Marine Weather and Tide Forecast for Costa Mesa, CA

DISCUSSION
FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

This evening...Sfc pressure gradients are trending stronger onshore and currently supporting wind gusts of 20-30 mph in the mtn passes and on adjacent desert slopes. Winds will continue to weaken overnight then strengthen tomorrow afternoon with the diurnal cycle. The marine layer has deepened to about 1700 ft and low clouds are increasing in coverage as they spread farther inland. Low clouds could reach up to 20 miles inland by sunrise on Tuesday.

From previous discussion...
A series of passing troughs this week will maintain onshore flow across the region. This will cause the marine layer to deepen through the week reaching the western valleys by tomorrow and filling in much of the coastal basin by Wednesday. In addition, elevated sea breeze winds can be expected most afternoons and evenings for the mountains, deserts, and passes.

A cooling trend for the coast and valleys will continue through Saturday. The mountains and deserts will warm a few degrees tomorrow, before a cooling trend sets in through Saturday. For early next week, high pressure will begin to strengthen off the West Coast with warming for southern California.

There remains uncertainty in the upper level pattern for Friday through the weekend. While there is high confidence the pattern will continue to be dominated by low pressure troughing through at least Saturday, there are multiple ensemble solutions regarding the placement of the passing trough. Solutions with more influence from the ECMWF show the trough digging further south which would result in cooler and windier conditions for Southern California with the potential for marine layer drizzle. Solutions that have more influence from the Canadian and GFS keep the low further north, which would result in less influence on the weather in Southern California overall. NBM chances for wind gusts exceeding 40 mph Saturday evening are 15 to 25 percent for the deserts, with chances increasing to 60 to 70 percent through the passes and locally on desert mountain slopes.

AVIATION
220300Z
Coasts/Valleys
Low clouds based 1100-1600 ft MSL with tops to 2000 ft MSL have moved into parts of the coast, and will continue to push ashore and northwards through early Tuesday morning to fill much of the coastal basin. 60% chance for impacts at KONT by 12Z, with lower chances (around 30%) at KSBD. Vis reduced 1-5 SM inland and on higher coastal terrain. Scatter out from east to west 16-18Z Tues. Low clouds at 1500-2000 ft MSL will reform and push inland again after 02Z Wed to again cover much of the coastal basin.

Otherwise...Mostly clear tonight through Tuesday morning, with FEW-SCT high clouds Tues afternoon and evening.

MARINE
No hazardous marine conditions are expected through Saturday.

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

SGX WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...None.