What is a "bomb cyclone" and what does it mean for Lake Tahoe?
Submitted by paula on Wed, 01/04/2023 - 2:51pm
SOUTH LAKE TAHOE, Calif. - A term that has been getting a lot of coverage with the incoming storm is "bomb cyclone," but was is it? A "bomb cyclone" is an area of a low-pressure system that intensifies by 24 millibars within 24 hours (millibars are a unit used to measure atmospheric pressure).
This is not a new meteorological term and has been around for quite some time, but it hadn't been used much. It is more common in the northeast where they see rapidly changing pressure systems more often, but it happens in the west as well.
In the book and movie, The Perfect Storm, what the crew of the Andrea Gail experienced in 1991 was a bomb cyclone and a rapidly changing tropical storm between the fishing boat and Gloucester, Mass.
Meteorologist Scott McGuire of the National Weather Service (NWS) in Reno said the bomb cyclone off the coast of California is a rapidly depending low-pressure system and as the gradients tighten the stronger the winds change. It creates an impressive-looking storm on radar with its large circle and tail features.
McGuire said the trajectory of the current deep low is lifting it to the north, so it will not be moving into California but still sending damaging effects along the coast and Central Valley of the state.
Governor Newsom has declared a state of emergency throughout California to support the ongoing response to recent winter storms.
Heading from the western Pacific is also a long atmospheric river starting in the Philippines. The "bomb cyclone" will be pulling moisture from that river to bring to California, Oregon, and Nevada. Following storms will also be moisture-rich.
For the Lake Tahoe Basin and Western Nevada, this storm looks like the New Year's Eve storm but it shouldn't be as crippling based on the cyclone features. Snow forecast: 8 to 14 inches at Lake Tahoe, except 1 to 2 feet above 7000 feet. Localized amounts up to 3 feet are expected for the Sierra crest. Winds could be 100 mph over Sierra ridgelines with gusts up to 40 mph at lake level.
This overnight and Thursday storm is only one of several waiting in line after a break on Friday. This coming weekend will see a potent system, and another on Monday-Tuesday, with others waiting.
"We remain in a very active pattern," said McGuire.
The weekend storm will be a medium-intensity system with about a 6-12 hour period of heavier snow in the Sierra.
To follow road conditions during the storm, visit https://quickmap.dot.ca.gov/ in California and https://www.nvroads.com/ in Nevada. NWS Reno updates the forecast twice a day and can be found HERE.