Refer to figure.
WINDSHEAR

Windshear is a sudden, drastic shift in wind speed and/or direction that occurs over a short distance at any altitude in a vertical or horizontal plane. It can subject your airplane to sudden updrafts, downdrafts or extreme horizontal wind components, causing loss of lift or violent changes in vertical speeds or altitudes.

It can be associated with:

• convective precipitation
• gust fronts
• jet stream
• frontal zone
• strong low-level temperature inversion (when cold, still surface air is covered by warmer air that contains winds of 25 knots or more at 2000 to 4000 ft above the surface.

A gust front is a line of dangerously gusty winds. When a Cumulonimbus cloud/thunderstorm begins to rain, cooler air descends to the surface. That cool air and rain create something called a downdraft. When that cool air descends and hits the ground, it spreads out in all directions (like when you pour a column of water on the floor) => This air can be moving fast, so this spreading out can create a gust front. This is a line of sometimes dangerously gusty winds. It’s also called an outflow boundary.