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Understanding Severe Storms. National Weather Service Shreveport Working Together to Save Lives. Topics. Global Circulations Thunderstorm Ingredients Lightning Hail Tornadoes and Downbursts Flooding. Global Circulations. Jet Stream. Thunderstorm Ingredients.
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Understanding Severe Storms National Weather Service Shreveport Working Together to Save Lives
Topics • Global Circulations • Thunderstorm Ingredients • Lightning • Hail • Tornadoes and Downbursts • Flooding
Thunderstorm Ingredients
Thunderstorm Ingredients Moisture - Preferably in the lower or mid levels of the atmosphere
Thunderstorm Ingredients Source of lift – Agent which lifts the warm, moist air starting the thunderstorm
Thunderstorm Ingredients Instability – Ability for air to accelerate upward/downward when started up/down
Dissipating Stage Cumulus Stage Mature Stage Thunderstorm Life Cycle
motion Squall Lines (Cross section)
Supercell Thunderstorms N downdraft Tornado
Shear vs. Rotation Rotation Shear
Weather Related Hazards Hail Baseball size hail can do severe damage
Tornadoes Fujita Scale F0-F1 Winds 60 - 115 mph F4-F5 Winds > 205 mph F2-F3 Winds 115 - 205 mph
Damaging Wind • Cold air ‘bursts’ down from cloud • Spreads on ground contact • Accelerates on outwash • Can reach 150 mph • Tornado-like damage
Weather Related Hazards Flash Flooding Safety Tips • Do not drive across a flooded roadway or low water crossing • If your vehicle stalls in high water, leave it and seek higher ground • Be especially careful at night when it is harder to recognize the dangers of flash flooding
Acknowledgments • Jetstream website – Southern Region Headquarters , National Weather Service • www.srh.noaa.gov/srh/jetstream