What In Tarnation Happened to the Snow?







This was how I felt yesterday…disappointed.  Disgusted.  Depressed…not really.  But maybe a little.  This was supposed to be our shot at a decent winter event.  The synoptic track was near-perfect.  Thermodynamics appeared very supportive of a winter weather event.  What happened?  I’m still wondering about that myself, and I’ll address that below.  This stanza is more about therapy.  After a missed, or a “busted”, event, I often find myself looking back and trying to understand what went wrong.  It’s how I deal with the agony of defeat.  Reliving the event, I’ve found, is very cathartic for me and affords me the ability to apply what I’ve learned to future events.  Some people have $200/hour therapists, I have a blog.  I’m already $200 richer.  #Winning.


The Aftermath

Nationally, this storm put the hammer down across the Deep South.  From northern Mississippi, early Wednesday morning to central AL, northeast GA around dinner time, and up through the East Coast today, Winter Storm Pax (Weather Channel’s name, not mine) laid down a swath of snow and ice that would make the Ice Age proud.  Some totals from across the area:

Crossville – 6″

Chattanooga – 8-12″

Morristown – 7″

Totals across North Carolina and Virginia were nothing short of crazy.  If even half of those totals fell across Middle Tennessee, the midstate would be shut down until Spring.  Atlanta got hit with another ice storm, causing over 130,000 people to lose power Wednesday morning, and that was before the storm got ramped up. 

Here locally, the National Weather Service in Nashville received scattered reports of one-inch totals, mainly across the southern half of the county.  The northern half, I’m betting, didn’t see the first flake.  I know I didn’t.  That’s right…I went all day without seeing a single, solitary wet snowflake.  Now you understand the depth and magnitude of my depression.

The Lead-Up

As I’ve stated previously, the synoptic setup for this event was as favorable a setup as we’ve seen this entire winter.  We had a strengthening low across the Gulf of Mexico that was going to throw moisture northward into a thermodynamically-favorable airmass.  This was never going to be a huge storm by any stretch of the imagination.  The most favorable dynamics were always slated to stay to the south.  As such, the NWS issued a Winter Weather Advisory for most of southern Middle Tennessee – including Rutherford Co – for the expectation of 1-3″ of snowfall.  The numerical models supported this forecast.  Climatology supported this forecast.  The combined weather-forecasting experience contained inside the walls at Old Hickory were the foundation of this forecast.  So, what happened?

What Happened?

Mother Nature and Old Man Winter conspired to ruin everyone’s day, that’s what happened.  Well, not really.  It would be easy to place blame like that, but in reality, it’s not that simple.  Numerical models have been around for decades and are purposely built, maintained, and programmed to correctly foresee ripples in the meteorological universe that ultimately become systems that effect our weather.  Several days prior to the event, numerical models were insinuating that temperatures would be supportive of accumulating snowfall all day yesterday.  Virtually every global model (European, GFS, CMC) was in fairly decent agreement that temperatures would cooperate.  

As the number of days leading up to yesterday’s event lessened, a warming trend began to appear, leading many in the weather community to speculate as to what the models were seeing.  A day or two prior, a fellow weather hobbyist of mine, Justin Mundie, hypothesized that the result of these temperature anomalies were from downsloping winds coming off the Plateau into Middle Tennessee.  The physics behind that are rather difficult to explain, but, put simply, as an air particle decreases altitude, it warms up via an adiabatic process (a process that occurs without the transfer of heat or matter between a system and its surroundings).  Whether that original hypothesis was right or wrong, I’m not smart enough to dispel it.  After the moisture pulled out, Justin applied his own “debrief” of the event via Twitter (@justinmundie): 

“Debrief on what happened today: in short – I’m not sure. Short term models last night were showing a huge rise in surface temps.  I was sure about it as the global models had been consistent on temps being right at or below freezing. Obviously by this am, everyone knew it was going to be a concern. QPF came in about as was predicted, little if any north of I-40 – plenty south.  But with marginal surface temps, and marginal temps around 2000ft – the rate of precip wasn’t able to drag down cold air.  In fact – that dry, slightly above freezing air may have contributed to warming the surface – as precip wasn’t making it to the ground.  Another factor I believe was the cold air damming on the other side of te apps. Our cold high pressure was funneling cold east of the apps  All the way down to Atlanta – causing the severe winter storm they have seen today. That effectively cut off our cold air source.  So even with east/northeast winds, we weren’t able to keep temps cold enough for snow.”

With my limited knowledge of meteorology, and Justin’s knowledge of winter weather systems, I’m inclined to believe this hypothesis more than his previous iteration.  Some at the NWS hypothesized that the marked increase in progged surface temps could have been the result of increased solar angle and increasing solar insolation (the heating of the Earth’s surface by the sun).  I see no reason to doubt this hypothesis, either.  

Perfect Storm

So, it appears as though a perfect storm of inhibiting factors precluded us from getting a piece of 2014’s “perfect storm” across the South.  Snow is so inherently hard to get in Tennessee, whether it be by warm surface temperatures, imperfect storm tracks, or a blasted #SnowDome over Middle Tennessee.  Honestly, I’ve been quite skeptical of a #snowdome, but I’m a converted believer.  For my own sanity, I do hope this was the last winter weather system we’ll have to face across Middle Tennessee this season.  I love snow as much as the next person, but if I’ve got to sacrifice a limb to see fluffy, wet snow, I’d just assume pass.  





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