The San Francisco Bay Area is under a Red Flag Warning, which remains in effect until 5 PM today, for the Bay Area and Central Coast, barring coastal Marin, Monterey, and Sonoma Counties, as the National Weather Service San Francisco reported. The region is grappling with dry and windy conditions due to an inside-slider weather pattern, which typically exacerbates fire weather concerns.
A detailed analysis of current conditions obtained by the National Weather Service San Francisco reveals relative humidity levels dropping drastically by 50-70% from the day before and wind gusts reaching 50 mph at higher elevations. Mt. St Helena was reported to have experienced gusts soaring to 75 mph. Notwithstanding, the wind gusts remained largely at 25-35 mph, with isolated spikes up to 65 mph at the highest terrain and ridgetops and through gaps and passes.
While these rigorous winds and low humidity significantly threaten wildfires, the situation is expected to improve gradually. The National Weather Service forecasts a diminishing offshore pressure gradient, ushering in a renewed calm with onshore flow starting Saturday night. This transition is anticipated to bring more moderate temperatures, re-establishment of the marine layer, and a reduction in fire weather concerns as we head into next week. At the start of the week, a quiet profile with a stable zonal flow pattern is expected, according to the National Weather Service Area Forecast Discussion.
In the marine sector, strong winds are forecasted to persist today, potentially reaching gale force in the northwest zones this afternoon. However, winds are projected to subside to a moderate breeze by Sunday, and wave heights will reduce to 5-7 feet. The outlook for next week shows consistent conditions until the possibility of another cold front next weekend. Mariners are advised by the National Weather Service to exercise caution and take note of a Small Craft Advisory across several zones through Saturday.
Focusing on fire weather, though near average for this period, fuels are responding to the current dry and windy conditions, remaining "below record territory," as stated by the National Weather Service. With some stations reporting winds at 50 mph and relative humidity dropping to alarmingly low levels, all efforts to prevent wildfire ignition are prioritized. The Bay Area's populace is urged to be vigilant during these critical conditions, particularly through Friday night into Saturday morning, as the window for Red Flag conditions remains open.
