As much as four inches of rain are expected across Scott County through the weekend and into early Monday, which will bring a slight risk of flash flooding to the region.
The National Weather Service has not issued any flood watches or advisories for the northern Cumberland Plateau region, but has issued a Hydrologic Outlook, which reads thusly:
Periods of rain, heavy at times, are expected across the area
Today through early Monday morning. The heaviest and more
widespread rainfall will likely fall across the entire region
Sunday afternoon through early Monday morning when 2 to 3 inches
are possible. Storm total rainfall through Monday morning may
range up to 3 to 5 inches with locally heavier amounts.
The rainfall Today through Saturday will help saturate the soils
across the entire region. Therefore, any additional rainfall may
lead to flash flooding concerns across East Tennessee, southwest
Virginia, and southwest North Carolina beginning late Sunday.
Flash flooding of roadways, low lying areas, small streams, and
possibly mainstream rivers are possible. Mud slides are also a
There is still some uncertainty on the timing of periods of the
heaviest rainfall and exact amounts over the next couple of days.
However, confidence is increasing for the potential of heavy
rainfall and flooding. We will continue to monitor this situation
and will issue more information as the system approaches.
This is all associated with a warm front that will slowly lift north through the weekend, spreading copious amounts of gulf moisture into the region interacting with several pieces of energy to bring multiple rounds of moderate to heavy rain across the entire area.
The first of what will be multiple rounds of moderate to heavy rain is approaching the region late Friday morning. So far, the heaviest rains have remained south of Interstate 40.
On-and-off rain showers will be a safe bet throughout the weekend, but the next round of heavy rain can be expected on Saturday, and may be more focused on the northern plateau region than this first round is. Then, on Sunday, we could see the heaviest rain of the entire weekend ahead of a cold front that will be approaching from the west.
The NWS’s forecast is for 3-4 inches of rain for most of East Tennessee (with lesser amounts in the mountains and upper East Tennessee and heavier amounts possible for the rest of us). That’s a little less than some earlier forecasts, but still enough to cause issues, depending on how quickly and heavily the rain falls.
For now, it appears we’ll see heavier rain late tonight and tomorrow morning than we’ll see today, and heavier rain Sunday evening and Sunday night than we’ll see tomorrow. As the NWS indicated in its hydrologic outlook, rain totals remain uncertain. For now, the GFS is easily the wettest of the models, with up to 5 inches of rain for the northern plateau region. The ECMWF is somewhat drier but still shows close to 4 inches of rain for the region. The NAM shows about 3 inches of rain. The HRRR shows a little more than an inch of rain through 7 a.m. Sunday morning, before (potentially) the heaviest rains of the weekend move in.
Soils aren’t terribly saturated as the weekend begins. Several days of dry weather, plenty of sunshine, and some nice gusty breezes helped dry things out quite a bit this week. But it won’t take long for rainfall today and tonight to saturate things and begin to cause runoff and ponding issues. Then, if the heavier rainfall materializes on Sunday, that’s when we could see some isolated flooding issues — particularly in the usual trouble spots.