Chapter 11 Hurricanes

Maritime Tropical air-masses (mT) air Streamlines are used to analyze and track

weatherTropical 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

HurricanesIntense 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 latitudesThey are pushed by easterly windsAs 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 HazardsStorm surge

Hurricane pushes ocean out ahead of stormHeavy rain-flooding

Rainbands associated with hurricanesStrong 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 TermsQuestions 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