Accumulating Snowfall Likely For Most Around WNC Christmas Eve & Into Christmas
Short range models continue to bring in new data as we progress towards Christmas Eve night, but the theme over the past 24 hours has been to increase the potential for very strong backside snow showers. After heavy rainfall moves through tomorrow morning, winds will pick up and moisture will begin to stream in from the West. Models continue to amp up this Upper Level Low and its been a while since we have seen one this strong, so I believe accumulating snowfall will be possible even in many valley locations.
Short Range Model Data & Timing
Model data continues to come in and a more clear picture continues to be resolved. What appears likely now is a strong push of rain Christmas Eve morning, then as the sun sets tomorrow evening.. snow showers will develop along the NC/TN border and high winds will propel those flakes into the valleys below. Below you can see a precipitation depiction from the most recent HRRR model.
Here is another short range index that I like to look at called the SREF Plumes. For the Asheville Airport, current plumes are showing around and inch of accumulation possible. As you work farther north from this station those totals will likely increase.
How Long Will Snow Showers Last
Several short range models are indicating that a batch of moisture will be created over the Great Lakes area and then move towards WNC. This Northwest flow moisture will re-energize the trough that has been laid down, and will likely create another batch of snowfall for many through the late hours of Christmas night. I have attached the most recent snowfall accumulation map per the NAM 3km as well as the precipitation depiction. Watch that backside Upper Level Low slam into the mountains of WNC at the end of the run. That indicates snow flurries will last through most of Christmas day, and then another batch of moisture could bring snow showers as the sun sets.
Isolated Flash Flooding Possible Christmas Eve AM
The trough that moves through beginning early Christmas AM will bring heavy rainfall, especially along The Blue Ridge Escarpment. Isolated totals of 4”+ will be possible. Around Asheville, I am expecting a quick 1”-2” for most in and around the city, with higher totals when you travel South, and lower totals when you travel North. Below you can see the most recent Nam3km precipitation projections for the first initial push of moisture.
Bitter Cold To Follow
The European temperature spread shows a very bitter weekend for WNC and I am going to advise that you leave those Christmas lights up until next weekend! Check out that low for Sunday morning at 12 degrees! Also check out the Nam3km wind chill projection for Friday night! Many high elevation locations will easily go into negative territory. This will be the coldest air in a couple of years that we have had here in WNC. It will be wise to keep a facet dripping at night to help keep your water from freezing up! Bundle up because its going to be a cold weekend!