<< Trough-type Cyclone | Guide to Baroclinic Disturbances | Longwave Lows >>
Upper Level Cyclonic Systems
Hybrid-type Storms
“Hybrid-type” storms are so called because they combine the progressive nature of a trough with the energy and abundant upper dynamics associated with closed 500MB lows. There may or may not be a closed contour in the upper level height display. But the extent of these systems is always synoptic-scale, with precipitation and cloud arrays covering a wide geographic area that at some point can cover most of the U.S. as well as portions of Canada and Mexico.
A hybrid disturbance can produce astounding amounts of severe weather, as evidenced by such events as the Nov 15 1989 (see graphic below), April 3 1974, and April 11 1965 outbreaks. Frozen precipitation tends to occur over a lesser time frame, given the tendency for linear advection of vorticity at the upper levels. The hallmark of these storms is the well-defined satellite signature of the cold front associated with the low.
Content on this page is Copyright 2008 by Larry Cosgrove
All rights reserved.
What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value.
