IJ411 turbulence forecast
IJ · Tokyo (HND) to Sapporo (CTS)
Next departure at its usual time · Sat 7 Nov, 04:35 Tokyo time
This date's schedule isn't confirmed yet. This is the air IJ411 flies through if it leaves at its usual time.
Bumpy in places. The belt sign may come on for a while. Airliners are designed for much stronger turbulence than this.
- Bumpiest stretch
- Moderate
- Flight time
- 1h 35m
- Distance
- 820 km
- Cruise altitude
- 33,000 ft
- Weather models
- 3 blended
- Model agreement
- Medium
- Aircraft
- Airbus A321
Bumpiness along the flight
Takeoff on the left, landing on the right. The higher the line, the bumpier the air the forecast expects at that moment.
Where, and why
The flight split into stretches: how bumpy each is forecast to be, and what causes it.
HND · Take off0m – 14mLight
Jet-stream wind shear
Where fast air slides over slower air, usually at the edge of the jet stream, the boundary ripples like a flag. It's the most common kind of turbulence, and it's on the crew's charts before departure. When they meet it, they slow to a set turbulence speed and ride it out.
The first minutes are flown through the lowest, liveliest air. Sun-warmed ground sends up thermals and wind bends around hills, so a bump or two while climbing is normal. It fades as the aircraft climbs into the smoother air above.
Cruise14m – 52mModerate
Jet-stream wind shear
Where fast air slides over slower air, usually at the edge of the jet stream, the boundary ripples like a flag. It's the most common kind of turbulence, and it's on the crew's charts before departure. When they meet it, they slow to a set turbulence speed and ride it out.
At cruise the air is thin and cold, and most of it is calm. The bumps up here come from the jet stream, a band of fast wind whose edges stir the air, or from waves set off by mountains far below. This forecast shows where those edges are.
Cruise52m – 1hLight
Jet-stream wind shear
Where fast air slides over slower air, usually at the edge of the jet stream, the boundary ripples like a flag. It's the most common kind of turbulence, and it's on the crew's charts before departure. When they meet it, they slow to a set turbulence speed and ride it out.
At cruise the air is thin and cold, and most of it is calm. The bumps up here come from the jet stream, a band of fast wind whose edges stir the air, or from waves set off by mountains far below. This forecast shows where those edges are.
Cruise1h – 1h 12mModerate
Mountain waves
Wind blowing over a mountain range makes waves in the air downstream, the way water ripples over rocks in a stream, and those waves can reach cruising height. They are forecast from the same wind and terrain data used here, so the crew knows where they are before departure.
At cruise the air is thin and cold, and most of it is calm. The bumps up here come from the jet stream, a band of fast wind whose edges stir the air, or from waves set off by mountains far below. This forecast shows where those edges are.
Descent into Sapporo1h 12m – 1h 35mLight
Mountain waves
Wind blowing over a mountain range makes waves in the air downstream, the way water ripples over rocks in a stream, and those waves can reach cruising height. They are forecast from the same wind and terrain data used here, so the crew knows where they are before departure.
Coming down means flying back through the low, lively air near the ground: afternoon thermals, gusts around the airport. It is the busiest part of the flight for the crew, and the part they train for most.
Thunderstorms near the route
Between 12m and 54m into the flight the forecast has a few thunderstorms, some on the planned line itself.
The ride line can stay calm with storms nearby. It follows the planned track at cruise height, above most storm tops. Pilots don't fly through storms: the weather radar in the nose shows each one, and the rule is to stay at least 20 nautical miles (about 37 km) away. Usually that means a detour of a few minutes.
The closest of these is within the 20 nm the crew has to keep, so expect a small turn around it. The line on the map is the planned route; the real track will bend around the storm.
This forecast changes. FlyBud tells you when.
A new weather model run lands every few hours. Add IJ411 in FlyBud and you get the full turbulence map along your route, a push when the forecast for your flight changes, live tracking and your flight on the lock screen.
The aircraft
What IJ411 is flown with, and how it handles bumpy air.
Airbus A321
Bigger and heavier aircraft are moved less by the same patch of air, and every airliner is designed for much stronger turbulence than it will meet.
The airline
IJ
IJ operates IJ411.
The route
Tokyo (HND) → Sapporo (CTS)
- Distance
- 820 km
- Flight time
- 1h 35m
- Usual departure
- 04:35 local
- Usual arrival
- 06:10 local
What each level feels like
- Smooth
- Calm air. Nothing to notice beyond the hum of the engines.
- Light
- Gentle ripples and the odd dip. Drinks stay put, and walking to the toilet is fine.
- Moderate
- Clear bumps. Drinks may slosh and the belt sign comes on. Uncomfortable, but the pilots stay in full control.
- Severe
- Strong jolts, and loose items can move. This is rare, and it's why the belt sign exists. Crews slow down and change altitude to get out of it.
How this forecast is made
The planned route is sampled from gate to gate at the altitude the aircraft flies, through 3 independent global weather models, and corrected with turbulence reports radioed in by pilots in the last few hours. Each new model run replaces the forecast; nothing here is a guess from the airline's history.
The weather models behind this forecast mostly agree; the bumpy patches may shift a little.
Planned route · timing and conditions may change.
Why turbulence isn't dangerous
Aircraft are designed for much worse.
Airliners are tested to loads well beyond anything turbulence produces. The wings are meant to flex, so seeing them move is normal.
Crews know where it is.
Your crew has forecasts like this one, live reports from other pilots and their own weather radar, and they change altitude to stay out of bumpy air.
Keep your belt on.
Almost all turbulence injuries happen to people who are standing or not buckled in. Seated with your belt on, turbulence is uncomfortable but not dangerous.
Questions about IJ411
Will IJ411 be bumpy?
For the flight on Sat 7 Nov: Bumpy in places. The belt sign may come on for a while. Airliners are designed for much stronger turbulence than this. The forecast is replaced with every new weather model run, so check back closer to departure.
How long is IJ411?
About 1h 35m gate to gate from Tokyo to Sapporo, a distance of about 820 km.
What time does IJ411 leave?
IJ411 usually departs Tokyo at 04:35 local time and arrives in Sapporo at 06:10 local time. Times change; the app tracks the live schedule.
Is turbulence dangerous on IJ411?
Turbulence is uncomfortable, not dangerous to the aircraft. Airliners are certified for loads far beyond anything turbulence produces, and crews plan around the bumpy patches with the same kind of forecast as this one. Injuries are almost always to people who were standing or unbuckled, so keep your seatbelt fastened whenever you're seated.
How accurate is this turbulence forecast?
It is a forecast, so it is best within a day or so of departure and improves with every model run. The bumpy patches it finds are usually in the right place, but their timing can shift by a few minutes and the crew may change altitude to avoid them, so the ride you get is often smoother than the forecast.
Fly IJ411 knowing what's ahead
The turbulence forecast for your exact flight, live tracking, delay alerts and arrival weather. Built for people who'd rather know.