A local region of clearing skies or reduced cloud cover, indicating an intrusion of drier air; often seen as a bright area with higher cloud bases on the west or southwest side of a wall cloud. A clear slot is believed to be a visual indication of a rear flank downdraft.
CLEAR SLOT
Meaning of CLEAR SLOT in English
Weather and meteorology English vocabulary. Английский словарь погоды и метеорологии . 2012