Air pressure is usually measured in millibars or in inches of this metal
Its life cycle usually has 5 stages: dust-whirl, organizing, mature, shrinking & decaying
As seen in Los Angeles, a thermal inversion of warm air covering cool air can cause a buildup of this
In 1995, 11 tropical storms in the Atlantic strengthened to these, the most in one year since 1969
In the winter of 1997, the Great Lakes' lake effect dumped over 90" of this on Montague, New York
This phenomenon begins with an invisible electric discharge called a stepped leader
In early 1997 floodwaters trapped 2,200 visitors in this California national park
(Here's Al Roker with the clue) This type of low-pressure area provides the title for chapter 1 of "The Wizard of Oz"
James Whitcomb Riley wrote of the time when this "is on the punkin", & he didn't mean a fellow poet
The Pacific Northwest is the setting for David Guterson's novel "Snow Falling on" these