On Friday, Decoded Science warned that an Alberta Clipper coming through the Great Lakes could develop into a big storm off the Atlantic Coast. And so it will.
The Weather Channel (TWC) has named the storm Juno, but Decoded Science has chosen Garbanzo Bean. Readers can decide whether the queen of the Roman gods or a nutritious legume is a more appropriate name for a nor’easter that could be a historic storm.
A Previous Storm Sets The Stage For Juno/Garbanzo Bean
The minor storm which TWC called Iola brought only nuisance rain to the big cities of the northeast because the freezing isotherm (line of equal temperature) was a little too far inland. However, Iola set the stage for Garbanzo Bean by bringing in colder air on its backside (sort of a bum steer). Now it will be cold enough for Garbanzo Bean to be all snow throughout its range.
As Iola continues to move away, high pressure will build behind it, press southward, and keep the cold air in place at the surface from New Jersey to New England.
Wave Goodby To Iola And Hello To Garbanzo Bean
As Decoded Science has discussed previously, the weather is all about settling the atmosphere’s energy accounts. Direct sunlight near the equator creates an energy surplus, while at the poles, the low angle of the sun results in an energy deficit. The imbalance is corrected by continual movement of heat poleward, primarily accomplished through mid-latitude storms.
The jet stream girdles the globe in mid-latitudes at a height of about 20,000 feet, generally aligned with the zone of greatest temperature gradient (difference in temperature). Within the jet stream, which commonly whizzes from the west at 100 miles per hour or more, waves ripple from west to east at around 25 miles per hour.
High and low pressure areas travel at the surface in the shadows of the waves. Occasionally, when the atmospheric stars line up, a wave intensifies into a major storm, then blows itself out. The process is roughly comparable to that of an ocean wave ‘breaking,’ then dissipating, when it encounters a beach.
Iola, as Decoded Science pointed out on Friday, was handicapped by the fact that it was not in synch with the Canadian Clippers coming out of Alberta, and the latter sapped some of Iola’s strength. Garbanzo Bean has no such impediment. The entire wave structure of the atmosphere is conducive to Garbanzo’s rapid development into a megastorm as it reaches the Atlantic coast.
The Role Of The Ocean In Developing Nor’easters: Water — Warm
As Decoded Science has pointed out many times, mid-latitude storms derive their fuel from the potential energy of adjacent air masses of different densities and temperatures (warm air is light; cold air is heavy). This high potential energy state is lowered by a realignment of the air masses so that cold, dense air lies below warm, less-dense air. The conversion is mediated by kinetic energy (wind).
The prominent contrast between cold and warm air masses over the North American continent is often exacerbated by proximity to two oceanic sources of heat: The Gulf of Mexico and the Atlantic Ocean. The heat of the ocean is rapidly transferred to the air above it. When a wave in the jet stream reaches the Atlantic coast, the warm ocean adds immediate fuel to the atmospheric fire. When Garbanzo Bean reaches the Atlantic coast, where the cold backside of Iola will a-butt the warm Atlantic air, the fuse will be lit.
The Role Of The Ocean In Developing Nor’easters: Water — Period
Alberta Clippers frequently move southeast from Canada into the midwestern US. These storms drop light to occasionally moderate snow, just a few inches, because they are generally moisture-starved, except in the lee of the Great Lakes, where Lake-Effect snow can be measured in feet.
The Atlantic Ocean contains an unlimited supply of water vapor for developing storms like Garbanzo Bean, and snowfall can reach up to several feet.
The Cresting Wave Slows Down, Bringing A Prolonged Period Of Snow
The average speed of jet stream waves is 25 miles per hour. However, when a storm is fully developed, the cold front catches up with the warm front, squeezing the warm air upward (the single front is called an occluded front and the storm is said to have occluded).
The low pressure center reaches up to jet stream level and ‘closes off,’ which means the wave becomes a closed low pressure center, now separate from the jet stream; a closed low in the jet stream moves very slowly — sometimes not at all. So when Garbanzo Bean is fully developed, it will linger over New England for a day or longer.
Who will Feel Garbanzo Bean’s Wrath?
As a Clipper, Garbanzo is moisture-poor and will drop only a couple of inches of snow in the midwest. But when it reaches the coast, the abundant moisture from the ocean will result in heavy snow from New Jersey to Maine. Current forecasts call for more than a foot in New York City and over two feet in Boston, as the storm slows down in the Gulf of Maine. The snow will begin in New York Monday morning and fall in Boston from midday Monday to late Tuesday night.
As the pressure drops in Garbanzo Bean’s center, the wind will increase (wind speed is proportional to pressure gradient). There is a formal definition of a blizzard, but to put it simply: A blizzard is a lot of wind coupled with reduced visibility in snow that lasts for several hours or more. Blizzard warnings are in effect for eastern Massachusetts, where winds could reach 50 miles per hour in Boston and gust to hurricane force (75 miles per hour ) on Cape Cod.
Is There A connection To Global Warming? A Good Bet
All models of climate change predict an increase in extreme weather. If Garbanzo Bean drops more than 20 inches of snow in New York, it will be the sixth time on record. Four of the snowfalls will have been within the last 20 years.
Does this storm ‘prove’ global warming is real? No. But it would be foolish to ignore the totality of evidence that screams that the burning of fossil fuels is raising the temperature of the earth at an alarming rate.
Decoding Science. One article at a time.