Millions of Americans learned about something called “bombogenesis” and the phrase “bomb cyclone” for the first time last week. When the Blizzard of 2018 moved up off the east coast, it carved a place for itself in meteorological history … the bomb of bombs.
Bombogenesis refers to extraordinary deepening of central barometric pressure in a nontropical low-pressure system. If the pressure fall is at least 24 millibars in 24 hours, that qualifies. It occurs infrequently but is not exactly what you would characterize as truly rare.
THIS baby did "bombogenesis" up to the max. It dropped 59 millibars in 24 hours. Mashable’s Andrew Freedman reports that research done by a SUNY Albany meteorologist and an National Weather Service Weather Prediction Center meteorologist shows this to be the biggest and fastest intensification of any Atlantic storm since at least 1976.
That other term, “bomb cyclone,” rubbed me the wrong way, as it did some other meteorologists who hadn’t heard it before. We thought it was a new bit of hype for a well-known extreme process. Turns out I/we were wrong. (What?? A meteorologist wrong?? How could that be?) “Bomb cyclone” is a term that has appeared in weather literature for years. It is defined as a cyclone that underwent bombogenesis. Fair enough; we were oversensitive curmudgeons. (By the way, “cyclogenesis” is the development and strengthening of a cyclone, or low pressure system. All lows are cyclones, tropical or nontropical.)
The setup for this blizzard was extraordinary from the beginning. Most deep Nor’easters get their start in a zone of sharp temperature gradients from arctic cold on land to much warmer air over the Gulf Stream near Cape Hatteras, N.C.
This low got its start off the Florida coast instead of North Carolina because of extraordinarily cold air in place all the way down to northern Florida. The more southerly point of origin gave the cyclone a longer-lasting path over a zone of extreme temperature contrast and readily available subtropical moisture on its eastern flank. That makes for a tremendous energy source for fuel and generates strong lift in the atmosphere, tossing the tropical moisture up into the cold air aloft, where it will condense into precipitation, along with pressures falling at the surface.
There was nothing tropical about the structure of this massive storm, but its central pressure was more typical of what you would find in a Category 2 hurricane.
The peak gust of 122 mph in Mount Washington, N.H., during the storm was nothing historical, but gusts of over 100 mph were also recorded on Nova Scotia, Newfoundland and at several NOAA Atlantic buoys. The storm, as you know, crippled air travel for days in the east, with national effects. Charleston, S.C., received 5.3 inches of snow on the coastline. Unlike most such snowstorms, the snow stayed on the ground for several days due to the record-breaking arctic cold in the wake of the storm. Freezing rain fell in some parts of north Florida, along with some snow at Florida State University. Boston suffered its highest Nor’easter tide on record, aided and abetted by the increased gravitational pull from the supermoon at high tide and, to a lesser extent, the higher sea levels that exist now compared to the previous record storm tide in 1978.
The biggest effect on Western New York from the Blizzard of 2018 was the brutal cold the storm left in its wake, with the northwest flow behind it. We had daytime highs of 4 degrees and overnight lows of -1 and -3 on Jan. 5 and Jan. 6, with wind chill values in the negative 20s on Friday and Friday night.
The extreme cold on Friday was well-predicted, so that some school superintendents made closing decisions during Wednesday evening, enabling working parents to make arrangements for child care. No doubt this brought many smiles to students and teachers. There were probably some snow dances done in celebration in lieu of nonexistent cold dances. Canada’s The Weather Network even caught a squirrel going a little nuts: