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Proposed Severe Thunderstorm Warning Categories for Impact-Based Warnings
Approved for Experimental Implementation
Data Mining Tool
Outreach / Education
All Forecast Regions
The National Weather Service (NWS) is collecting comments on the proposed additions of Impact-Based Warning (IBW) damage threat categories in Severe Thunderstorm Warnings (SVR). The proposed changes are similar to the current operational format for Tornado Warnings (TOR), with the IBW coded damage threat tags. These coded threat tags appear below the double ampersand (&&) in the supplemental information portion of the alphanumeric/text product. The proposed IBW coded tag, called the Thunderstorm Damage Threat, mirrors the Tornado Damage Threat IBW coded tag in TORs in terms of displaying one of two possible damage threat categories. For SVRs, the two new proposed IBW category terms are “considerable” and “destructive”, each with a set minimum criteria that will trigger their appearance in the new IBW coded threat tag line. The criteria to trigger these categories is based on selections of thunderstorm wind and/or hail selections. This is being done now in SVRs, as these amounts appear and will continue to appear in the IBW coded tag section, such as HAIL...1.00IN, for one-inch hail. The IBW format became operational nationwide for NWS Tornado, Severe Thunderstorm Warnings, and associated Severe Weather Statements, on February 5, 2018. The IBW format for the warning products displays key information about the characteristics of threat(s) in the warning in a more visually-accessible manner, as well as the addition of machine-readable tags to compliment this same key information in the message body product. These proposed changes will allow the NWS to identify and alert for higher tiers of threat levels to the public, emergency managers, and the media within warnings, further highlighting the associated impacts and protective actions already denoted in the warning message.
Product information and survey access
Point of Contact
Gregory Schoor firstname.lastname@example.org
Document (e.g. PDD)
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Comment Start Date:
0000-00-00 Comment End Date: 0000-00-00
Last edit date to this meta-data: 2020-07-01