Before we get to the weather, let me say this: I love The Simpsons. LOVE. When I was in college and grad school, I used to tape every episode — I had about 20 full VHS tapes on the shelf by the time DVDs came around. And then they started releasing whole seasons of TV shows on DVD, and I realized…



So, that’s the reason for the theme to this post: because I wanted to, and because I can usually come up with a Simpsons reference for pretty much any occasion. Impressive or sad? You be the judge.

Anyway…the forecast is a little snowier compared to what I discussed in this space 24 hours ago. Just a tiny bit, but if you’re a snow-lover I’m sure you’re doing this:



And if you’re one those people who could happily live the rest of your days without seeing another snowflake…sorry:



We had some sleet and snow mixed with the cold rain this morning, even some minor accumulations on elevated surfaces to the north and east of Nashville. But as moist air surges up from the south, it’s dragging along slightly warmer air above ground level — that means we’re in for mostly cold rain showers through this afternoon. Still, the radar view just before noon looked like this:



Now, most of what you’re seeing in pink (rain/snow mix) and white (snow) isn’t sticking to the ground, just decks and rooftops before it melts. But it still indicates that the warm air with this system is having a hard time displacing the cold air already in place, and that in turn means the cold air should have an easier time making eastward progress this evening.

Let’s fire up the Futurecast computer…



…and show you the cloud/radar simulation for this afternoon:







Notice the northwestern corner of the Midstate at 5pm. The cold air looks like it’s going to catch up to the moisture to prompt a changeover from the cold rain and rain/snow mix we’ve seen there for much of the day, to just plain old snow that has a chance to stick. (IMPORTANT: This is always the most challenging part of any winter weather forecast — if the cold air is slower, or if the showers move faster, they won’t coincide to produce ANY accumulating snow, let alone the small amounts we’re forecasting for this evening and tonight.)



But for right now, here’s how it looks like the rain/snow progression will unfold across the Midstate this evening:















Now, if all of that blue and white on the Futurecast simulation gives you visions of doing this…



…or nightmares of this…



…just slow your roll for a second.

A few factors will limit our snow accumulations, even once the precipitation is all snow:

1) the snow will fall on wet ground, helping to melt the flakes

2) the ground will also be relative warm, helping to melt the flakes

3) air temperatures aren’t likely to drop below freezing until after the snow ends, helping to…well, you get the idea. Basically, our accumulations will be about half (or less) of what would add up if the snow was to fall on frozen ground.



So, how much will add up? Here’s what the various models are saying…don’t worry, I won’t just throw computer data at you — my overall forecast is after the model stuff. But I want to give you an idea of how many different data sources are considered when it comes to putting together these forecasts. If you want to skip past all the models, just scroll down until you see Comic Book Store Guy (if you don’t know who that is, please re-evaluate your life choices, or at least your television choices).

First up, the “RPM” (the model used in the Futurecast images above):



Sometimes we use the “BAMS” model to feed Futurecast…it’s not impressed with this storm system AT ALL:



The “NAM” model (one of the NOAA computer models) is the snow-friendliest:



Snow lovers, commence your drooling…



…but keep in mind that if the NAM was a Simpsons character, it would be:



The “GFS” model (the other main NOAA model) is a little more reasonable in its depiction…weather nerds recognize how hard it is for me to acknowledge that fact:



The “ECMWF” (the European model you’ve probably heard about in national news stories, because it beats the pants off the American models when it comes to long-range forecasting) ignores the Cumberland Plateau for reasons that mystify me:



The “HRRR” (a very short-range model that sometimes is very accurate, and sometimes not so much) basically says “a little, not a lot”:



Finally, the “SREF” (an ensemble model, or combination of multiple data sources) is almost as unimpressed as the BAMS:



Head spinning?



Here’s what I’m thinking for the “at-most” snowfall potential tonight. ANOTHER IMPORTANT NOTE: the “at-most” phrasing means that you likely will see less in your back yard. If you’re in the area that says “Dusting – 0.5″ you’re more likely to see a dusting that you are 0.5”, and you’ll probably get even less than that. Don’t think of it as “this is what we’ll get,” think of it as “we’ll get less than these amounts unless everything works out juuuuuuuuuuuust right.” This map is a result of combining the model data, an analysis of how this storm system has been behaving so far (both in terms of temperature and precipitation), and how similar storms in the past have behaved.



Enough snow to shut down society? No. Do you need to rush to the store to stock up on perishable items? NO. But it is enough that I’ve adjusted the needle on the Panicometer:



LATE-AFTERNOON UPDATE: the National Weather Service revised their predictions (upward), and is now predicting these amounts:



Also, both NWS-Nashville and NWS-Louisville have issued Winter Weather Advisories (purple counties on the next map) for portions of the Midstate — the advisories for the eastern half of southern Kentucky are in effect until 4am Saturday, the advisories for NW Middle TN are in effect until 6am Saturday.



Regardless of how much we get, any snow that does accumulate won’t last long. The sun will break through quickly on Saturday morning, and temperatures will reach the mid 40s by Saturday afternoon. Even Hank Scorpio can’t melt snow that fast.



Um…maybe he can.

Yet another chance of mostly-rain-but-a-little-snow is on the way for Sunday and Sunday night. We’ll keep a close eye on that over the weekend…because there ain’t no party like a weather-nerd party.



Follow us on social media for updates over the next couple of days…links to the relevant accounts are at the bottom of this post. Lisa Spencer and Dan Thomas will have updates this evening, and I’ll be filling in for Nancy Van Camp on the air Saturday morning to put a bow on things as the last of the flurries exit the area.

And if you’re sick of winter…well, before you know it, summer’s heat and humidity will be here.



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Social media links

Twitter: @WSMVweather, @PaulHeggenWSMV, @WSMVLisaSpencer, @WSMVDanThomas, @WSMVNancyVanC, @NWSNashville

Facebook: 4WARN Weather, Paul Heggen WSMV, Lisa Spencer, Dan Thomas WSMV, Nancy Van Camp WSMV, NWS Nashville