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Wild Weather

Hurricanes, Tornadoes, and General Wacky Weather!

Hurricane: An intense tropical Low Pressure system of strong thunderstorms spinning counterclockwise with maximum winds of 74 mph or higher.  Most Damaging Storm.

  • Hurricanes gain energy over water and lose energy over land
  • Categorized according to the strength of their winds
  • The Saffir/Simpson Hurricane Scale
  • Storm Surge: is the most destructive part of a hurricane
  • Generally move from the Atlantic to the East Coast of the United States.  Hurricane Paths
  • Hurricanes are called cyclones in India and Typhoons in Asia

What should you do if you are caught in a hurricane?

Tornadoes: nature's most violent wind storm.  An average of 800 of these vortices spin up beneath thunderstorms year round in the USA and can generate wind speeds faster than 250 mph, at times devastating whole communities.

  • Most last for only a few minutes but can be desasterous
  • Most tornadoes occur in "Tornado Alley"
  • Categorized by damage and wind speed
    Fujita wind damage scale: F-0, F-1, F-2, F-3, F-4, F-5

What should you do if you are caught in a tornado?

Thunderstorms: are heavy rainstorms accompanied by thunder and lightning. Only thunderstorms have enough up-and-down air movement to produce hail.

  • Thunderstorms often occur along cold fronts
  • More people are killed by lightning than any other weather related cause

What should you do if you are caught in a thunderstorm?

Clouds

Cloud images found at: http://physics.uwstout.edu/wx/U4/img012.htm

Can you see water vapor?

Can you see clouds?

Are clouds water vapor?

Clouds are made up of tiny condensed water droplets!
They are not water vapor!

  • Note: One raindrop contains up to 1 million tiny cloud droplets

Clouds come in three basic shapes

  • cumulus clouds (heaped and puffy)
  • stratus clouds (layered)
  • cirrus clouds (wispy)

Clouds occur in three altitude ranges

  • High, Middle, and Low

High clouds (above 6,000 m) "cirrus or cirro-"

Cirrus: high and wispy  Cirrostratus: high layered Cirrocumulus: high puffy

Middle clouds (2,000 - 6,000 m),  "alto-"
Altostratus: middle layered Altocumulus: middle puffy
Low clouds (below 2,000 m), no prefix
Stratus: low-layered
Cumulus: low-puffy
Nimbus = Storm Clouds = Precipitation
Nimbostratus: layered-storm clouds
Cumulonimbus: puffy-storm clouds

Questions for review

  1. Which process most directly results in cloud formation?
    1. condensation
    2. transpiration
    3. precipitation
    4. radiation
  2. Air pressure is usually highest when the air is
    1. cool and dry
    2. cool and moist
    3. warm and dry
    4. warm and moist
  3. The weather map shows part of the United States.  Letters A through E represent weather stations.  At which weather station is the barometric pressure reading most likely to be 1,018.0 millibars?
    1. A
    2. B
    3. C
    4. D
  4. Cities A, B, C, and D on the weather map are being affected by a mid-latitude low-pressure system (cyclone).  Which city is located in the warm air mass?
    1. A
    2. B
    3. C
    4. D
  5. Which map below correctly shows the wind directions of the high-pressure and low-pressure systems?
  6. Which weather station model indicates the greatest probability of precipitation?
  7. As warm, moist air moves into a region, barometric pressure readings in the region will generally
    1. decrease
    2. increase
    3. remain the same
  8. A station model is shown in the diagram. 
    What is the air pressure at this location?

    1. 902.9 mb
    2. 1002.9 mb
    3. 1029.0 mb
    4. 9029.0 mb
  9. The characteristics of air masses depend chiefly upon the
    1. rotation of Earth
    2. surface over which the air mass was formed
    3. barometric pressure of the air mass
    4. wind velocity within the air mass
  10. Which diagram below best represents the air circulation around a Northern Hemisphere?