If you’re on spring break this week and you’re looking for fun in the sun, good luck. A volatile spring weather pattern continues across the Mid-South region with a lot of rain, a lot of wind, a possibility for severe thunderstorms, and then a lot of cold to end the week. Tuesday and most of Wednesday look good, but that’s about it for this week.
The main threat for severe weather will come on Wednesday, although there are some questions about just how much potential will exist for severe thunderstorms here in East Tennessee. Otherwise, it looks very rainy for Monday, very windy for Thursday and also very cold for Thursday and Friday.
The Storm Prediction Center in Norman, Okla., has our area under a “marginal risk” for severe weather today, as a storm system currently located over Missouri and moving northeast helps to pull a lot of warm, moist air in from the Gulf of Mexico. In a weather impact briefing this morning, the National Weather Service in Morristown says that some severe storms could develop late this morning, with isolated damaging winds up to 60 mph, quarter-sized hail and localized flooding.
For the most part, though, we’re just going to see a lot of rain, as any severe weather threat today should be limited to areas south of Interstate 40. A look at the current radar reveals a lot of rain to come before things begin to taper off later this afternoon, and that’s no surprise, with precipitable water values between 1.5 and 2 inches in the atmosphere. In its forecast discussion this morning, NWS-Morristown mentioned that another round of scattered thunderstorms could develop this evening as the attendant cold front with this system approaches our region. However, the NWS also says that “the severe threat will be very low after sunset.”
The severe weather threat will be greater across the board on Wednesday than it is today, but there are still a lot of unanswered questions. For now, the SPC has all of East Tennessee under a “slight risk” for severe weather on Wednesday, which equates to a 15% chance for severe storms.
As is the case today, the bullseye for severe weather will be to our south on Wednesday. The SPC has an area extending from Mobile to western South Carolina under an “enhanced risk” for severe weather, and it wouldn’t be surprising to see the threat ratcheted up some more between now and then, depending on how this system evolves. There, the SPC says that there will be a risk of storms capable of producing tornadoes, “at least a couple of which may be strong.”
The National Weather Service office in Birmingham, Ala., has mentioned the potential for supercell storms capable of producing long-track tornadoes, large hail and damaging winds, but that possibility seems to be greatest well south of Tennessee; NWS-Birmingham mentions a Selma-to-Anniston line. The SPC also mentions the potential for discrete supercell storm structures for the Gulf Coast states, “accompanied by the risk for large hail and tornadoes.”
However, the SPC points out that more uncertainty exists for the Ohio and Tennessee valleys, which includes our region. In this morning’s update, the SPC points out that “severe storm development sees possible over a fairly broad area,” and includes mention of a risk for discrete supercells from late Wednesday afternoon into Wednesday evening.
In its hazardous weather outlook this morning, NWS-Morristown mentions “widespread strong to severe thunderstorms” Wednesday afternoon and evening, with damaging straight-line winds and large hail being possible with the strongest storms, along with an isolated tornado or two. More specifically, the NWS currently says that the tornado potential is low, with potential for hail up to golf ball size and maximum wind speeds of 60-70 mph.
While NWS-Morristown is expected to have an updated weather impact briefing for Wednesday by 4 p.m. this afternoon, meteorologists there mentioned the uncertainties that exist in their forecast discussion this morning. As the NWS points out, a warm front will push through the region on Wednesday, placing East Tennessee in the “warm sector” of the storm, which always carries an attendant risk for severe weather. There should be enough mid-level instability, wind shear and forcing to create a risk for strong or severe storms, as well. But the NWS points out that the exact track of the low pressure system as it moves across the Midwest, its timing, and whether thunderstorms develop across the Gulf Coast that could inhibit the influx of moist unstable air to our region will all play roles in determining the severe weather threat on Wednesday.
The NWS says that “storm potential should quickly end Wednesday night as a strong cold front pushes through.”
Rain showers look like they’ll continue throughout the day on Thursday and into early Friday. In fact, Thursday looks downright miserable as dogwood winter settles into the region. High temperatures likely won’t get out of the 40s and there will be a strong northwest breeze to make it feel even colder. Thursday looks quite windy, and Friday may not be much better. Temperatures will drop into the 30s at night, and it’s looking increasingly as though we could see a light freeze Saturday morning, before the warming trend begins.
The good news is we should return to 70 degrees by Sunday.
The Bottom Line
In a nutshell, spring break week looks pretty rotten, weather-wise, with a lot of rain on Monday, a threat of strong to severe thunderstorms on Wednesday, and then rainy, windy and cold conditions Thursday and Friday. Tuesday and much of Wednesday look good, weather-wise.
The severe weather potential this week looks to be limited to Wednesday afternoon and evening. We’re currently under a “slight risk” for severe weather, with the primary risks being damaging wind gusts and large hail. The tornado threat is low for those of us in East Tennessee, but cannot be completely dismissed, particularly if discrete supercells manage to develop ahead of the main line of storms. The current best-guess scenario is for a line of strong thunderstorms that will push through the region late in the day on Wednesday, bringing a relatively short-lived window of opportunity for severe weather. But there’s still time for the system to evolve, and there’s a lot of uncertainty revolving around how things will organize on Wednesday. Some of those questions will be impossible for meteorologists to answer until Wednesday gets here. One thing seems pretty certain at this stage, though, and that is that the greatest risk for severe weather will stay well to our south.