Transcript Test Resource - Severe Weather

Severe Weather
Chapter 25
Midlatitude Cyclones
• Areas of low pressure characterized by
rotating wind that moves toward the
rising air of the central, low-pressure
region.
• Last several days
• Pass from Pacific coast to Atlantic coast
• Strongly influence weather in middle
latitudes (us!)
Stages of a Midlatitude
Cyclone (Page 607, Figure 3)
Thunderstorms
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•
•
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Rain
Strong Winds
Lightning
Thunder
Stages in Thunderstorm
Development
• Stage 1:Cumulus Stage
– Air rises, condenses, forms cumulus cloud
• Stage 2: Mature Stage
– Becomes Dark Cumulonimbus Cloud, heavy rains cause
down drafts
• Stage 3: Dissipating Stage
– Downdrafts end updrafts, storm loses moisture, storm
dissipates
Lightning Formation
Lightning forms
due to the
attraction of
opposite electrical
charges
Tornadoes
• Smallest. Shortest,
and most violent
storms.
• Forms when a
thunderstorm meets
high altitude
horizontal winds
• Winds cause rising
air to rotate
Other Tornado Characteristics
• Usually cover paths
<100m wide
• They have occurred
in all 50 states
• Most common in
Tornado Alley
• Winds greater than
400 km/h
Enhanced Fujita Scale (EF
Scale)
• Adopted Feb. 1st,
2007
• Takes into account
damage and wind
• Link to NOAA
website
• March 12th, 2006,
Springfield, IL