Chapter 11 Hurricanes Maritime Tropical air-masses (mT) air Streamlines are used to analyze and track weather Tropical waves  Clusters of thunderstorms  Tropical squalls  Easterly waves Hurricanes  Same as typhoons, cyclones  Form in different parts of the world  West of Dateline: called typhoons

Hurricanes Intense storm of tropical origin with sustained winds exceeding 64 knots (74 mi/hr) Hurricanes, typhoons, cyclones  All form in warm tropical waters.  They occur in the North equatorial Pacific Northwest Atlantic  Sea surface Temperatures must be in the low 80’s  Dept of warm water needs to be at least 300 ft.  Enough water vapor must be in the air for a tropical wave to become a hurricane  Winds need to be calm from surface to upper atmosphere for hurricanes to form

Hurricane Movement Hurricanes develop in the low latitudes They are pushed by easterly winds As they move north, they encounter winds of higher latitudes  Subtropical High Pressure systems to the north  Sub polar low or low pressures systems to the north  Hurricanes are difficult to forecast beyond about three days  Hurricanes tracks are getting better to forecast, but their intensity remains an issue

Hurricanes Hazards Storm surge  Hurricane pushes ocean out ahead of storm Heavy rain-flooding  Rainbands associated with hurricanes Strong winds  Associated with storm, especially around the center Small tornadoes  Around the northeast part of the storm  Wind shear develops as the storm moves ashore

End of Chapter 11 Key Terms Questions for Review: 1, 2, 3 4, 5, 6, 7a-b, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 21, 22 Questions For Thought and Exploration: 3, 4, 6, 5