Severe storms possible late today and tonight, Drying out but colder for rest of the work week

 

The Storm Prediction Center maintains a Level 2 out of 5 risk of severe weather for this afternoon and tonight across a large part of our coverage area.  The risk extends from Booneville, MS to Waterloo, AL to Lawrenceburg, TN and then south and east of that line.  That means it includes the immediate Shoals metro and all of northwest Alabama.  Overall, this doesn’t appear to be any kind of major severe weather risk, just the “standard” type of risk you may see during the winter months.  The wind energy with this storm will be very strong, but the instability (or fuel) to drive storms will be very low.  That is despite warm and humid air that will be in place by late afternoon and evening, after a chilly start to the morning.  Warm temperatures in the mid-levels of the atmosphere means that temperatures won’t decrease that quickly at all with height, and there’s even a layer in which they warm with height.  This will significantly lower the amount of instability that will be available for storms to tap into.  Having said that, the dynamics and shear will be strong enough to possibly overcome this limitation and allow a few storms to still grow strong to severe.  We expect the storms to be in the form of a line that will move from west to east across the area.  Damaging wind gusts of 50-60 mph will be the primary hazard with this line, although trees may still be knocked down by gradient winds well out ahead of the storms during the afternoon.  There is still the risk of a few tornadoes with the line late this afternoon and tonight as well, but the overall risk is fairly low.  Still, a tornado is a tornado, and even a lower-end type tornado can be dangerous and deadly, especially to people in mobile homes and manufactured housing.  As long as the current risk levels stay in place, it is likely that a large part of the area will be placed in a Tornado Watch during the afternoon hours.  Having said all of that, the biggest concern is still likely to be the potential for more flooding and flash flooding.  A general 1 to 2 inches of rain is expected through tonight, and the ground across our area really can’t hold anymore water at all.  Any additional heavy rain, even if it doesn’t last all that long, will have the potential to significantly increase the threat of flash flooding across the area.

This is the general timeline when we want you to be prepared and alert for the potential for severe weather this afternoon and tonight.  This does not mean that it will storm the entire time in these locations, but for the areas highlighted, this is the window of opportunity where there is the potential for a severe storm as the line moves through.  The general window of opportunity for the coverage area as a whole is in the 4:00 pm to Midnight time frame.

The cold front moves through late tonight and during the early morning hours of Thursday, not only bringing an end to the rain, but also significantly cooler air.  Morning temperatures in the mid 40s on Thursday will drop into the mid 30s by the end of the day.  Then, as clouds clear out overnight Thursday night, temperatures will drop significantly.  The majority of the coverage area will be at least as low as the low to mid 20s by daybreak on Friday, and our southern Tennessee counties may be as cold as the upper teens or near 20 degrees.  That will be a big shock to the system after being near 70 degrees later this afternoon!  That cooler weather continues right on through Friday with high pressure in the area and light northerly winds in place, with afternoon highs in the lower 40s.  There is some forecast data that suggests we may struggle to get to 40 degrees.  We can’t completely rule that out, and the forecast highs for Friday might get nudged down a couple of degrees.

After a chilly start Saturday morning, a moderating trend begins for the weekend.  Afternoon highs on Saturday climb into the lower 50s with clouds gradually increasing during the afternoon.  Those clouds help hold temperatures up overnight with lows only reaching the low to mid 40s.  Despite increasing clouds and a wind out of the south to southwest, it looks like we stay dry through the weekend.  Afternoon highs climb into the upper 50s, and if there is a little more sun than currently expected, we wouldn’t be shocked to see lower 60s.

Rain chances return early next week though as the next weather system approaches from the west and southerly winds bring moisture northward from the Gulf of Mexico.  We expect thunderstorm chances to return Monday night into at least part of Tuesday.  Exact timing is to be determined, but the better chance of rain may be overnight Monday into the morning on Tuesday.  The good news is that it does not look like necessary ingredients will be in place for a risk of severe weather with this system.  That can always change though, and we will watch things carefully.