It appears that we may get our first decent round of thunderstorms of the year over the Mid-South on Thursday. Today looks like it’ll be a pretty nice day, with only mostly cloudy skies to complain about. Some decent winds out of the south will keep the temperatures warm today and tonight, as the high will approach 70 with a low in the mid-50s. But the significant weather will arrive tomorrow, as a low-pressure center advances into the area from the west. This system will provide the lower-Mississippi valley with some severe weather this afternoon and evening. We may see a shower or possibly a thunderstorm overnight, but I doubt anything will arrive until at least tomorrow morning.
As the system approaches from the west, it will deepen very quickly under an intense vorticity max. In fact, this system will become strong enough at the surface to pull cold Canadian air as far south as Oklahoma and Missouri while maintaining a strong low-level jet of heat and moisture from the Gulf into the lower-Mississippi valley and Mid-South out ahead of the system. The models appear to be in fair agreement that some significant rains will arrive around noon on Thursday, with some embedded thunderstorms – some severe – getting here during the afternoon hours. The severe potential is largely attributed to the northward advancement of the subtropical jet into Tennessee, the amount of vorticity at 500 and 850 mb, and the dry slot at 700 mb that is necessary for severe development. The biggest question still with this system is how it will pass through the region once it arrives. The current track takes it north toward the Great Lakes, meaning that any potential squall line of thunderstorms associated with this system would also advance northward and perhaps miss Bowling Green altogether. The models reflect this in that they are generally calling for about an inch of rain from northern Indiana south to Louisville while Bowling Green is expected to get 0.5-0.75 inch tomorrow afternoon. With our dew points into the 50s and the freezing level aloft over Nashville currently at 750 mb, any thunderstorms tomorrow will likely bring gusty winds, significant rains, and hail.
Have a great day!