Thunderstorms have been difficult to come by these past number of weeks as dry air has dominated. There is a decent chance of such storms on Tuesday with some of them maybe even severe. With a chance of severe storms, it is a good time to check in on Storm Prediction Center (SPC) issued watches for the year. The featured chart presents year to date metrics for each year since 1997. The top panel is the total number of watches over the contiguous US. The middle panel is the number of watches whose watch polygon overlapped Iowa and the bottom panel shows the same value expressed as a percentage. Roughly one in ten watches touch Iowa and that percentage has not changed much over the period of record shown on this plot. One may wonder why the overall number of watches appears to have decreased over the years. An initial guess is it is due to increased collaboration on issuance, which tends to make the watches larger in space and time. Additionally, NWS offices can now expand watches in space when necessary, which likely has cut down on followup / small watches to cover downstream activity.

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Bad = 1