Cold Air Funnels

The slow-moving, upper-air disturbance that churned its way across the country last week didn't just bring drought-busting rain to our state; it also spun off numerous cold air funnels. I wouldn't say these tornado-looking wannabes are rare for Oklahoma, but they do require certain atmospheric conditions to occur as frequently as they did last Wednesday.

Unlike most Tornadoes, which are associated most often with supercell thunderstorms, cold air funnels develop in a shallow, cool, moist air mass. This air mass is typically established behind a cold frontal passage, or directly underneath a cut-off (removed from the Jet Stream) low pressure system like we had last week. The air aloft in these types of environments is much colder than the air near the surface. The colder air, along with weak directional wind shear, sparks the rotation that spins up the funnel.

Cold air funnels are usually weak and short-lived. Cold air funnels rarely make contact with the ground, but they may touch down briefly and become weak tornadoes.