IEM Daily Feature
Tuesday, 28 March 2017

Wind and Hail Tags

Posted: 28 Mar 2017 05:33 AM


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0.5inch and 50mph thresholds are typically for forecasted values less than those levels.
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This is Severe Weather Awareness Week in Iowa, which features a different aspect of severe weather each day. On Monday, the focus was Severe Thunderstorms and the primary product the National Weather Service issues to alert of these storms is the Severe Thunderstorm Warning. These warnings contain tags identifying the magnitude of threats associated with the storm. The featured chart looks at the combination of wind speed and hail size tags included in warnings issued by forecast offices with Iowa coverage. The most common combination is of one inch hail and 60 MPH winds, which are the minimum thresholds for severe storms (strictly speaking, only one of the two is necessary and the wind threshold is 58 MPH). Thankfully for us, the frequencies of storms predicted to have giant hail and/or hurricane force winds (75+ mph) are rather small. One of the reasons these tags exist are to provide the NWS with an additional information point to alert the public to when these extreme severe thunderstorm events are predicted.

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Tags:   warnings