A strong surface low deep in Texas is currently beginning to push moisture into our area. As this surface low continues to move into the Southeast, the chances for severe weather will increase. Monday and into Tuesday morning appears to be the most active timeframe for NC, but rain could linger all the way into Wednesday with this frontal passage. Below you can see a GIF of the most recent NAM 3km run showing the progression of the storms. It appears storms development will be likely around 3-4pm in WNC, and then those storms will progress East.
Will It Hail At Your Location?
It is possible that some hail could be embedded with the storms that develop tomorrow afternoon. Higher elevations are more susceptible to hail reaching the ground.. but updrafts will be strong with this system, and temperatures aloft will be cold, so some hail development is possible. Rain, lightning, and strong winds though will be the main story with this system in WNC.
Isolated Southeast Tornado Threat
The Severe Prediction Center or SPC has placed a slight risk for severe weather tomorrow over portions of NC/SC?VA for tomorrow. Further analysis of model data shows favorable conditions for isolated tornado development between Greenville, SC & Raleigh, NC. The exact timing here is uncertain, but isolated supercells look to develop out in front of the main line of storms sometime later tomorrow afternoon. That line will then sweep across the states of NC & SC, causing isolated wind damage and hail throughout the night in both states. Below you can see the SPC image regarding the severe threat, and then a corresponding hodograph that I pulled from Upstate SC tomorrow around 6pm. Notice how the the storm motion(circled) is in the form of a spiral. That tell me that as air rises, it will naturally spin due to the variation in wind direction and speed as a parcel of air is lifted. If lifted parcels spin, the likelihood for tornadic development is increased.
Chances For A Spin-Up Tornado In WNC?
Those chances are always low, but they are never zero. We have had a few isolated tornados over the years, but the chances are always higher outside of the mountains due to updrafts constantly being undercut. I remember as a kid a tornado occurring in 1999. Here’s a link to the survey done by the National Weather Service, Asheville Tornado. The chances with this system will be very low, but always remember it can happen, and it will likely be very hard to predict when the conditions will be perfect for tornadogenises to occur in the mountains of WNC. As always though, it is so important for you to report anything you see. Whether its on social media, or calling your local national weather service office (GSP).. take a picture and post it so it can be evaluated by experts.
Flash Flooding Possible Through Wednesday
Isolated flash flooding cannot be ruled out all across WNC with the possibility of over 2” of rainfall falling in many locations through Wednesday. This surface low will meander across the Southeast, crawling towards the coast. As it stalls out, several rounds of rainfall will move through WNC. I am not expecting extensive flooding, but isolated street flooding due to high waters could be a problem. Some streams could rise, and even some rivers could reach very minor flood stage, but again I am not expecting extensive flooding since we have been dry for the past week. The water table is still high though, so be careful and turn around.. don’t drown. Be sure to check out the WNC Weather Camera Network to watch storms move into the area tomorrow afternoon, I will try and go live sometime today to give more details. Have a great Sunday!