Winter Speculation 17/18 -December Thread

[BNAwx]

If anything, you’d think we could squeeze out a decent clipper in this pattern.  Seems like back in the day you could count on a clipper to put down a quick, powdery inch or two with this kind of flow.  They’re usually not picked up well long range so maybe we’ll get lucky.

[jaxjagman]

GFS 0.5 Degree FORECAST FOR: BNA    LAT=  36.12 LON=  -86.68 ELE=   591

                                            18Z DEC30   * - APPROXIMATED
                 SFC     SFC     2 M     SFC     SFC     SFC    6 HR    TOTAL
                 MXT     MNT     TMP     DEW     WIND    PCP     QPF    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   TYPES   (IN)    (PCT)
SAT 18Z 30-DEC                  35.3    27.8    35007                           
SUN 00Z 31-DEC  35.6    25.6    25.7    13.8    36008           0.00      83    
SUN 06Z 31-DEC  25.6    18.8    18.8     4.4    02008           0.00       2    
SUN 12Z 31-DEC  18.8    16.4    16.4    -0.2    02007           0.00       0    
SUN 18Z 31-DEC  24.4    16.1    24.4     2.4    01008           0.00      15    
MON 00Z 01-JAN  25.4    20.0    20.0    -2.9    00009           0.00      20    
MON 06Z 01-JAN  20.0    15.8    15.8     1.8    00009           0.00       0    
MON 12Z 01-JAN  15.8    12.4    12.4     3.4    36009           0.00      21    
MON 18Z 01-JAN  20.3    11.8    20.3     5.8    36009           0.00       7    
TUE 00Z 02-JAN  21.8    16.1    16.1    -9.9    36007           0.00       0    
TUE 06Z 02-JAN  16.1    12.2    12.2   -12.8    01006           0.00       0    
TUE 12Z 02-JAN  12.2    10.0    10.1    -8.4    02005           0.00       0    
TUE 18Z 02-JAN  22.7     9.8    22.7    -1.0    02004           0.00       0    
WED 00Z 03-JAN  25.5    19.1    19.1    -7.7    01004           0.00       0    
WED 06Z 03-JAN  19.1    16.1    16.1    -6.7    02002           0.00       6    
WED 12Z 03-JAN  16.1    15.2    15.4    -7.1    25002           0.00      35    
WED 18Z 03-JAN  29.7    15.0    29.7    -1.7    24006           0.00       3    
THU 00Z 04-JAN  31.9    24.6    24.6    -1.9    28005           0.00       4    
THU 06Z 04-JAN  25.3    20.3    20.3     8.5    34009           0.00      57    
THU 12Z 04-JAN  20.4    14.8    14.8     3.4    34009           0.00      81    
THU 18Z 04-JAN  22.0    14.2    22.0     8.4    34009           0.00      14    
FRI 00Z 05-JAN  23.3    17.9    17.9    -2.4    33006           0.00       0    
FRI 06Z 05-JAN  17.9    14.1    14.1    -5.8    33006           0.00       0    
FRI 12Z 05-JAN  14.0    11.1    11.1    -5.1    33006           0.00       0    
FRI 18Z 05-JAN  21.1    10.6    21.1    -2.5    33006           0.00       0    
SAT 00Z 06-JAN  23.4    18.1    18.1    -8.9    35004           0.00       0    
SAT 06Z 06-JAN  18.2    15.3    15.3    -7.4    05003           0.00       4    
SAT 12Z 06-JAN  15.4    14.5    14.6    -7.3    10003           0.00      70    
SAT 18Z 06-JAN  29.7    14.4    29.7    -3.7    15004           0.00      40    


Record for BNA is nine days straight without getting above freeze,doubt it breaks it,impressive none the less.

[jaxjagman]

URGENT - WINTER WEATHER MESSAGE
National Weather Service Nashville TN
308 PM CST Sat Dec 30 2017

...Expect Frigid Conditions at Outdoor New Years Eve
Celebrations...

.Cold Arctic air will pour into Middle Tennessee tonight and
persist into the New Year. Steady winds ushering in this cold air
will begin to drop wind chill values below zero New Years Eve,
with some locations approaching -5 degrees by midnight. By the
morning hours of New Years Day, most of the mid-state may see
wind chill values below -5 degrees. Another night of cold air
is expected Monday night, and thus another Wind Chill Advisory
likely will be needed.

TNZ005>011-023>034-056>066-075-077>080-093>095-311000-
/O.NEW.KOHX.WC.Y.0002.180101T0400Z-180101T1500Z/
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston-
Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-
Jackson-Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-
Maury-Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-
Coffee-Warren-Grundy-Van Buren-Wayne-Lawrence-Giles-
Including the cities of Dover, Clarksville, Springfield,
Hendersonville, Gallatin, Goodlettsville, Lafayette, Celina,
Byrdstown, Erin, Waverly, New Johnsonville, McEwen, Dickson,
Ashland City, Kingston Springs, Nashville, Lebanon, Mount Juliet,
Hartsville, Carthage, South Carthage, Gordonsville, Gainesboro,
Cookeville, Livingston, Jamestown, Allardt, Linden, Lobelville,
Centerville, Hohenwald, Franklin, Brentwood, Columbia, Lewisburg,
Murfreesboro, Smyrna, La Vergne, Woodbury, Smithville, Sparta,
Crossville, Shelbyville, Tullahoma, Manchester, McMinnville,
Altamont, Coalmont, Spencer, Clifton, Waynesboro, Lawrenceburg,
and Pulaski
308 PM CST Sat Dec 30 2017

...WIND CHILL ADVISORY IN EFFECT FROM 10 PM SUNDAY TO 9 AM CST
MONDAY...

* WHAT...Very cold wind chills expected. The cold wind chills will
  cause frostbite in as little as 30 minutes to exposed skin.
  Expect wind chills to range from zero to 8 below zero.

* WHERE...Portions of Middle Tennessee.

* WHEN...10 PM Sunday to 9 AM Monday.

* ADDITIONAL DETAILS...Expect wind chill values to fall below zero
  as Sunday evening progresses, creating frigid conditions at any
  outdoor New Years Eve Celebrations.

[jaxjagman]

2 hours ago, Carvers Gap said:

Was reading JB this afternoon...MJO is showing signs of going into phase 3 of the MJO at a strengthening amplitude.  That would also give it a chance to make it to phase 4...though it does go COD prior to that.  But the trend is for warmer phases of the MJO.  

Now, my thoughts...Connects well to th SOI flip.  Connects well w a warm western Atlantic.  Also connects well to the models flipping back and forth at LR w the trough placement....my official guess now is that by mid January the trough will be in the West as the base pattern for the 3-4 week period beginning Jan 10-15.  How far west is the question.  I think it will be centered further east than most western troughs.  Maybe I can jinx it.  Thank me later.  What can save us?  -QBO, decent Pacific setup, current pattern may be stubborn to leave, climo.  But this is how I see things now...we are about to enter a time where the Atlantic will be extra hostile towards winter in the East.  If the EPO goes positive, we lose our advantage.  I certainly hope I am wrong.

MJO looked like the GEFS showed yesterday trying to retrograde it back into the IO,different today slightly more progressive like the Euro going into P3 AND 4 

[jaxjagman]

Nice storm on the 8th,looks like it could be a decent front coming through.DP's in the 60's into the Ozarks .IF the cold air leaves quicker than i think it will could but strong storms even into West Tn.Looks like the potential for some wind advisories into next weekend

[jaxjagman]

CMC is just amazing with its consistent cold,unreal.That would be mind blowing if its even near close to being right.

[John1122]

It certainly isn't backing down. It's getting close to put up or shut up time with it's -10s. It has some super low day time highs too.

Otherwise same ole same ole from the models. Cutter, with possibly some moisture catching the retreating arctic air and a big, cold high pressing towards the western forum while battling the SE ridge. That showed up a few weeks ago for this time period as well and we see how that turned out. But verbatim the GFS look would be a nice winter storm for a lot of the forum as that high would provide plenty of cold all the way to the Apps, and undercutting would cause rain to change to ice across the state with snow in the deeper cold in the western forum.

[ShawnEastTN]

Keep noticing that the RGEM run after run wants to put a bit of QPF in East Tennessee this afternoon into the evening.   Also notice forecast for the day is sunny, but cannot seem to shake the overcast conditions IMBY today.  Trapping some low level moisture it seems.

 

[Carvers Gap]

17 minutes ago, ShawnEastTN said:

Keep noticing that the RGEM run after run wants to put a bit of QPF in East Tennessee this afternoon into the evening.   Also notice forecast for the day is sunny, but cannot seem to shake the overcast conditions IMBY today.  Trapping some low level moisture it seems.

 

Good catch, good model.  Not seeing much on other models though.  That said, I would not be surprised to see some flakes squeezed out.  Looked like the RGEM had a bit of upslope from lake effect moisture.

[Carvers Gap]

Definitely watching to see how much northern stream energy has been missed.  Have been reading that northern Canada systems are often missed or modeled incorrectly.  This week will be a good test.  Today does not fall into that category.  I am talking clippers and shortwaves.  I continue to suspect that something is missing.  Now, I am not talking big storms...just very light systems that accompany many cold air masses...even lake effect and upslope stuff.

[Kasper]

6 minutes ago, Carvers Gap said:

Definitely watching to see how much northern stream energy has been missed.  Have been reading that northern Canada systems are often missed or modeled incorrectly.  This week will be a good test.  Today does not fall into that category.  I am talking clippers and shortwaves.  I continue to suspect that something is missing.  Now, I am not talking big storms...just very light systems that accompany many cold air masses...even lake effect and upslope stuff.

It wouldn't take much qpf to give some folks an 1inch or 2, I read that some NC folks seen some last night, came out of nowhere! Hopefully we can get enough energy to squeeze out something!

[Kasper]

Would be nice to squeeze this out!

[Carvers Gap]

5 minutes ago, Kasper said:

It wouldn't take much qpf to give some folks an 1inch or 2, I read that some NC folks seen some last night, came out of nowhere! Hopefully we can get enough energy to squeeze out something!

Would not surprise me above say 4,000'.  Just a different world up there.  And I don't want to provide false hope either...but once these patterns settle-in, the models will pick-up on smaller events if there are any at all.

[Carvers Gap]

For example...when this storm scrapes the eastern seaboard...I would expect some upslope or lake effect in the northern areas.

[Will (little rock)]

Is it possible that the piece of energy at hour 66 produces anything?

[Kasper]

8 minutes ago, Will (little rock) said:

Is it possible that the piece of energy at hour 66 produces anything?

Hour 66 on what model?

 

[weathertree4u]

The Canadian model is still indicating super cold air, compared to what is being forecasted, I dont think we see 20 today imby, which throws the rest of the week into question because we get lower tonight since we didnt make it as high, lower tonight means lower highs tomorrow and lower lows tomorrow night. Pretty amazing with no snow on the ground imo

[Kasper]

5 minutes ago, weathertree4u said:

The Canadian model is still indicating super cold air, compared to what is being forecasted, I dont think we see 20 today imby, which throws the rest of the week into question because we get lower tonight since we didnt make it as high, lower tonight means lower highs tomorrow and lower lows tomorrow night. Pretty amazing with no snow on the ground imo

Truly amazing Cold with no snow! Unprecedented imo! 

[PowellVolz]

Definitely watching to see how much northern stream energy has been missed.  Have been reading that northern Canada systems are often missed or modeled incorrectly.  This week will be a good test.  Today does not fall into that category.  I am talking clippers and shortwaves.  I continue to suspect that something is missing.  Now, I am not talking big storms...just very light systems that accompany many cold air masses...even lake effect and upslope stuff.

Just an FYI, I’m getting some flurries at my house in North Knox Co. I’m in Halls area.


.

[PowellVolz]

RadarScope is on high sensitivity but you can see the haze starting to grow.




.

[Carvers Gap]

3 minutes ago, PowellVolz said:

 

Just an FYI, I’m getting some flurries at my house in North Knox Co. I’m in Halls area.


.

 

Awesome.  Was up on Bays Mountain today, and there was some light stuff falling.  Definitely noticed a couple of clippers on the 12z Euro.  Makes much more sense.  Nothing big, but always have to watch clippers as right now the ratios would be so high...would not take much to get an inch or two of snow.

[Kasper]

I was just checking out the water vapor image loop from noaa, it looks like there is a clipper moving rapidly SE through Nebraska, I wonder if that can make its way through and give some of us a quick dusting or so? Maybe some of you seasoned guys can help my untrained eyes!  Couldn't post the loop, file is too large! 

[Carvers Gap]

The 18z 12K NAM has two systems late in its run...proceed w/ caution as we are talking the NAM at range.  One piece of energy is rotating down through the northern Plains.  Another is rotating southeast through KY in association w/ the energy that will eventually phase w/ the NE coastal.

[Kasper]

39 minutes ago, Carvers Gap said:

The 18z 12K NAM has two systems late in its run...proceed w/ caution as we are talking the NAM at range.  One piece of energy is rotating down through the northern Plains.  Another is rotating southeast through KY in association w/ the energy that will eventually phase w/ the NE coastal.

Speaking of NE coastal, have you seen the latest trends on this? Seems everything keeps it trending west! How far west remains to be seen!

[Carvers Gap]

17 minutes ago, Kasper said:

Speaking of NE coastal, have you seen the latest trends on this? Seems everything keeps it trending west! How far west remains to be seen!

Very unlikely it gets this far back...but I learned in w/ wx to never say never.  Barely enough room to get it to the precip shield to the coast near Hatteras.  But the northern energy that produces the storm might provide some light precip for areas north of I-40.  

[Carvers Gap]

The 12z NAVGEM has an upslope event beginning at 96.  You can see a little of that on the 18z GFS...just look at the plumes that come of the Great Lakes.  Again, not much in the valleys...but something is better than nothing.

[jaxjagman]

Strong system still being shown in South Korea,would really like to see the heights rise into the Bearing Sea tho,plenty of time.Need that system South of the Aleutians to not be there,its holding back the heights in the West Pac

[John1122]

I'm sure it's a .001 percent chance but the Euro at day 10 looks like the start of something great. Too bad we've seen a dozen runs of perfect day 10 storms already this winter that have came to absolutely nothing. Rest assured though, the cutter advertised prior to it will come off without a hitch.

 

1043 high in the Upper Midwest and a Low getting going in southern Texas about to move into the GOM. Snow from Arkansas across the entire forum area except the far NE corner with temps across the forum area in the mid 20s or lower across the whole region as the run ended.

[Kentucky]

Nice little surprise coating here in Corbin, still snowing 

[weathertree4u]

3 hours ago, John1122 said:

I'm sure it's a .001 percent chance but the Euro at day 10 looks like the start of something great. Too bad we've seen a dozen runs of perfect day 10 storms already this winter that have came to absolutely nothing. Rest assured though, the cutter advertised prior to it will come off without a hitch.

 

1043 high in the Upper Midwest and a Low getting going in southern Texas about to move into the GOM. Snow from Arkansas across the entire forum area except the far NE corner with temps across the forum area in the mid 20s or lower across the whole region as the run ended.

 

 

 

 

 

So, the precip shield would be what is just entering the graph for Nashville then? I am not sure honestly it will warm as fast as models are predicting. We do not usually have cold this entrenched.