A TAF remark for the operating area includes 'WS010/23045KT' while the surface wind is reported as 180 at 8 knots. A remote pilot is planning to climb a small UA through 1,000 feet AGL during departure. What does this information indicate, and why is it significant?
- AThe UA will experience a smooth, gradual increase in headwind with no directional change up to 1,000 feet
- BWind will be calm below 1,000 feet, so no shear hazard exists during climb
- CA layer of low-level wind shear exists, with winds shifting to 230° at 45 knots at 1,000 feet AGL, creating a rapid change in speed and direction during climb-out
- DThis is a routine METAR remark indicating visibility restrictions, not a wind hazard
Show answer & explanationAnswer & explanation
Correct answer: C. A layer of low-level wind shear exists, with winds shifting to 230° at 45 knots at 1,000 feet AGL, creating a rapid change in speed and direction during climb-out
The coded group 'WS010/23045KT' is a low-level wind shear (LLWS) forecast indicating that at 1,000 feet AGL the wind will be from 230° at 45 knots. Comparing this to the surface wind of 180° at 8 knots reveals a difference of about 37 knots in speed and 50° in direction over just 1,000 feet, a significant shear that can cause abrupt performance changes and loss of control for a small UA transitioning through that layer.
Why the other options are wrong
- A. The change involves both a large speed increase and a 50° direction shift, not a smooth gradual increase.
- B. The shear group specifically forecasts strong wind at 1,000 feet, so significant shear—not calm air—exists in that layer.
- D. WS### groups specifically denote wind shear layers, not visibility remarks.
Low-Level Wind Shear (LLWS)
A rapid change in wind speed and/or direction over a short vertical or horizontal distance near the surface, often noted in TAFs as 'WS(height)/(wind)'.
- Coded as WS### where ### is height in hundreds of feet AGL
- Followed by wind direction and speed at that height
- Common near frontal boundaries, inversions, and thunderstorms
- Extremely hazardous during takeoff and climb/descent transitions
Memory trick: 'WS010/23045KT' = 'Watch Shear at 1,000, 230 at 45' — big change, big danger.