Dear Tom,
A friend who lives near Glasgow, Mont., tells an unbelievable weather story. He claims, once upon a time, the temperature in Glasgow shot up into the 90s in the middle of the night. Nineties at night? Maybe in Las Vegas, but in Montana?
–Ron Smithson
Dear Ron,
Believe him; it occurred Sept. 9, 1994, in Glasgow. It was an odd atmospheric event known as a “heat burst” that occurs near thunderstorms. Thunderstorms usually produce cooling gusts of rain-chilled wind, but on rare occasions a parcel of dry air is pushed from an altitude of 20,000 or 30,000 feet down to the surface, warming by compression all the way down. On that Sept. 9 day, Glasgow’s temperature at 5:02 a.m. was 67 degrees. A thunderstorm heat burst shot the reading to 93 degrees at 5:17 a.m., but by 5:40 a.m. it cooled off to 68 degrees.
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