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.