November 19, 2024
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‘Bomb Cyclone’ and Atmospheric River will hit the US West Coast
A large windstorm and an atmospheric river will release “fire-friendly” precipitation from California to British Columbia.
A “bomb cyclone” and atmospheric river will bring damaging winds, heavy snow and heavy rain to the West Coast.
NOAA/NESDIS/STAR GOES-West
A”bomb cyclone“Damaging winds are pushing into parts of the U.S. Northwest and northern California today, and the storm is helping to create a powerful atmospheric river that a forecaster says will open a ‘firehose’ of rain and snow to parts of the West Coast. Northern California is particularly hard hit.” will suffer extreme precipitation rates.
The term bomb cyclone refers to an area of low atmospheric pressure that suddenly “deepens” or even drops in pressure. This process, called bombogenesis, occurs when a storm system’s pressure drops over a 24-hour period based on the system’s current latitude. At a latitude of about 45 degrees north, bombogenesis occurs when the pressure drops to at least 18 to 20 millibars. This storm will easily clear that barrier, dropping between 60 and 70 millibars in 24 to 36 hours, climate scientist Daniel Swain wrote. in a recent post on his blog. “This is likely to be one of the fastest non-deepening low pressure systems on record in this region,” he added.
The storm will bring winds of up to 70 miles per hour to parts of Washington State, Oregon and California, where it could knock out power and damage trees, according to the National Weather Service. Food conditions are forecast for Washington’s portion of the Cascade Range.
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A front associated with the bomb cyclone (essentially a boundary between two air masses with different temperatures and humidity) is expected to stall near northern California on Wednesday, which will produce water vapor. atmospheric river. Such streams can be 2,000 kilometers long, 500 kilometers wide and two kilometers high, with a flow of moisture 25 times that of the Mississippi River. This atmospheric river will pull tropical moisture from around Hawaii and send it to the West Coast in several waves of heavy or extreme precipitation, especially in mountainous areas. It’s somewhat uncertain which areas will have the biggest impacts, as the river can “move” up and down the coast, Swain said on his blog.
He also noted that this atmospheric river will expel even more water vapor in its path due to unusually high ocean temperatures.
Although atmospheric rivers are critical in supplying winter precipitation, which then supplies water to the arid West during the dry season, the nature of such rains can also be dangerous. They can cause mudslides and floods, hazards especially worrisome near fire burn scars because the burnt soil cannot absorb the water attack, increasing the risk of landslides.
