Ingredients for hurricane formation

  • warm sea-surface temps- greater than 26C (79F)
  • 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


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.