Gusty Offshore Winds and Dry Conditions for Interior North Bay
Mountains Wednesday night through Thursday morning.
A shift towards a drier air mass and offshore flow will lead to
locally critical fire weather conditions across the interior
North Bay Mountains tonight through Thursday morning. 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 including the Vaca and Mayacamas ranges. These
areas will see the strongest winds, lowest humidity, have the
driest fuels, and they received little to no wetting rainfall
earlier this week.
RED FLAG WARNING IN EFFECT FROM 11 PM THIS EVENING TO 11 AM
PDT THURSDAY FOR GUSTY OFFSHORE WINDS AND LOW HUMIDITY FOR
INTERIOR NORTH BAY MOUNTAINS...
The National Weather Service in San Francisco has issued a Red
Flag Warning for gusty north to northeast winds and low humidity,
which is in effect from 11 PM this evening to 11 AM PDT Thursday.
The Fire Weather Watch is no longer in effect.
* AFFECTED AREA...Fire Weather Zone 507 North Bay Mountains
focused on the Vaca and Mayacamas ranges in Napa County and
including the border area of Sonoma and Napa counties
* TIMING...11 PM Wednesday to 11 AM Thursday.
* 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 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.