SAN DIEGO (KGTV) — Areas of dense fog are affecting the coastal mesas and western valleys this morning and again tonight into Monday morning. Well above normal high temperatures will continue with periods of weak offshore flow through Thursday. Gradual cooling with more widespread night and morning low clouds and fog is expected Friday into next weekend.
Marine layer low clouds and fog have spread into the western valleys this morning. Several sites on the coastal mesas and valleys in San Diego County are reporting quarter-mile visibility in fog, and a Dense Fog Advisory is in effect for the San Diego County coastal areas and western valleys through 9 a.m.
Clouds and fog will clear back to the coast by late morning, though some beaches could remain overcast through the afternoon once again. Otherwise scattered high clouds are expected today with high temperatures around 10 to 15 degrees above normal inland, and near normal along the coast.
A weak short wave trough will pass over the region today into tonight. This will help deepen the marine layer slightly, allowing low clouds to spread a little further inland and resulting in less widespread dense fog.
Once this wave goes through, surface pressure gradients turn offshore Monday morning with north to northeast winds gusting to around 30 mph developing below the passes and canyons. Weak offshore flow persists into Tuesday.
Upper level ridging and the offshore flow will combine to bring warmer and drier conditions Monday and Tuesday, especially west of the mountains. If enough dry air makes it to the coast, the marine layer will struggle to develop each night, limiting the risk of fog development.
By Tuesday, highs will be close to 15 to 20 degrees above normal in the inland areas again with highs in the low to mid-80s across the valleys and low deserts.
