Hurricane season may be winding down, but worry not, lovers of rapidly intensifying weather. Bomb cyclone season is upon the Northeastern hemisphere.
OK, so it’s not an official meteorological season, but storms that bomb out along the American East Coast tend to happen in late autumn through spring. And this week is when the U.S. could see its first bomb of the season, as a storm ramps up near the Northeast and brings a stinging slap of rain and gusty winds. The storm could also knock leaves and even limbs off the trees and put an abrupt stop to peak foliage season in parts of New England all while challenging all-time low pressure records for October.
This week’s bomb cyclone is already ramping up as a regular ol’ area of low pressure off the Mid-Atlantic. The storm is in part being fuelled by a sharp wave in the jet stream and a low-pressure system dipping out of the Great Lakes. That plunge in the jet stream from north to south and then back up will allow for different air pressures and temperatures to come into contact. The tug-of-war between these contrasting air temperatures will lead to pressure rapidly dropping just offshore on Thursday.
The rapid drop thing is the hallmark of a bomb cyclone. In nerd terms, a storm that bombs out occurs when surface pressure drops by at least 24 millibars in 24 hours. In normal-people terms, a storm that bombs out gets really strong really fast. This storm isn’t just likely to fit the meteorological definition of bomb cyclone, it’s also likely to break low-pressure records for October near New England.
The rain associated with the developing system has already lead the Yankees to cancel Game 4 of the American League Championship Series with the Astros on Wednesday evening. But the storm really gets going and bomb out as it approaches New England. Wind advisories and high wind warnings stretch across coastal New England where the U.S. National Weather Service is warning gusts could reach as high as 97km/h on Thursday into Friday.
A few centimetres of rain could fall (if it was colder, the snow totals would be a bit more eye-popping). The National Weather Service is also warning coastal flooding could cause “around 1 to 2 feet (30 to 60 centimetres) of inundation above ground level in low lying, vulnerable areas” (thanks, sea level rise) and that rainfall could compound flooding woes in some locations.
The storm won’t just affect coastal areas, however. Winds will whip further inland as well and could knock the foliage off trees. Bad news for leaf peepers, sure, but the real concern is that those leaves will catch wind before being knocked off and bend limbs to the point of breaking. Power outages will almost certainly be a problem for parts of New England that could last after the bomb cyclone blows by.