High pressure will continue to dominate the region over the next week, bringing warmer than average weather with minor day to day changes. This will keep the marine layer thin, leading to low clouds and fog near the coast, where the fog may be locally dense over the next couple of nights/mornings.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
A high temperature record was broken today at Campo. Interestingly, Borrego Springs tied both the high max temp and the high min temp records today. Check out our record report for the deets. Meanwhile, we're keeping a close eye on our coastal fog situation. A dense fog advisory is in effect through 10 AM Saturday. While much of the coast has some fog, most of it is not dense, at least initially; visibilities are merely 2-5 miles as of 8 PM. There is medium to high confidence the near surface inversion of our marine layer will work its magic to eventually produce dense fog right on the deck overnight. Enjoy the non- hazardous driving conditions for now, but prepare for very low visibility later tonight into Saturday morning.
The most subtle of changes are expected in coming days. Our high pressure aloft that has brought us such anomalous (in some cases record-breaking) warmth, is going to break down very slightly through Sunday night. This should keep temps rather static this weekend, especially west of the mountains, and could deepen our marine layer slightly, despite some very weak offshore flow. On Monday and Tuesday the ridge makes a brief return, along with some very weak offshore flow. That should allow temps to rebound by a few degrees and encourage the coastal fog to retreat again. .previous discussion (146 PM Friday), The ongoing active troughing pattern in the Gulf of Alaska and off the Pacific Northwest will begin to weaken this area of high pressure by the middle and end of next week. This will bring greater onshore flow and subtle cooling to our region, but dry weather will continue. Long-range ensemble models increase chances for the trough to push further south, where chances for precipitation may increase toward the Christmas holiday.
130330z, Coast/Valleys, Patchy low clouds with bases around 500- 800ft MSL are already beginning to push inland, with spread up to 10 miles by 10z. VIS generally 2-6SM but periods of 1/2SM-1SM possible for both coastal and valley areas, primarily from 05z-09z, with VV002. Very localized areas of full obscurations of 0-1SM in FG. VIS restrictions begin to improve after sunrise, and low clouds and FG scatter out by 17-18z for San Diego County, with Orange County seeing clouds linger until 18-20z. Another round of low clouds/FG beginning around 02z Sun, with similar bases to tonight.
Mountains/Deserts, SKC and VFR conditions expected through Saturday. High clouds AOA 20,000ft MSL into Saturday.
Low clouds/fog will continue through Saturday morning. Visibility reductions to 1 NM or less expected at times. A Marine Weather Statement is in effect until noon Saturday for the impacts from fog and contains more details. Conditions expected to improve late Saturday morning. Otherwise, no hazardous marine conditions are expected through Wednesday.
Ca, Dense Fog Advisory until 10 AM PST Saturday for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
