GEOL 1030 Lecture Notes - Lecture 8: Vertical Draft, Ice Crystals, Lightning
Document Summary
Air temperature decreases upward from the surface at about 6 /km. Rising warm, moist air begins condensation release of latent heat of vaporization provides energy for severe weather by building cloud tops higher. Mostly occur in areas near moist, warm bodies of water. Need moist, warm air to be produced. Requires a continuous supply of rising warm, moist air to keep updraft and cloud mass growing. Ice crystals and water drops become too heavy for updraft to support upper-level precipitation. Falling rain causes downdrafts pulls in cooler, drier air. Updrafts and downdrafts blow side by side create gusty winds, heavy rain, thunder and lightning, and hail. Downdrafts draw in so much cool, dry air that updrafts necessary to fuel the thunderstorm are depleted. When two air masses collide and form a front, then begin to rotate. Northern hemisphere: counterclockwise air mass rotating at low-pressure core.
