Wednesday, September 11, 2013

Humberto... Stunningly close to a record

This morning, the National Hurricane Center issued an advisory stating that Humberto, a tropical system in the Atlantic Ocean, had officially become a hurricane, with winds reaching above the 74mph (65kt) threshold. There is nothing remarkable about this hurricane. It's a Category 1 storm, it isn't a threat to land over the next 5 days, and it is forecast to be a hurricane for a short amount of time. I guess it's fitting, because this storm is just barely missing out on having its own unique place in history!
If Humberto had gained strength just a little bit later in the day, it would have set a new record for the latest first hurricane in a calendar year during the satellite era. What do I mean about the satellite era? As I mentioned in an earlier article, the first weather satellite wasn't even launched until 1961. That means we couldn't see tropical systems from above, and it's pretty easy to spot most tropical storms on satellite imagery because of their circular structure and rotation (see picture below).
A classic hurricane structure is evident when viewed from above,
using modern satellite imagery. (Courtesy of USAToday)
It's not just the satellite technology that helps us spot storms. Also, the system of using reconnaissance aircraft to study hurricanes was first used in the 1940s, which is decades after we started keeping official records of tropical storms and their impact on the United States. The aircraft's structure, and its data collection methods, are much more sophisticated now than they were back in the '40s. Today, we fly airplanes into developing systems to get accurate measurements for central air pressure, core wind speed, and other parameters. It's possible that, because of our more advanced technology, there are storms that were out there in the ocean and were never acknowledged as being tropical storms or hurricanes!
Based strictly on the data we have, the "official" record for the latest hurricane belongs to Hurricane Alice, going all the way back to 1954. As mentioned above, this is before the satellite era. Alice became a Tropical Storm on December 30th, and a hurricane on December 31st! The Atlantic Basin almost got through an entire calendar year without a single named storm... as far as we know.

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