FIRE DANGER: First Red Flag Warning of Season Issued for North and East Bay Hills This Weekend
SAN FRANCISCO (CBS SF) -- The Bay Area office of the National Weather Service on Friday morning issued a Red Flag Warning for parts of the North and East Bay hills with offshore winds and lowering humidity expected through Monday morning.
The warning is set to go into effect at 11 p.m. Friday night and is currently expected to expire at 6 a.m. Monday morning.
The Twitter account for the National Weather Service Bay Area office first posted about the warning Friday just after 10 a.m., following up with a map that showed the areas of concern less than a half an hour later.
Image shows officially where the Red Flag is in effect from 11 pm Friday through 6 am Monday (red color on map). #RedFlagWarninghttps://t.co/N8DS9N2c6Xhttps://t.co/HPZw8oiUgp pic.twitter.com/XyAHtB0BZL
— NWS Bay Area ???? (@NWSBayArea) May 7, 2021
Forecasters characterized the weekend warning as a "moderate early season offshore wind event" starting Friday evening.
"This will occur as fuels are near record dry levels after a very dry winter. 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," the Red Flag Warning message on the National Weather Service Bay Area website read.
Wind gusts in excess of 50 mph are expected at elevations above 2,000 feet. The increased winds will usher in much drier air. On Saturday, breezy north winds will continue along with a warming trend that will see temperatures rise into the 80s with humidity values lowering into the teens and single digits.
The weather pattern will continue to rapidly dry out the potential wildfire fuels throughout the weekend. Forecasters say there is the potential for some moderate humidity recovery overnight Saturday, but the warm and dry weather will persist Sunday with continuing dry northerly winds. The conditions will be ripe for rapid fire spread on any new ignitions, especially in the grass and dry brush.
National Weather Service meteorologist Ryan Walbrun said the first Red Flag Warning of a year typically doesn't come until June or later, but the weather conditions combined with dry vegetation due to a lack of a rainy winter prompted the earlier warning this year.
Temperatures could reach into the upper 80s or lower 90s and "we're not going to get a lot of help from the marine layer," Walbrun said.
The Bay Area has already seen an alarming rise in the number of fires, with multiple grass and house fires reported in the East Bay on Wednesday and Thursday, including a large two-alarm structure fire at a Walnut Creek senior center and an early morning fire near the Antioch Marina.
On Wednesday, there was a 15-acre vegetation fire in Discovery Bay that firefighters suspect was started by fireworks.
Cal Fire on Wednesday suspended burn permits in six Northern California counties -- Napa, Solano, Sonoma, Colusa, Lake and Yolo.
This first Red Flag Warning of the Bay Area fire season also comes just a day after the U.S. Drought Monitor put the entire region at the D3 extreme drought level.
The expanding areas of extreme drought are a result of a combination of factors including back-to-back dry water years, above-normal temperatures, below-normal snowpack, and drought impacts (agricultural, ecosystem health, water supply, recreation).
In the west, 83% of the region is currently in moderate-to-exceptional drought with the most severe conditions centered on the Four Corners states, California, and Nevada.
The extreme drought conditions mean Bay Area residents will likely see additional water restrictions on top of those already enacted.