San Diegans can anticipate a shift in weather patterns as an upper-level low introduces a deepening marine layer, bringing cooler temperatures throughout the region. Today's highs are expected to range from 3 to 8 degrees below average away from the coast, while desert areas will maintain slightly above-average temperatures. Coastal fog will also be less of an issue on Sunday, staying confined to higher inland terrains, according to a forecast by National Weather Service San Diego.
Diving further into the week, a cooling trend remains as the low-pressure system located over southeastern Oregon and northern Nevada makes its way southward. With marine layer clouds to retreat to coastal areas by the late morning, patches of fog that once draped valleys are now dissolving into clearer skies as the low continues its journey south through Tuesday morning. This was outlined in a discussion for extreme southwestern California, including parts of San Diego and Riverside counties, detailed in a statement by the National Weather Service San Diego Area Forecast Discussion.
Towards midweek, another amplified upper trough is set to pass across the Western US, introducing further cooling and breezy conditions to the area. West winds impact the mountains and deserts. However, these changes bring less than a 15% chance of precipitation, leaving San Diegans with the faint hope of some isolated drizzle amidst the deep marine layer.
As the week progresses, uncertainty lingers among forecast models about whether a closed low will develop and move south into Nevada and Arizona by Friday. Should the closed-low scenario evolve, it could result in cooler weather, stronger Santa Ana winds, and potentially light precipitation by the weekend. Despite these mixed signals, the forecast, leaning on guidance from the National Blend of Models (NBM), suggests a trend towards warmer and drier conditions as the weekend approaches. Significantly, no hazardous marine conditions are expected through next Thursday, keeping the seas amicable for those on the water, as National Weather Service San Diego reports.
Aviation forecasts for the region indicate that coastal and valley areas will enjoy clear skies after the morning's low clouds and fog clear, while mountain and desert locales should expect uninterrupted visibility through tonight. Skywarn activation is not currently requested, but spotters are always encouraged to report significant weather conditions.
