textproduct: San Diego

SYNOPSIS

Patchy marine layer low clouds and fog can be expected overnight and in the morning as high level clouds from Tropical Cyclone Marie move over the area this weekend. Periods of light to locally moderate precipitation are possible, highest chances on Sunday. There is a slight (5-10%) chance of thunderstorms, mainly over the San Bernardino Mountains and High Desert on Sunday afternoon. Warming high and low temperatures through the middle of next week. Slight chance of mountain showers and thunderstorms return for mid-week.

..UPDATED AVIATION DISCUSSION FOR 00Z TAF PACKAGE

Tropical Cyclone Marie is about 800 miles south of San Diego, CA this morning. A swath of high clouds and moisture from the cyclone have made their way into Southern California. The only radar returns over SoCal as of 11 AM were in Imperial County. As Marie continues to track north and west this weekend, additional moisture will be pushed into the area increasing chances of showers. The highest chances are tomorrow north of San Diego County. Total rainfall amounts may reach over a half an inch over the San Bernardino Mountains, and generally 0.20 to 0.30 inches for the Inland Empire, with slightly lesser amounts to the coastal areas of Orange County, tapering off to lesser amounts over San Diego County. It's possible some areas in southern San Diego County may not see any accumulating rainfall. There is a 5 to 10 percent chance of thunderstorms over the San Bernardino Mountains and High Desert Sunday afternoon. Drier conditions expected for Monday and Tuesday.

For this weekend, high temperatures will remain below average inland with highs near the coast running a few degrees above average. Overnight lows will also return to above average for this time of year by Sunday. By Tuesday, high temperatures will be within a few degrees of average for the mountains and deserts and 3 to 8 degrees above average for the coast and valleys. Above average low temperatures will be maintained into next weekend. Widespread minor to moderate HeatRisk is expected for inland areas Wednesday and Thursday. Temperatures will peak on Wednesday and gradually cool into Friday.

The upper level flow turns southeasterly Wednesday and Thursday, which may allow for some additional moisture to creep into the area. There still remains some uncertainty in the upper level pattern with the position of the upper level ridge over the southwestern US and a trough off the US West Coast. A more easterly position of the trough would result in drier conditions with a more westerly position of the ridge allowing more moisture into the area. Current forecast follows the NBM which has 20 to 40 percent chance of showers and a 15 to 20 percent chance of thunderstorms over the mountains Wednesday and Thursday afternoon.

AVIATION

060000Z...Coast/Valleys/Mountains...Mid and high level clouds around 10,000-15,000ft MSL continue to stream into the area associated with the influx of tropical moisture. SCT-OVC mid/high clouds will continue for much of today and into Sunday. With this increasing cloud cover and moisture, marine layer clouds will struggle to develop, though some localized patches based near 2500ft MSL are possible overnight near the coasts. Shower activity will be largely focused across Orange County, the Inland Empire, and the mountains, with VCSH increasing by 12z Sunday. More steady -SHRA expected around 16-23z for the northern areas, with only VCSH expected across San Diego County for 16-23z. Brief instances VIS to 4-6SM and BR as well as BKN-OVC CIGs at 5000ft MSL or lower in areas of SHRA. In the mountains, pockets of TSRA may briefly occur, especially in the San Bernardino Mountains 18z Sunday through 00z Monday. Precipitation chances rapidly wind down by 00-03z Monday.

Deserts...Breezy southwest winds with intermittent gusts up to 35 knots on the desert slopes of the mountains continue this evening. Winds weaken after 03z Sun. Mid-level clouds AOA 10,000ft MSL have increased today, and will persist into Sunday. VCSH possible in the deserts after 12z, with instances of -SHRA in the High Desert. Otherwise, VFR with no significant impacts expected.

MARINE

No hazardous marine conditions are expected through Wednesday.

BEACHES

A large south swell from Hurricane Marie has been building today, and is set to peak 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 6.2 to about 6.8 feet will lead to tidal overflow and coastal flooding through Tuesday during evening high tides, especially for south and southwest-facing beaches as well as low-lying areas.

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.