The National Weather Service (NWS) Bay Area issued a Red Flag Warning for North Bay and East Bay hills, effective Friday, May 7 at 11 p.m. and extending through 6 p.m. on Tuesday, May 11.
The warning initially extended from Friday, May 7 at 11 p.m. to the morning of Monday, May 10 but was extended further on Sunday morning due to continued dry and breezy conditions.
According to the NWS, “The initial burst of dry offshore winds will reach the Napa County hills around 11 p.m. Friday night and then spread across the East Bay overnight into early Saturday. These winds will usher in much drier air along with wind gusts in excess of 50 mph above 2,000 feet. On Saturday, breezy north winds will continue as temperatures warm well into the 80s with humidity values lowering into the teens and single digits. This pattern will help to rapidly dry out the fine fuels through the weekend.”
Some humidity recovery will occur on Saturday night, but warm, dry weather will continue on Sunday.
“Winds and warm temperatures that will allow for rapid fire spread on any new ignitions, especially in the grass and dry brush,” states a May 7 weather prediction update from the NWS.
Northerly winds in the 15 to 30 mph range will hit the area, with gusts of 40 to 50 mph. Areas above 2,500 feet may see gusts of 60 mph.
Humidity is expected to lower to 20-30% by Saturday morning, dropping to 10-20% on Saturday and Sunday afternoons.