National Weather Service Weather Forecast Offices (WFO) in the upper Midwest will issue Extreme Cold Warnings on an experimental basis from January 10, 2011 through April 15, 2011. The experimental Extreme Cold Warning will be issued for South Dakota and northeastern Wyoming when air temperatures are 35 degrees below zero or colder but winds are calm. Wind Chill Warnings and Advisories will still be issued when wind contributes to the dangerous conditions.
Extreme Cold Warnings will be issued as Non-Precipitation Weather (NPW) products and will use the EC.W Valid Time Event Code (VTEC).
A Product Description Document (PDD) provides additional information about this product. Comments may be submitted via an online survey. Upon the completion of this experimental period and the close of the comment period, the NWS will evaluate comments to determine whether to proceed with national implementation of the Extreme Cold Warning. Other comments or questions may be directed to the Rapid City National Weather Service.