Snow On The Way!

UPDATE POSTED 12:15PM: As the newest data has come in, it looks like the storm track is jogging ever-so-slightly to the east, which means the heaviest snow bands will also line up farther to the east. It’s not a monumental change from the earlier forecast (see below), but enough for me to adjust the snowfall forecast map a little bit:

The latest run of the HRRR model (High-Resolution Rapid Refresh, for those of you who are curious) shows the bulk of the precipitation missing the Triangle entirely. (It also shows some rain mixed with the snow, but I’m not buying that.)

The big-picture scenario hasn’t changed: we still expect the highest snow totals east of I-95, with rapidly diminish amounts as you head westward. The heaviest snow will still fall this evening and early tonight, and will be out of here by sunrise Thursday. More updates coming throughout the afternoon on television, on social media, and here on WNCN.com.

———————
POSTED 9:00AM: As the storm system that will race up the East Coast is getting its act together, the snow forecast for central North Carolina is coming into better focus. Not perfect focus, because that 20/20 vision is reserved for hindsight and second-guessing –- but our confidence is growing that this will be a significant snow event along and east of I-95.

Before the snow moves in, it will be another cold day overall. Temperatures this morning started off in the single digits and low teens:
Raleigh’s low of 9 degrees ties this morning’s record low, set all the way back in 1887! We’ll only warm up to the low to mid 30s this afternoon:

The big story, of course, is the developing storm system that will send snow across the eastern half of North Carolina. This is going to be a HUGE and powerful storm, partly because of the enormous temperature contrast between the cold air over the eastern United States, and very warm air farther offshore:
That kind of contrast will really juice the developing storm, helping it “bomb out” as it moves up the coast. That term has nothing to do with explosives -– it means that the area of low pressure will strengthen by more than 24 millibars over the course of 24 hours. (More on that in the nerd-links below.)

We’re seeing increasing clouds overhead this morning, with overcast conditions prevailing throughout afternoon. The first wave of moisture will evaporate in the very dry air over central North Carolina, but by late this afternoon we’ll start to see some flakes flying in the Sand Hills and near Fayetteville. The accumulating snow really won’t kick in until this evening and overnight, as shown here by the RPM model’s radar simulation:


Keep in mind, these forecast models aren’t perfect -– they give us a good idea of what to expect, but the atmosphere will do what it wants, when it wants. So we’ll keep this snowfall forecast map updated throughout the day:
The National Weather Service’s forecast is very similar:
Look at how quickly you can go from NO snow to over 3” on the ground – just 60-70 miles! That tight gradient makes this a very tricky forecast…a little ten-mile jog in the path of this huge storm system could dramatically alter the forecast in your neighborhood. In fact, this is the very newest (as of 8am) version of the RPM model’s snow forecast:
We try to not overreact to every single model run -– otherwise we’d be whiplashing back and forth between various forecasts -– but “the trend is your friend” in the forecasting world. We’ll be carefully watching to see if that westward trend continues…or if it’s just a bad model run!

With that in mind, let’s look at the “boom” and “bust” scenarios…the National Weather Service office in Raleigh estimates a 10% chance of either extreme:


What could happen in the atmosphere to push us toward either end of the spectrum? The two big variables are 1) the exact path of the overall storm system, and 2) how quickly the falling snow will overcome the dry air in place. If the storm system tracks farther offshore and the dry air is stubborn, we’ll end up with lower amounts areawide. Conversely, if the area of low pressure tracks just a bit closer to the coast and is able to send more moisture ashore (lower odds, but not impossible), we’ll overachieve on our forecast amounts. For you snow-lovers in the Triangle, here are your odds of hitting the snow jackpot over the next 24 hours:
That’s why it’s so important for you to stay weather-aware throughout the day –- we’ll be monitoring the latest data as it comes in, and we’ll keep you updated on what to expect.

In terms of impact, the ground is definitely cold enough for the snow to stick to the roads -– we’ve been below freezing since Sunday! I’m cautiously optimistic that we’ll be able to get through the afternoon/evening commute without major problems, but I would count on a significantly longer drive to work and numerous school delays/closings on Thursday morning:

The snow will be gone before sunrise on Thursday, and it looks like most of the clouds will be gone already as well. That leaves us with plenty of cold sunshine Thursday, Friday and Saturday, with a miniscule warm-up on Sunday:
We’ll finally climb to near-normal temperatures early next week, with a few plain ol’ rain showers possible late Monday and early Tuesday.

LINKS

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