By Sara E. Pratt, NASA Earth Observatory
December 17, 2021

December 15– 16, 2021

Hurricane-force winds, dust storms, twisters, wildfires, snow squalls, heavy rain, and record-breaking heat accompanied an uncommon December storm system.

An anomalous and historical December derecho– a windstorm related to an uncommonly strong and fast-moving line of thunderstorms– swept from the U.S. Southwest to the Upper Midwest on December 15,2021 High-wind cautions were released from the Central and Southern High Plains to the Great Lakes, consisting of storm cautions over the Great Lakes.

The storm brought hurricane-force winds, dust storms, twisters, wildfires, snow squalls, and heavy rain throughout the middle of the nation. Numerous countless houses and companies lost electrical power, and approximately 100 million Americans were under some kind of weather condition caution that day.

The animation above reveals the advancement of the storm front and wind field in between 6 p.m. Central Time on December 14 (midnight UTC, December 15) and 3 a.m. CT (9: 00 UTC) on December16 The greatest winds appear intense yellow to white; more moderate winds (still gale-force) are tones of orange and brilliant purple. (35 meters per 2nd equates to approximately 80 miles per hour.) Climatic information were gone through the Goddard Earth Observing System Model-5 ( GEOS-5), an information assimilation design that researchers at NASA utilize to evaluate worldwide weather condition phenomena. The GEOS design consumes wind information from more than 30 sources, consisting of ships, buoys, radiosondes, dropsondes, airplane, and satellites. The model output is spaced out on a 0.25 to 0.3 degree grid, so it does not always record peak gusts and extremes as determined by specific instruments on the surface area.

The natural-color image listed below was gotten around 2 p.m. CT (20: 00 UTC) on December 15 by the Visible Infrared Imaging Radiometer Suite ( VIIRS) on the NOAA-20 spacecraft.

VIIRS December 2021 Annotated

December 15, 2021

The derecho was generated by the interaction of a deep-low pressure system over the Northern High Plains and a high-pressure system to the west. This developed a tight pressure gradient over the Rocky Mountains that produced intense winds. The storm produced a minimum of 55 hurricane-force gusts (those going beyond 75 miles per hour), breaking the previous one-day record (given that tracking started in 2004). All previous records were set throughout the summertime.

In Colorado, wind gusts went beyond 100 miles (160 kilometers) per hour and dust storms swirled in the southeastern part of the state and in western Kansas. Snow and shower, together with a minimum of 20 twisters, were reported along the squall line.

Meanwhile, ahead of the front, parts of the Southern Plains into the Upper Midwest saw record-breaking warm temperature levels. In Wisconsin and Iowa, temperature levels reached above 70 degrees Fahrenheit(21 ° Celsius). The heat and the high winds likewise triggered severe fire weather condition cautions for parts of the Central and Southern Plains, as wildfires broke out in Kansas, Texas, and Oklahoma.

NASA Earth Observatory images by Joshua Stevens, utilizing VIIRS information from NASA EOSDIS LANCE, GIBS/Worldview, and the Joint Polar Satellite System ( JPSS), and GEOS-5 information from the Global Modeling and Assimilation Office at NASA GSFC.


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