SPC Watches (Severe Thunderstorm + Tornado)

Severe-thunderstorm and tornado watch boxes covering specified areas and times. Watch boxes unioned from the per-county WWA segments — category, onset and expiry, issuing office and VTEC event number — together with the 7 WWP probabilities (2+ tornadoes, EF2+ tornado, 10+ severe wind events, 65kt+ wind, 10+ severe hail events, 2in+ hail, and 6+ combined events). Every probability carries a bound qualifier, so a scale floor such as "<02%" is never published as though it were a measurement; we also store max tops in feet MSL, storm motion, and — when the SPC publishes it — the "particularly dangerous situation" qualifier. Map overlay + ground-stop guidance for affected airports.