The past week saw several unusual weather events, including a heat burst in south-central Nebraska and a derecho across the central United States.
From my reporter's notebook:
• The amount of warming during the heat burst was about 15 to 20 degrees, said Rick Chermok, meteorologist with the National Weather Service.
The phenomenon is known as compression heating, which occurs when air warms as it descends.
Data gathered from weather balloon launches indicated that temperatures increased about 15 to 20 degrees over a drop of 2,000 feet, Chermok said.
In some areas of Nebraska, temperatures went from the upper 70s to nearly 100 degrees at daybreak.
In Lincoln, the temperature rose from 73 to 94 degrees and back down to 82 within an hour, Chermok said.
• The derecho occurred the next day, Wednesday, from northeast Iowa to the Atlantic Coast. It's when fast-moving, straight-line winds travel on the ground for at least 240 miles.
Here's a map of the derecho's path: https://twitter.com/NWSSPC/status/345664990495256576/photo/1
Source: National Weather Service, Storm Prediction Center