Warmer weather will continue into the early part of the week as high pressure remains overhead. The marine layer will begin to slowly build through the week, leading to a better chance for clouds and foggy conditions closer to the coast each night and morning. Offshore winds will be fairly week through Monday with locally higher winds in the mountains on Tuesday. A cooling trend begins on Wednesday into late week as a low pressure system moves closer to the region, helping build the marine layer even further.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
A beautiful picture of cirrus clouds above us today is all thanks to an area of low pressure moving northward far off the coast. High pressure will continue to dominate the weather pattern over the next few days with warm temperatures and light offshore winds across the mountain areas. Currently, most mountains spots are seeing winds less than 25 MPH. As offshore flow continues to weaken and pressure heights fall, the marine layer will begin to slowly build in depth. Latest model guidance shows areas within 5 miles of the coast seeing best chances for fog later tonight into Monday morning, some of which could be dense. By Tuesday, an increased offshore gradient will occur. This will increase winds a bit further with local gusts over 40 MPH across mountain passes and foothills. This will also help suppress the marine layer again, in which winds will aid in pushing most clouds offshore. Confidence still remains low if this occurs the entire night and early morning, but mostly clear skies remain in the forecast. This weather pattern will continues our warm temperature forecast with highs 5 to 15 degrees above average each day through Tuesday.
Models show an area of low pressure moving closer to the region on Wednesday into later in the week. This will enhance onshore flow and build the marine layer with greater cloud coverage into the western valleys each night and morning. High temperatures will lower a few degrees each day starting Wednesday into Friday as the low pressure system moves closer. There is still great uncertainty on the path of this low pressure system. Model ensembles have decreased in total rain accumulations since yesterday, along with lower chances from the NBM, indicating less than a 15% chance of any measurable rainfall by Friday into next weekend.
By early next week, model guidance is fairly agreeable to weak high pressure moving back into the area with potentially more offshore flow. This pattern would give us warmer and drier weather as we head into the last full week of January.
190000z, FEW-SCT high clouds and VFR conditions prevail for most of the region through Monday afternoon. Patchy low clouds/dense FG 100- 300 ft MSL and vis 1/4-1 SM will form off of the coast late this evening, with localized areas moving into the immediate coast. There is a 20% chance for FG impacts at KSAN/KSNA and a 10% chance at KCRQ 08-15Z Mon.
Patchy dense fog is possible (30-40% chance) tonight into Monday and again Monday night into Tuesday. Patchy fog can result in visibility dropping locally below 1 nautical mile. Otherwise, no hazardous marine conditions are expected through Thursday.
Ca, None. PZ, None.
