On Wednesday, Democrats announced that they would move President Obama’s Thursday night acceptance speech indoors, citing a threat of stormy weather at the Bank of America Stadium in Charlotte, N.C.
The Weather Channel’s forecast as of early Wednesday, when Democrats announced their decision, called for a 30 percent chance of rain on Thursday night. (The forecast has since been revised to a 40 percent chance of rain.)
But is a 30 percent chance of rain really all that far out of the ordinary? Rain is hardly unknown in the South — especially in the humid evenings of the late summer.
Perhaps Democrats are using the weather threat as an excuse to protect against the possibility that they couldn’t fill a football stadium?
Or perhaps they liked how Michelle Obama’s speech came across indoors at the Time Warner Cable Arena, preferring its intimacy to an outdoor stadium’s grandiosity?
Specifically, I looked at how often there had been rain or thunderstorms between 8 p.m. and 11 p.m. local time — the key hours for the speeches, and the logistics for getting everyone safely into the stadium.
In the Septembers since 2002, it has rained 13 percent of the time during these prime-time hours in Charlotte. Thunderstorms, however, are relatively rare during these hours, occurring just 3 percent of the time.
The Weather Channel did not provide a precise estimate of the chance of thunderstorms specifically, as opposed to any kind of rain. But if we infer that the chance of thunderstorms is 15 percent on Thursday night — half the chance of there being any type of precipitation — it is considerably greater than Charlotte’s long-term average.
Still, the threat of thunderstorms hasn’t stopped the Democrats before. Denver, where Mr. Obama made an outdoor address at the convention in August 2008, is a city prone to storms.
Thunderstorms are a little different in Denver. They tend to formulate quickly over the turbulent air of the Front Range, but also pass through the town quickly rather than linger. Fairly often in Denver, in fact, there is thunder and lightning that is not accompanied by rainfall.
Nevertheless, scheduling an outdoor speech in Denver is not something you do if you are extremely skittish about a severe weather event and its impact on optics, logistics and security.
In Denver, the thunderstorms tend to occur in the late afternoon or early evening. However, this was not necessarily helpful from the standpoint of the 2008 convention because the speaking events had to be held at an earlier time locally to accommodate prime-time viewing hours on the East Coast.
On August evenings between 6 p.m. and 9 p.m. locally — equivalent to 8 p.m. through 11 p.m. Eastern time — there is a thunderstorm 15 percent of the time in Denver, according to weather records between 2002 and 2011.
In other words, because Denver is such a thunderstorm-prone city during the summer, the general threat of a storm there was about as high as the specific threat of a storm in Charlotte on Thursday, based on the current forecast. If something in the neighborhood of a 15 percent chance of a thunderstorm were considered sufficient to force cancellation of an outdoor speech, Democrats ought never to have scheduled one in Denver to begin with.
Obviously, this is a close call — both in terms of the decision by the Democrats, and in interpreting their motivation for it. But some skepticism is warranted that the weather is the only thing they were thinking about.