Cooler daytime highs return as onshore flow develops

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Posted at 4:42 AM, Apr 20, 2021
and last updated 2021-04-20 10:32:22-04

Between the return of onshore flow and an upper-level trough near the southern Oregon coast, conditions across the central coast will be foggy and cooler Tuesday.

Starting with the fog, as the trough of low pressure continues to move southeast, it should help with the development of fog and overnight marine layer in the coming days. Weather models are showing the cloudy conditions could continue through Thursday and clearing will be gradual along the coast. As a result of the increasing clouds and fog, drizzle will be a possibility in the overnight hours and through the morning commute Wednesday.

As onshore flow starts to develop once again, daytime highs will start to trend down. For Tuesday, temperatures along the coast will range from the upper 50s to the upper 60s, while coastal valley areas won't be too far off and range from the low 60s to the low 70s. Perhaps the most significant change will be felt across the interior valleys where temperatures are trending down to the upper 60s to upper 70s.

North to northwesterly winds will be breezy at times throughout the afternoon. The south coast region will remain under a wind advisory through 6 a.m., and even after that, wind speeds are expected to range from 15 to 25 miles per hour across the region, especially for coastal areas in San Luis Obispo County.

Looking ahead to the start of next week, the GFS model is showing rain in the forecast Sunday night through Monday. Right now, the system looks light, but as the event nears more details on rainfall estimates will become available.