UPDATE 9/29/21 AT 12:00 P.M.
Gusty offshore winds and dry conditions will lead to locally critical fire weather conditions across the interior North Bay Mountains. Locally gusty north to northeast winds overnight will coincide with poor humidity recoveries. Winds are expected to diminish through the day Thursday, but widespread critically dry humidities will prevail throughout the day. The areas of greatest concern are locations in Napa County and into interior Sonoma County at or above 1000 feet. These areas will see the strongest winds, lowest humidity, have the driest fuels, and they received little to no wetting rainfall earlier this week. NOTE: The Fire Weather Watch is no longer.
* AFFECTED AREA… North Bay Mountains and areas above 1000 feet in Sonoma County.
* TIMING… 11 PM Wednesday (9/29) to 11 AM Thursday (9/30)
* WINDS… North 15 to 25 mph with gusts up to 35 mph.
* RELATIVE HUMIDITY… As low as 8 to 15 percent during the day with poor recoveries overnight ranging only 15 to 30 percent.
* TEMPERATURES… In the lower 70s.
* IMPACTS... Any fire starts would likely see rapid spread due to dry fuels, low humidity and gusty winds in areas that did not receive wetting rains over the weekend.
A combination of strong winds, low relative humidity and warm temperatures can contribute to extreme fire behavior. Residents are encouraged to review information that includes our evacuation checklist at srcity.org/ReadySR.
ORIGINAL MESSAGE 9/28/21
Following the light rain we received locally yesterday (9/27), the gusty offshore winds and dry conditions that arrived today in the North Bay are forecasted to continue and steadily increase tonight, however, overnight humidity values in the 45-55% range will mitigate fire weather risk through the night. By tomorrow (Wednesday, 9/29) a much drier air and breezy conditions will persist through the day. Locally, gusty offshore winds will ease somewhat but persist through Wednesday night and will lead to critical fire weather conditions, particularly into the sunrise hours Thursday (9/30).
* TIMING... 11AM Wednesday (9/29) to 6PM Thursday (9/30). The time of highest concern is late Wednesday night into sunrise Thursday morning.
* AFFECTED AREA... Upper Elevations of North Bay over 1000 ft. The area of highest concern are the interior ranges throughout Napa county above 1000 feet.
* WINDS... Sustained N-NE winds 10 to 25 mph with gusts up to 35 mph. Winds will ease during the day and be strongest overnight.
* RELATIVE HUMIDITY... As low as 10-15% during the day Wednesday, overnight recoveries to 25-35% Wednesday night, then dropping as low as 8-13% during the day Thursday.
* IMPACTS... Any fire starts would likely see rapid spread due to dry fuels, low humidity and gusty winds in areas that do not receive wetting rains over the weekend.
Residents are encouraged to review preparedness information at srcity.org/WildfireReady and srcity.org/ReadySR.