Hiding under a freeway overpass will protect me from a tornado. Bellwork 4/29 “Two Truths & A Lie” (Identify the lie) Tornadoes may occur in the middle of the night and even during the winter. Tornadoes have picked people and items up, carried them some distance and then set them down without injury or damage Hiding under a freeway overpass will protect me from a tornado.

Severe weather types Tornadoes Local storm of short duration Features Rotating column of air that extends down from a cumulonimbus cloud Low pressures inside causes the air to rush into the center Can have more than one vortex

Severe weather types Tornadoes Occurrence and development Most frequent from April through June Exact mechanism of tornadoes formation is not known Basic observations show us: 1. Strong winds create horizontal rotation 2. Updrafts (associated with thunderstorm) force the rotation in a vertical position 3. Mesocyclone created & MIGHT touch down on the ground

Only about HALF of the mesocyclones formed become tornadoes!

How a Tornado Forms

Severe weather types Conditions for the formation of tornadoes Occur most often along a cold front During the spring months Associated with huge thunderstorms called supercells Cold cP air mixing with warm mT air Larger the difference, larger the storm

Severe weather types Tornadoes Characteristics Diameter between 150 and 600 meters (500 and 2000 feet) Speed across landscape is about 45 kilometers (30 miles) per hour Cut about a 10 km (6 miles) long path Most move toward the northeast Maximum winds range beyond 500 kilometers (310 miles) per hour For Comparison: Category 5 Hurricane = 150mph winds

How do we track a tornado? Doppler Radar VORTEX2 projects TOTO…(didn’t work)…Twister instrument was modeled after this

Measuring a Tornado Can only be measured AFTER a tornado has passed Intensity measured by the Enhanced Fujita intensity scale Can only be measured AFTER a tornado has passed

Severe weather types Tornadoes Tornado forecasting Difficult to forecast because of their small size Tornado watch To alert the public to the possibility of tornadoes Issued when the conditions are favorable Covers 65,000 square km (25,000 square miles)

Severe weather types Tornado warning is issued when a tornado is sighted or is indicated by weather radar Use of Doppler radar helps increase the accuracy by detecting the air motion