December and January Pattern Discussion

[HKY18]

January 2-3rd looked interesting pre-truncation

[jaxjagman]

January 2-3rd looked interesting pre-truncation

Hopefully it will get better.

[BNAwx]

I'd love a nice moisture laden synoptic event over the next 2 weeks that's cold enough for snow.  If not, perhaps we can at least get into some clipper action with high ratios.  It's been a while since we've had a clipper juicy enough to lay down some good accumulations.  I picture the mountains really cashing in with the pattern depicted.

[jaxjagman]

More juice for the 30 weak system,might even get lucky and get a dusting.Should be in the eastern parts.Over all through 144 colder also

[Carvers Gap]

Out to 192, the 0z GFS shows one moderate upslope event and one clipper w/ minor interaction w/ the GOM. If it snows, it is not going anywhere.

[Carvers Gap]

What a pattern this is shaping up to be if correctly portrayed by the GFS. Cold HP sagging south over the Great Lakes. The GOM open for business. This pattern may be a TN Valley special.

[jaxjagman]

What a pattern this is shaping up to be if correctly portrayed by the GFS. Cold HP sagging south over the Great Lakes. The GOM open for business. This pattern may be a TN Valley special.

Thinking the same thing,hopefully the esms.show this pattern also

[John1122]

After posting my lows since 1975 post, you can see these last 15 years were soooooo much warmer than the 22+ that came before it. At some point there will be a return to true, epic cold and most people won't know how to take it. Good old nostrils freezing shut, ice crystals in the air even with the sun out kind of days. I'd love to see this pattern produce that. It usually takes around -5 for that to happen in my experience. 

[Carvers Gap]

Thinking the same thing,hopefully the esms.show this pattern also

I try not to get overly excited as the models have so much variability with new patterns. However, this is several days in a row of cold being shown to varying degrees. Everyone better get plenty sleep. My bet is someone in the Valley cashes in soon.

[John1122]

It even appears to be reloading in the last frames, another area of -20s is rolling into the Western Lakes and pointing towards our area. 

 

Everything can always flip, but the models certainly are being very persistent with cold driving into the area as the heart of winter (Jan 15th-Feb 15th imo) is on tap. 

[Reb]

You have to love the pattern we are heading into.  Good thing I got a Keurig coffee maker for Christmas looks like I'm gonna need it!

[John1122]

MRX pointed out that the GFS was, in their opinion, underplaying how cold the temps will be next week. I can see that it could be doing it now in it's extended unless it's too cold in the Midwest. With the big trough in the East and those -20 to -30 temps where they are, I can see us being much colder than the 10s for lows that the GFS seems to be showing now. Especially if we get even an inch of snow on the ground. When the trough was centered a bit west of here earlier, we saw 0 degree lows in Northern Arkansas and Southern Missouri in November.

[Clarksville Snowman]

You have to love the pattern we are heading into.  Good thing I got a Keurig coffee maker for Christmas looks like I'm gonna need it!

Love my Keurig coffee maker, hope I need it following late night winter storms!!

[jaxjagman]

The Euro is freaking garbage,it can't figure out anything.One extreme to another,at  least the GFS is somewhat consistent with the cold.Not saying it's right,just saying.

[tnweathernut]

Not a fan of the CFSV2, but will be rooting hard for it to be right..........jan on left, feb on right.

Sent from my iPhone using Tapatalk

[Carvers Gap]

I am sure most of you have seen this...but the Euro and GFS couldn't be further apart. The 0z Euro has the trough in the west Atlantic. The 6z GFS has the trough in the East or central areas of the country. Does anyone have the ensembles for the Euro and would be willing to describe? Just wondering if the operational is east of its members. Also, the GFS really winds up the feature three to four days from now. I think it is what is driving the pattern. The Euro looked less enthused.

[franklin NCwx]

I am sure most of you have seen this...but the Euro and GFS couldn't be further apart. The 0z Euro has the trough in the west Atlantic. The 6z GFS has the trough in the East or central areas of the country. Does anyone have the ensembles for the Euro and would be willing to describe? Just wondering if the operational is east of its members. Also, the GFS really winds up the feature three to four days from now. I think it is what is driving the pattern. The Euro looked less enthused.

the ensembles look much different from the op. The euro op IMHO is useless past day 6. It changes dramatically from run to run and is a lot different from its own ensembles.

Just looking at the ensembles for next weeks storm at 168 it has a low in southeast Texas by 180 its over New Orleans. Then by 192 its off the Virginia coast. Much faster and different from the op. In fact it looks more like the gfs op.

[jmundie]

Lots of run to run variability in the models - the NAO is starting to look more east based, which is why we're not getting as cold.

 

The 0z GFS ensembles seem to support more moisture with the system end of next week than does the op. I'm still pretty confident that jan 2-4 is decent bet for some accumulating snow for much, if not all of TN>.

[jaxjagman]

the ensembles look much different from the op. The euro op IMHO is useless past day 6. It changes dramatically from run to run and is a lot different from its own ensembles.

Just looking at the ensembles for next weeks storm at 168 it has a low in southeast Texas by 180 its over New Orleans. Then by 192 its off the Virginia coast. Much faster and different from the op. In fact it looks more like the gfs op.

That's what the 12z said 0z has it surpressed heading to Fl and OTS..Go figure

[Carvers Gap]

It would appear HPC is seeing this as well.  The Euro could be seeing more warmth accurately...but it is difficult to tell what is the predicted outcome w/ so much variability.   Seems like the GFS has handled this pattern slightly better, and HPC hints at that as well.  I can't tell if the NAO, if it goes negative, will be east or west based.  The GFS is strongly hinting at cold in the East w/ heights rising ever so slightly over Greenland.  I am sticking w/ the GFS since it has been more consistent.  Anyway, HPC has some highly interesting comments below..............

 

UPSTREAM ENERGY IS FCST TO PASS THROUGH/AROUND THE WEST COAST
RIDGE AROUND MON-TUE AND FEED INTO THE MEAN TROUGH THEREAFTER.
DIFFS AMONG SOLNS AND IN CONSECUTIVE RUNS WITH THIS ENERGY AS WELL.
AS WITH SRN CANADA/NRN CONUS FLOW HAVE YIELDED CONSIDERABLE SPREAD
WITH THE EXPECTED SFC PATTERN... MOST DRAMATICALLY FROM THE
NRN-CNTRL PLAINS INTO THE NORTHEAST.  BY WED-THU THE LAST FEW
ECMWF RUNS HAVE BEEN MOST ERRATIC WITH ALTERNATING HIGH AND LOW
PRESSURE SYSTEMS OVER A PARTICULAR LOCATION.  GFS RUNS HAVE BEEN
VARIABLE BUT TO A LESS EXTREME DEGREE.  THUS PREFER THE MORE
CONSISTENT ENSEMBLE MEANS UNTIL BETTER OPERATIONAL AGREEMENT
DEVELOPS.  AROUND DAYS 4-5 MON-TUE THE 18Z GEFS MEAN IS A LITTLE
WEAKER THAN THE 12Z ECMWF/CMC MEANS WITH THE WEST COAST RIDGE
ALOFT... FAVORING 2/3 WEIGHTING OF THE ECMWF MEAN.
 

[Carvers Gap]

the ensembles look much different from the op. The euro op IMHO is useless past day 6. It changes dramatically from run to run and is a lot different from its own ensembles.

Just looking at the ensembles for next weeks storm at 168 it has a low in southeast Texas by 180 its over New Orleans. Then by 192 its off the Virginia coast. Much faster and different from the op. In fact it looks more like the gfs op.

 

Wow.  I thought that might be the case.  Sometimes the operational has a tendency to jump on the wrong sw or wx feature and it impacts the entire model run.  In the medium to long range, I like the ensembles.  In the short range, I like the operational because it picks up on data trends.(And I know you know all of that...)  And thank you for sharing the ensembles.  We'll see what 12z has to offer. 

[Carvers Gap]

Lots of run to run variability in the models - the NAO is starting to look more east based, which is why we're not getting as cold.

 

The 0z GFS ensembles seem to support more moisture with the system end of next week than does the op. I'm still pretty confident that jan 2-4 is decent bet for some accumulating snow for much, if not all of TN>.

 

That is the million dollar question.  GFS looks much more west based.  The Euro has almost a completely different pattern past seven days over North America, more of a strongly positive NAO.  To me, I think the trough is going to set-up in the East for about ten days.  I think we will have below normal temps, to what degree I really could only guess. 

[Mr Bob]

Just a reminder as we head into a busy weather pattern....we have a banter thread for offhand comments...please keep to weather analysis and discussion here. Also...you don't have to be technical to post....we welcome all of you to jump in with your views on the upcoming pattern.

[Carvers Gap]

If I was to look only at the CPC ensembles for each index, this is what I would say(having not looked at any model)...A strong shot of cold, Arctic air is on its way.  Even chances on where it goes in North America because the NAO is slightly positive and the PNA is slightly positive.  Once the GFS and Euro are factored in...one would think we will see cold in the East, but with no blocking in place it probably continues to rotate through from the high over the Hudson Bay region.  In other words, a normal winter pattern is on its way w/ periods of cold and warm, with a notable warm and cold event present.  The good thing is that we will see some cold during the time that climo is coldest.  In my experience, that has almost always yielded some wintery precip over at least the eastern half of the valley.  If the NAO stays positive, and AO goes strongly negative...the Memphis to Nashville area look in better shape for snow and ice IMO with a similar pattern that brought wintery wx to the western half of the state already. 

 

NAO

 

AO

 

PNA

[tnweathernut]

I am becoming more and more optimistic of an event around the Jan 2-4 timeframe.  If we look at the short range, we are seeing more dynamic systems as we get closer to those events.  Look at this weekend.  Almost a perfect track and a juicy little system that a few days ago was forecast to slide harmlessly through Florida and off the coast as a weak system.  If cold air were in place we'd be getting a dump here in the southern apps this weekend. 

 

Most every system has been coming further north and west.  Without a -NAO this makes a LOT of sense. Looking at latest guidance, the NAO will be around neutral next week.  It stands to reason that next weeks system will have a very good chance to be both stronger and further north and west of the gulf coast track currently shown.  That could put the TN Valley in a great spot for a potential snow. 

 

Furthermore, this time frame has been really consistent on the modeling (GFS) as a time period to watch.  It was there at 240+ and it's still there now.  Don't be surprised if we have a defined threat to track in the coming days.

[tnweathernut]

Larry Cosgrove - per his FB account  https://www.facebook.com/larry.cosgrove

This is a sequence of satellite images that show systems which will likely have major impacts on U.S. weather starting this weekend:

1) JMA MTSAT view shows a regrouping of the Madden-Julian Oscillation. As the thunderstorm groupings expand from Indonesia to the International dateline and just beyond, energy and moisture feed from the MJO will intensify the sub-Aleutian vortex (pumps up a ridge into western Canada and Alaska), setting up cold air drainage into the lower 48 s...tates to the right of the Continental Dateline.

2) GOES WEST full disk shows an important storm with an equatorial connection (fed in part by the aforementioned MJO signal) southeast of Hawaii. Just as the intense Arctic chill reaches the U.S. next week this disturbance will be marching across northern Mexico into the Gulf Coast and then up and off of the Atlantic shoreline. It is a recipe for an important snow and ice event just after the New Year in portions of Dixie and perhaps snow in Appalachia and the Eastern Seaboard.

3) An equatorial wave over South America is a driver in the future development of an mAk vortex over the Grand Banks. Teleconnections on the linkage of the moisture stream to a vast oceanic low are very supportive of explosive cyclogenesis and sudden cold air drainage into the eastern half of the U.S., if this feature persists and grows over the next eight days.

[franklin NCwx]

Lol we went from a weak low crossing Florida to an amped solution running from Athens ga to Raleigh.

[tnweathernut]

Interesting light snow event shown on the 12z GFS for the 30th across much of the state of TN.  This feature was more robust on modeling several days ago and then was taken away largely for several runs.  This is the first run in a while that juiced it back up.  Keep an eye on this, could be a nice little light surprise. Under 100 hours, not to mention what looks even better coming behind it.

[tnweathernut]

Lol we went from a weak low crossing Florida to an amped solution running from Athens ga to Raleigh.

 

 

Talking about the weekend system, right?

[jaxjagman]

I am becoming more and more optimistic of an event around the Jan 2-4 timeframe.  If we look at the short range, we are seeing more dynamic systems as we get closer to those events.  Look at this weekend.  Almost a perfect track and a juicy little system that a few days ago was forecast to slide harmlessly through Florida and off the coast as a weak system.  If cold air were in place we'd be getting a dump here in the southern apps this weekend. 

 

Most every system has been coming further north and west.  Without a -NAO this makes a LOT of sense. Looking at latest guidance, the NAO will be around neutral next week.  It stands to reason that next weeks system will have a very good chance to be both stronger and further north and west of the gulf coast track currently shown.  That could put the TN Valley in a great spot for a potential snow. 

 

Furthermore, this time frame has been really consistent on the modeling (GFS) as a time period to watch.  It was there at 240+ and it's still there now.  Don't be surprised if we have a defined threat to track in the coming days.

Right,i don't get the surpressed look.The NAO isn't tanking and we continue to watch the models at times show surpression and as the event starts to get closer we watch  a shift