TORNADOES Wizard of OZ Conditions for formation Heat Moisture Conditionally unstable environment Vertical wind shear

Tornadoes Local storms with violent winds that take the form of a rotating column of Air that extends from a cumulonimbus cloud. Form in association with severe T-storms Interaction between strong updrafts And winds in the troposphere MESOCYCLONE: precondition For intense tornadoes

Tornadoes Inflow and Outflow convergence rapidly increases into Updraft and Wall cloud

The first observable step in tornado formation is the slow, horizontal rotation (a) of a large segment of the cloud which begins deep within the cloud interior. The resulting large vortices are called mesocyclones. Under the right conditions, strong updrafts cause the horizontal vortex of air to be tilted upward (b).

Tornadoes 2 Ways for formation 1. Top-down process “dynamic pipe effect” Air beneath wall cloud is Stretched by the updrafts Within Stretched column of Air the flow is constricted Leading to a tighter vortex Continues until tornado touches the ground

Tornadoes 3 Ways for formation 2. Bottom-up process Vertical wind shear Causes a spinning effect In the lower atmosphere This spinning air is tilted in the vertical As it moves under the updrafts of the storm Near its base

Tornadoes Formation in a non-supercell storm These are generally weaker tornadoes AKA: landspout Short lived Occur ahead of the frontal boundary Occur in the NE quadrant of a hurricane Occur over water “waterspout”

Tornadoes STATS Diameter: ft Speed: 30mph Lifetime: 3mins. To 3 hours Intensity: Based on the Fujita Scale (“F-Scale”) Observed in EVERY state of the US Top nine states: Texas Oklahoma Nebraska Iowa Illinois Missouri Indiana Mississippi Florida

The Fujita Scale F0 gale tornado mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards. F1 moderate tornado mph Lower limit is the beginning of hurricane-force winds. Peels surface off roofs; mobile homes pushed over; moving autos pushed off roads. F2 significant tornado mph Roofs torn off frame houses; mobile homes demolished; boxcars pushed over, large trees snapped or uprooted; light-object missiles generated. F3 severe tornado mph Severe damage. Roofs and some walls torn off well- constructed homes; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown. F4 devastating tornado mph Well-constructed homes leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated. F5 incredible tornado mph Phenomenal damage. Strong frame homes disintegrate or lifted off foundations and carried considerable distance; trees debarked. Measuring A Tornado

Tornado Watch: possibility Tornado Warning: Sighting