Let Discuss Flying in Scattered Thunderstorms

MBDiagMan

MBDiagMan

Final Approach
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Doc
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KOSA Mount Pleasant, Texa
Well, this is the time of year in Texas when so many days are forecast with scattered thunderstorms. Taking a 200 to 250 mile trip on one of these days has a large chance of one popping up in your path or near by. ADS-B weather lags by fifteen minutes or more and I understand that one can pop up in fifteen minutes.

I would like to hear what the experienced pilots have to say about how to watch for them and how to avoid them.
 
I either stay on top or below the average cloud layer so I can see the buildups or rain shafts and avoid them. I don’t do IMC with thunderstorms possibly building or around. I always have clean divert options available.

I flew into some embedded storms at 19 and that was enough for a lifetime for me.
 
In my area (great lakes) the pop-up afternoon thunderstorms are easy to see, and tend to be sporadic and contained. Yes, I've found ADS-B lags by at least 15 minutes, but it still can be useful, especially when you can compare it to what you are seeing out the windshield. I've found flying around them to be no problem, even in a slow Cherokee. I know I've heard differences of opinion about how far you should stay away, and I tend to push the limits a bit on that one depending on the strength of the storms...the pop-up summer stuff I've gotten 7-10 nm from no problem...I know some say 20nm, but I reserve that for the severe stuff myself. If you're new at it, 20 nm would be a good start.
Now imbedded storms? Fuhgeddaboudit!
 
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Flying home from rough River last month, stoners popped up. I left the plane in Arkansas and got an Uber to the nearest airport and flew commercial home.

Land and wait it out.
 
Radar Contact said:
I either stay on top or below the average cloud layer so I can see the buildups or rain shafts and avoid them. I don’t do IMC with thunderstorms possibly building or around. I always have clean divert options available.

I flew into some embedded storms at 19 and that was enough for a lifetime for me.
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I never got caught in embedded because there are two things I won't do: ICE and TSRA. If it's 30% or less coverage, I will generally launch. And there's been times where I have had to put it down and wait, also. 50% I am probably going to watch Netflix. I have a strike-finder which helps immensely if I am in IMC and the monsters are out there. Generally I will just get on top out of the crap and do my Floyd Mayweather impression. I will go under depending how high the bases are, but remember, this is unstable air, and that ride underneath can be fun. I should really get some O2 just so I can get up to 16 or 17 if need be.
 
As an inexperienced pilot, I see it as another component of risk management. If it’s scattered storms and clear above with a real good view of the shape / height / power of the thing and corroborates what radar/ADS-B says, then my “minimums” will be to fly closer. Never under the anvil (which could be 40+ miles ahead of the core sometimes - because they could throw hail or other nasties). I probably fly closer to the back end than the front end of the storms. If there are layers blocking my view of tops, and ATC can’t provide any added info, I’ll expand how far I deviate. I like ADS-B because even though it’s not live, it can tell me direction and speed a cell is moving, then just be conservative navigating around it. Again, verify with the eyeballs.

My preference is to get higher so that I may better plan my route around them. I don’t like not being able to see the storm / embedded stuff. I think some like to stay under and navigate via rain shafts. Makes sense, but I’ve never done that.

Being on an IFR plan is fine for occasional IMC, bet definitely be ready to ask for deviations. Don’t fly through embedded storms without onboard radar. Also, if you’re at 8k or 10k, you should start thinking twice about penetrating anything taller than you - lots of energy - lots of nastiness, like embedded storms which is no go.

Here’s a recent flight on an IFR plan where some ugly stuff popped up 100nm west of Waco/Temple right after take off. I was cleared direct but ended up on tons of deviations from Mineral Wells to Austin (It was actually two entire additional clearances). I was at 8k and my rule was if I pushed through a column, I had to be near the tops. I was VMC 90% of this trip.

20CFA309-08EE-4D2E-AC5F-6FFF86F5F03C.jpeg

Ask for help if you need it. If you don’t get it, land, connect to live radar / Wx and reassess. Always have an out.
 
EdFred said:
I never got caught in embedded because there are two things I won't do: ICE and TSRA. If it's 30% or less coverage, I will generally launch. And there's been times where I have had to put it down and wait, also. 50% I am probably going to watch Netflix. I have a strike-finder which helps immensely if I am in IMC and the monsters are out there. Generally I will just get on top out of the crap and do my Floyd Mayweather impression. I will go under depending how high the bases are, but remember, this is unstable air, and that ride underneath can be fun. I should really get some O2 just so I can get up to 16 or 17 if need be.
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I’m with you. I was 19 in a clapped out rental Seneca I 21 years ago. Would never have done that flight with an adult brain.

I bought an O2 system recently for just that reason.
 
SixPapaCharlie said:
I left the plane in Arkansas and got an Uber to the nearest airport
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Isn't it maybe a little bit too conservative to land somewhere other than an airport to wait out weather?

I've been looking at doing a long cross-country trip this weekend, about 1200 miles out and a bit more back due to a stop in Iowa. But there is an area of scattered thunderstorms forecast that roughly corresponds with the Reconstruction-era map of the USA. That seems like a lot of work to dodge.
 
So on a literal cross county once we put down due to thunderstorms that were popping up ahead on Foreflight and it was looking ugly. Since we landed at a strip with zero services or civilization near by we decide to make run for it to the next airport 15 miles away that at least had a hotel so we could wait it out of needed. Once we got in the air and saw what was ACTUALLY happening...it was "oh, we can dodge these" and proceeded on course dodging the storms on the outer line with being careful to always leave an out before there was even a chance of setting stuck. By using our actual eye balls saved getting stranded another day. Now embedded or scenarios where you do not have CLEAR visual on what is happening and all your escape options at all times...no way!
 
kaiser said:
As an inexperienced pilot ...
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It sounds like you have been lucky and from that have concluded that you are a thunderstorm genius. Remember that the goal for inexperienced pilots is to fill the bag of good judgment before the bag of luck is empty.
 
airdale said:
It sounds like you have been lucky and from that have concluded that you are a thunderstorm genius. Remember that the goal for inexperienced pilots is to fill the bag of good judgment before the bag of luck is empty.
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That seems a bit harsh...did he say something that wasn't right? How else do you "fill the bag of good judgment" without gradually testing the limits?
 
XM weather and now ADS-B wx have been a godsend overall but carry their own risks. They make it tempting to try to thread the needle, etc., which I will admit I’ve done to a minor degree in a past more recent than I want to admit.

The data for both lags at least 15 minutes, I assume. Animating the weather has been a big help for decision making: it gives a hint at what’s actively blooming, which way and how fast it’s moving, etc. Also, knowing if it’s associated with a cold front vs.something else has helped assess risks.

But to more specifically answer the OP, I work hard to stay on top of the deck so I can navigate more clearly around buildup that’s then more visible. I toyed with staying below but there be dragons: you can’t see where and how high the buildups are plus there’s a lot more outflow areas down there. Even in my lowly Cherokee I carry oxygen and, especially en route to OSH each summer, am frequently using it by afternoon to keep above the “deck” so I can steer around the buildups.

I also tend to route myself well behind the cells (typically going more west).

ATC has been nothing but awesome helping with all of this, including even offering routing suggestions before I’ve even recognized the risk. Sounds like they can only see yellow and above (which is where the greatest risk is), so their data is less complete than mine/ours.
 
Sometimes those storms build so fast that your outs disappear quickly. You may find about halfway through that big hole in the weather you found, you look back and it's closed up behind you. Flying in Florida during summers is tricky like that, leave a lot of time in your schedule to weave around weather or wait some out.
 
Just got back from my first California to the east coast and back VFR adventure. 3/4 of the flight was in these conditions and it sucked. Very hard to plan anything with certainty and the FAA briefings were pretty much useless in understanding the challenges I would face each day.

Living in CA all my life did not prepare me for this kind of weather flying. I found it very stressful.
 
tawood said:
That seems a bit harsh...did he say something that wasn't right?
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" ... my rule was if I pushed through a column, I had to be near the tops. ..."
tawood said:
How else do you "fill the bag of good judgment" without gradually testing the limits?
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IMO he will find out plenty enough about limits without deliberate testing. In airplanes exceeding a limit can get you killed. Better to learn about limits from others' experiences and, inevitably, testing some accidentally.
 
airdale said:
In airplanes exceeding a limit can get you killed. Better to learn about limits from others' experiences and, inevitably, testing some accidentally.
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I'm not referring to aircraft limits, but personal limits.
 
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Radar Contact said:
I either stay on top
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The problem I ran into last trip was thinking I could get over it in my little 180 horse Mooney. I ended up having to drop into some smaller clouds to get out of the mess. It was only moderate turbulence in IMC for a minute at most, but it scared the heck out of me. Headed to the coast where there was blue sky and flew the rest of the way home over the coast looking at the mess over land.

Definitely a learning experience for me. Don't try to get above Tstorms in Florida in the afternoon. Ever. They weren't really high yet, and it was early afternoon, so I thought we could make it. Nope. Ceilings were not that low, it would have sucked, but we could have gone underneath without issues.
 
Around here if you aren't willing to fly with a chance of thunderstorms you might as well sit the summer out. In flight radar is to be used strategically, i.e. if they're ahead how scattered are they? Back in the beforetime I'd land and check the FBO radar. These days I got it onboard. But I never every want to run afoul of one of those things. I think I must be doing something right, since I'm here 20 years later.
 
Way too many factors. How scattered are the thunderstorms, how far are the gaps between, how big are the thunderstorms, what are your diversion options, what kind of performance does your airplane have. Having flown a significant chunk of Texas every single week for the last 7-8 years, I've flown through some stuff I would warn students to stay away from.
 
steingar said:
Around here if you aren't willing to fly with a chance of thunderstorms you might as well sit the summer out. In flight radar is to be used strategically, i.e. if they're ahead how scattered are they? Back in the beforetime I'd land and check the FBO radar. These days I got it onboard. But I never every want to run afoul of one of those things. I think I must be doing something right, since I'm here 20 years later.
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You don't have on board RADAR you have something that's up to 15 minutes old being fed to you. And the nexrad you are being fed is precipitation. What's the life cycle of a thunderstorm again?
 
RyanShort1 said:
Way too many factors. How scattered are the thunderstorms, how far are the gaps between, how big are the thunderstorms, what are your diversion options, what kind of performance does your airplane have. Having flown a significant chunk of Texas every single week for the last 7-8 years, I've flown through some stuff I would warn students to stay away from.
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Agree...the pop-up sporadic stuff is one thing, while a significant front means landing before the front gets there and waiting it out (or making other plans).
 
EdFred said:
You don't have on board RADAR you have something that's up to 15 minutes old being fed to you. And the nexrad you are being fed is precipitation. What's the life cycle of a thunderstorm again?
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No different from what I had when I landed and checked the FBO radar. We've never had access to anything that current.
 
Lots of good advice here, personally, I stay out of the clouds if there are t storms nearby. I've found ATC very proactive so far in routing me around the bad stuff and very helpful when I question weather. On board satellite weather is great, but I don't trust it for steering around storms unless I can see those storms visually.

Flying down to Sun and Fun, there were a lot of T storms around. I was in NC, had successfully maneuvered around a bunch of good sized cells. Told ATC I was direct destination, about 100 miles away, about 5 minutes later, I noticed the sky ahead getting darker, so I asked for 15 left, around the dark sky. As I was passing that dark area, a wall of water started dumping out of the bottom of it. It had just started showing as light precip on the onboard satellite radar, took another 5 or 10 before it showed as red precip. I've fortunately had good instruction on weather. Be careful out there.
 
steingar said:
No different from what I had when I landed and checked the FBO radar. We've never had access to anything that current.
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You are right, just as useless as the FBO radar on the ground for dodging t-storms in your airplane real time. Be careful out there Steingar.
 
PaulS said:
Lots of good advice here, personally, I stay out of the clouds if there are t storms nearby. I've found ATC very proactive so far in routing me around the bad stuff and very helpful when I question weather. On board satellite weather is great, but I don't trust it for steering around storms unless I can see those storms visually.

Flying down to Sun and Fun, there were a lot of T storms around. I was in NC, had successfully maneuvered around a bunch of good sized cells. Told ATC I was direct destination, about 100 miles away, about 5 minutes later, I noticed the sky ahead getting darker, so I asked for 15 left, around the dark sky. As I was passing that dark area, a wall of water started dumping out of the bottom of it. It had just started showing as light precip on the onboard satellite radar, took another 5 or 10 before it showed as red precip. I've fortunately had good instruction on weather. Be careful out there.
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Yeah, when I see the TCU's pushing through FL250 and ATC says they show nothing....RADAR doesn't mean anything.
 
EdFred said:
Yeah, when I see the TCU's pushing through FL250 and ATC says they show nothing....RADAR doesn't mean anything.
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I remember my instrument training, we were on the long x country and my instructor pointed out a large cumulus cloud about 20 away, that was maybe 15 thousand feet tall and obviously building. He said, don't ever fly into a cloud like that. We were at 9,000 feet and I thought to myself "that doesn't look that bad", a few seconds later I realized another valuable lesson learned.
 
Separate "pop-up" activity from frontal storms. If it's a typical day in FL or the South East you'll never fly in the summer if you have 0 tolerance. Pop-ups, stay below cloudbase and look for and avoid the rainshafts. Don't go into IMC unless you have on-board radar.
Frontal storms - an organized line of storms moving quickly across the the ground - land or don't take off in the first place.
 
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Learned my lesson when I was 12 in the back seat of a Comanche following a King Air who we were getting a pirep from. "We've been on better rides at Great America"...we eventually did a 180.
 
Hang 4 said:
Separate "pop-up" activity from frontal storms. If it's a typical day in FL or the South East you'll never fly in the summer if you have 0 tolerance. Pop-ups, stay below cloud base and look for and avoid the rain-shafts. Don't go into IMC unless you have on-board radar.
Frontal storms - an organized line of storms moving quickly across the the ground - land or don't take off in the first place.
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This is by far the best advice on this thread.
Tony T.
Central FL based since my PP in '86.
 
overdrive148 said:
Sounds like it's story time :popcorn:
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Here’s the short version…

Not a great ADM story. As I said, I was 19 (naive) and a current DAL captain and I were building twin time for the airlines (back then you needed 200 hours to be considered for interview at the regionals). We decided to rent a Seneca I and fly down to Key West from ATL area. Around the GA/FL line we were at 110 trying to stay above and work around storms. Ended up in a gap that was closing and they were growing so fast it felt like we were falling while level. Turned out and tried to fly around. Way over the Atlantic we realized we’d never get around it. Came back down low to avoid rain shafts but there were bad forest fires and couldn’t see so we landed at TPA and got dinner/called off Key West.

Then flew to Tallahassee to get fuel and check the weather. This was no GPS/ForeFlight/etc. Weather looked like we could make it to Auburn, AL and then land to wait/check again for the flight into ATL area.

My leg left seat and as we narrowed in on Auburn the storms started back building. While IFR at night we flew into embedded storms on the VOR-A approach (ILS was OTS). The plane was shaking so bad I could barely make out the instruments. The lighting flashes were so bright it was temporarily blinding. On the approach the right engine started rolling back. Still power but not much…turned out it was a partial blockage in the fuel line that was changed prior to our flight. At mins nothing. Seneca I hard decisions were being discussed and all the sudden the beacon hit his peripheral and he said I got it. He turned it over and we landed. Taxied to the ramp, got out in the torrential rain and kissed the ground. Slept in the plane and vowed NEVER again. 21 years later and still flying GA and avoiding TS at all cost.

Long I know but for sure the cliff notes version. :)
 
Radar Contact said:
I either stay on top or below the average cloud layer so I can see the buildups or rain shafts and avoid them. I don’t do IMC with thunderstorms possibly building or around. I always have clean divert options available...
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No need to type and answer, when Chicago Approach already typed it for me.

Also, Steingar's observation above is salient - you have to accept the possibility of pop-up storms, but in the summer, there will usually be plenty of options to avoid the storms visually and safely. Better (typically in Texas) early than later in the day.

I need to get my Strikefinder fixed - very potent tool and very instantaneous.
 
MBDiagMan said:
Well, this is the time of year in Texas when so many days are forecast with scattered thunderstorms. Taking a 200 to 250 mile trip on one of these days has a large chance of one popping up in your path or near by. ADS-B weather lags by fifteen minutes or more and I understand that one can pop up in fifteen minutes.

I would like to hear what the experienced pilots have to say about how to watch for them and how to avoid them.
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  1. Stay in VMC if at all possible. If underneath an overcast, avoid the rain shafts. If above an undercast, avoid anything climbing up through it (even if it looks like just a little bump up ahead), because it will build up fast.
  2. Avoid fronts with any storm activity. It will probably form into a solid line, even if it hasn't done so yet.
  3. Hills and ridges will make storm activity worse downwind. Large bodies of cool water (like the Great Lakes) will sometimes calm them down a bit (but don't count on it).
  4. Divert early. The sooner you change your flight path, the less extra distance you'll have to fly.
  5. Give anything on your satellite weather radar a wide berth. An afternoon storm can pop up faster than the 10–20 minute lag in ADS-B or SiriusXM.
  6. If you don't have at least 40 nm gap between storms, turn around and land somewhere to wait it out. Threading the needle is a fool's game. Storms are more fun to watch through FBO windows, with a hot drink in your hand.
  7. If you have a Stormscope, use it. It gives you instant feedback, and lightning is a good early warning sign (it will be inside the cloud first, and not visible during the day, but the Stormscope can still detect it). If I had to choose between satellite radar imagery and a Stormscope, I'd pick the Stormscope (though both together are far better, obviously).
  8. Make sure you're on the Centre frequency with flight following. ATC might not necessarily be able to give you convective alerts, but you'll be able to hear where everyone else is asking for diversions.
  9. Be ready to hold for up to an hour outside your destination if there's a risk of a storm over the airport. Carry a bigger fuel reserve than normal.
With all that in mind, go ahead and have a great flight. Afternoon summer storms are a fact of life in much of North America, and if we didn't fly when there was a risk of isolated storms, we'd be grounded for half the summer. Flexibility (willingness to change your plans in the middle of the flight) is the biggest survival skill.
 
Flying in Florida in the summer, every trip is a slalom course weaving between cells. As Hang 4 said, stay below the bases and look for rain. And fly in the morning. Usually takes until 2 or 3 pm for cells to develop.

ADS-B data lags a bit, but cells don't develop or move that fast. You can usually look at the NEXRAD and correlate it directly to what you see in front of you. Animation is of course a big help to see which way they are going. Sometimes reception with my Stratux is an issue and I get incomplete data. When that happens, I land every hour and refresh from a cell tower.

But mostly, fly in the morning.
 
David Megginson said:
  1. Stay in VMC if at all possible. If underneath an overcast, avoid the rain shafts. If above an undercast, avoid anything climbing up through it (even if it looks like just a little bump up ahead), because it will build up fast.
  2. Avoid fronts with any storm activity. It will probably form into a solid line, even if it hasn't done so yet.
  3. Hills and ridges will make storm activity worse downwind. Large bodies of cool water (like the Great Lakes) will sometimes calm them down a bit (but don't count on it)
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#3 reminded me of flying back from Oshkosh in 2019. Heading east over W VA, there was a line of rain showers over the mountains. Found a gap in the rain and flew through. The storm was barely moving, but was a solid N-S wall for quite a ways. Was an interesting day, watching the clouds grow as the day warmed up. I was above scattered clouds, but as things warmed up, the clouds rose up above the ceiling of my 172 and had to duck under. Went from smooth sailing to a bumpy ride.
 
One more tip: if near the ocean, understand the storm-generating function of the onshore breeze, and how those storm cells move in your area once they form.
 
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