Dangerous Heat, Severe Storms and Tropical Trouble
We are tracking three potential weather hazards in the next week for Green Country, the first of which is ongoing. Significant heat combined with extreme levels of moisture in the air is creating a dangerous heat index through midweek. This first hazard may fuel our second: severe weather. Finally, a potential Tropical system may impact Green Country as early as this weekend – that’s the third weather hazard at play. I break down each threat below.
The heat: We are no stranger to it this time of year, but the amount of moisture in the air is the key issue. Our record rainfall this year has contributed to high levels of evapotranspiration (veggie sweat in layman’s terms). Now that this moisture is sending our dewpoint into a miserably muggy range nearing 80° in some spots, the heat index can be over 10° hotter than the air temperature. That is the case through Wednesday with a Heat Advisory posted for almost all of Green Country. Even today, those heat index values have topped 110° in places like Bixby and Poteau! Below is a projection of Wednesday’s heat index by mid-afternoon. To make matters worse, the wind will slacken by then, making it even harder for your body to cool off outdoors.
The storms: While not everyone will deal with the severe weather on Wednesday, the threats should be taken seriously. Strong instability (as a result of our heat wave) will likely allow the CAP to break and scattered thunderstorms to form late Wednesday afternoon. In this weakly-sheared environment, the storms will be a bit less organized, but can still produce strong, damaging winds. That will be the greatest concern with any storm through Wednesday evening. Below is a ranking of the other storm threats. It is not a weather set-up primed for tornadoes, but it is hard to ever rule them out. Hopefully these storms advance fast enough to limit flooding, but it would not take long for a severe storm to cause ponding on area roadways. A cold front will be the focus for these storms. Behind this boundary, slightly cooler, but much drier air will allow for more pleasant summer conditions into the weekend.
The Tropics: It is early in Hurricane Season, but the ingredients are coming together for a Tropical Storm or even a Hurricane to form in the next few days in the northern Gulf of Mexico. The impulse that might spawn this system just dropped south into the northwestern Gulf and will be drifting westward over very warm ocean waters this week. If this system can overcome some wind shear, (it needs little wind shear to organize) then we will have a rapidly strengthening system on our hands. Its name will be Barry and he could be a menace to a broad swath of the coastline from Florida to Texas.
Where it goes from there is the big question for us. A strong ridge centered to our west is likely to steer it west until it receives a lift northward. The steering currents are subtle, especially with the jet stream displaced so far to the north. However, our longer-range computer models do bring the center of Barry into Arkansas. Previous model runs have even put it right over Oklahoma. Some have even kept it down in Texas until it dissipates. Below is a "Spaghetti Plot" showing potential tracks of this system in our computer models. At the very least, this system will likely cause flooding rainfall across parts of the Deep South. Should it form rapidly into a hurricane, the problems will heighten and extend hazards further inland. If Barry made it to Oklahoma, it would be the first tropical system to track directly over our region since the remnants of Tropical Storm Bill in 2015. Green Country still falls within a range of its possible track and there’s a chance we could receive gusty winds and flooding rainfall if it heads our way. There’s a low chance of that worst-case scenario. There is moderate confidence that this system will have some impact on our weather by Sunday and Monday of next week, even if it just brings more clouds and takes the edge off the heat. This bears watching closely, especially if you have travel plans to the Gulf Coast through the weekend. In Oklahoma, the last thing we need is more prolific rain. We will be tracking this closely.