Full Notification

Critical fire weather conditions from late Tuesday evening into Wednesday afternoon over the interior North Bay Mountains and portions of the East Bay Hills/Diablo Range due to gusty offshore winds and low humidity.

A period of gusty, offshore winds and low humidity are expected late Tuesday evening into Wednesday afternoon and locally again the following night. The areas of greatest concern are across the hills and mountains of Napa County where minimum relative humidity values will drop into teens along with wind gusts up to 45 to 55 mph. There is the potential these stronger winds and low humidity could also spread into the interior hills of Sonoma County and into the East Bay Hills /Diablo Range of Alameda and Contra Costa counties. Meanwhile, the risk is significantly lower across Marin and Santa Clara counties.

RED FLAG WARNING IN EFFECT FROM 11 PM THIS EVENING TO 3 PM PDT WEDNESDAY FOR GUSTY OFFSHORE WINDS AND LOW HUMIDITY FOR THE INTERIOR NORTH BAY MOUNTAINS AND PORTIONS OF THE EAST BAY HILLS/DIABLO RANGE.

* AFFECTED AREA...Fire weather zones 507 and 511. Area of greatest concern will be across the interior North Bay Mountains of Napa County.

* TIMING...11 PM Tuesday through 3 PM Wednesday.

* WINDS...North to northeast winds 10 to 25 mph with gusts up to 45 mph, locally up to 55 mph in the highest peaks.

* RELATIVE HUMIDITY...Minimum humidity of 10 to 15 percent expected Wednesday.

* IMPACTS...Any fire starts would likely see rapid spread due to dry fuels, low humidity and gusty winds.

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.