Dry gusty offshore winds as well as strengthening high pressure enabled the generation and rapid spread of the Glass Fire across Napa and Sonoma counties at the end of September. The mountains of the North Bay saw wind gusts of 40 to 65 mph into the morning of the 28th with 30 to 40 mph gusts across the East Bay Hills. These gusty winds along with dry conditions enabled the Glass Fire to spread almost fourfold in one day. Tens of thousands of residents were evacuated and nearly 80 homes were destroyed along with numerous additional structures including a famous Napa winery. Offshore flow and strong high pressure also broke several daily temperature records across the SF Bay Area. High temperatures were in the mid/upper 90s to low 100s inland and mid 80s to low 90s along the coast.

Strong Wind in NORTH BAY MOUNTAINS, CALIFORNIA
From 27-SEP-20 18:30:00 to 28-SEP-20 06:40:00 (PST-8)
Magnitude: 43.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Healdsburg Hills North mesonet (PG&E) station recorded gusts of 50 to 60 mph with a peak gust of 68 mph.

Strong Wind in EAST BAY HILLS AND THE DIABLO RANGE, CALIFORNIA
From 27-SEP-20 13:50:00 to 27-SEP-20 16:50:00 (PST-8)
Magnitude: 29.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Grizzly Peak Blvd mesonet (PG&E) station recorded gusts of 30 to 35 mph.

Strong Wind in EAST BAY HILLS AND THE DIABLO RANGE, CALIFORNIA
From 28-SEP-20 02:10:00 to 28-SEP-20 10:50:00 (PST-8)
Magnitude: 30.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Diablo-Blackhawk mesonet (PG&E) station reported gusts of 30-35 mph with peak gust of just under 40 mph.

Dense Smoke in NORTH BAY INTERIOR VALLEYS, CALIFORNIA
From 28-SEP-20 00:00:00 to 30-SEP-20 00:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

Smoke from the Glass Fire blanketed the North Bay throughout the week with ash fall also reported near the fire. This all prompted a spare the air alert by the Bay Area Air Quality District https://www.baaqmd.gov/news-and-events/page-resources/2020-news/092820-sta.

Rip Current in SAN FRANCISCO, CALIFORNIA
From 27-SEP-20 08:00:00 to 27-SEP-20 08:30:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A swimmer was rescued at Dead Mans Point at El Camino Del Mar in San Francisco https://twitter.com/SFFDPIO/status/1310252717386813440.

Wildfire in NORTH BAY MOUNTAINS, CALIFORNIA
From 27-SEP-20 02:48:00 to 30-SEP-20 23:59:00 (PST-8)
Reported by: Fire Department/Rescue

Dry gusty offshore winds as well as strengthening high pressure enabled the generation and rapid spread of the Glass Fire across Napa and Sonoma counties at the end of September https://www.fire.ca.gov/incidents/2020/9/27/glass-fire/. Tens of thousands of residents were ordered to evacuate including the entire city of Calistoga. Over 50,000 acres burned by the end of the month along with nearly 80 residential structures and numerous additional structures. Strong and dry offshore winds enabled the Glass Fire to grow nearly fourfold in just one day https://www.latimes.com/california/story/2020-09-29/glass-fire-quadruples-in-size-burning-80-homes-in-napa-valley.  The fire was still burning well into October.