A river of moisture will set up in the atmosphere over the southeast during the next four days, and that will bring ample amounts of rainfall to the entire area. Many locations will see over 2.5” of rainfall through Thursday evening, and isolated locations in SW WNC and along the Blue Ridge Escarpment could see over 6”. This will fall on already saturated soil that just received 4”+ of rainfall over the past 4 days. Several concerns are increasing around WNC including the threat for mudslides. If this pattern continues, slopes around the area will continue to be jeopardized. Below you can see the most recent GFS model precipitation output for the next 5 days. Notice how there are higher totals around locations like Andrews & Franklin compared to Asheville. That is due to the Southwest enhancement that naturally occurs when precipitation infiltrates from this direction.
Where Will The Most Rain Fall?
With this type systems, where there is great Southwest push out ahead of the main front, locations along the Blue Ridge Escarpment will rake in the most precipitation. That means that places like Lake Toxaway, Highlands, Cashiers, Brevard, Rosman and other locations along the NC/SC border should be on alert for mudslides and the possibility for flash flooding as the week moves on. Looking at short range models, the Nam 3km shows over 5” of rain falling in the above mentioned locations through Tuesday afternoon. This is extremely concerning to me. Below you can see the most recent Nam 3km precipitation amounts, and several locations along the Escarpment crest that 4” mark.
Where Will Flash Flooding Be Most Likely?
From the topographic map above, you can see how when the flow of moisture sets up from the Southwest, it is enhanced. Areas that are nestled close to the Blue Ridge Mountains experience more rainfall compared to those that are tucked in the valleys between the Blue Ridge Mountains & The Appalachians. Locations like the Nantahala Gorge are very susceptible to mudslides and traveling through these locations over the next 4-5 days should be done with extreme caution.
When Will Rain Move In?
Below you can see the simulated radar from the 3km Nam, and scattered showers will be possible during the day on Monday, but as Monday night progress those showers will increase into a steady rainfall. By Tuesday Morning it appears that strong lift will be in the area and locations along the Blue Ridge Escarpment could be experience very heavy rainfall.
Please be mindful of this when traveling around WNC on Tuesday Morning, ponding on the roadways appears to be certain and several streams and rivers could very well be out of their banks. I say this often, but please turn around and don’t drown. There are so many alternative routes here in the mountains of WNC.
Another Round of Rain Through Thursday
This push of moisture will retreat after Tuesday, and another round of rain will Wednesday and into Thursday with flash flooding concerns again for the same areas. This week is going to be an absolutely nasty week around WNC to be honest. If you have desires to complete outdoor activities, Sunday (today) and Monday are going to be your best days to accomplish anything. After Tuesday, your mud is going to be wet again and any outdoor activity will be slippery. Trust me I know!! Many locations could break February monthly rainfall records this week already! Needless to say this has been a very wet winter, and if you read my winter weather forecast for this year I indicated that. I also indicated that below average snowfall would be likely. There will still be chances for snowfall as we move through late February, but any chances during this week will be of the Northwest flow variety on Friday AM.
Northwest Flow Snow Possible Friday AM
High elevations be on guard for you next snowfall event that will come on Friday morning in the way of Northwest flow on the backside of the system that will affect the area all week. Finally Thursday afternoon the frontal passage will occur, and temperatures will plummet late Thursday. Winds will pick up and moisture will be strained out along the backside. Elevations above 3500’ on the NC/TN border will see some form of accumulating snowfall. Details still need to be hammered down, but this is the next chance for accumulating snowfall in the mountains of WNC. Check back soon for another update, and more details regarding this flow.