As the Bay Area basks in what is expected to be the week's highest temperatures, a significant cooling trend looms just around the corner. Today's warmth will be chased away by a robust onset of gusty onshore winds tonight, with a speed ranging from 30 to 40 MPH in elevated inland areas. Potential gusts reaching 40-50 MPH along the immediate coast, particularly near the Bay Area, Big Sur, and Santa Lucia coastlines, according to the latest briefing from the National Weather Service San Francisco.
The NWS reports that the strengthening winds will stick around through Saturday before diminishing by early Sunday. A closed low, slowly trekking inland from the Pacific Northwest, carries two shortwave troughs, the second forecasted to be the strongest, stirring up the gusty conditions. Fire weather concerns escalate early next week as weak offshore flow may follow, lingering due to a blockage by high pressure to our east, especially if it lingers with nowhere to go, blocked by high pressure to the east.
Aviation-wise, a bumpy transition is on the horizon, with low-level wind shear anticipated at certain airports and a mixed bag of forecasts regarding the return of nighttime stratus clouds. The NWS San Francisco details, "Low level wind shear is expected at STS late this evening into tomorrow morning due to strong directional and speed shear in the lower levels." Coastal regions like Half Moon Bay (HAF) are expected to see stratus rolling back between 03-06Z, while stratus return to Monterey Bay area airports like MRY and SNS is less certain.
Mariners, too, are advised to take heed as Gale Warnings have been hoisted for coastal jet areas south of Point Reyes and Point Sur, stretching across the outer coastal waters. "Gale Warning until 9 AM PDT Thursday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm," states the National Weather Service. This bout of rough seas will add heightened challenges with wave heights expected to surge to 10 to 12 feet across the coastal waters through the weekend, underscoring the need for vigilance among seafarers.
