The Tomorrow.io REST Weather API thunderstorms insight category will trigger for any of the events below.
Severe Thunderstorm (Watch/Warning)
Issued when severe thunderstorms are possible in and near the watch area, in cases where the following criteria are met:
(1) winds of 58 mph or higher
(2) hail 1 inch in diameter or larger
Near Severe Thunderstorms (Statement)
Issued when severe thunderstorms are possible in and near the watch area, in cases where the following criteria are met:
(1) winds of 40-58 mph
(2) hail less than 1 inch in diameter
Significant Weather (Advisory)
Issued when the winds are 40+ mph (35 kts) and hail 1/2 inch or greater and/or frequent/continuous lightning.