textproduct: San Diego

SYNOPSIS

Patchy marine layer low clouds and fog can be expected this morning as mid to high level clouds from Hurricane Marie begin to move over the area by later today. Due to this, periods of light to locally moderate precipitation later this evening through Sunday. There is a slight (10-15%) chance of thunderstorms, mainly over the San Bernardino Mountains and High Desert on Sunday afternoon. Warmer and drier conditions Monday and Tuesday. Slight chance of mountain showers and thunderstorms return for mid-week.

..UPDATED AVIATION DISCUSSION

Today through tomorrow night...

Latest GOES night fog reveals that there is very little in the way of any marine layer present over the inner waters, with mostly just patchy areas of low clouds along portions of the coastal areas of San Diego County. There are also some passing mid to high level clouds funneling up from the transverse banding associated with Hurricane Marie, which is located roughly around 800 miles to the south-southwest of the region. This will continue to track towards the northwest and some of the moisture will become advected up ahead of a longwave trough upstream and with some forcing, will result in some developing bands of precipitation, which given where the best convergence aloft is located, has the best chance over Riverside and San Bernardino Mountains, tapering to lesser amounts to the south of San Diego County. Given the timing and position of where these bands of light to moderate rain establish themselves in a southwest to northeast orientation, the better chance of rain looks to be during the morning hours of Sunday with the highest PWAT values overhead. Total rainfall amounts may reach over a half an inch over the San Bernardino Mountains, and generally 0.20 to 0.30 inches within the IE, with slightly lesser amounts to the coastal areas of Orange County, and drastically tapering off to lesser amounts over San Diego County (with possibly some areas over southern San Diego County receiving little to no precip). These bands of rain will eventually dissipate by later in the evening on Sunday. Temperatures will remain on the cooler side, around and slightly below the seasonal average for this time of year, and especially for tomorrow as extensive cloud cover increases over the region.

Monday through Friday...

Drier conditions will return by Monday, with most of the moisture associated with Hurricane Marie exiting the region, and only some lingering moisture being advected up some the south which may allow for a slight chance of a afternoon shower or storm to develop over the mountains. As the ridge continues to build into the middle of the week, with will warm temperatures back above the seasonal average, with the warmest day peaking on Wednesday, which will find high temperatures returning back into the low to mid 90s for the inland areas. There will still be moisture in place that will move up clockwise around the high pressure centered over the Four Corners area that will keep a slight chance of afternoon showers and thunderstorms for the mountains and adjacent deserts, along with a gradual cooldown throughout the rest of the work week. The marine layer will likely also continue to be displaced and patchy throughout this next week.

AVIATION

051200Z...Coast/Valleys...Some patchy low clouds with cigs will remain very patchy coverage around 2,000ft MSL through this morning. Low clouds are not expected to push very far inland with any Cigs that may develop to be SCT or briefly BKN. Any low clouds will clear out 10-13z. SCT-BKN mid-level clouds at 8-10kft move into the region after 18Z along with a slight chance for -SHRA in San Diego County. Low clouds will be even more patchy for tonight into tomorrow morning, with increasing clouds and cigs lowering to around 6000- 8000 ft MSL, with a slight chance of -SHRA after 12Z, and increasing chances thereafter throughout the rest of the forecast period.

Mountains/Deserts...VFR conditions prevail through the period. Breezy westerly winds mainly through mountain passes and along desert slopes. Gusts 25-35 kts with pockets of moderate up/downdrafts over and in lee of ridges. Winds taper off slightly after 09Z. Mid-level clouds 8-10kft will increase after 18Z, bringing slight chance for -SHRA late evening, mainly in San Diego County initially, then Riverside and San Bernardino counties with higher chances of precipitation towards the end of the forecast period.

MARINE

No hazardous marine conditions are expected through Wednesday.

BEACHES

A large south swell from Hurricane Marie will move into the region tonight and Saturday, peaking Sunday into Monday, before gradually diminishing Tuesday. This will result in elevated to high surf and strong rip and longshore currents at majority of beaches. Additionally, waves will occasionally run much farther up the beach than expected, especially during increasing and high tides.

For south and southwest-facing beaches, expecting high surf 6-10 feet. This includes Orange County and north San Diego County beaches. For west-facing beaches, expecting elevated surf 4-7 feet. This includes most of southern San Diego County beaches.

High surf combined with high astronomical tides 6 to about 6.8 feet will lead to tidal overflow and coastal flooding Saturday through Tuesday during evening high tides, especially for those south and southwest-facing beaches as well as low-lying, typically impacted areas.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory until 11 PM PDT Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.

High Surf Advisory until 11 PM PDT Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...None.