textproduct: San Diego

SYNOPSIS

Gradual cooling through the middle of the week. For Tuesday and Wednesday, increased mid and high cloud cover is likely along with a 5 to 15 percent chance of light precipitation as moisture from Tropical Cyclone Karina potentially gets pulled northward. This tropical system is forecast to remain well to our south. Gradual warming for the latter half of next week. Night and morning low clouds will be more widespread for the upcoming week, reaching into the western valleys at times.

..UPDATED AVIATION DISCUSSION

Patchy low clouds are developing over the coastal areas and far western valleys this morning with just a few high clouds elsewhere. Marine layer low clouds will continue to develop through the morning with the greatest coverage in San Diego County, then clear by late morning.

Satellite water vapor imagery shows an upper level trough just off the West Coast and a weak short wave moving through the Bay Area. This trough will bring us some long-awaited cooling as high temperatures return to near normal today. Highs will be in the low to mid 80s in the coastal areas, upper 80s to mid 90s for the western valleys, mid to upper 90s in the inland valleys, 70s and 80s in the mountains, mid 90s in the high desert, and around 100-108 in the low desert. No signs of dew points dropping yet for the coastal areas and lower elevation valleys though, so despite some relief from the heat it will remain humid.

The upper level trough remains in place for much of the week with several short waves moving through the mean flow. This will maintain high temperatures near to a few degrees below normal through Friday. The marine layer rebuilds through this period for more widespread night and morning low clouds for the coastal areas and western valleys. The GEFS and Canadian ensembles have backed off on the amount of moisture that gets pulled into So Cal from Tropical Cyclone Karina on Tuesday and Wednesday. While we may still get an increase in mid and high clouds from this system, precipitation chances have lowered to around 5-15%.

Late in the week, ensembles begin to diverge on the placement of the upper trough near the West Coast and the upper high over the Southern Rockies, with a trend towards a more eastward placement of each. This more eastward placement of the ridge and troughing closer to the coast would limit the amount of warming late in the week into next weekend. This would also affect the steering flow of a potential tropical system and any moisture and precipitation we'd receive from it over the weekend into early next week. While the National Hurricane Center has a 90% chance of this disturbance developing into a tropical cyclone off the coast of Mexico in the next 7 days, it is far too early to tell what, if any, impacts we'll see locally, especially given the ensemble spread in the upper level pattern. Current forecast has at least a chance of precipitation next Sunday.

Mtns/Deserts

Occasional FEW high lvl clouds AOA 20,000ft MSL through the period. Breezy west to southwest winds 20Z Sun to about 05Z Mon on the desert slopes into the deserts, with gusts to 25-40 kts.

MARINE

Gusts around 20 knots expected each afternoon through Thursday in the vicinity of San Clemente Island. Otherwise, no hazardous marine conditions are expected.

BEACHES

A 3-foot swell from the south-southwest (200 degrees) at 15-17 seconds will persist through today. This will bring localized elevated surf of 3-5 feet with sets to 6 feet, along with a high rip current risk to southwest-facing beaches, mostly in north San Diego County and Orange County. A new pulse of southerly swell (180-190 degrees) from Tropical Storm Karina will keep surf elevated at 3-6 feet for Monday through Wednesday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.