Tuesday, December 16, 2008

Hurricanes and snowfall in Houston

You have to love (or hate) what passes for "winter" in Houston. Last Wednesday, it snowed. A few days later, we had temperatures in the 70s. Yesterday morning, with early AM temperatures in the 60s and with the understanding that a cold front wouldn't arrive until the evening, I took Kirby to school wearing a t-shirt and shorts. Oops. Last night temperatures dipped into the 30s. By Thursday, we'll be back in the 70s again.

Many Houstonians perceive a relationship between a hurricane in the summer and snowfall in the winter; I, myself, have wondered if there is a connection between the two. Following last week's snowfall, KTRK Chief Meteorologist Tim Heller noted this relationship on his blog:
Yet, if you look at the weather records it seems that every time a big hurricane hits the Houston-Galveston area it snows during the month of December following the hurricane. It snowed in southeast Texas after Hurricane Carla in 1961, after Alicia in 1983 and after Jerry in 1989. Now we can add Hurricane Ike to the list as well. Furthermore, the December following Hurricane Jerry in 1989 was the coldest on record! The second coldest December on record was in 1983, following Hurricane Alicia.

Is there a connection between southeast Texas hurricanes and snowstorms? I don't know. But I do know there are larger patterns within the atmosphere that we don't completely understand. If someone had a lot of time and a lot of money, this would be an interesting weather connection to investigate.

See the graphic that accompanied his entry.

Correlation is not causation, of course, and it's worth mentioning that there are instances where December snowfalls in Houston were not associated with hurricanes; the White Christmas snowfall of 2004, for example, was not preceded by a hurricane making landfall that summer. Hurricane Rita's landfall in 2005, moreover, did not produce a snowfall that following December (even though Rita did not technically make landfall in the Houston area, it certainly affected the city). It should also be noted that 1989's Jerry, unlike Carla, Alicia or Ike, was not a major hurricane; I remember that it had such little local impact that schools weren't even closed, as they were the previous year when Gilbert threatened (Jerry was one of two weak hurricanes to make landfall in the Houston area in 1989; Chantal was the other).

With all that said, there may be more to this than just mere coincidence. As Heller says, there is a lot about larger weather patterns that meteorologists still don't understand. Tropical cyclones are enormous engines that transfer massive amounts of energy from the tropics to temperate latitudes, and in so doing could potentially affect the weather patterns of those regions long after the cyclones themselves dissipate. As Heller suggests, this is definitely a topic worthy of further study.

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