Tornadoes form when unstable air in a thunderstorm creates a horizontal rotation in the clouds and strong downdrafts draw that vortex down to the ground. Overlapping fronts can trigger the wind shear necessary to initiate a tornado's rotation, which is why meteorologists issue watches whenever severe thunderstorms threaten. Tornadoes can form with very little notice and are particularly unpredictable and dangerous weather events.Know More
When weather fronts clash, sometimes warm and cool air layers overlap at the boundaries. This can create strong updrafts and downdrafts, unpredictable winds that carry moisture and warm air into the various layers of the atmosphere. The temperature differences between these layers help trigger air movement, setting up the horizontal rotation high in a storm that can transform itself into a tornado.
Often, the only warning of a tornado is a sudden increase in wind shear. Meteorologists use Doppler radar systems to detect this wind shear, looking for particular signatures that can indicate the beginning of a tornado. The most common sign of a tornado's formation is a "hook echo," a spiral-shaped radar return that indicates clouds being wrapped around a vortex. In many cases, the National Weather Service announces a tornado warning based on one of these echoes before anyone has visually spotted the tornado.Learn more in Storms
The only significant similarity between tornadoes and hurricanes is that they both produce high-speed winds. Tornadoes form as the result of lingering strong vertical wind velocity and vertical temperature changes. Hurricanes form as the result of extended periods of weak vertical wind velocity and relatively low changes in atmospheric temperature.Full Answer >
Hurricanes form when rising warm, moist air displaces colder air high in the atmosphere. The cold air drops down on all sides of the warm spot, swirling slightly as it falls, then becomes warm and moist itself, repeating the process. Over time, the swirling grows into a hurricane.Full Answer >
According to the National Oceanographic and Atmospheric Administration, tornadoes form when warm air creates a rotating updraft in a powerful thunderstorm. When winds blow in sharply different directions or at different speeds in these storms, they can set up a rotation that feeds on itself, creating a condition called a mesocyclone. When this construct rotates and touches the ground, it becomes a tornado.Full Answer >
A thunderstorm is a storm with heavy rainfall accompanied by wind, thunder and lightning. These storms occur when air that is moist and close to the ground heats up and rises to form cumulonimbus clouds that produce precipitation. Electrical charges develop near the bottom of the clouds, resulting in lightning discharges.Full Answer >