TellicoWx

18z GFS...keep working that mojo Carvers lol

Up to 1365 w/o power now

Well that was interesting, temps went from 42 to 59 back to 39...in a span of 15-20 mins. Had wind gust close to 60mph, at the time..almost 1000 residences without power now.

Crazy to think as most of the state deals with freezing weather, I will be close to 60 up here in the mountains tomorrow. Everyone from the plateau west stay safe/warm.

If the cold can penetrate enough to give BHam 6" and New Orleans a major ice storm like the RAP showed..the valley would score as well. Has the bulk of the precip lagging behind the low

I could easily see somewhere between Jackson and Nashville topping 12"..best ratios and qpf.

West and Middle TN are about as locked in as you can get (barring a giant shift SE which would hurt western areas), the big question mark is the plateau/valley

Based off the depth of the cold banked against the plateau on soundings.. the Eastern valley is literally only a 100' or so from being a sig. ice event vs mainly cold rain. GFS/NAM doesn't pull enough thicker cold to clear the plateau until the system has passed (due to track)..Euro would be very similar to the RGEM/CMC except it has multiple lows vs one primary (@850), which mess it up for one frame. RGEM would be more ice than depicted, once that cold tops the plateau it will rush into the valley.

FRAM is the Freezing Rain Accumulation Model..similar to how Kuchera is used for snowfall...simulates the ice to liquid ratio for freezing rain events

UKie on pivotal combines freezing rain/sleet with the snow accum

Ugly 12z...systems almost train over the same areas

GFS is just one system after the next for middle/west TN

The higher the 850's are, the more heat that is trapped in the water molecules that must be released during the ice formation

Actually it's not...here's the process that happens, it's the reverse of what happens during evaporative cooling. Evaporative cooling is going from a solid (snow) to liquid (rain) as it falls thru the column..to complete the process it needs to absorb the heat from the surrounding air. Freezing rain just reverses that (liquid to solid). When water (in any of the three phrases) moves from a lower to a higher ordered state, the air surrounding the H20 will have energy added to it. This is called a release of latent heat (e.g. when heat is subtracted from liquid water, the individual water molecules will slow down. They eventually slow down to the point at which the hydrogen bonds do not allow the liquid to rotate anymore. Ice now develops. The energy the water molecules once had to rotate has been given up to the surrounding air). The three processes that add heat to the surrounding air are condensation, freezing and deposition (gas to solid).

Yeah it dropped the entire line about a county south

If the NAM 3k is off by a hair..Memphis is in trouble..2" amounts showing up just north of the metro

Example of how the rain droplets transports the warmer 850s to the surface..but it's only going to add a degree or so. Big Rock, TN as the moisture/drizzle moves in (temp rose from 29.8 to 30.4, even tho the winds remained from the north...elev 694'

Latency made add a degree at best...only way I see that helping is if you were borderline 30-31°

Agree 100%

If I lived within 50-75 miles of where the front (ice) was progged, I wouldn't let my guard down. Front is moving thru Nashville..Goodlettsville has been steadily falling just to the NW.

Euro has already failed in west TN vs reality (similar to how Oklahoma was playing out yesterday). 7pm modeled vs now

Posted by Alan Gerard on Twitter..excellent example of how globals near surface resolution don't allow them to see shallow level cold that well.

While the NAO can assist the TN valley (more the eastern side vs western side), the Pacific still/ and will always rule the roost. Until we can get the ridging off the west coast nudged closer to shore (GFS hints at that evolution toward day 7-8 beyond), I'm not that confident the cold will get shoved far enough east for the eastern valley..(different story for the western areas). Due to the shape of the state (horizontally oriented), it's what makes getting a statewide event so difficult. Place the ridge far enough offshore (west thrives), right against shore (east thrives/but systems can't get the moisture far enough back to help the west side.

Two things (which some of us have already discussed) #1 temps are usually overdone on high side at mid/long range modeling, and #2 models tend to underperform on qpf vs reality. Taking those two things in account, with the setup across all 12z modeling...those maps may unfortunately be on the light side if everything holds together.

12z CMC