San Francisco residents were awakened by a tornado warning Saturday morning during a powerful storm system that pounded the region with heavy rain and wind.
It was the first tornado warning in San Francisco, but not the first. quoted CBS News Bay Area Meteorologist Paul Heggen.
The National Weather Service issued the warning for northern San Mateo County and parts of central San Francisco shortly before 6 a.m. until 6:15 a.m.
According to the NWS, there was a cyclonic signature on the radar that had produced enough of a rotation signature to cause the warning.
“The radar scan at 5:52 a.m. clearly shows a ‘hook echo’ offshore; this is the signature we look for to identify a developing tornado. This feature was embedded within a wide area of very heavy rain, but it still stands out.” Heggen explained.
The NWS Bay Area said the advisory ended for San Francisco at 6:07 a.m And let the tornado warning expire at 6:15 am
The warning prompted a flurry of social media posts from residents who woke up to the alert on their cellphones. It was reported as the first tornado warning issued for San Francisco.
A special warning was also issued for a possible waterspout in San Francisco Bay in the area of ​​the Bay Bridge that expired ten minutes after the tornado warning.
Although the strongest part of the system has passed, isolated thunderstorms are still possible in parts of the Bay Area through the morning, the National Weather Service said.
The risk of a severe storm is marginal and the NWS said it will only last until Saturday morning. Storm conditions caused power outages for thousands of people in the Bay Area, according to PG&E.