Full Notification

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area

Red Flag Warning is now in effect for Critical Fire Weather Conditions for Early Wednesday Morning, Oct. 14, 2020 through Friday Morning, Oct. 16, 2020.

Critical fire weather conditions are possible mid to late this week across the higher elevations of the North and East Bay as well as the Santa Cruz Mountains. Some of these winds will possibly mix down into the North Bay and East Bay Valleys. Winds will begin to increase early Wednesday morning, especially over Napa County, but also farther south into the Diablo Range.

Significantly stronger and gustier winds will develop and become more widespread in the hills Wednesday evening and peak overnight Wednesday night into early Thursday morning, then diminish during the day on Thursday. An uptick in wind speeds is likely again on Thursday night, but winds then are not expected to be as strong as
those Wednesday night. In addition to gusty offshore winds, an extremely dry air mass will move in from the north and northeast.

Afternoon relative humidity values beginning Wednesday are forecast to drop as low as the teens, with some single digit RH values possible. Little to no overnight recoveries are anticipated. Winds are anticipated to subside over all areas by Friday afternoon.

RED FLAG WARNING IN EFFECT FROM 5 AM WEDNESDAY TO 11 AM PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND LOW HUMIDITY VALUES FOR FIRE WEATHER ZONES 507 AND 511...

THE NATIONAL WEATHER SERVICE IN San Francisco HAS ISSUED a Red Flag Warning...WHICH IS IN EFFECT from 5 AM Wednesday to 11 AM PDT Friday. THE Fire Weather Watch IS NO LONGER IN EFFECT.

* AFFECTED AREA...FIRE WEATHER ZONES 507 and 511 which includes the North Bay Mountains (including the Glass Fire) and the East Bay Hills.

* WIND...North to northeast winds 15 to 30 mph with gusts of 35 to 45 mph. Higher peaks and ridges can expect gusts of 45 to 55 mph. Strongest winds are anticipated Wednesday evening into Thursday morning.

* HUMIDITY...Daytime humidity values will drop as low as 8 to 18 percent with little to no nighttime recoveries.

* HIGHEST THREAT...Mountains of Napa and northeastern Sonoma Counties.

* IMPACTS...Any fires that start will likely spread rapidly due to the combination of dry fuels, strong and gusty north-northeasterly winds, and very low humidities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior.