Violent Weather Chp 20 Types of Clouds: High: 6000m & above (cirro) Middle: m (alto) Low: surface to 2000m (stratus) Which produce rain, snow, hail, lightning? Air masses: The main reason for violent weather in mid west
mA: cool, moist, unstable cA: cold, dry, stable mP: cool, moist, unstable cP: cold, dry, stable mT: warm, moist, usually unstable cT: hot dry, stable (high), unstable (surface) 1. Cold Front: Cold air hits warm air
Types of Fronts: 1. Cold Front: Cold air hits warm air Cloud formation precipitation 2. Warm Front: warm air hits cold air Cold Front cirrostratus Warm Front cirrostratus 3. Occluded Front: 4. Stationary front:
When an active cold front overtakes a warm front Cloud type formed Precipitation 4. Stationary front: Surface position of front does not move Precipitation (gentle to moderate if at all) Occluded front formation Stationary Front Thunderstorm Formation 1
Thunderstorm Formation 1. Cumulus cloud develops into thunderhead (cumulonimbus clouds) when warm humid rising air currents create an unstable environment, due to frontal lifting (cold front; cold vs. warm). 2. Mature thunderstorm: Ascending air reaches height where precipitation occurs (Cloud top, Anvil). Initially, cloud air warmer than surrounding air. Causing condensation and precipitation. Falling rain & ice cool cloud air (energy released). Downdrafts created. Up & downdrafts create friction (electric unevenness) make lightening. 3. Final: Entire cloud downdrafts. Surrounding air is adiabatic warmed. No airascending & cooling. Precipitation decreases (excess energy gone). Lightning Formation: Where there is lightning there is thunder. Why
Lightning Formation: Where there is lightning there is thunder. Why? Can lightning hit the same place twice? Up & down drafts charge partials Lightning review: What areas have what charge? Why?
What is the charge of the step leader, dart leader and return stroke? What is the difference between the stepped leader and the dart leader? What will cause the cloud to neutralize? Can lightning hit the same place twice?
What causes thunder? Can lightning hit the same place twice? You will not be tested on this. For your information only. Hail formation: ice circulation in cumulonimbus cloud due to updrafts
How does hail become golf ball sized? Overshooting top Tropopause Anvil Mammatus Warm Front Cold Front Associated with supercells (severe thunderstorms)
Tornado Formation Associated with supercells (severe thunderstorms) 1. Wind shear: sudden change in wind speed & direction 2. Updrafts tilt rotation of funnel cloud to vertical (in developing thunderhead) Tornado formation continued
3. Up drafts (mesocyclone) accelerate rotation removing air from center (eye) creating low pressure. Funnel could touches the ground -Air of funnel cloud & tornado can be see due to condensation (like cloud) -What does the low pressure of the eye do? Tornado formation pictures
2. Funnel Cloud 1. Wind Shear 3. Tornado Super cell Anatomy Anatomy: tropopause, overshooting top, mammatus, anvil, up-drafts, warm air, down-drafts, cool air, tornado, hail, heavy rain, light rain, cold front, warm front Tornado Classification:
Frequency: 29% 40% 24% 6% 2%