Winter Speculation 17/18 -December Thread

[John1122]

That is literally the most bizarre thing I've ever seen from a model. The storm cuts into the western lakes and can't go anywhere because of the monster highs to it's north. So it begins to retrograde westward and sends a blizzard on it's back side down to the western half of the forum. 

[John1122]

The High to the NE of the storm finally gets out of the way and lets it go on into Quebec. 

I don't ever recall seeing a monster high suddenly start moving back to the NW like that.

 

 

[Windspeed]

The High to the NE of the storm finally gets out of the way and lets it go on into Quebec. 
I don't ever recall seeing a monster high suddenly start moving back to the NW like that.
 
 

I've seen intense Gobi surface and 500mb heights retrograde NW. Also, a very strong Azores will do it if the polar jet tilts over the northeast Atlantic. But yeah, it's not very common over interior Canada.

[John1122]

The Euro has the post Christmas return of the snow/ice. Ice moves into the western forum late Christmas day into the 26th. A few waves ride up the front with a 48 hour window of freezing rain/snow. Because the clown can sometimes get ice, the final map is QPF that falls as snow. In this case the clown map seems to line up reasonably well with that and doesn't seem to include ice as snow fall that much.

 

 

 

 

 

[AMZ8990]

7 hours ago, John1122 said:

That is literally the most bizarre thing I've ever seen from a model. The storm cuts into the western lakes and can't go anywhere because of the monster highs to it's north. So it begins to retrograde westward and sends a blizzard on it's back side down to the western half of the forum. 

I just got a chance To look at this.  The CFS threw down quite a storm I see!  I know it won't, but if that even came close to verifying then we would be in business.  

[ShawnEastTN]

1 hour ago, John1122 said:

The Euro has the post Christmas return of the snow/ice. Ice moves into the western forum late Christmas day into the 26th. A few waves ride up the front with a 48 hour window of freezing rain/snow. Because the clown can sometimes get ice, the final map is QPF that falls as snow. In this case the clown map seems to line up reasonably well with that and doesn't seem to include ice as snow fall that much.

 

I hope it isn't accurate on depth of cold air, or that the depth is deep enough for at least sleet, as modeled IMBY 24 hours of freezing rain sounds awful.

[Carvers Gap]

The overnight runs were interesting.  The 0z/6z GFS is more progressive.  To me, that look makes more sense...but no way am I hitching my ride to the GFS.  The 0z Euro holds energy back some.  Now, we finally had some runs w known biases that actually matched their models.  The NAM slowed and dug slightly more at 6z.   Short range models can now give us clues w the energy approaching Seattle.  The less it digs(also means less strong), the more likely the trough goes eastward more quickly.  The more it digs, the more it resembles the Euro.  As DT stated, might be the Euro is playing to biases.  If so, the cold will be here earlier like the GFS.  But the Euro has support from the UKMET, the CMC, the EPS, and the GEPS.  Give me that big high over the Plains...and let's see what happens.  But here is the deal...the Euro, GFS, and the CMC all have winter storm potential for the forum area. Just pick your poison.  It is pay me now or pay me later.  The EPS is slower than the GEFS, but its overall pattern continues winter well into January.  The GEFS is cold quickly arriving Christmas Eve(not the day after like the Euro), but it and its operational show a decent winter storm the day after Christmas, and then barely moved with he trough in the east for the entire run once it is here.  The CMC....stone cold w a 1069 hp.  Probably over done...it is video game football scoring meets weather modeling.  The Weeklies might be interesting tonight...but they can be pretty infamous for missing big cold.  Good trends.  Now, can we get some runs to support the midnight ride of the 0z suites?  Seems like we get good news overnight, then 12z drops the hammer.  Interesting to see the Euro bring back that storm.

[Carvers Gap]

Just took a closer look at the 0z Euro...it is slightly quicker with the trough in the Southwest...and does not connect w an incoming western trough late in its run.  The trend is also to keep the EPO ridge taller and not bend it over the top towards Greenland.  This allows the base of the cut off to get kicked out.  So...decent trends there.  But can they cold at 12z?  We are getting to the point where trends matter...especially even on these short range models like I said earlier.

[J.C.]

Well models are finally being more consistent now.  After Saturday looks like the cold is really taking hold, but it doesn't look like the storm track is very favorable, and the wall to wall cold air is suppressing.  However, we should definitely see numerous up-slope chances in the favored areas.  

Thanks for all those providing analysis, so nice to read about this region.

[Carvers Gap]

12z NAM update.  Proceed at your own risk as this is iffy using the NAM in this manner at this range.   While still not as progressive as the GFS, the NAM is north and east with its cutoff in the southwest when compared to 6z.  Might not look like much....but the short range models need to be progressive in their trends and not backing.  So, good trend for the NAM.

[ShawnEastTN]

6 minutes ago, Carvers Gap said:

12z NAM update.  Proceed at your own risk as this is iffy using the NAM in this manner at this range.   While still not as progressive as the GFS, the NAM is north and east with its cutoff in the southwest when compared to 6z.  Might not look like much....but the short range models need to be progressive in their trends and not backing.  So, good trend for the NAM.

50 to 100 or so miles different, that can make a big difference further downstream

[Kentucky]

Back in the game, now the euro will come in with something totally different 

[Carvers Gap]

The 12z CMC moved the base of its trough axis from Los Angeles to Austin, TX, at 156.  Not quite there yet...but massive move.

[Mrwolf1972]

12 hrs looks close to the gem on Christmas. Just not as strong as gem.

 

 

[John1122]

All the models are showing some snow in the Christmas time frame a week out from it. That's a strong sign most years but still not quite sure with this much model madness. The down side is that they all depict a fairly narrow band of snow with each of them having their heaviest accumulation in a band about 6 counties wide due to the steep angle of the stalled front that allows the moisture to ride SW to NE. Would be much better if we could get a classic system to move from Texas to South Carolina. Some are probably going to cash into winter and others will be on the outside looking in at them.  The EURO is the best case/worst case. Best in that it's wintry precip is the most wide spread, worst in that it's showing a lot of ice potential.

[PowellVolz]

All the models are showing some snow in the Christmas time frame a week out from it. That's a strong sign most years but still not quite sure with this much model madness. The down side is that they all depict a fairly narrow band of snow with each of them having their heaviest accumulation in a band about 6 counties wide due to the steep angle of the stalled front that allows the moisture to ride SW to NE. Would be much better if we could get a classic system to move from Texas to South Carolina. Some are probably going to cash into winter and others will be on the outside looking in at them.  The EURO is the best case/worst case. Best in that it's wintry precip is the most wide spread, worst in that it's showing a lot of ice potential.

I like the fact the GFS had this same setup a few days ago and came back to it. Might not mean anything but it sounds good.


.

[ShawnEastTN]

If this scenario played out, which has randomly been modeled, we would still want to factor a NW tick to it and even with tight gradient usually still a bit more precip further west than is usually modeled.

 

Think confidence is building that someone in the forum area will see something.

 

Sent from my SM-G920V using Tapatalk

 

 

 

 

[AMZ8990]

8 minutes ago, ShawnEastTN said:

If this scenario played out, which has randomly been modeled, we would still want to factor a NW tick to it and even with tight gradient usually still a bit more precip further west than is usually modeled.

 

Think confidence is building that someone in the forum area will see something.

 

Sent from my SM-G920V using Tapatalk

 

 

 

 

I agree, someone in the forum will see some wintry precipitation.  Hopefully it's more wide spread but thats a lot to ask for.

[J.C.]

5 minutes ago, AMZ8990 said:

I agree, someone in the forum will see some wintry precipitation.  Hopefully it's more wide spread but thats a lot to ask for.

Its been a while for Chattanooga I believe, hopefully they can get something out of this like the models are hinting at.

[John1122]

13 minutes ago, AMZ8990 said:

I agree, someone in the forum will see some wintry precipitation.  Hopefully it's more wide spread but thats a lot to ask for.

The Euro is probably the best case right now for those that want the wintry precip. It had 1-2 inches from Memphis to Nashville with heavier totals further east. The only areas left out are far NW Tn and the southern valley areas towards the east, as they get ice instead of snow. 

We will see in a few minutes where it goes with the 12z run.

[PowellVolz]

I believe the euro is coming in colder but can’t tell just yet.


.

[Carvers Gap]

The 12z Euro (throw out the details) is much more realistic now w its trough. Significant changes.  No more trying to connect w the HI trough so early.  It does hang back w its usual bias.  While faster...I think it is now fair to ask if it should be faster?   The trough has corrected big time and is hanging back less...but it might have one more correction in it.

[nrgjeff]

12Z Euro appears reasonable on temperatures, little colder. I like the way it handles the fronts. Friday front passes (partially) and does not really retreat like on previous runs. Just kind of holds over/including the Plateau per pattern recognition. Then Monday the arctic blast comes on through. 

GFS is likely too fast. It drops temps quickly behind the Friday front, and reinforces Sunday. 12Z Euro seems more realistic with southwest flow; two incremental fronts. 00Z Euro did not respect the arctic air; GFS does not respect southwest flow. 12Z Euro could be striking the right balance. If I am right precip is mainly cold chasing rain though. Mid-South to Kentucky would see frozen.

[John1122]

Euro is dry, no waves riding the front. Has maybe 1/2-1 inch of back side snow far NW TN, Northern Plateau and Mountains. 1/2 or less elsewhere.

[PowellVolz]

Euro is dry, no waves riding the front. Has maybe 1/2-1 inch of back side snow far NW TN, Northern Plateau and Mountains. 1/2 or less elsewhere.

The Euro hasn’t really lost a storm but it’s in that 5-8 day range where it has issues with sustaining them. At least we’ll have the cold just in case.


.

[jaxjagman]

The outcome is never good here for cold air trying to catch the moisture,just hope we see some flakes fly around some.Least it will feel like Christmas.

[Carvers Gap]

Check this out.  Look at the correction it made from 0z to 12z on the Euro.  The one on the left is 12z. Now, the GEM and GFS both had winter precip.  If the Euro corrects one more time where it lags a bit over the Four Corners in the SW...there may be a storm signal.  Finally, a 12z suite that is reasonable, and the models are now playing by their usual biases.  

[Mrwolf1972]

18z gfs is suppressed and goes no where near any snow for east Tennessee. 

[PowellVolz]

18z gfs is suppressed and goes no where near any snow for east Tennessee. 

Maybe a over correction? Seems like mods will go to far and then work their way back. Either way I’m fine with being a little to far NW on a system at this point.


.

[Stovepipe]

That's a stout arctic blast on the 18z GFS.  Down to 15 here Tuesday with a wind chill of 5.