Wind shear

A sudden change in wind speed or direction over a short distance, horizontally or vertically. It can rapidly change an aircraft’s airspeed and lift, and is most dangerous close to the ground during takeoff and on approach.

Typical causes are thunderstorms and microbursts, fronts, temperature inversions, and terrain or buildings near the runway. Pilots report it on the radio, e.g. “wind shear on final, loss of 15 knots”, and METARs can carry it as WS. Met close to the ground, the answer is full power and a go-around.