calm before the storm

scit106

scit106

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scit106
Twice in the past month or so I have been flying and a thunderstorm popped up somewhere (relatively) near me - at least near enough that I could see lighting. Both of these times though, before I went flying, I noted the air was really still and the winds were very calm/ non existant. The flights also proceeded very smoothly, hardly a single bump. This confuses me because thunderstorms are supposed to be mean and nasty and have lots of wind and rough air instead of this eerie stillness... maybe I wasn't close enough to feel the bumps? is there some sort of buffer zone thing where the weather is still there? am I just going crazy? Can someone please explain this phenomena?
 
scit106 said:
Twice in the past month or so I have been flying and a thunderstorm popped up somewhere (relatively) near me - at least near enough that I could see lighting. Both of these times though, before I went flying, I noted the air was really still and the winds were very calm/ non existant. The flights also proceeded very smoothly, hardly a single bump. This confuses me because thunderstorms are supposed to be mean and nasty and have lots of wind and rough air instead of this eerie stillness... maybe I wasn't close enough to feel the bumps? is there some sort of buffer zone thing where the weather is still there? am I just going crazy? Can someone please explain this phenomena?
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Scott,
Scott D or Rudy will hopefully pipe in and correct me where I'm wrong, but the popup thunderstorms we can get in the midwest can be extremely localized phenomena. If there's a good wind aloft and the cells are high (>FL400?) then there's a real danger of hail being blown downwind significant distances. Generally, though, that type of thunderstorm isn't going to be a popup; it'll be with a whole lot of others in an organized system. Ask any of the folks in FL. They fly with popups all the time and just avoid them. You DO need to be sure to avoid them, though, because you don't want to be in ANY thunderstorm, not even a little one!


That said, when you say the thunderstorm is quite near based on the fact that you can see lightning, do you have a good sense of how far that really is? I know from experience that lightning at night is visible from well over 100 miles, and quite impressive, at that. Obviously it's a shorter distance during the day, but you don't have to be only five miles away to see it. That's important, because an isolated thunderstorm is largely a vertical event. Much of the motion is up and down, and the lateral portion is from either winds aloft drifting detritus or the downward motion striking the ground and being pushed along.

Now, those who know a lot more about weather than I do please pipe in and correct any of my errors!:yes:
 
gprellwitz said:
Scott,
Scott D or Rudy will hopefully pipe in and correct me where I'm wrong, but the popup thunderstorms we can get in the midwest can be extremely localized phenomena. If there's a good wind aloft and the cells are high (>FL400?) then there's a real danger of hail being blown downwind significant distances. Generally, though, that type of thunderstorm isn't going to be a popup; it'll be with a whole lot of others in an organized system. Ask any of the folks in FL. They fly with popups all the time and just avoid them. You DO need to be sure to avoid them, though, because you don't want to be in ANY thunderstorm, not even a little one!


That said, when you say the thunderstorm is quite near based on the fact that you can see lightning, do you have a good sense of how far that really is? I know from experience that lightning at night is visible from well over 100 miles, and quite impressive, at that. Obviously it's a shorter distance during the day, but you don't have to be only five miles away to see it. That's important, because an isolated thunderstorm is largely a vertical event. Much of the motion is up and down, and the lateral portion is from either winds aloft drifting detritus or the downward motion striking the ground and being pushed along.

Now, those who know a lot more about weather than I do please pipe in and correct any of my errors!:yes:
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Yes to all of the above.

I'd like to add that all that air feeding the thunderstorm has to come from some place. So all that uplift (ie turbulent) air is getting funneled up into this 35-50k foot monster.

Guess what's filling in the resultant vacuum?

Right -- colder air from aloft.

Since cold air being drawn down from aloft is stable, it's not very turbulent.
 
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interesting... that stable air gives me this really strange feeling like... this weather is too nice...

and keep in mind i only have 150 hours, and haven't dealt much with t-storms before, so "close" is relative. probably talking something like 30 miles.
 
Well, in an interesting twist, we had a TS come through the field today. It was nice, with winds about 5 - 10 kts from the south. Then in the span of about 1 - 3 minutes, the winds shifted to the north at 15G20, at a guess. The leaves and stuff on the ground were being blown along at a pretty good clip, where they'd been laying still a couple moments before. This all happened with a plane in the pattern, of course. So his nice planned headwind landing turned into a helacious tailwind one and we all rushed out to see if he'd perform a successful go-around. It was truly scary there for a couple of moments! Within about five minutes the rain started. We had received a call from a nearby (LL10, 4nm NW) field about 5 minutes before this event that they had received a similar wind reversal and gusting winds.
 
Especially at night, it's amazing just how calm the air can be 20 NM from a major TS. I was flying along side a long line of severe to extreme TS (tops in FL500s) for over an hour recently in Oklahoma. There wasn't a single bump along the way, but also nothing but lightening off our right windows for the entire time. It's pretty spooky....and then of course ATC comes on and casually asks "umm N123, have you had any time to think about those TS and your routing?" :)

All of the above is correct, though.

-Felix
 
sba55 said:
Especially at night, it's amazing just how calm the air can be 20 NM from a major TS. I was flying along side a long line of severe to extreme TS (tops in FL500s) for over an hour recently in Oklahoma. There wasn't a single bump along the way, but also nothing but lightening off our right windows for the entire time. It's pretty spooky....and then of course ATC comes on and casually asks "umm N123, have you had any time to think about those TS and your routing?" :)

All of the above is correct, though.

-Felix
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I have proof. Heres the link to the pictures I took of the lightning:

http://www.flickr.com/photos/hpnflygirl/2574622830/
 
Most of the time in the midwest, you are looking at some type of system pushing through. Winds can be calm or strong ahead of the front/trough depending on the pressure gradient. If you have a front/trough producing lift 30 miles away, winds will most likely be calm until the front approaches. In Grant's description it sounds like frontal passage, due to the south winds switching to North Gusty winds. Here is a diagram showing how the winds work around a frontal system.
The cold air being pushed down creates the lift for the thunderstorm as it pushes the moist warmer air up.



Best,
 

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Those thunderstorms came in in a hurry today.
With regards to lightning, lightning is pretty complicated. Once, I did the same thing as you.
In the summer of 1992, we were trying to beat the weather into Cushing Field in Newark, Illinois. We departed Lewis Lockport and headed west. We saw some spindly, wimpy lightning near the field. We went in and landed without the slightest bump. The hanger bums gave us some looks as we taxied in. But there was no windshear or turbulence.
I have seen some freight dogs land at Dupage in some wicked thunderstorms. I did not think that it was wise.
But, even though I did it and got away with it, I don't think you should aviate near lightning, if you can avoid it.
Reading the summary in Flying magazine, the Scott Crossfield story deserves some serious contemplation.:blueplane:
ApacheBob
 
qbynewbie said:
I couldn't find any pictures of lightning.

I found lots of pictures of guys :rofl: but no lightning. Perhaps I was looking in the wrong place???
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What???? You didn't see the pictures of me and Kim????? It's not all guys. ;)
 
Diana said:
What???? You didn't see the pictures of me and Kim????? It's not all guys. ;)
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You quoted me before I could delete it! :eek::D

(I didn't want to embarrass Brooke. :p)
 
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