Slow warming will continue for the inland areas through mid week, bringing high temperatures to 4 to 10 degrees above average for Wednesday and Thursday. The coast and valleys will cool a few degrees on Tuesday, then warm a few degrees for Wednesday and Thursday, with night and morning coastal low clouds spreading into portions of the valleys late each night. A low pressure system moving into the western states will bring a cooling trend for Friday through the weekend, with high temperatures for next Sunday falling to a few to about 10 degrees below average by Sunday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Predominately zonal flow aloft today has resulted in what some may call Chamber of Commerce weather, i.e. Sunny and warm. Weak troughing moving into the western part of the region late tonight will lead to the marine layer moving in earlier this evening, likely moving into the immediate coast along San Diego County 5-6 PM. Clouds will be around 2000-2500 feet above the ground+ and will move a little farther inland than this morning, including into parts of the Inland Empire. These will clear out, similar to this morning, mid to late morning Tuesday. The weak trough will also lead to a few degrees of cooling between this afternoon's highs and Tuesday's highs outside of the mountains and deserts, where it will warm a degree or two for tomorrow.
This trough will swiftly move southwest out of the region as a weak ridge moves in from the east mid-week. Temperatures will warm a tad over the region for Wednesday and Thursday to 4-10 degrees above average for inland areas, and the marine layer will get a bit shallower (travel less far inland overnight). Broad, stronger troughing moving into the western U.S. Will lead to a cooling trend Friday through at least Sunday, though persisting model differences in strength and position lead to a bit of uncertainty regarding degree and longevity of the cooling. The current forecast is for high temperatures 5-10 below average inland for Sunday. Marine layer clouds will deepen again, reaching farther inland to cover most of the valleys over the weekend.
011730z, Coast/Valleys, Low clouds have cleared the Inland Empire and are making a quick retreat out of the valleys and clearing to the coast. Low clouds based 1500-2000 ft MSL will hang out over the coastal waters with a few low clouds wafting in over coastal areas at times. Low clouds with bases 1000-2000 ft MSL will begin to push back in after 23Z along the coast and further inland into OC and SD after 03-04Z Tuesday and into the Inland Empire after 6-10Z.
Mountains/Deserts, Mostly clear skies and VFR conditions expected through the period.
No hazardous marine conditions are expected through Saturday.
Ca, None. PZ, None.
