Past IEM Features tagged: bombogenesis
The featured chart presents an IEM computed analysis of the surface low minimum pressure from Monday afternoon thru Tuesday. The low pressure center developed in Kansas and then rapidly intensified as it moved to the north and east into Minnesota. The values shown set various records for all time lowest pressure and may go down as the most powerful continental storm system in US History (as measured by pressure). The rapid intensification met the 'bombogenesis' criteria, which is an informal term that describes 'explosive' storm development by having its surface low center's pressure drop by 24+ mb in 24 hours. The primary impact of this storm on Iowa continues to be the strong winds which will continue today. Many parts of Eastern US felt this storms impact in the form of severe winds and tornados.
The featured plot presents the 24 hour difference in observed altimeter (atmospheric pressure) for the upper mid west. Values lower than 24 mb (bombogenesis criteria is 24+ mb drop in 24 hours) are highlighted. If you measure storm strength by the minimum pressure observed, this storm may go down as the most powerful storm on record in October and the strongest storm in 70 years. The altimeter reading at Des Moines 28.94 inches around 1 AM this morning. A value below 29 has only happened four times since 1977 for Des Moines.
Update: It was pointed out that bombogenesis refers to the center of the low pressure system dropping at the 24mb/24hr rate, looking at individual station data is not sufficient.