What are pulse type thunderstorms?

Question

What are pulse type thunderstorms?

Answer 1

It's a short-lived intense thunderstorm.  It's a 'pulse' storm because it happens very quickly and dies out very quickly.

When there are weak winds in a moist, strongly unstable environment, the air is able to 'overturn' very quickly.  By that I mean that a thunderstorm normally results in making the air more stable.  Once it has acheived that, the t-storm generally dies off.  When there is light wind, this can happen more quickly.  

Moisture for a t-storm is very important.  Moisture of course is what enables the rain, but moisture also aids in the instability.  Moist air at a certain temperature is less dense than dry air at the same temperature, so tends to rise more readily.  In a pulse-storm, the thunderstorm only works with the moisture it had underneath it at the time of initiation.  It doesn't draw additional moisture from the surroundings which could help keep it going.  So it's just a quick burst of convection when the temperature reaches a critical level close to the surface.  That air rises quickly, forms a t-storm with whatever moisture was basically underneath it, and then is choked off very quickly after that.

Answer 2

Single Cell Thunderstorms also known as pulse thunderstorms typically do not produce severe weather and usually last for 20-30 minutes. Also known as pulse storms, single cell storms seem quite random (perhaps because of our lack of understanding) in the production of brief severe events such as downbursts, hail, some heavy rainfall, and occasional weak tornadoes.