July represents the "middle" month of summer. It's Columbus's warmest and stormiest month of the year: the 30-year average temperature of 82.5º noses out August by about a half-degree, though there are years when August is hotter than July. Last year we had our highest readings of the year in late August and the heat continued through the first week of September!
Our low of 68º this morning is a rarity, and came about because of a surge of cool, dry air that followed last night's batch of thunderstorms. Many years it won't get below 70 the entire month of July. And the next week or two do not look to be extreme as far as heat goes; the evolving pattern keeps the bulk of the heat out west, with near normal July temperatures expected over the Southeast. Our normal daily highs and lows peak just after mid-month, topping out at 92 and 73 and then only gradually falling off starting the last week of July.
As for the storms, Columbus gets as average of 12 thunderstorm days in July, by far the most of any month, and our average rainfall of 4.76" makes July the second wettest behind March. July can treat us to some spectacular lightning displays and amazing downpours, the latter due to the fact that the atmosphere is often loaded with tropical moisture. On July 15 last year I was hit by a one-two punch of afternoon storms that gave me 5½ inches of rain in just a few hours and turned my backyard into a lake. The airport wound up with less than an inch.
Severe weather isn't usually an issue in July, other than an occasional straight-line microburst that can knock down trees. Those are most likely on a really hot day when the temperature gets close to 100º, as the heat provides added energy for intense downdrafts in storms that develop. Tornadoes are extremely rare in July, even in the strongest storms, as the weak midsummer upper winds don't provide the necessary shear for twisters. In fact, in the absence of actual data, I would contend that July is the month we are least likely to see a tornado here. (A landfalling tropical system changes the equation, but those are not common in July.)
The biggest threat from July storms is, of course, lightning, which by definition is present with even ordinary storms. The old advice of "when thunder roars, go indoors" is a good rule to follow. The U.S. has seen 14 lightning fatalities so far this year, including two in Alabama (from the same bolt!) and three in Florida. And the year's only half over - in recent years the number of deaths from lightning strikes has been in the 20s range. Don't be a lightning statistic!
Looking ahead to Independence Day on Saturday, it doesn't look like the Fourth will be extremely hot this year, but look for plenty of humidity to go along with highs near 90º. There will probably be a threat of thunderstorms well into the evening, with activity somewhat isolated so odds are good that fireworks displays will go off as planned.
Have a safe holiday, and enjoy the shows whether they be man-made or provided by nature!
Kurt Schmitz, Senior Meteorologist