Low clouds and dense fog will form tonight and spread up to 10 miles inland. For tomorrow through Friday, a weakening trough of low pressure will move slowly into California. It will bring cooling and extensive high clouds to SoCal. High pressure and weak offshore flow will bring a warming trend this weekend. High pressure will begin to weaken early next week bringing cooler weather, and the possibility of some rain mid to late next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
At 1 PM, a few patchy low clouds were sticking around the immediate coast, but otherwise mostly clear skies prevailed across the region. High temperatures will be slightly warmer today than yesterday due to a more shallow marine layer earlier this morning. Low clouds and fog will form again tonight and spread up to 10 miles inland by morning.
High pressure aloft will continue traversing over California today, weakening tomorrow as low pressure moves in behind it. Onshore flow will gradually strengthen Wednesday through Friday, cooling most locations through the end of the work week. Southwest flow ahead of the trough will usher in extensive high clouds at times.
For the weekend, an upper level ridge expands across California, bringing weak offshore flow and warmer weather to SoCal. There will be gusty northeast winds along the coastal slopes of the mountains and through the passes and canyons at times. This ridge will weaken early next week, decreasing northeast winds and bringing cooler weather to the region.
A pattern change is possible mid to late next week, as models are indicating a trough of low pressure moving into California from the northwest. Both the Euro and the GFS indicate this pattern change, but their ensemble members are not in good agreement about the placement and timing of this low. It could potentially bring some precipitation to the region as early as Tuesday. We will continue to keep an eye on model trends to see how this pattern evolves in the coming days.
122030z, COAST, SCT004-008 at the coastal airports through 03Z with vis 2 miles in HZ at KSNA. After 03Z, skies becoming BKN- OVC003-007 through 08Z, then lowering to OVC001-004 with vis 1/4 to 1 mile between 11Z-17Z. After 17Z, clearing skies and improving vis through 20Z.
VALLEYS/MOUNTAINS/DESERTS, Mostly clear with unrestricted vis through tonight.
No hazardous marine conditions through Saturday.
Ca, NONE. PZ, NONE.