Busy times in the weather department these days…let’s start with some good news: Saturday looks pretty nice! A cold start with lows in the upper teens, but we’ll see lots of sunshine throughout the day…that will help push temperatures up to the mid 40s. After that, things get complicated.



SUNDAY: Rain showers will become likely Sunday, spreading from west to east. Cold air is going to be charging in right on its heels, changing the rain to snow. Both of our in-house Futurecast computers (the RPM and BAMS models, for the geekily curious) are in remarkably good agreement with the arrival time of the rain, the transition time to snow, and the amounts of snow that could accumulate. They don’t agree perfectly, but they’re definitely in the same ballpark. For what it’s worth, I’m leaning toward the “BAMS” model (on the right in the images below). Graphics time!

9am Sunday: rain just moving in.



Noon Sunday: heavy rain NW.



3pm Sunday: heavy rain in Nashville, snow to the NW.



6pm Sunday: heavy snow in and around Nashville, tapering off west, rain to the east.



9pm Sunday: snow tapering off in Metro, heavy snow east.



Midnight: heaviest snow exits, just flurries the rest of the night.



Here are the computer-generated snowfall forecasts, in all their high-res full-scale glory. Again, computers are guidance-not-gospel, but it gives you an idea of this storm’s potential impact. I won’t be ready to bless one of these with the official “kiss of inaccuracy” until tomorrow…or more likely, Sunday morning.





As of this post (early Friday afternoon), here’s what the National Weather Service is saying (EDIT: NWS has bumped up their forecast amounts just slightly):



“Rain changing to snow” probably sounds familiar, since that’s what we saw just yesterday (when amounts were limited to 1″ at the most). Why will this storm be different from Thursday’s? Several reasons:

1) the ground will be colder

2) the snow will be more intense while it’s falling

3) the snow will last longer

4) the snow will impact a much larger portion of the Midstate.

5) much colder air will follow the snow, allowing it to stick around for a while

MONDAY AND TUESDAY: The last time the official temperature in Nashville dipped below zero was in February of 1996. Record low Monday morning is -10, record low Tuesday morning is -6. Record for the coldest-high-temperature Monday is 10. All-time record low temperature in Nashville is -17. Why am I telling you all of this? Wellllllllll…

It’s gonna get #StupidCold.

Every new batch of computer data has trended colder and colder with Monday and Tuesday’s temperatures. Here’s Futurecast’s version of Monday’s and Tuesday’s lows and highs…keep in mind this is ONE computer’s version of what’s going to happen over 60 hours into the future:







Unfortunately, I don’t have wind chill simulation maps yet (we’ll have to wait until tomorrow for those), but you can plan on wind chills in the -15 to -25 range all day Monday. Wind won’t be as much of a factor Tuesday…hooray?

Common sense reactions to the snow and cold will keep you safe 99% of the time. If there’s snow on the roads, just slow down, allow extra time to reach your destinations, and allow extra stopping distance. And if you don’t have to drive, don’t! If you’re going to be outside for anything more than a couple of minutes, make sure all exposed skin is covered with a hat, scarf, gloves, etc. Wind chills in the -15 to -25 range can result in frostbite in as little as 15 minutes.

Recommended mode of travel (and emergency warmth) from Sunday night through Tuesday morning:



Since I started this post with good news, I’ll try to end it the same way: there’s still time for this to change! People who don’t understand how forecasting works always gripe about how “the forecast always changes” (well, because that’s what it does), but in this case a changing forecast is the best we can hope for! I’ll post an update tomorrow afternoon about both Sunday’s snow and next week’s cold.