January 5: VERY Light Snow Chances, Daily Links

WEATHER

Before we get into the details, let me say this right up top: this is NOT going to be a major snow event for the Midstate.  Almost all of us will see less than one inch of snow…and you’re much more likely to get ZERO than you are to pick up 1″.  That said, we live in the South, and just one layer of flakes between your tires and the road is enough to cause some problems.

The tricky part of snow forecasting stems from the fact that it takes so little water to produce snow.  In the spring, summer and fall, you really don’t care if you get 0.05″ of rain instead of 0.15″ — but with temperatures in the 20s, that the difference between a half-inch of snow and almost two inches!  So as I get into the outline of what I think is the most-likely scenario, keep in mind that our forecast confidence when it comes to low-moisture winter weather events is best described as:
jck

Light snow showers will be moving in from the west by midday and through the evening.  The forecast models aren’t handling this well…plenty of discrepancies between the various models, and plenty of changes within the same models from run-to-run.  Our RPM model shows this scenario throughout the day:
rpm-10a-thu rpm-12p-thu rpm-2p-thu rpm-4p-thu rpm-6p-thu rpm-8p-thu
I think that model has a good handle on the pattern, but it’s probably underestimating the effect of dry air near the ground eating away at the falling snow.  The dry air shows up very clearly on this morning’s weather balloon data from Nashville (in the oval):
bna
That’s why I lean toward the HRRR model, which isn’t as impressed overall:
hrrr_2017010512_ref_nashville

Accumulations will be light, but could be enough to produce slick spots on the roads.  The RPM model thinks the snow pattern shapes up like this:
paul-rpm-4km-snow-accum
The latest version of the HRRR (which updates every single hour) shows this:
hrrr_snow_nashville_16
That’s a big ol’ nothing-burger for most of us.  (Very similar patterns shown by those two models, finally!)  Factoring in the data from those two models (plus data from the SREF model and other acronyms you really don’t care about), here my estimate:
paul-snowfall-2
Let me shout this at you: YOU’RE MORE LIKELY TO GET THE “BUST” AMOUNTS AS OPPOSED TO THE “BOOM” NUMBERS.  In Nashville, I’m betting on flurries, but it’s a close enough call to include Metro in the “minor accumulations” possibility…plus, it’s winter, and weird stuff can happen.  The best chance of more than 1″ of snow will be in the higher terrain of eastern Middle Tennessee.

Another chance of snow showers for southern Middle Tennessee arrives early Friday…once again it will be very brief and very light:
rpm-6a-fri rpm-8a-fri rpm-10a-fri
I’d expect a half-inch or less out of those snow showers — we’ll keep you updated if that changes.

In terms of temperatures, it’s going to be COLD!  High temperatures will reach the low to mid 30s today:
thursday-highs
We drop to the low 20s overnight:
friday-lows
Temperatures will remain below freezing all day on Friday:
friday-highs

The sunshine returns this weekend, but it won’t help temperatures very much:
wsmv-4-plus-4-am

A more-substantial warm-up starts to kick in on Monday, and will be much more noticeable by Tuesday through Thursday:
wsmv-4-plus-4-am-2
Just plain old rain showers in the forecast late Tuesday into Wednesday.

 

LINKS

I’m back from vacation, and so are the nerd-links!

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About paulheggen33

Morning meteorologist for WSMV-TV in Nashville.
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One Response to January 5: VERY Light Snow Chances, Daily Links

  1. Amy says:

    Great detailed report and explanations, thank you!

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