Blizzards and Cold Outbreaks Flashcards
Cold front
where cold air replaces warm air; warm air is displaced up and over an approaching cold front; short-lived rains at frontal boundary
Warm front
where warm air replaces cooler air; rises up and over but the warm air doesn’t rise as rapidly; precip ahead of the front
Stationary front
doesn’t move; winds parallel but opposite directions; clear to partly cloudy but there can be light precip
Occluded front
cold front catches up to and overtakes a warm front
Dry line
a (moisture) boundary between air masses but NOT a front; a narrow boundary of steep change in dew point; location of summer thunderstorms
Cyclogenesis
any development or strengthening of a mid-latitude cyclone
Bomb
Explosive cyclogenesis; pressure drops by more than 24 mb in 24 hours
Sleet
snow melts and refreezes before reaching the surface
Freezing rain
snow melts and refreezes on contact with the surface
Blizzard
blowing snow, reduced visibility (less than 1/4 mi), and strong winds (more than 30 kts)
Nor’easter
Mid-latitude cyclones that develop or intensify off the eastern seaboard of North America, then move along the coast; temp difference in warm air over the water and cold Arctic air over the land feeds the nor’easter
Post-tropical cyclones
can no longer be considered a tropical cyclone; carry heavy rains and high winds
Subtropical cyclone
form when a deep cold-core extratropical cyclone drops down into the subtropics; requires some central convection around a warm core but without fronts; wider wind fields with the max sustained winds located further from the center than typical tropical cyclones
Polar vortex
large area of low pressure and cold air surrounding both poles; always exists but strengthens in winter
Wind chill
the temp the air feels like to the human skin due to cold temps and wind
