About VTEC Event Tracking
The National Weather Service uses a system called Valid Time Event Code (VTEC) to provide more accurate tracking of its watch, warning, and advisories. The IEM attempts to provide a high fidelity database of these products.
The following table shows the largest VTEC eventids (ETN) for each NWS Forecast Office, each phenomena, and significance for the given year. Pro-tip: Use the search functionality to filter by a specific WFO.
Year Selection
JSON API
This data is available via our JSON Webservice:
Max VTEC ETN Listing for 2025
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