The southeast is melting under the influence of an unusually brutal early-season heat wave, with temperatures soaring into the upper 90s and low 100s for four days now. Temperatures will moderate somewhat for a day or two this weekend, but the heat is going to crank back up for most of next week.
Last year’s cool summer aside, it’s not unusual for it to get very hot for a few days in June, but the intensity and duration of this heat wave has only happened once or twice every decade in recent years. This heat wave really is something else when you put it into perspective.
Florence, South Carolina—which is the first big (“big”) city you hit in S.C. as you drive south on I-95—has hit at least 97°F for the past six days (three of which had a high of 101°F), and the 97+ streak will last through at least Saturday the 27th if The Weather Channel’s forecast verifies. This 15-day streak would tie the record for consecutive days with temperatures at or above 97°F, which was set back in July 1993. Even worse, Florence has hit 100°F or warmer three times so far this month (all this week), and since 1948, the city has never seen more than four 100+ degree days during the month of June. They look to be on track to break that record, as well.
It’s a similar story for many cities across inland parts of Georgia, South Carolina, and North Carolina, where record highs and records for consecutive days at or above a certain temperature are falling and topping themselves with each passing day. It seems that the only thing that will prevent a challenge to these records is the potential for pop-up thunderstorms, which would disrupt the heating of the day.
The second half of this heat wave will encompass a much larger area than the first, with the heat stretching from the Carolinas through parts of Mississippi, Alabama, and northern Florida. Several days with temperatures at or near 100°F are possible as far west as the border between Alabama and Mississippi.
The reason for the heat is the ridge of high pressure that’s parked itself over the area. Ridges are stubborn, promoting sinking air that allows for calm, warm weather to prevail for as long as the ridge lasts. When you get a persistent ridge like the one we’re seeing over the southeast right now, it takes a major shift in the jet stream to break its influence and allow the pattern to moderate itself. It’s the same reason that California was so hot and dry this past winter.
A small upper-level trough—the remnants of Tropical Storm Bill—will make its way through the Tennessee Valley on Saturday, but it doesn’t look like it’ll be strong enough (or dig far enough south) to allow temperatures to return to normal for the majority of the area affected by the heart of the heat wave. If anything, the trough will prevent temperatures from topping 100°F on Saturday and Sunday, before they once again reach the century mark when the ridge builds back in next week.
How bad is it looking? Here’s a look at possible highs and lows according to the GFS model—these are model-generated forecasts without expert intervention, so they’re not completely accurate, but it gives you a good picture of general trends.
Fayetteville, North Carolina:
Florence, South Carolina:
The forecasts produced by experts aren’t much prettier. Since we’ve focused on Florence so much (hello to all two readers from Florence!), here’s what The Weather Channel is forecasting for the city over the next couple of days, beginning with tomorrow (Friday), in degrees Fahrenheit: 98, 98, 98, 100, 98, 101, 97.
And so the story goes for Augusta, Charleston, Columbia, Charlotte, Atlanta, Birmingham, Montgomery, and on and on for countless more cities across the southeast. Highs will be warmer in urban areas, and exact readings from place to place will depend on variables like thunderstorms, winds, and proximity to bodies of water. A few degrees won’t make too much of a difference, though: the bottom line it’s going to remain dangerously hot and humid for another week.
Heat is dangerous on its own, but when you factor in the moisture in the air, it’s even worse. Unlike that dry heat in Tucson that dehydrates you, the heat is almost worse east of the Rockies because of the heat index, or the combined effect of the actual air temperature and the humidity on your body. High levels of moisture in the air make it harder for sweat to evaporate from your skin, making it harder for your body to cool off. This effect makes it feel hotter than it actually is; that humid 99°F has the same effect on your body as a much, much hotter temperature. Heat indices will hover between 105-110°F or warmer on the hottest days, which makes it dangerous for even healthy individuals to spend more than a couple of minutes outdoors without shade and water.
If you live in this or any area affected by extreme heat, make sure you check on your neighbors, especially if they’re vulnerable to heat-related illnesses, or you know they don’t have access to basic conveniences like fans or air conditioning. Buildings that aren’t air conditioned don’t always cool down at night, especially with low temperatures staying as warm as they are during this heat wave.
[Images: National Weather Service, Tropical Tidbits, WeatherBELL]