Early Sunday morning, the Des Moines NWS Office issued a few tornado warnings during the 3 and 4 AM hour. The featured chart looks at the frequency of issuing tornado warnings by the office by hour of the day. As one may suspect, tornado warnings are rather rare at that hour, but the overall minimum is a bit later in the morning. The vast majority of warnings are issued in the late afternoon and evening hours as strong thunderstorms need the heating of the sun to drive instability in the atmosphere. You can generate this plot online and you may wish to compare this plot with one from a gulf coast forecast office, like Mobile.

Voting:
Good = 13
Bad = 6
Abstain = 1

Tags:   tornado