OPAL: Minimum sea-level pressure in Opal as
it intensified during its approach to landfall. Intensity
forecasts are important because the major hurricanes almost
always reach extreme intensity not through continued slow
strengthening but through a process called "rapid deepening"
that completely transforms the storm in a day or two. The
difficulties that rapid deepening poses for forecasters are
twofold: the hurricane becomes devastatingly intense, and
events can outrun forecasts. A scenario for disaster - that
nearly became a reality in Hurricane Opal of 1995 - is a
category 2 hurricane that strengthens to a category 5
overnight. In the morning the storm strikes a populated
coastline where the residents had prepared for the weaker
hurricane they saw on television before they went to bed. The
worst-case scenario was not realized in this instance because
Opal weakened just offshore.
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