December/January 2019/20 Winter Speculation Thread

[jaxjagman]

2 hours ago, Carvers Gap said:

Want a really good example of an EPS bust, look at last November(2018).  I was all-in on warm and made it clear.  John challenged the model, and he was right.  I have rarely seen the EPS so locked into a solution and see it bust.  November went cold.  It basically did the same thing this fall...but those were shoulder seasons and we are on different ground now as it is deep into winter.  But sometimes modeling can seem locked and miss.  So, never hurts to question modeling even if it is likely to be correct.  The GFS shows one way to cold compared to an abundance of paths going warm.  But again, if it was cold forecast and the 18z hiccuped...I would be watching the next few runs. 

About sick of even looking at the weeklies.EPS around day 9-10 shows the 850's around -20c in SW KY while the Euro today looks around +10c,same time

[jaxjagman]

4 hours ago, Holston_River_Rambler said:

It could for sure. Masiello was commenting how warm the waters were there now, thanks to the IOD causing the extreme heat in Australia. I wonder if once it gets going, it it will even out do modeled expectations. 

 

That's because of the +IOD  being so strong,they are on fire

[Carvers Gap]

You can see on the 0z GFS about the energy having to go west or east of the Rockies.  The energy at 0z was over the Seattle and tried to dodge east like 18z and split.  It regrouped to the West.  Sent some energy west of the Coastals.

[Carvers Gap]

That little piece of energy at 240 is where the run hangs on an edge.  Probably won't stay that way.  The 18z and 0z were nearly identical until that piece of energy headed west of the Rockies instead of east.

[Carvers Gap]

At 240, you can see the energy at 500 split over Seattle as if it couldn't decide to go west or east.  As is, looks like it will deepen the western trough vs allowing it to slide eastward with cold air.  Model is literally splitting hairs with that piece of energy.  Something to keep an eye on.

[Carvers Gap]

The energy has to go west or east of the Rockies...can't ride the spine.  The front on this run will hold up in the Plains vs coming east.  We need that piece of energy to come across the continental divide and not dive west and dig that trough.  Both are realistic possibilities.   

[Carvers Gap]

And yet, here comes the front with cold air pushing under the 500 ridge yet again.  I still think it hangs up, but at 312 her she comes into west TN.  Yes, that is PBP at 300...that is how bad it is (for future readers referencing this post)!

[Carvers Gap]

Did the 0z GFS just hold serve past 300 hours?!

[Wurbus]

That snowfall map looks pretty for the mid-west. That is one impressive cold front moving through past 300 hours though. Temps go from 69 to 25 in 6 hours in Memphis.from 312 to 318.

[Carvers Gap]

Despite the 500 pattern, cold has overwhelmed the pattern at this point out to 354.  The cold front at 18z was a 10+/10.  This one was a 9.5/10.

[Carvers Gap]

And the 0z GEFS has broken a bit from continuity post 300.  Still not there yet, but the trough out West has been really disrupted.

[jaxjagman]

2 hours ago, Carvers Gap said:

Despite the 500 pattern, cold has overwhelmed the pattern at this point out to 354.  The cold front at 18z was a 10+/10.  This one was a 9.5/10.

Dont think the problem is the short range or even mid range its when the MJO gets into the Maritime this is is when the jet extension starts to cause havoc, along with HP on the Aleutian Islands,this is where you have a more pronounced -PNA.JMHO

[jaxjagman]

Just saying the pna is fixing to crash big time in the long range

[weathertree4u]

2 hours ago, jaxjagman said:

Just saying the pna is fixing to crash big time in the long range

So that is good right? 

[weathertree4u]

The overnight run of the CFS was crazy lol that would be a historic run if that occurred fun to look at!

[John1122]

8 hours ago, weathertree4u said:

So that is good right? 

It is the opposite of good. You want a +PNA that's rising.  We can't have any kind of sustained cold or winter weather with a bad Pacific. At most we can get a lucky shot but even that's uncommon.  I haven't looked but I'd bet 85+ percent of our cold/snow events feature either s positive or neutral PNA. 

[weathertree4u]

1 minute ago, John1122 said:

It is the opposite of good. You want a +PNA that's rising.  We can't have any kind of sustained cold or winter weather with a bad Pacific. At most we can get a lucky shot but even that's uncommon.  I haven't looked but I'd bet 85+ percent of our cold/snow events feature either s positive or neutral PNA. 

Oh

[John1122]

Just now, weathertree4u said:

Oh

Our best hope is that this is a 6 week type pattern. If it is we will see it start breaking down in about 2 weeks.  Which would be great for us because January 15th - February 15th is the prime winter timeframe here when temps are at their lowest and snowfall is at it's most likely.  But last year we never got out of a similar 500mb pattern, even though other drivers are different this year, we may not get out of this one.  If this one doesn't change even the Smokies would struggle to see even close to normal snow during it. Right now it's probably a coin flip on whether we get a shift. Most other times I'd say we would, but in the current ecosystem we tend to fall into every way possible to stay warm and wet.  

[TellicoWx]

It is the opposite of good. You want a +PNA that's rising.  We can't have any kind of sustained cold or winter weather with a bad Pacific. At most we can get a lucky shot but even that's uncommon.  I haven't looked but I'd bet 85+ percent of our cold/snow events feature either s positive or neutral PNA. 

Agree completely, basically need the mjo to cycle around into phase 7/8 (promotes +PNA/-NAO) or take our chances in the COD (rely on other drivers to pop a +PNA)...where the MJO currently is headed (high amp 4/5), above normal temps and precip until we get thru it.

Sent from my SM-S767VL using Tapatalk

[Carvers Gap]

The 12z GFS(we all know the rules with this model) showed a fourth run straight of a fairly significant cold front right in the middle of the Jan 10-20th warm-up.  The 12z GEFS also shows a fairly strong trend to reduce ridging late in the time frame.  I am only looking at trends at this point...but that is all we have.  I said last night that if I had a certain cold shot(that had been shown for weeks) heading for MBY, and I saw a warm run on the 18z GFS flip warm...I would be a bit nervous.  Last night was of course the opposite of that...but the happy hour run can sometimes catch trends.  Who knows?  Guess we are about to find out.

[John1122]

1 minute ago, TellicoWx said:

Agree completely, basically need the mjo to cycle around into phase 7/8 (promotes +PNA/-NAO) or take our chances in the COD (rely on other drivers to pop a +PNA)...where the MJO currently is headed (high amp 4/5), above normal temps and precip until we get thru it.

Sent from my SM-S767VL using Tapatalk
 

Last year we went from 7-2 during the warmth and the Pacific didn't even blink.  Last year was the queen mother of bad winters. 

[AMZ8990]

12 minutes ago, John1122 said:

Our best hope is that this is a 6 week type pattern. If it is we will see it start breaking down in about 2 weeks.  Which would be great for us because January 15th - February 15th is the prime winter timeframe here when temps are at their lowest and snowfall is at it's most likely.  But last year we never got out of a similar 500mb pattern, even though other drivers are different this year, we may not get out of this one.  If this one doesn't change even the Smokies would struggle to see even close to normal snow during it. Right now it's probably a coin flip on whether we get a shift. Most other times I'd say we would, but in the current ecosystem we tend to fall into every way possible to stay warm and wet.  

 We’ve broke records the past 2 years for yearly rainfall totals, would not surprise me if we do it a third year in a row.  It Stinks we can’t get some sustainable cold to set in to work with the moisture though,  your warm and wet scenario is spot on.  It Sucks we have to wait and see if we’re gonna get bailed out in the next 60 days.  I’m not feeling very optimistic though,  something feels off this year,  More so than last year from my perspective.  

[Carvers Gap]

I wil also add...cold can and does overwhelm MJO patterns.  The volume and severity of the cold on some modeling could do that.  Not saying that happens...but that is realistic.  The GFS is also depicting the variability that I would expect from modeling...not those runs where the entire northern hemispheric circulation complex is arrested and stops.  So, one would expect cold fronts coming east IF the cold can get east of the Rockies.  There is really no physical feature to hold it in place other than high pressure that seems to be willing to move at times.

[AMZ8990]

3 minutes ago, John1122 said:

Last year we went from 7-2 during the warmth and the Pacific didn't even blink.  Last year was the queen mother of bad winters. 

Off topic John- but do you remember the last time we had a good February snowstorm in the sub forum?

[Carvers Gap]

14-15 had some decent snows in NE TN in February.  Most snow I can remember in February in my lifetime in Kingsport.

[AMZ8990]

13 minutes ago, Carvers Gap said:

The 12z GFS(we all know the rules with this model) showed a fourth run straight of a fairly significant cold front right in the middle of the Jan 10-20th warm-up.  The 12z GEFS also shows a fairly strong trend to reduce ridging late in the time frame.  I am only looking at trends at this point...but that is all we have.  I said last night that if I had a certain cold shot(that had been shown for weeks) heading for MBY, and I saw a warm run on the 18z GFS flip warm...I would be a bit nervous.  Last night was of course the opposite of that...but the happy hour run can sometimes catch trends.  Who knows?  Guess we are about to find out.

Plenty of cold air at the end of its run,  Canada is an ice box from west to east.  Too bad it’s all the way out at the 15th timeframe 

[John1122]

8 minutes ago, AMZ8990 said:

Off topic John- but do you remember the last time we had a good February snowstorm in the sub forum?

The last time that basically the entire sub forum had winter weather was February 2015. On February 16th-18th almost the entire forum had at least an inch of snow and mixed precip too. It was also close on February 25th the same year.  

Large snow events for the entire sub forum are rare.   You almost never see snow in both Chattanooga and Dyersburg because the events that drive snow for both places are usually different.  

[Carvers Gap]

23 minutes ago, AMZ8990 said:

Plenty of cold air at the end of its run,  Canada is an ice box from west to east.  Too bad it’s all the way out at the 15th timeframe 

The energy that "could" force part of the trough east temporarily is inside of(edit) 240.  

[Carvers Gap]

FWIW, the 12z Euro and GFS look very similar at 168 with the Euro Pac ridge pushing towards the coast a smidge more than 0z.

[Wurbus]

The difference in temps on the Canadian and GFS in southwest Canada at 240 is pretty remarkable. GFS has southwest Canada between -25 to -40 degrees, while the CMC is 15-20 degrees. Almost a 50-60 degree difference!