A thunderstorm which contains winds of 35 to 49 knots (40 to 57 mph), or hail 1/2 inch or larger but less than 3/4 inch in diameter. See severe thunderstorm.
APPROACHING (SEVERE LEVELS)
Meaning of APPROACHING (SEVERE LEVELS) in English
Weather and meteorology English vocabulary. Английский словарь погоды и метеорологии . 2012