Cooler weather for inland areas is expected this weekend into the first half of next week as a trough of low pressure moves over the region. This will also bring breezy conditions across the mountains and deserts this afternoon through Saturday evening. High pressure looks to expand over the West Coast by the latter half of next week, which would lead to a warming trend.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Zooming out, we see a 591 mb high to our southwest over the East Pac and 540 mb low off the coast of British Columbia. The high's influence has led to a shallower inversion, leading to some hazy conditions in the western valleys and clouds sticking closer to the coast. Clouds will struggle to clear at the beaches, but may do so intermittently later this afternoon. Heights lower as the area of low pressure to the north moves closer to our region over the weekend. This will lead to increased winds over the mountains and deserts starting later this afternoon through Saturday. Winds will mostly be near 25-40 MPH with highest winds in the San Gorgonio Pass locally over 50 MPH, so please be sure to drive with care. Cooler weather will also occur inland over the weekend with Sunday being the coolest day overall. Highs in the 70s and 80s will occur across most areas with highs 95-100 degrees across the lower deserts.
The trough will remain in place into early next week, with minimal changes in the weather from day to day. Marine layer clouds will work their way into most areas west of the mountains each night and morning into the middle of next week. Cluster analysis shows fair agreement on a ridge off the coast strengthening by the latter half of next week. This will lead to a warming trend with less wind and a deeper marine layer, but how warm we become is still something to be determined as the timing and strength of the departing trough may try to influence our weather pattern as well.
051800z, Coast/Valleys, Low clouds based 1100-1500 ft MSL with tops to 2000-2200 ft are lingering along the coastal region, where it will see only partial/intermittent clearing today, especially in southern San Diego Co. Low clouds will spread inland again after 00Z and spread more fully inland overnight into Saturday, including into parts of the Inland Empire. Bases/tops will be a bit higher at 1400- 1800 ft with vis 4-6 SM for inland edge of clouds in valleys/Inland Empire. Clouds will struggle to clear from coastal regions again Sat morning.
Mountains/Deserts, Expect clear skies and VFR conditions today, with increasing clouds above 20000 feet tonight. Southwest-west winds will increase in the mountains and deserts with gusts reaching 30-40 knots after 21Z, the decrease after 03Z tonight. MOD up/downdrafts and pockets of LLWS in lee (north and east) of mountains. Similar winds Sat afternoon and evening.
No hazardous marine conditions are expected through Tuesday.
Ca, None. PZ, None.
