Wednesday – WINTER WEATHER ADVISORY 3 AM THRU 6 PM – Wake Up: 23°, High: 36°
Both Williamson and Davidson counties are under a Winter Weather Advisory tomorrow:
NWS is calling for about 2 inches of snow. Models are pulling about 3 inches, so that range looks like the sweet spot … Snow is more likely north than it is south…. Model data also has temps at 5,000 feet below freezing in Davidson County, above freezing in Williamson County. That means we may see snow only along and north of I-40, with a mixed bag of snow, sleet, and freezing rain south of I-40….After noon, the precip will change to rain as we rise above freezing, then move on out.
NWS has added a tenth of an inch of ice to everyone’s forecast, which is bad news for morning travel.
Review precip types & what makes them different:
Freezing rain is the worst, because it freezes on contact with surfaces, including roadways.
It appears we will have to deal with some of that tomorrow, so we’ll need to be aware. A breakdown of what we think will happen tomorrow is below.
Precip will begin to arrive overnight, around 3 AM for us, which is when the Advisory kicks-in for everyone.
Models have come into an okay agreement that we have a good shot to start things off as snow. Models generally keep the line where snow changes over to freezing rain south of Davidson County early in the day, but that line is a constant mover, and we’ll have to watch it very closely.
Here’s the NAM:
HRRR shows better odds:
Here’s the GFS:
We continue to have confidence in us seeing some snow early in the morning, because the Euro model (which we are not allowed to show you) keeps Davidson County & points north in snow territory through noon. In fact, the Euro thinks we could see a couple of inches. However, the Euro keeps a steep snow drop-off over Williamson County. We’re afraid this could be where the snow/freezing rain line will be dancing early in the morning.
Even if we see some snow, we’re all likely going to be faced with some freezing rain by mid-morning. In the 6 AM GFS model above, notice the big blob of pink just to the west of us. That’s freezing rain, and we’re concerned that blob will nail us late in the morning.
Here’s the NAM at 9 AM showing freezing rain passing through:
After a little snow and some freezing rain, by noon we think temps will rise above freezing.
Here’s the NAM, showing a transition from freezing rain to plain rain at noon:
The GFS shows some snow, some freezing rain and liquid rain accumulations all from 6 AM to noon:
Like the NAM, it is hinting at a changeover to all rain around noon, as rain begins to work in from the west.
Once we head into the afternoon, the worst of it will be east of both counties.
The NAM shows just light rain at 3:
The GFS just keeps some light plain rain around from 12 PM to 6 PM:
One thing that remains constant: both counties are in the zone that could see all types of precipitation (snow, freezing rain, rain), and that inherently causes uncertainty. The line where snow changes to freezing rain and freezing rain to rain is a fickle one, and is hard to pinpoint. Because we’re in the “zone,” the forecast will be evolving and changing, probably up to the point where we’re watching it all unfold tomorrow to our west.
Prepare for undesirable & potentially dangerous travel conditions. It doesn’t take much freezing rain at all to send roadways into mayhem. Be smart and check the roadways if you have to get out. As always, we’ll be updating you here and on Twitter.
Tomorrow evening looks very cloudy, but all rain/freezing rain/snow issues will be gone.
Thursday & Friday – Another (hopefully more clear-cut) Winter Weather Chance
Another storm system will impact us Thursday afternoon and into Friday.
This one looks like a quick and painless change from rain on Thursday…
…to snow by Friday:
Taking the ice/freezing rain component out of it looks to make this a less-impactful event than Wednesday’s.
But, snowfall may hang around until Saturday, with accumulations up to another 2 inches on top of what we get tomorrow.
This website supplements @NashSevereWx on Twitter, which you can find here.
Categories: Forecast Blogs