What is the difference between a tornado and a hurricane?

Both tornadoes and hurricanes are characterized by extremely strong horizontal winds that swirl around their center and by a ring of strong upward motion surrounding downward motion in their center. In both tornadoes and hurricanes, the tangential wind speed far exceeds the speed of radial inflow or of vertical motion.

Hurricanes always and tornadoes usually rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. The Earth's rotation determines this direction for the storms' rotation in each hemisphere. Local winds are sometimes able to cause a tornado to form that spins in the opposite direction from the typical direction for that hemisphere.

The most obvious difference between a tornado and hurricane is that a hurricane's horizontal scale is about a thousand times larger than a tornado. In addition, hurricanes and tornadoes form under different circumstances and have different impacts on the atmosphere.

Tornadoes are small-scale circulations, that are rarely more than a few hundred feet across when they touch the ground. Most tornadoes grow out of severe thunderstorms that develop in the high wind-shear environment of the United States Central Plains during spring and early summer.  Many tornadoes form when the large-scale wind flow leads to a violent clash between moist, warm air traveling north from the Gulf of Mexico and cold, dry, continental air coming from the United States Northwest. Tornadoes can also form in many other locations and from other forcing factors. For example, a hurricane making landfall may trigger many tornadoes to form.

Tornado wind speeds may reach 100 to 300 mph and cause havoc on the ground, but tornadoes typically last only a few minutes and rarely travel more than 10 or 20 miles along the ground. Tornadoes have little impact on storms that spawn them or collectively on the global circulation of the atmosphere.

Hurricanes, on the other hand, are large-scale circulations that are 60 to over 1,000 miles across. Hurricanes form near the Equator, generally between 5 and 20 degrees latitude, but never right on the Equator. Hurricanes always form over the warm waters of the tropical oceans and generally where the sea-surface temperature exceeds 26.5°C (76°F).

A hurricane may travel thousands of miles and persist over several days or weeks. During its lifetime, a hurricane will transport a significant amount of heat up from the ocean surface and into the upper troposphere or even lower stratosphere. Even though hurricanes form only sporadically, they do affect the global atmosphere's circulation in measurable ways, although this is still an active area of research.

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2002

IMERG Measures Historic Rainfall With A Nor'easter and Joaquin

NASA's Integrated Multi-satellitE Retrievals for GPM (IMERG) data were used to estimate the historic amount of rain that fell during the past week in the Carolinas. A "fire hose" of moisture has been pumped into the Carolinas from hurricane Joaquin resulting in wide spread flooding. Over two feet of rain have been reported in South Carolina. This analysis indicated that major hurricane Joaquin also dropped over 700 mm (27.5 inches) in the Bahamas. Hurricane Joaquin has weakened from a category four hurricane in the Bahamas to a category one hurricane affecting Bermuda. Click here to see a

Joaquin Becomes a Hurricane, Could Impact the US East Coast

Joaquin, which became a tropical storm Monday evening (EDT) midway between the Bahamas and Bermuda, has now formed into a hurricane, the 3rd of the season--the difference is Joaqin could impact the US East Coast. GPM captured this image of Joaquin late yesterday afternoon at 21:39 UTC (5:39 pm EDT) on the 29th of September as Joaquin was moving very slowly towards the west-southwest about 400 miles east of the northwestern Bahamas. This first image shows rain rates derived from GPM's GMI microwave imager (outer swath) and DPR space-borne precipitation radar (inner swath) overlaid on IR data

Typhoon Dujuan Batters and Drenches Taiwan

Typhoon Dujuan formed in the western Pacific Ocean northwest of Guam on September 21, 2015. Dujuan intensified to a super typhoon with winds of 125 kts (144 mph) on September 27, 2015 as it approached Taiwan. The island of Taiwan experienced extreme rainfall and damaging winds with the passage of typhoon Dujuan. The typhoon also caused hundreds of injuries and at least three deaths in Taiwan. After pounding Taiwan the typhoon started weakening before hitting China. Dujuan dropped light to moderate rainfall over a large area of coastal China while dissipating. A preliminary analysis of Rainfall

Tropical Storm Joaquin forms in the Western Atlantic

Tropical Storm Joaquin became the 10th named storm of the season after forming late last night (EDT) in the western Atlantic midway between the Bahamas and Bermuda from what was previously a tropical depression (#11), which itself had formed a day earlier from an area of low pressure that had been lingering in the region since Saturday. GPM captured this image of Joaquin early this morning at 8:16 UTC (4:16 am EDT) on the 29th of September as the storm was slowly drifting westward about 390 miles east of the northern Bahamas. The image shows rain rates derived from the GPM GMI (outer swath)

Tropical Storm Marty Tries to Strengthen South of Mexico

Tropical Storm Marty, which formed into an depression from an area of low pressure about 300 miles southwest of Acapulco, Mexico Saturday afternoon (local time), has been trying to strengthen while drifting slowly northward toward the southwest coast of Mexico. This first image was captured by NASA's GPM core satellite at 00:11 UTC 27 September (7:11 pm CDT 26 September) just a few hours after Marty had formed into a tropical depression. GPM shows substantial areas of rain on the eastern half of the storm, but more importantly, there is already evidence of curvature and banding within those