A week-long forecast looks a little gloomy for coastal regions as strengthening onshore flow and a deepening marine layer dominate the weather narrative.
From today through Thursday, low clouds, fog, and drizzle are set to blanket coastal areas and valleys, keeping temperatures several degrees cooler than average.
The short-term forecast, spanning from today to Thursday, underscores the persistence of strong onshore pressure gradients.
As Wednesday transitions into Thursday, a midlevel low will traverse eastward across the East Pacific, making its way over the Central Coast. This movement is anticipated to intensify and deepen the marine layer, enveloping coastal regions in widespread low clouds and fog. Expect daytime highs in the 60s across most areas throughout this period.
Additionally, the marine layer is projected to deepen significantly, reaching depths exceeding 2500-3000 feet tonight into Tuesday, and surpassing 4000 feet by Thursday. This atmospheric setup will support the occurrence of drizzle, particularly during the evening, overnight, and morning hours. While measurable rainfall is unlikely due to dry conditions in the mid and upper levels, isolated light showers may accompany the passage of the midlevel low late Wednesday night and Thursday morning.
Looking ahead to the long-term forecast spanning from Friday to Monday, a gradual shift is expected following the passage of the midlevel low. Cooling temperatures aloft and a weakening of onshore pressure gradients will lead to a reduction in the depth and intensity of the marine layer. Consequently, the prevalence of fog and drizzle is anticipated to diminish. However, a deep midlevel trough amplifying over the Great Basin late Friday into the weekend may maintain cool temperatures in the 60s through Friday, followed by a slight warming trend by Sunday.
While the weakening marine layer suggests a decreasing chance of precipitation, a second disturbance glancing the area on Friday could bring a slight chance for drizzle or light showers into Friday night. Beyond that, dry conditions are expected to prevail.
The 8-14 day outlook from the Climate Prediction Center calls for roughly average temps and precip chances.
