Forecasting: Uncertainty
Answer: It's Later than You Think


As shown in the figure to the right, the eye of a hurricane is 500 miles due east of Ocean City, MD, and the storm is traveling at 15 mph. Landfall is expected in 33 hours. If the speed stays the same, but the track changes to northwest, will the time to landfall at Newport, RI change?

  1. No, landfall will still be about 33 hours.
  2. Yes, the time to landfall will increase.
  3. Yes, the time to landfall will decrease.

The correct answer is #3. Because the coast curves to the northeast, beginning at about Long Island, Newport is closer to the eye of the storm-360 miles as opposed to the 500 miles at Ocean City. To estimate the time of landfall, divide 360 miles by 15 mph = 24 hours. To an emergency manager in Rhode Island, that would mean that he or she just lost 9 hours of preparation time (33-24=9 hours), unless that manager had been considering in advance what steps should be taken if the storm changed course. Coordinating with the local WFO would provide some insight into the likelihood of that possibility.

The point is that, depending on the geography of your area, you may have less time to prepare than you might otherwise assume. Did you notice that the problem talked about the location of the eye of the storm, but said nothing about the location of the tropical storm-force winds? Remember, you should not focus on the hurricane's eye. If you do, you will have even less time than you think. Your preparations must be geared to the timing of the onset of tropical storm-force winds that will arrive well before the eye.