Waves increase in the outer waters mid to late week with waves expected around 5 to 7 feet.
A persistent background long-period southwesterly swell (2-3 feet at 17-19 seconds) keeps surf elevated at around 3-5 feet with sets to 6 feet into Wednesday. By Wednesday afternoon/evening, a much higher amplitude swell associated with Hurricane Genevieve is set to build. Some uncertainty exists in exactly how strong this swell will be as it depends on the strength and track of Genevieve, but current guidance suggests the swell could be around 5-7 feet, with a period around 14 seconds. Should this come to fruition, breaking waves of 9- 11 feet are possible for south-southwest facing beaches for Thursday and Friday.
In addition to elevated surf, tides are expected to increase to a height of 6.0 to 6.5 feet MLLW by for this evening's high tide and continue at that height through most of the week. The combination of surf and tides will likely result in at least minor tidal overflow during the evening high tides. More notable coastal flooding is possible when the high tides combine with the elevated surf brought with Genevieve's swell later this week. It is worth noting, that with the effects from this year's El Nino, observed tides have been consistently about 0.3-0.5 feet below many baseline predictions.
A Beach Hazard Statement remains in effect through 6PM Wednesday due to the elevated surf, rip current risk, and concern for minor tidal overflow. Additional products for coastal flooding and high surf are looking increasingly likely for later this week.
Ca, Beach Hazards Statement through Wednesday afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.
Heat Advisory until 8 PM PDT Monday for Orange County Coastal Areas-Orange County Inland Areas-Riverside County Mountains- San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Coastal Areas-San Diego County Mountains-San Diego County Valleys-Santa Ana Mountains and Foothills.
Extreme Heat Warning until 8 PM PDT Monday for Apple and Lucerne Valleys-Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
