2016-2017 Great Tennessee Valley Winter Discussion

[Carvers Gap]

12 hours ago, jaxjagman said:

Dont mean to be the,but teleconnections dont add up and neither does the SOI,look at the GEFS and i believe should be even warmer.I think Mr.Wolfs pic he just posted could be possible though,but you should expect a big warm up upcoming into the mid month

 

Point made.  I don't think anybody is calling for anything other than a generally, very warm pattern for the next 2-3 weeks minimum.  But we can get winter even when teleconnections and the SOI are not advantageous...just much, much more difficult.  As outlined above in my earlier comments, there is a way...as shown on the 18z. 

Generally, Mr Wolfe, the major global models are the way....Euro, UKMET, GFS, CMC and probably in that order.  Ensembles are pretty easily available for all but the UKMET.  The CFS is a very average model at all ranges IMO and sometimes seems like a broken clock.  It is right twice a day.  Just my opinion.  Also, if you don't have a subscription...might look into some pay sites such as this or wxbell.  I just unsubscribe after winter for wxbell.

Lastly, very glad to see the drought eased out West.  They have needed the snowpack.  

Probably a good couple of weeks to relax, enjoy looking at LR models, and recharge with a chance at a decent Feb.

[JayCee]

Moonlight and snowpack equals something unique and beautiful.  Ya'll enjoy.

 

[Mr Bob]

1 hour ago, Mrwolf1972 said:

Is the CFS model any good was watching it and it shows 2 winter storms the 24 and 27th of this month.?

We don't make a habit of posting fantasy snow progs in the main weather discussion thread. 

[Jed33]

24 minutes ago, JayCee said:

Moonlight and snowpack equals something unique and beautiful.  Ya'll enjoy.

 

I agree JayCee. I just took the kids outside again with the telescope and we were all amazed! So pretty.

[jaxjagman]

The NMME'S ae showing a wet Feb.we just need cold

[weathertree4u]

4 hours ago, bigdog660 said:

Send it on to me. I feel like winter is slipping away. Until this system came along, I didn't see our winter weather being much different than in west central California (and how boring they are). Don't get me wrong, I appreciated the 2 inches of snow, but I'd really like to see 4" or more in one clip. And if we got some ice, and as long as does no real damage, it's okay with me. I'd just be not fool enough to try to drive on it.

Thanks for posting!

[John1122]

4 hours ago, Carvers Gap said:

I am torn in thinking this retroging trough into AK is a stable, new pattern...or if is a transition to an eastern trough.  The AN heights build into Canada scouring the cold there.  Takes us right back to November when the pattern changed and it took three weeks to build cold.  But what is interesting is seeing some BN or normal heights at 500mb try to sneak under those very high heights in the East.  Several strong pieces of energy cutting at the base of the eastern ridge.  When a cold front manages to crash the ridge...would be interesting to see if timing would allow for one of those potent systems fo get picked-up.  Enough marginal cold around since it is Jan.  Bit of a long shot in what is looking more and more like a very warm pattern that has more holding power than I thought.  I hope the MJO can work its magic as it is forecast to roll through phases 8,2, and 1 later this month. So my questions as we go forward....Does the warm-up really hold?  (modeled long term heat or cold has never held in the East) When the MJO hits prime territory, will we have any cold left in Canada which by then will have been well above normal for 2-3 weeks?

Side note...95-96 (on a very scaled down level) comes to mind as does '89.  One good.  One not good.  Also, the blocking signal from a couple of weeks ago bore some fruit.  Something to watch for if it happens again...even if transient.

While I'd rather have a cold Canada. Last year showed we don't really need it to produce wintry weather here. Even well above average temps up that way are still cold enough to send enough cold into our back yard.  Last year Canada was a super torch. Especially so in the areas we normally look at to send cold south and east towards us.  The upper Midwest also torched.  The map below wasn't just because of December in Canada. It literally looked similar for Jan and Feb too.  We pulled out several big storm chances from late Jan into mid Feb even in a hostile pattern. 

 

[jaxjagman]

Yeah but we had a AK ridge back then,not now.Not even a -PDO showing up

[jaxjagman]

Even around the 24th by the look you should be looking at  strong S-Jet with some good rain,nothing frozen,maybe a brief cold spell but the rest of this winter looks blahish to me

 

 

http://blog.organicforecasting.com/p/bsr-forecast-maps.html

[jaxjagman]

The euro shows a warm front lifting North into next weekend with a slow moving line of deep low level convergence,this would be a big rain maker with some parts of the Valley getting around 3-4" of rain

[weathertree4u]

5 hours ago, jaxjagman said:

Even around the 24th by the look you should be looking at  strong S-Jet with some good rain,nothing frozen,maybe a brief cold spell but the rest of this winter looks blahish to me

 

 

http://blog.organicforecasting.com/p/bsr-forecast-maps.html

That could be the case but I would think that we have at least one more chance to see something. Now, if we get to the second and third week of Feb and maps like above are being posted, then yea, we need to move on to tracking heavy rain events and severe weather and start looking at long range 2017/2018 possibilities.

[Carvers Gap]

Not going to cancel winter on Jan 8th.  The map below is from the 0z EPS.  I usually don't post WxBell Euro maps as there is a blurry rule about posting them.  Anyway, this is not the beginning of a trend on my part.  However, IMO it makes the point that some energy is going to try so sneak under the eastern ridge during the warm-up.  It has shown this from time to time during recent runs.  What will be interesting is where this pattern goes after this.  The PNA is forecast to go positive on both the Euro and  The AO is forecast to go neutral to slightly positive.  The NAO is forecast to go negative on the Euro or slightly positive on the GFS.  The WPO is forecast to go weakly positive.  The EPO will be strongly positive.  There is some conflict about the teleconnections.  If the Euro has a +PNA and -NAO in the LR as modeled, that makes things interesting.  The upcoming 2-3 weeks will be generally warm, but warm patterns can have surprises.  The weeklies have been decent this year and they like a +PNA long term.   The transition on the models was shown on the weeklies several runs ago. Last year, we had just finished a torch of a December....and we still managed to get winter.  I think the end of January and a good chunk of February look decent.  The look below eventually (on the weeklies) transitions into an eastern trough w the AN heights moving into AK in a couple of weeks.  JB actually discussed this shift today.  It may or may not verify...but the weeklies have supported this transition for several runs.  The solid line is the path that the AN heights are forecast on the weeklies to take during the next 2-3 weeks.  The dashed line is the path that is EPS is showing some storms taking under the ridge.

edit: I also added the teleconnections from the last eight forecasts of the Euro and GFS.

[Carvers Gap]

The MJO has been a decent forecast tool this winter.  For winter in the East it needs to be in phases 8, 1, and 2.  Decent signal in the LR and has been there for some time.  (Edit) For those new to the forum, it needs a higher amplitude to have bigger impacts and not inside the circle which many term the COD or circle of death. Though this winter even weak amplitude plots have seen some correlation IMO.

[weathertree4u]

3 minutes ago, Carvers Gap said:

The MJO has been a decent tool this winter.  For winter in the East it needs to be in phases 8, 1, and 2.  Decent signal in the LR and has been there for some time.

So, the take away is not to get hung up on the ups and downs of individual model runs but to rather look at the bigger picture.

[Carvers Gap]

7 hours ago, weathertree4u said:

So, the take away is not to get hung up on the ups and downs of individual model runs but to rather look at the bigger picture.

I think so.  There is pretty clear model support for a general warm-up for 2-3 weeks.  There will still be cold fronts and storms...just tougher to get it to snow, thread the needle type stuff...but not impossible.  It is the last week of January and into February that we have an opportunity to return to winter.  Just seems like a winter with wild swings and strong cold fronts which is typical of Nina climo.  I do think in about a week or so, we will see the way out of this big warm-up shown on modeling.  There is no guarantee it gets cold again, but models seem to support the idea that it probably will.  Still a ton of winter to go...

[weathertree4u]

2 minutes ago, Carvers Gap said:

I think so.  There is pretty clear model support for a general warm-up for 2-3 weeks.  There will still be cold fronts and storms...just tougher to get it to snow, thread the needle stuff...but not impossible.  It is the last week of January and into February that we have an opportunity to return to winter.  Just seems like a winter with wild swings and strong cold fronts which is typical of Nina climo.  I do think in about a week or see, we will see the way out of this big warm-up shown on modeling.  There is no guarantee it gets cold again, but models do support the idea that I probably will.  Still a ton of winter to go...

I totally agree, most people that post on here have a ton more weather knowledge than me, I usually just lurk, but I like the fact that we are staying generally moist, though would like to see more of it further east into TN than simply stopping in the Middle TN area

[jaxjagman]

I never said cancel winter.The MJO does indeed look better upcoming,but we're wasting our coldest days of the year upcoming.That was my meaning of looking "blahish"

[tnweathernut]

It's pretty obvious we are entering an ugly looking period for snow lovers over the next couple of weeks.  Hoping we can reset things........ and not wait 60 days for another opportunity, lol.

[John1122]

This is one of those mystery panels. There's no way you can have a 1055mb HP right there with -30 degree temps under it and have temperatures above freezing on this side of the Apps.  That would be a fire hose of frozen precip directly over us. Instead it's just panel after panel of relative warmth. 

[PowellVolz]

Trading my snow boots for golf shoes this weekend. #feelsgoodman


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[tnweathernut]

Man, things look about as ugly as possible with regards to the long range.  One last BIG high coming, but doesn't look to have much of an impact south of the OH river.  I'm not sure this look can be gotten out of easily.  You never want to see the blue vortex of doom over Alaska.  Our cold air source is about to be vanquished to the north pole and most of North America flooded with warmth!  :-(  I sure hope modeling isn't right, but it's been pretty consistent on OP modeling and ensembles.

 

[Carvers Gap]

This is how we can get out of this.  Not saying this is how it happens, but the BN heights over AK are gone.  Trough off the west coast.  PNA ridge goes up.  Canada is above normal, but it does not take much imagination to roll that into a pretty cold pattern for the EC.  This look is showing-up in both the EPS and GEFS varying degrees.  MJO pattern actually supports this look as well.

[Carvers Gap]

Here is the MJO from the BOMM.  I like this because it seems to fit the pattern where the pattern is not locked into place.  The Australians do a decent job w the MJO as it is on their side of the planet.  So, here is a different MJO forecast than the low amplitude Euro which is admittedly pretty anemic.  So, I tread with caution knowing it is a lower amplitude than the American model. The GEFS/GFS still go to a decent amplitude in phase 1-2.  The JMA looks decent as well.  

Here are the others so it does seem that I am cherry picking.  Part of this is just trying to figure things out.  For those of us who have been here for a while, it is not really a contest to be right, but trying to unlock the pattern. 

[nrgjeff]

Welp. When's the next chance of severe weather? Just kidding!

I do agree that arctic front later this week needs to be watched. Robust southwest flow should keep Tennessee and points south all rain, but we are playing with a 1044+ high press. Back in the Plains, we just forecast that to come straight south regardless. The difference this week, esp this far east, is a robust SSW flow aloft vs general WSW flow.

Weather looks warm the next couple of weeks, with perhaps a mild week 3 as well. Turn of the month into February may bring another turn to colder weather. Majority of LR model ensemble members try to build another AK ridge. MJO could be a driver. Also the 500 mb arctic chart is still a mess (good for cold). PV is intact but 500 mb and below is blocky in some parts of the World. Europe's turn the next 10-15 days!

[Carvers Gap]

Here is the 12 GEM ensemble at 500mb at it progresses from 252 through the LR to 384.  Notice the extreme BN anomaly diminish and the PNA ridge increase.  The eastern trough deepens in turn.  Also, not the trough east of Hawaii.  Great pattern if it verifies.  The fly in the ointment is the missing cold temps at 2m.  The 850s look good.  So, how do we get them after two weeks of AN heights in much of North America?  Well, IMO there are two ways...1.) The cold from AK could be forced into the developing eastern trough AND/OR 2. The PNA ridge could push northward and create cross polar flow.  Fortunately, we are not erasing summer's warm anomalies as this is mid-winter.  IMO, the GEM ensemble have moved this up a bit...so we need to see if it is too fast or if it is on to a trend.  This lines up w/ the MJO, climo, and the idea that the western trough/ eastern ridge pattern is overdue in ending.  During the last cold outbreaks the GEM was late to the party and left early.  Like the RGEM, I like to see it on my side at this range...even more so than the GEFS.

[jaxjagman]

3 hours ago, nrgjeff said:

Welp. When's the next chance of severe weather? Just kidding!

I do agree that arctic front later this week needs to be watched. Robust southwest flow should keep Tennessee and points south all rain, but we are playing with a 1044+ high press. Back in the Plains, we just forecast that to come straight south regardless. The difference this week, esp this far east, is a robust SSW flow aloft vs general WSW flow.

Weather looks warm the next couple of weeks, with perhaps a mild week 3 as well. Turn of the month into February may bring another turn to colder weather. Majority of LR model ensemble members try to build another AK ridge. MJO could be a driver. Also the 500 mb arctic chart is still a mess (good for cold). PV is intact but 500 mb and below is blocky in some parts of the World. Europe's turn the next 10-15 days!

Wouldn't say you'd be wrong about severe.One thing for sure,shouldn't be any question that we won't be in a drought anytime soon.They finally fixed this model,it's been stuck on the 4th the last few days.The CFS has been showing it will be turning colder into Feb.,who knows with that model or any model that far out.

[Carvers Gap]

I thought the Euro weeklies this evening looked good. Transition to a decent 500mb pattern begins during week 3 which is basically a western ridge and eastern trough...strong PNA...weakly negative to neutral NAO.  

[John1122]

1 hour ago, Carvers Gap said:

I thought the Euro weeklies this evening looked good. Transition to a decent 500mb pattern begins during week 3 which is basically a western ridge and eastern trough...strong PNA...weakly negative to neutral NAO.  

I just hope they are right and don't keep seeing that at week 3.

[John1122]

GEFS baby steps. The last 48 hours of the run shows the end of the Alaskan death vortex and shows above normal heights building from the west up to there.

[Carvers Gap]

16 hours ago, John1122 said:

I just hope they are right and don't keep seeing that at week 3.

They seem to be continuing to move that week forward in time w each of the last few runs. Been showing this for about two weeks. Plus, the operational/ensemble models are showing the transition in the d13-16 range now.  (The Weeklies were run from the 0z model yesterday I think.)  They are certainly not infallible as they were too cold at one point this winter and too warm during another.   The biggest concern that several have expressed is the source region for cold.  To me, this looks like a pretty big 500mb pattern shift if they verify.  Now, it could easily be same thing that happened last weekend, meaning transient.  Taken verbatim, it looks reasonably stable.  That said, this winter has been a tough one to forecast.