Disclaimer *First of all, I apologize for formatting. I was not able to get the text to wrap around the images like I usually can, so things might look a little wonky on the mobile version of this post*...
The "What"
Models were hinting at a major winter storm this weekend around this past Monday or Tuesday, and now that we're within 48 hours models are aligning in their predictive calculations. If you just want totals, types of precipitation, and impacts expected, you can skip to the end. The 4 .gif files that I'm using are the surface and 850 mb model guidance temperature for the GFS and NAM weather models from the 06Z model run through 48-66 hours. I used these to show the differences in each model with respect to temperature at the surface as well as in the mid-atmosphere so that you can see where the model is getting it's guidance from.
The Setup
The surface low will be moving up through the western Piedmont of NC, which will cause strong warm air advection from the Atlantic to heat the mid-atmosphere to temps above freezing for central NC, however the surface cold pool from the
Types of Precipitation by Region:
Mountains
If you want to see snow, the mountains are where you'llFoothills
Places like Hickory, Statesville, and especially further north like Mount Airy and Pilot Mountain will experience mostly snow through the event and due to surface temperatures should have some nice accumulation of up to 8-9 inches, especially areas further north which will benefit from additional accumulation on Monday morning as the low continues to track north.Western Piedmont
Getting into Winston Salem and down to Charlotte will experience still snow but less than foothills, however due to that pesky warm nose in the mid-atmosphere the temperature will rise above freezing by mid-afternoon on Sunday which will cause falling precipitation aloft to melt prior to coming into the surface air. The surface air, however, will still be below freezing and thus liquid precipitation will freeze on contact. This is freezing rain. After a few inches of snow (4-6" for this area), precipitation will transition to freezing rain before making a transition back to snow by dinner time for a short while before the precipitation ceases to fall.
Central Piedmont into Sandhills
This is where things get really messy. Precipitation will begin as early as 4 am Sunday morning in the Sandhills but hold off until around 10-11:00 am as far north as Henderson. The reason behind this is because the cold air settling in on Saturday night is not only cold, but also very dry. Part of the cooling will come occur from a process known as "evaporative cooling", which is the short and sweet describing the process by which liquid moisture evaporates into dry air as it falls, working to saturate the air with respect to water vapor, absorbing heat from the atmosphere to do so.
I'm expecting precipitation to start as snow prior to lunch in this area, transitioning quickly to sleet then freezing rain before early afternoon.
Afternoon hours will experience a surface temperature rising above freezing, which will cause liquid rain to fall at the surface and work to reduce accumulations of all types of wintry precipitation.
Getting into dinner time the temperature will drop back below freezing at the surface, and precipitation will make a shift back to freezing rain before ending around mid-evening on Sunday.
Coastal Plains
The Coastal Plains will experience mostly liquid rain for the duration of the event, with the heaviest rain occurring mid-afternoon Sunday into dinner time (timing from south to north) as the low tracks northward.
Types/Accumulations Summary:
Mountains:
