NASA has posted low and high resolution satellite photos of the record-setting low-pressure system that rolled through the Midwest last week. They say:
The storm that swept across the center of the United States on October 26 and October 27, 2010, was memorable to those who experienced it because of its strong winds, rain, hail, and widespread tornadoes. Meteorologists get excited about the storm because it set a record for the lowest pressure (not associated with a hurricane) measured over land in the continental United States. At 5:13 p.m. CDT, the weather station in Bigfork, Minnesota recorded 955.2 millibars (28.21 inches of pressure). Pressure is one indicator of a storm’s strength, and this measurement corresponds to the pressure seen in a Category 3 hurricane.
You can read the full story and see the images here.