Snow Tuesday; Cold through Thursday
Good morning folks! We are less than 24 hours from our 1st region wide snow event of the season and as of now it doesn't look like a major event, more of a travel nuisance during the morning rush hour on Tuesday. The timeline has shifted somewhat as the models show the changeover from rain to snow occurring shortly after midnight as opposed to our previous window during the evening hours. The temps and snow totals remain the same and we still expect some sunshine later in the day Tuesday. Sunny skies will dominate the forecast after the arctic front sweeps the region, with sunny skies overhead Wednesday through Sunday. Temps will remain well below average through Wednesday, only reaching highs typically experienced during the month of January and a slow warming trend begins Thursday, culminating in temps a touch below normal by this weekend.
The arctic front will push a band of showers through the region late this evening and in typical frontal form, the colder air will lag behind, however this go around the cold air and supporting high pressure system is strong enough to kick rain over to snow. We expect a transition to snow above 5500' sometime around 10 - 11pm, with snow levels falling to the valley floor by 3 - 5am. There is the possibility our deeper valleys like Franklin, Sylva, and Cullowhee hold out the longest, resulting in a wintry mix as opposed to a sharp transition from rain to snow. The main concern will be crashing temps as enough water will be on local roads to cause flash freeze issues, which is when temps crash fast enough to freeze any standing water; normally this water is evaporated well before temps become cold enough. Not all of SW NC will undergo a flash freeze, mainly locations above 3000' as a 10° drop in temps occurs within an hour sometime during the pre dawn hours.
As for how much snow, be sure to check out the SNOWCAST Map on the home page, but generally we expect nothing more than a dusting up to a half inch for the valleys, especially valleys closer to the TN line. The notable cutoff from accumulating snow to passing snow showers will be around the Southern Highlands Plateau (Lake Glenville, Big Ridge and so on) as this event looks more like a NW flow event than a passing clipper system (tougher for continuous moisture/showers to hold on past the TN line). As you go up in elevation, so do the totals with 1 - 2" above 3000' and 2 - 4" above 5500'. The TN line will produce the highest totals, with 6" possible for Mt LeConte as they are likely to see a changeover to snow as soon as 10pm, coupled with ground temps well below freezing before the event even begins.
Temps Tuesday will actually reach their high shortly after midnight, with temps peaking to the upper 20's - mid 30's but falling throughout the day. Eventually temps plummet to the single digits along the ridgelines, while the valleys hold to the mid teens overnight into Wednesday. We encourage everyone to bundle up and dress for a blustery day as NW winds pick up to 10 - 20mph region wide throughout the day Tuesday and overnight into Wednesday, gusting up to 25mph in the valleys and 40mph along the ridgelines. This translates to below zero wind chills above 5000' and its even possible Mt Mitchell makes a run at a below zero temperature reading (not wind chill, actual temperature)!!!
Sunshine moves in late Tuesday as the moisture clears out, setting up clear skies Tuesday night and sunny skies Wednesday, with dry weather continuing throughout the week. Temps climb to the low 30's - mid 40's depending upon elevation Wednesday, eventually warming to the low 40's - mid 50's by Friday.
We'll circle back Wednesday morning to report snow totals and we encourage everyone to submit an observation as to how much snow they picked up or experienced. You can do so by email at firstname.lastname@example.org or via our various social media accounts.