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Jan. 12-13, 2018 winter storm Nowcast and Forecast

nrgjeff

By nrgjeff,
in Tennessee Valley

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tnweathernut

tnweathernut

Posted
Posted
2 hours ago, John1122 said:

Euro seems to be caving to the GFS and it's weaker, less snowy solution, freezing rain will be the predominant p-type in western areas, with 1-2 inches of snow at the very best on top of some ice.

Basically a bad run for everyone. 

 

Bad time for the Euro to flip out.  Wonder if it got a better data ingest?  Normally don't see it change this much at the surface.  Perhaps the margins are so razor thin, very small changes will cause big surface changes...

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John1122

John1122

Posted
Posted
Just now, tnweathernut said:

Bad time for the Euro to flip out.  Wonder if it got a better data ingest?  Normally don't see it change this much at the surface.  Perhaps the margins are so razor thin, very small changes will cause big surface changes...

If the Euro was ever going to fold to the GFS we should have known it'd be when it was showing a major snow event for the forum area and the GFS was showing much less.

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nrgjeff

nrgjeff

Posted
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Posted

12Z Euro was a bit disappointing, but ensembles offer a few better solutions. Few lows farther south, even a couple with inverted troughs. Brief pause on the soap box now.

Before Euro shaming, it was the first model to show a wave of low press in the South, when the silly GFS had cold chasing rain. Euro is, was, and probably always will be better. Check stats at all regions, all levels, all layers of atmo. Euro is still a day better than the GFS. Euro day n+1 > GFS day n, which is a wide and statistically significant improvement.

18Z NAM brings back the TROWAL feature, and more robust comma head. Remains to be seen if it happens, but it's the road to more robust snowfall totals. TROWAL would cut back on the dreaded ice too, speeding the rain to snow. Due to mesoscale features it's still too early to pin down amounts and locations. Somebody in the western or middle third of our Region could get several inches of snow.

Might be my last post for the event. If the ice situation becomes significant it will be all work for a couple days. So if you are in the snow zone, have fun!

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Carvers Gap

Carvers Gap

Posted
Posted
27 minutes ago, AMZ8990 said:

NWS Memphis decided to issue a winter storm watch for all of west Tn and parts of North Mississippi.  Calling for 1-4 inches of snow, with .10 to .30 of ice/sleet.  

First WSW of the season for the valleys.  

We missed a great day of weather disco w the forum down.

Lastly, there are some flatter solutions out there.  The 18z NAM seems overly amped, but it did ok w the recent coastal.  The 12z JMA, 12z NAVGEM, 12z EPS/Euro, and the 18z GFS are flatter.  Some actually find a way for the low to transfer to the east of the Apps.  Again, angle of entry into the Valley is tricky with this.  The macro part of this has been certain for days...a storm was going to develop between the two highs.   Seems most guidance really likes west TN for snow.  Fits climo.  Fits what most of us said for a month or so...this winter is a great opportunity for Memphis.  Still...the EPS has me skiddish with this.  It looked like a slider that was a bit too far north.  Some models sped up the hp in the Plains which leaned the system northeast.  Some room for minor changes.  Looks like West TN has a real chance....then I am most interested to see if this slides across the upper south or cut west.  

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Stovepipe

Stovepipe

Posted
Posted
11 minutes ago, *Flash* said:

Yeah...give me 45 miles of gas and I'm heading towards LBL. Granted, I can't complain as MBY is in a WSW. Not sure if the Friday AM commute to downtown Nash is a good idea as I have a very strong 'just say no to gridlock' philosophy... 

Yeah, if this was looking to be a pure snow event I think I'd certainly be burning a vacation day and driving west to experience it.  But with the amount of potential ice and sleet before the snow it's looking to be chaos.  I recall driving through Nashville in the late 90s after an ice storm and rednecks were doing donuts in the middle of I-40, wrecks everywhere.  I hope y'all get a nice crazy winter storm over there but I'd plan to hunker down at home if I were you.

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John1122

John1122

Posted
Posted
32 minutes ago, *Flash* said:

For real...not a good day for server issues. Thankfully other forums exist though they leave something to be desired. Frustration compounded by negative guidance trends as Jeff/Carver noted...though I still don't buy the progressive solutions. Concerning the 12z Euro + last few op runs of the GFS...I don't think it's worth putting so much stock into them as we're now in Hi-Res territory. Someone correct me if I'm wrong, but it seems that 24-48 hour time frame can be wonky in terms of main models second guessing themselves only to go the other way last minute. Noticed this with several storms this decade. I'll wrap this up by saying I think a flatter, weaker solution can't be ignored, but not to the extent it's been presented today. Frankly, there hasn't been any op run today that I felt I could hang my hat on. Even Chris Bailey up at KWYT isn't ready to pull the accumulation map trigger and we're 24-36 hours from impact. 

I never doubt the Euro any more. Unless it shows a big snow event for the area! Honestly, it's a long range, higher res model. It's higher res than the 84 hour NAM and the RGEM. 

The GFS is 15k or 13k I think, the  84hr NAM is 12k, the RGEM is similar and the Euro is 9k, I think the short range version of the UKMET may be 7.5k. There is of course the 3k NAM but you always have to keep in mind the bias of the NAM is to dump copious precip, especially the 12k. 

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John1122

John1122

Posted
Posted
Just now, *Flash* said:

That is true. Sorry, meant to say short-term higher res. At any rate, for those in east TN...if you saw that 0z NAM...things are falling apart for west/middle snow potential. That ol' KY/TN dividing line narrative seems to be rearing its ugly head again. Here's hoping we got a Music City Miracle left in the tank.

It's all about the strength of the low and it's ability to create that TROWEL. Wound up and it will mix down cold and switch to snow, strung out and it'd ice ice baby for the western half of the forum.

The NAM that run was a cow killing ice storm for the western 2/3rds of the forum. Really just socks it to Memphis, to Nashville to Clarksville and that area with .5 inches of freeing rain, moderate sleet and an inch or two of snow on top of it. If it does that and the cold arrives as advertised you guys out west will be chipping out for a while.

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Carvers Gap

Carvers Gap

Posted
Posted

Getting ready to hit the sick.  Seeing another potential solution as two waves of energy per the 0z NAM.  Getting into range where it can be taken seriously.  One wave goes to west TN.  The other slides across the mid-South and re-emerges somewhere near the base of the southern Apps.  One scenario is that it cuts east of the Apps.  The other is that it cuts west and goes as a far inland runner.  That is a new wrinkle...the two parcel deal.  So, I am rolling with energy just east of Memphis w snow/ice for the west end of the state...then the wild card.  Slider or weaker cutter up the eastern Valley.  Not sure.  I have liked the idea of a low just west of Charlotte.  That seemed to be out of the cards.  But the GFS and CMC at 0z are allowing some energy now to round the base of the Apps.  New box of worms if true.  But seriously...somebody get some snow before the warm-up. Here’s to good overnight trends.

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jaxjagman

jaxjagman

Posted
Posted

Euro shows something in Memphis,unlike last evening,looks more a mix bag,tough to tell when the freezing level actually falls for what,but looks at least 0.13 snow

  

ECMWF Deterministic FORECAST FOR: MEM    LAT=  35.05 LON=  -90.00 ELE=   285

                                            00Z JAN11
                 2 M     850    1000    FZING    SFC     SFC    6 HR    SNCVR
                 TMP     TMP     850     HGT     WIND    PCP     QPF     LIQ 
                 (C)     (C)     THK    (FT)    (KTS)   TYPES   (IN)    (IN) 
THU 00Z 11-JAN  13.7     9.2     136   13754    15007           0.00            
THU 06Z 11-JAN  14.8     9.8     137   13457    16013           0.01            
THU 12Z 11-JAN  15.4    10.2     137   11174    18008           0.14            
THU 18Z 11-JAN  16.4     9.7     137   11779    18009           0.06            
FRI 00Z 12-JAN  14.9     8.7     137    9917    17003           0.15            
FRI 06Z 12-JAN   3.3     4.9     132    8935    34017           0.69            
FRI 12Z 12-JAN  -3.3     1.1     129    6442    35015           0.49            
FRI 18Z 12-JAN  -2.4    -3.1     127       0    35014           0.13            
SAT 00Z 13-JAN  -1.7    -5.8     127       0    35008           0.00            
SAT 06Z 13-JAN  -5.0    -3.1     127       0    35010           0.00            
SAT 12Z 13-JAN  -6.1    -5.2     126       0    35009           0.00
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John1122

John1122

Posted
Posted

Significant ice from South Central Arkansas to Memphis to Nashville on the Euro. The models have almost locked this one down now. The snow maps etc won't ever be exact but freezing precip at some level will likely accumulate almost forum wide. Nashville west will basically be an iceburg if tonight's trends continue. 

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TellicoWx

TellicoWx

Posted
Posted

MRX AFD: 

Total snow accumulations are still in flux and
will be largely dependent on how quickly the changeover from rain to
snow occurs Friday night. However, it appears at this point that any
accumulations in the valley will be under one inch with slightly
higher amounts in the mountains and across NE TN/SW VA. We could
also see some light ice accretion across the Plateau, but again this
is very dependent on how quickly the rain to snow changeover occurs.
For now this appears to be solidly within the bounds of our winter
weather advisory criteria, but with the amount of uncertainty that
still exists, will hold off on issuing any products until we get a
little closer to the event, in hopes that details on the rain/snow
transition will become a little clearer and give us a better feel
for accumulations.
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Carvers Gap

Carvers Gap

Posted
Posted

0z EPS now has a significant cluster of solutions which move into north Georgia and then into western NC, even a cluster into upstate SC.  The meso scale models ticked West a hair at 6z.  I still like the ideas of my previous post...the multiple wave/slp solution w a final slp moving up the spine or just east of the Apps.

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ShawnEastTN

ShawnEastTN

Posted
Posted
32 minutes ago, Carvers Gap said:

0z EPS now has a significant cluster of solutions which move into north Georgia and then into western NC, even a cluster into upstate SC.  The meso scale models ticked West a hair at 6z.  I still like the ideas of my previous post...the multiple wave/slp solution w a final slp moving up the spine or just east of the Apps.

Yep I was just looking at the 0Z, looks like the OP has a weak SLP in NE GA on that run...  Interesting.

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