Daily Storm Based Warning Summaries
This application displays an image summary of NWS Storm Based Warnings for a given UTC date (0z to 0z). This summary is based on an archive the IEM maintains and so is unofficial. Also, prior to 1 October 2007, these warnings were not official and their shapes may or may not have been considered by the issuing forecaster. This page works for dates between 1 Jan 2002 and 10 Dec 2024. Areas are computed and polygons shown using a US National Atlas Equal Area projection (EPSG:9311).
Related Data Links:
You can download a GIS dataset with these polygons via the
GIS WWA Download. For convenience,
here is a direct shapefile link with the polygons
you see below. The summary size statistics page
provides an overview of the size of these polygons. The actual image below
was generated by Autoplot #203.
Image Legend:
Red text indicates less than 25% reduction in size
Green text indicates greater than 75% reduction in size