Records continue to fall across much of the U.S., as the
extraordinary March heat wave rolls onward. The warm weather, with
daytime high temperatures close to 40°F above average in some places,
set the stage for severe thunderstorms that spawned rare, damaging March tornadoes near Detroit.
The warm weather is the result of a weather pattern that has become
stuck in place, known as a “blocking pattern,” with a stubborn,
sprawling area of high pressure in the eastern U.S. that is pumping warm
air northward into the Great Plaines, Midwest, Ohio Valley and
Northeast. The West, on the other hand, is cool and stormy, with
mountain snows and valley rains associated with a big dip or “trough” in
the jet stream. As this trough slides slowly east, it may set the stage
for an outbreak of tornadoes in the Plains late this weekend, as the
cool air collides with the warm and more humid air that lies to the
east.
