textproduct: San Diego

SYNOPSIS

The thick band of mid and high level moisture and clouds has moved east of the area this afternoon. High temperatures will be a few degrees lower today, followed by a warming trend into early next week, with widespread moderate or greater HeatRisk in the coastal and valley areas for Thursday through the weekend. Those areas could see near record warm overnight temperatures Friday through Sunday.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

This afternoon...the thick band of mid and high clouds that brought us rain and showers overnight has moved east and south as the low pressure system to our northwest moves to the southeast. This low pressure system has brought us cooler conditions and stronger onshore flow. Temperatures are mostly lower than at this time yesterday, especially in the mountains and deserts where temperatures are anywhere from 3-12 degrees lower. High temperatures will be a few degrees lower today, followed by warming on Tuesday and greater inland warming on Wednesday. High temperatures on Wednesday will range from around 80 near the coast to the upper 80s to mid 90s for the Inland Empire with the lower deserts in the upper 90s. The onshore flow is currently producing westerly winds gusting 25-30 mph in the mountain passes, canyons and on adjacent desert slopes. The gusty westerly winds will weaken this evening. Low clouds persist over and west of the mountains. Significant moisture remains through a depth of the atmosphere and the possibility of showers over the mtns can't be eliminated, but conditions are stable enough to make that outcome unlikely.

By Tuesday morning, the low pressure system will move far enough to the southeast so that the upper low is over the lower Colorado River valley with northerly winds aloft on the west side of the upper low. A warming trend begins on Tuesday with locally gusty north to northeast winds at the surface.

Thursday into early next week... High pressure aloft will continue the warming trend into the weekend with only slight cooling on Sunday. Widespread moderate or greater HeatRisk is expected for the coast and valleys for Thursday through the weekend, with widespread major HeatRisk for inland coastal areas and the western San Diego County valleys.

High temperatures for next weekend will range from a few degrees above average for the lower deserts to as much as 12 to 18 degrees above average for the coast and valleys in San Diego County. High temperatures for next weekend will range from the 80s near the coast to the mid 90s to around 100 for the inland valleys with the lower deserts around 100.

For the weekend, overnight low temperatures for the Orange County coastal plain, and for the coast and western valleys in San Diego County will be mostly in the lower to mid 70s. For Friday through Sunday, there could be several records tied or broken for record warm low temperatures, mostly for coastal and valley locations. The existing records for some of those locations was from 1997.

AVIATION

281800Z...BKN middle and high clouds above 9k ft MSL will continue to exit to the southeast this morning. Some cumulus based at around 10 kft should develop over mountains and deserts after 20Z into tonight. Patchy coastal low clouds based at 1200 feet MSL to develop after 03Z, but random and intermittent. There will be better coverage right along the coastal areas after 06Z, but remain patchy, with best chance of cigs remaining close proximity to the coasts. Bases expected to be around 1000-1500 ft MSL; slowly rising towards early morning, with any cigs beginning to scatter out by 14-16Z from east to west.

MARINE

Northwest winds gusting to 20-25 knots in the outer waters this afternoon and evening, generating choppy seas. The Small Craft Advisory contains more details. No hazardous marine conditions are expected Tuesday through Friday.

BEACHES

Southwest swell from former Hurricane Odalys will combine with south- southeast swell from Hurricane Polo today. This will elevate surf with expected sets up to 6 feet today in northern Orange County. There is a high risk for strong rip and longshore currents through Tuesday. In addition to elevated surf, high tides will peak at 6.8- 7.1 feet during the late mornings today through Wednesday, highest on Tuesday. High tides and elevated surf will combine to generate minor coastal flooding in low lying areas and coastal erosion. A Coastal Flood Advisory is in effect through Wednesday afternoon.

Please note - mentioned tide predictions in the Advisory have been adjusted to reflect actual measured tide observations.

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 5 PM PDT Wednesday for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...Small Craft Advisory until 11 PM PDT this evening for Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.