textproduct: San Diego

SYNOPSIS

High pressure aloft and weak offshore flow will bring warming of a few degrees today with northeast winds gusting to 40 mph near and below the Cajon Pass through this morning. For coastal areas, night and morning coastal low clouds and locally dense fog will continue through Wednesday. Onshore flow will spread cooling of a few degrees inland on Wednesday followed by warming with weak offshore flow on Thursday. Onshore flow and weakening high pressure aloft will spread cooling inland for Friday through Monday of next week, but with high temperatures remaining as much as 10 to 15 degrees above average for some inland areas for Saturday through Monday.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Tonight through tomorrow night...

High pressure conditions continue to dominate the region with above average temperatures in place. Persistent subsidence from this will result in in the formation of fog developing again along the coastal areas for tonight. There may also be some areas of patchy dense fog, especially along the coastal areas. Some of this may penetrate into the IE. The timing of this is somewhat finicky, although a consensus of high pres models puts the initiation of this sometime around 6 pm tonight, and then clearing out for most areas by tomorrow morning at around 10 AM. Temperatures will be similar tomorrow for highs, maybe only a smidgen cooler. Fog will likely form again along the coastal areas and portions of the inland valleys extending about 5 to 10 miles inland.

Thursday through early next week...

The ridge will continue to build ahead of an approaching major shortwave trough which will be approaching the region by this weekend. It will be considerably warmer on Friday as this occurs, with temperatures running around 20 degrees above average for the inland valley areas. As the trough continues to advance slowly eastward, with will help to bring about a cooling trend going into early next week, with the marine layer beginning to lift with strengthening onshore flow. Looking a little beyond the forecast, there is growing confidence with ensemble and deterministic models alike which show an increasing chance of precipitation across the region.

AVIATION

161615Z...Coast...Low clouds/FG based 200-400 ft MSL with tops to 600-700 ft and vis 1/4-2 SM fluctuating in and out of San Diego coastal areas and firmly entrenched in northern Orange County. Scatter out vcnty KSAN by 17Z, 18-19Z vcnty KSNA. Low clouds and fog to return to coastal airports 01-05Z, with slightly higher cigs/vis and extending a little farther inland overnight into Wednesday.

Otherwise...Mostly clear skies with unrestricted vis today and tonight.

MARINE

Areas of dense fog will continue this morning. A Marine Weather Statement contains the details. Otherwise, no additional 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...Dense Fog Advisory from 6 PM this evening to 10 AM PST Wednesday for Orange County Coastal Areas-Orange County Inland Areas- San Diego County Coastal Areas.

PZ...None.