A strong surface low pressure system crossed eastern Iowa Thursday afternoon with enough warmth and moisture to fire severe thunderstorms. NWS Davenport issued a Severe Thunderstorm Warning for an area just southwest of Cedar Rapids. It is certainly a bit rare to have such a warning during January in Iowa. The featured chart presents the period each year between the first and last Severe Thunderstorm Warning for Iowa with the number of events each day indicated by the red ticks within each bar. Four other years since 1986 have had such a warning during January with the most recent being during 2013. A simple average indicates that the average first date is around 7 March. The storms were helped by an anomalously moist air mass with dew point temperatures above 50°F, which is exceptional for January. Unofficial IEM archives indicated that a number of airport stations in southeastern Iowa were a few degrees from observed dew point temperature records for the month of January!

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