They can be caused by a combination of unstable air, solar heating, orographic lifting and an atmospheric trigger that lifts moist air parcels into areas of instability, amplifying buoyancy and propelling a building cumulus cloud to ever greater heights.
Absent orographic lifting as the mass of air moves upslope, air mass thunderstorms are driven by solar heating, so the driving mechanism shuts off at the end of each day.
had the potential to cause heavy rainfall as this flow reached the Coast Ranges.
Large water drops can also be chucked into the atmosphere by the energy of a thunderstorm or orographic lifting
The maximum reduction in rainfall amount is registered over the mountains and foothills and is associated with the reduction in orographic lifting
and the associated vertical water vapor flux.
produces regions of LWC accumulation on the windward slope.
In the world of meteorology, that is called orographic lifting
As winds force air up a mountain, in a process known as orographic lifting
, water vapor in the air condenses to form clouds, and further lifting "squeezes out" the rain.
Although orographic lifting
was a key process contributing to heavy rainfall, the southeast-to-northwest swath of heaviest rainfall (see Fig.
Although the layers had that breaking-up-after-a-storm look, it was cold enough and there was enough orographic lifting
to make what appeared to be benign clouds unflyable in an unprotected airplane.
has been widely proposed as the causative mechanism (e.g., Rotunno and Ferretti 2001; Bousquet and Smull 2006).
What's more likely is the flight encountered an area of turbulence--probably the result of localized orographic lifting
. But--and especially since Cherokees are tough little airplanes--why the pilot either lost control or the turbulence broke the airplane before he could react are mysteries.