How to know if ride will be smooth or bumpy?

RyanB

RyanB

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When i take first time flyers i like to try and predict a pretty smooth day for a ride. I usually look at surface charts, and winds aloft for around 3000' since its closest to what i would fly for a joy ride around town. Obviously i look at surface winds, but sometimes i notice it may not be too windy on the ground, but up at altitude it is. What is the best way to know? Right now winds aloft at 3000' here are showing about 34021. But surface chart isobars and very widespread and not even any over my area. Also from winds aloft how do you know if its a smooth 21kts or bumpy? If one can even predict that?
Thanks Ryan.
 
If there is a large velocity change between the different reporting levels for the wind, it will be bumpy. Think of a stream flowing rapidly into a calm pond and the eddies that are generated in the pond on either side of the flowing water. Now stand that picture up on its side. The eddies become vertical and represent what is happening between wind streams at different altitudes (wind shear).
 
Wind flowing over terrain, fair weather cumulus, and wind shear at altitude are all signs of bumpiness. The skew-Ts will show stability. Rucsoundings.noaa.gov. You can check the lifted index at ADDS, but it's at a much higher altitude and isn't really intended for light turbulence.
 
Sometimes those beautiful sunny days aren't the day to take new folks for a ride. Thermals.

Although less appealing, a light wind day with high overcast will likely be a nice smooth day.
 
So at 3000' it shows 2423 and 6000' shows 2734+5. Is that a large enough spread to create bumpy air around 2500' to 3000'?
 
Bill Jennings said:
Sometimes those beautiful sunny days aren't the day to take new folks for a ride. Thermals.

Although less appealing, a light wind day with high overcast will likely be a nice smooth day.
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I agree, i do find those are some of the best days.
 
Look for AIRMETs and PIREPs. Also remember that crystal clear days are not always smooth and days with an flat stratus overcast layer can be very smooth.
 
Ryanb said:
So at 3000' it shows 2423 and 6000' shows 2734+5. Is that a large enough spread to create bumpy air around 2500' to 3000'?
Click to expand...

I wouldn't sweat it, but it really depends on the stability. I've seen smooth 45 knot winds at 3000, when it was calm on the ground. Terrain shadowing really sucked that day.

Winds aloft is not really a very useful tool, as the stations are much too far apart. I've seen differences of more than 20 knots on several occasions.
 
Ryanb said:
So at 3000' it shows 2423 and 6000' shows 2734+5. Is that a large enough spread to create bumpy air around 2500' to 3000'?
Click to expand...

Today? If you look, we have an airmet tango just to the east of us surface to 8000. This large area is over the mountains mainly, so expect mechanical turb over any hilly features. It appears that one corner of the tango is right over our area.

I'd not take a newbie up today, it's likely to be rough.
 
Ryanb said:
When i take first time flyers i like to try and predict a pretty smooth day for a ride. I usually look at surface charts, and winds aloft for around 3000' since its closest to what i would fly for a joy ride around town. Obviously i look at surface winds, but sometimes i notice it may not be too windy on the ground, but up at altitude it is. What is the best way to know? Right now winds aloft at 3000' here are showing about 34021. But surface chart isobars and very widespread and not even any over my area. Also from winds aloft how do you know if its a smooth 21kts or bumpy? If one can even predict that?
Thanks Ryan.
Click to expand...

Look at winds aloft the same way you are looking as isobars, only in the vertical. The bigger the change per distance (tightly packed isobars with a big spread in values) the more turbulence you will have. Near the edges of 'streams' is where it's worst. Wind sheers, always turbulent there, so look at direction change interfaces.

That is not the only factor involved though, there are different kinds of turbulence. Even on no wind days you can still get convective turbulence from solar heating.
 
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A small plane flying relatively low to the ground is nearly always going to have a few bumps during the flight... that's just part of the experience in flying a small plane. If the passenger is the type that freaks out at the slightest movement or bump then flying in a GA aircraft is likely not for them.

Regarding anything more than minor bumps:

1) Rapid changes in direction and windspeed between altitudes will cause bumps

2) Any changes on the ground elevation below you (e.g., some rolling hills can cause bumps in the same way pebbles on the bottom of a stream cause ripples in the water

3) Any changes in the type of surface below you, especially on a hot sunny day. For example, if you fly a landing approach and cross a large paved parking lot on a hot sunny day there will be some hot thermals coming up off the parking lot.

4) Any sort of wake from other airplanes can leave bumps behind, especially on a calm day when the wind doesn't blow the wake away quickly. If you've ever executed a perfect steep turn maneuver you'll feel the 'thud-thud' on the wings as you fly back through your own wake.

Cool cloudy days with calm winds often have the smoothest flying (at least in the Northeast). I'd always just make sure too with passengers that haven't flown in a GA aircraft before to expect a bit more movement. If that's going to freak them out then best we get that out of the way on the ground.
 
Bill Jennings said:
It appears that one corner of the tango is right over our area.
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Yup, ChooChoo VOR is one corner of the tango.

WAUS42 KKCI 191445
MIAT WA 191445
AIRMET TANGO UPDT 2 FOR TURB VALID UNTIL 192100
AIRMET TURB...NC SC GA ME NH VT MA RI CT NY LO NJ PA OH WV MD DC
DE VA AND CSTL WTRS
FROM YSC TO 40S BGR TO 20SE ACK TO 40SE SIE TO 40E RIC TO 60SSW
RDU TO 30NW IRQ TO 50SE LGC TO GQO TO HMV TO HNN TO 50W SYR TO
MSS TO YSC
MOD TURB BLW 080. CONDS CONTG BYD 21Z THRU 03Z.
 
Ryanb said:
So at 3000' it shows 2423 and 6000' shows 2734+5. Is that a large enough spread to create bumpy air around 2500' to 3000'?
Click to expand...

That's about what it was reading yesterday in the Tulsa, OK area. 30-40kts at 3K'. It ended up being accurate as I was cruising in the 172 @ 75% power, seeing 155kts on the 430 at one point. It was a little choppy but not terrible, and I did have two "first-timers" in the aircraft with me. The little girl was just fine, my older friend was a bit more antsy, but he doesn't like flying that much in airliners much less a 172. The thing that tends to cause more issues isn't the bumpiness at altitude, it's the gusts and wind shifts when you get to pattern altitude and below where terrain starts playing with wind direction.
 
As you know the soundings for winds aloft begin at 3,000 agl. What has been proposed is either you make a prior flight for a look see or that you look to the FD for shear. But blo 3,000 how do you really know?

Inquiring to recent arrivals or departures is one way. Another is, believe it or not, the prog chart. This chart is not simply for large regional weather patterns. With a deeper understanding one can know what to expect for their area. Also, by watching the flow develop over consecutive days they can make a more educated estimate.
 
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Bill Jennings said:
Yup, ChooChoo VOR is one corner of the tango.

WAUS42 KKCI 191445
MIAT WA 191445
AIRMET TANGO UPDT 2 FOR TURB VALID UNTIL 192100
AIRMET TURB...NC SC GA ME NH VT MA RI CT NY LO NJ PA OH WV MD DC
DE VA AND CSTL WTRS
FROM YSC TO 40S BGR TO 20SE ACK TO 40SE SIE TO 40E RIC TO 60SSW
RDU TO 30NW IRQ TO 50SE LGC TO GQO TO HMV TO HNN TO 50W SYR TO
MSS TO YSC
MOD TURB BLW 080. CONDS CONTG BYD 21Z THRU 03Z.
Click to expand...

Just looked at that, that will alter my plans, thanks bill!
 
Predicting turbulence is a regional thing. A hot Oklahoma afternoon would be an unknown for me. Where I live there are mountains in every direction. A simple 25kt wind may be benign or it may indicate a bumpy ride. It all depends on the direction. It may be calm in Anchorage and blowing 40 ten minutes out. That's common. The difference between a southeast, northwest, or north wind is big.
 
jordane93 said:
Look for AIRMETs and PIREPs. Also remember that crystal clear days are not always smooth and days with an flat stratus overcast layer can be very smooth.
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Good answer jordane93. One of the bumpiest flights I had was from Chicago to Knoxville. Broken cumulus cloud layer, hot summer day. Convective turbulence below clouds, flying above the broken layer was very smooth. In Alaska were I fly stay away from leeward side of mountains if possible. Flying over water, down the channels is much less turbulent than flying over land masses. Local terrain has a lot to do with the type of turbulence you encounter.
 
Yesterday at KSAR Sparta IL. 10G22 at ground level and at 3000 the ground speed was 145 mph, air speed at 85. Smooth ride in Ercoupe, which is not noted for being bounce resistant.

Certainly surprised me. I had a single bounce when crossing bluffs into Mississippi flood plain, as expected. The climb out had some turbulence but ended at 2000 ft AGL.

So, the flow must have been continuous through several levels? Makes sense.
 
Go to aviationweather.gov and click on G-airmets. Then go down on the page and unclick the ones you don't want. They display it graphically. Turb lo is the one you want to pay attention to.
 
Easy, for just a short local flight, stick your head out the door, generally when it's windy = bumpy, calm = smooth except on a warm summer afternoon.
Take your passengers out on a morning before the noon time bumps or in the evening before sunset.
 
Flew today from Wilgrove (8a6) to Kirk air base (t73) and yeah, it was bumpy but we stayed low, 2500 there and back. Probably the 'queasiest' I've been in a while but not a big deal.
 
eman1200 said:
Flew today from Wilgrove (8a6) to Kirk air base (t73) and yeah, it was bumpy but we stayed low, 2500 there and back. Probably the 'queasiest' I've been in a while but not a big deal.
Click to expand...

Must have been rough all around the southeast today, texted a CFI a few hours before i was going to fly and he said it was ugly. Decided to postpone, hopefully another day this week.
 
The best time that i love to fly is right at dusk, calm air + sunset, gives an amazing time to fly.
 
mtl035.jpg
 
eman1200 said:
Flew today from Wilgrove (8a6) to Kirk air base (t73) and yeah, it was bumpy but we stayed low, 2500 there and back. Probably the 'queasiest' I've been in a while but not a big deal.
Click to expand...

Similar experience yesterday in Central Florida ..flew from Ocala (OCF)down to Bartow (BOW) had a weather brief for some moderate turbulence but it certainly felt more than what I consider moderate at times ! Tried climbing tried decending to get the best ride...found it worked out best pretty low down at 2300. The bumpy ride continued for around 50 miles, Had to keep a close eye on airspeed too, glanced down once to see it climbing into the Amber range, reduced power and slight nose up trim to keep it down in the green !
My wife is a good px but I could sense from the lack of conversation she wasn't a very happy rider....
 
This ( http://aviationweather.gov/gairmet ) and Pireps are prob. your best friend here, But.. There have been many times where they forecast turbulence and it has been smooth air and days they had no airmets and it shook me up.

So far I have noticed this trend. If its really windy out... bumpy. If its severe clear, likely its going to be bumpy. If its hot and there are cumulus clouds.... bumpy.

Many times you can climb above the bumps though. It easier to predict bumpy than smooth I think. I never can pick a perfect day for a passenger.
 
Changes in terrain can add some chop to the ride. Here in Arkansas, if you follow the Arkansas river valley, the ride is usually pretty much what you would expect based on winds. However, those same winds get lifted vertically by the mole hills we call the Ozarks (pretty, but not mountains by any stretch). The result - it can get bumpy. Solution - climb!
 
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