'Extreme Avoidance' Thunderstorm Avoidance Guidelines
* When the temperature at flight level is 0 degrees Celsius or higher (? 32? F), avoid all echoes (on the weather radar) by 5 nautical miles.
* When the temperature at flight level is less than 0 degrees Celsius (? 32? F), avoid all echoes by 10 nautical miles.
* Avoid all echoes by 20 nautical miles if the aircraft clears the tops (of the thunderclouds, as shown on the radar) by less than 5,000 feet. All weather with radar tops above 15,000 feet may be hazardous.
* All weather with radar tops above 20,000 feet is hazardous.
* When flying above 23,000 feet, avoid all echoes by 20 nautical miles.
* Never fly near an echo with a radar top above 30,000 feet.
* If possible circumnavigate echoes by flying on the up wind side.
* Circumnavigate all echoes with steep or asymmetrical gradients.
* Assume that all magenta radar returns are severe thunderstorms.
* NEVER assume that ATC (Air Traffic Control) will provide warning of hazardous weather. (Emphasis in original)
* NEVER assume that a PIREP (Pilot Report) will provide warning of hazardous weather.
* NEVER continue flight toward a radar shadow.
* Note: Although a general or severe thunderstorm may have a well defined base, hazards often exist from the ground to the base of the convective cell, even in VMC (Visual Meteorological Conditions).
Source: Southwest Airlines, Flight Operations Manual, Weather Procedures, reproduced with permission.
http://findarticles.com/p/articles/m...15/ai_73578136
I cannot give you a good answer on number 2
3. AKA Popcorn storms.
the tend to form at least in the midwest during late june, july and august.
what happens here is it gets hot and humid from rains, then it gets sunny and heats the ground and all the fields up, and then at night when corn is growing well strong and fast and is resperating quite a bit of moisture back into the air, and you can see this with low laying fog in the valleys, and then the sun comes up and heats the land up again, and then the becomes the lifting action for the moisture with the rising air. This cycle goes on for a few days untill a cold front passes through and starts the process all over again.
Airmass storm can get really bad, but most of the time they are just a quick light show and some rain. They most of the time just do not move very far and their life cycle is short.
One thing to notice with a long cycle of air mass, if there is any slight prevailing breeze when they build and and rain, you will see them form just a few miles in the direction of the previous days wind, because that is where the ground is the wettest.
the most often form from 3ish to 5ish in the afternoon, and pretty will fissled out by dusk. That just because they form and get ripping in the hottest part of the day, and when the sun goes down so does the source of lift. It is like it is almost artifical thunderstorms.
They are almost always in clear air, and not embedded. So they are easy to avoid. Sometimes around dusk and you got a few stronger ones still going they can embed in the clouds of the ones that have already died out earlier in the eveing.
Also with airmass thuderstorms, when one strom dies, the downdrafts of the dying storm can force moisture up and form a new storm, you just have to watch for more storms to form on the outflow boundries of the current storm.
Just watch it on radar and you will get the pattern of what is going on.
It is a great source of storm chasing here in Indiana. At least here they are rarley tornadic, and almost never get hail larger than pea size.
No thunderstorm is safe, but some leave you with better odds
Also, some can build high enough and become supercell storms, and every once in a great while you will find a group build high enough to find some upper level supprt to get their life longer, and those are the once you have to watch out for, but you can see it when you see a nice round top come poking out of the anvil. you just have to be careful and observe. Just look at the clouds, and they can tell you everything the beast is doing or about to do.
If you have more questions feel free to ask
Reeves
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