textproduct: San Diego

SYNOPSIS

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.

..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.

AVIATION

261800Z....Coast/Valleys...Prevalent mid level cloud cover associated with a monsoonal wave moving through severely limited the presence of lower marine layer clouds this morning. Very light rain showers were possible with this wave moving through, but most of these elevated showers that could bring precipitation west of the mountains have already departed. This mid level cloud cover and moisture is set to gradually decrease as the afternoon/evening progresses. Still, the low clouds will likely be sluggish to reform, and could be fairly patchy as they begin to redevelop after 04-06z Monday. Cloud bases should be around 1100-1400ft MSL, with more uniform coverage and about 10-15 miles of inland extent by 12z. Low clouds clear back to the coasts around 16-17z Monday morning.

Mountains/Deserts...VFR prevails with cumulus based near 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.

MARINE

Calm conditions over the weekend and into the early half of next week with waves 2 to 4 feet and afternoon wind gusts near 15 kts or less through Monday. Waves increase in the outer waters mid to late week with waves expected around 5 to 7 feet.

BEACHES

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.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

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.