Warm temps have returned. Windy and showery late tomorrow. Severe storms possible Thursday!
Beautiful, mostly sunny skies are in place across the Tennessee Valley this Monday afternoon! Temperatures are running warm too. That 74 degree reading over in Savannah is suspect, but we've been between the mid 60s and 70 degrees areawide for highs this afternoon! High, thin cirrus clouds are approaching from the west, and clouds will increase overnight and into tomorrow as the next weather system approaches.
Temperatures will quickly drop back to the 50s after sunset with the clear skies and dry air in place. That will allow us to drop into the 40s by midnight, but increasing clouds toward daybreak, as well as a southerly wind starting to kick up, will keep us from dropping out of the upper 30s and lower 40s for morning lows. Expect another warm day Tuesday as strong southerly winds continue to strengthen ahead of the approaching weather system. Clouds will be much more widespread, but daytime highs will likely once again be in the upper 60s to near 70 degrees. A few showers will be possible into the afternoon and evening hours ahead of the approaching front.
Winds in association with the pressure gradient will be strong beginning tomorrow afternoon, continuing through tomorrow night. Sustained winds of 20 to 30 mph are a good bet, and some gusts may be as high as 40 to 45 mph. For this reason, our local National Weather Service offices have put all of the viewing area in a WIND ADVISORY for tomorrow afternoon into Wednesday morning.
Showers and a rumble of thunder will continue to be possible into the evening and overnight of Tuesday, but that activity will be weakening as the upper-level system actually pulls northeast away from the area and weakens, with the front stalling near or just northwest of us... instead of sweeping on across. That will be important to the forecast going forward because that leaves the moisture to build over the Gulf and just inland to our south before it comes north ahead of the stronger system that ejects out Wednesday into especially Thursday. That front comes back north as a warm front Wednesday and Wednesday night with a few scattered showers and thunderstorms possible as that warm front moves northward. A few of those may be strong, but the main severe weather threat for Wednesday and Wednesday night will be off to our west, from the Mississippi Valley into Texas and southern Oklahoma. Wednesday and Thursday will both be warm, with highs in the area in the lower 70s. With a little sun being possible Wednesday, a few locations might make it toward the middle 70s.
The main storm system ejects out Thursday and approaches our area from the west. We are still working out the timing, but it seems like the best chance of strong to severe storms for our local area is between the late morning hours and the late afternoon or early evening. Models began trending toward a flatter and weaker system over the weekend, but as the upper air soundings over the U.S. started sampling that disturbance this morning instead of the models just guessing at its details, those models have begun to reverse that weakening trend and are starting to trend back a bit more organized with the surface low and the upper-level trough.
We are still working to figure out the magnitude of the threat, and it may be another 24-36 hours before we have a good handle on that because we need to get within the range of the higher-resolution models and the strength of the low pressure system is still trending in the models. Having said all of that, all threat types are possible with the storms... with the main threats being damaging straight-line winds and some magnitude of a tornado threat. While we don't expect this to be an "outbreak" or anything like that, the strength of the wind shear and the upper-level winds being more angled across the front instead of parallel with it suggest that a supercellular storm "mode" may be possible versus just a solid line of storms. That would help out the potential for tornadoes, but the magnitude of that tornado threat will depend a lot on how unstable the air is and how "clean" and storm free the warm sector is leading into start time, and that's something we just don't have a handle on just yet.
It is important, regardless of the magnitude of the severe weather threat, it is important that you remain in touch with weather information the next few days and go through your severe weather safety plans ahead of time. We will be here to provide updated forecast information the next few days, as well as live severe weather coverage later this week as needed!
Behind that system, high pressure sends in much cooler air behind the cold front that moves through. Daytime highs Friday are back to the lower 40s with overnight lows Friday night into Saturday morning well down into the 20s! Temperatures moderate again headed through the weekend into early next week.