Ingredients for hurricane formation

• warm sea-surface temps- greater than 26°C (79°F)
• deep moisture at low levels
• light winds throughout troposphere

• need convergence, a trigger
  • weak frontal boundary
  • ITCZ
  • easterly wave
• typically form between 5°-20° latitude, not on equator.... why?

Factors inhibiting hurricane formation:

• cooler SST's, drier air at low levels
• strong trade wind inversion (subsidence created by sub-tropical highs)
• strong upper-level winds

QUESTIONS FOR THOUGHT:

1.  Why are hurricanes more apt to form in October than in May?

2.  Would the winds of a hurricane decrease more quickly as the storm moves over cooler water or over warmer land? Explain.