PROPOGATION IS DEPENDENT ON
- OUTFLOW
- EVAPORATIONAL COOLING RELATED TO THE ENVIRONMENTAL HUMIDITY
- GUST FRONT SPEED RELATED TO TEMPERATURE DEFICIT BETWEEN OUTFLOW AND AIR AROUND IT.
- HON-HYDROSTATIC PRESSURE GRADIENTS
- INTERACTION OF UPDRAFT WITH ENVIRONMENTAL WIND
- WHERE THE STRONGEST LOW-LEVEL CONVERGENCE, MOISTURE AND INSTABILITY IS LOCATED
- STORM RELATIVE WINDS
- DETERMINES WHERE LOW LEVEL CONVERGENCE WILL BE LOCATED.