National Hurricane Center Hurricane Specialist Stacy Stewart spoke last Saturday at the Eastern U.S. Weather Conference in Baltimore. He is a U.S. Navy reservist as well, and recently was awarded the bronze star for his combat service in Afghanistan. I was lucky enough to get to hear him. All weekend, I will share some of his thoughts.
He led off the discussion by pointing out that recent hurricane forecast track improvements, while impressive, are due to improvements in the numerical weather prediction. He says that it is getting increasingly difficult to beat the performance of the models. (I could hear Dr. Tim railing against this way of thinking as he said it.)
Stewart pointed out that the 72 hour track forecast error has improved from 310 miles to 130 since 1990. This dramatic improvement is allowing the Hurricane Center to start issuing hurricane watches 48 hours in advance of landfall and hurricane warnings 36 hours in advance. This is critical, since it takes 36 hours to evacuate many areas. In fact, he says that the five most vulnerable areas in the U.S, the Florida Keys, Tampa, Houston/Galveston, New Orleans and New York City require 72 hours to effectively evacuate.
Interestingly, New Orleans and Houston have had close calls in the past five years. Despite the horrible outcome of the manmade disaster in New Orleans and Southeast Louisiana during Hurricane Katrina, it was not the Crescent City’s worst case scenario storm. We can only hope this year’s projected bus season doesn’t send a big storm spinning toward New Orleans. And Ike could have been much worse in the Houston/Galveston area.
He says that one of the Hurricane Center’s bigger challenges is to improve the 4-5 day forecasts. While they have only been shared with the public for a couple of years, the NHC has been doing them for several years. He quipped that he always breathes a sigh of relief when the official track position is over his house five days out, since the chance is very small that is where the storm will end up.
More interesting thoughts all weekend. Follow my daily weather history tweets on Twitter @wxhistorian.
