December 2018 Pattern And Forecast Discussion

[Math/Met]

You guys do a great job with the long range discussion. I enjoy reading your thoughts.

I just wanted to give a quick update on the mountain wave event for tomorrow. I’ll post some updates in the obs tomorrow. Everything still looks on track for a significant mountain wave event. MRX issued a High Wind Warning along the mountains, which is probably the right call because winds should easily meet the criteria in several locations along the mountains. I wouldn’t be surprised if there are some strong gusts in a few spots outside of the warning.  For example, parts of southern Washington County can get hit pretty hard with these events too.

[Carvers Gap]

4 minutes ago, jaxjagman said:

Problem with this winter is the Euro shows a split day 10 now but both daughters are weak looking and even the weaker one is in NA,guess we'll see how it plays out ,definite split @ 10hp tonight and almost 20,but it's later than what's been hinting at.now 1-5-19

Yep.   I think a non-textbook split(textbook for me is a PV that gets split right down the middle) is looking more likely than not.  Bout the best we can hope for is that it induces blocking which I think will happen during the last 1/3 of January at some point.  Cold going to Eur-Asia is pretty normal at first.  Sometimes, it will come back across the pole.  And as I noted before, I would be good w no strat split right now.  I think we would do OK without it.  It could really enhance what could be a good pattern or just foul it up.  No idea which at this point.  

[Carvers Gap]

IMHO, the biggest thing that we do not want to see is for that PV to get jostled around and then tighten back up.  That would reduce blocking and probably would not break up until spring.  We can make seasonal cold work at this time of year.  I just hope we see it induce a -NAO.   That would make things easier IMBY.  

[Carvers Gap]

9 minutes ago, Math/Met said:

You guys do a great job with the long range discussion. I enjoy reading your thoughts.

I just wanted to give a quick update on the mountain wave event for tomorrow. I’ll post some updates in the obs tomorrow. Everything still looks on track for a significant mountain wave event. MRX issued a High Wind Warning along the mountains, which is probably the right call because winds should easily meet the criteria in several locations along the mountains. I wouldn’t be surprised if there are some strong gusts in a few spots outside of the warning.  For example, parts of southern Washington County can get hit pretty hard with these events too.

Thanks for the updates....I have to head across the mountain at some point during the next couple of days.  Maybe I can get some video if it is really howling.  

[Holston_River_Rambler]

Speaking of the SPV, the GFS is now jumping on a second, smaller warming and hitting it again late in the run.  Not gonna worry about details of how it plays out at this range, but the GEFS and GEPS have some version of it too. I don't have EPS strat. maps out that far so can't speak to the Euro camp (actually the Euro kinda gets that far at 240 hours and hints at a renewed warming push at 10 hPa).  Even though the GFS has wavered a lot, it did at least point out that a warming was going to happen at range, so we may have another smaller event upcoming. It's amazing how man hits this PV has taken and how many pieces of vorticity have been shredded off of it and yet it still wants to stick it out. 

[Carvers Gap]

In terms of the 500 pattern, the EPS has shown pretty nice trends today...even at 850.  The 2m temps are seasonal which will do the job at this time of year.  The 12z has a stout PNA ridge.  Again, differences in its handling of the MJO are apparent...but I liked the run.

[Carvers Gap]

You know, weather stuff has come a long way when you can get a 3D model of a potential strat split...cool.

 

 

[AMZ8990]

1 hour ago, Carvers Gap said:

In terms of the 500 pattern, the EPS has shown pretty nice trends today...even at 850.  The 2m temps are seasonal which will do the job at this time of year.  The 12z has a stout PNA ridge.  Again, differences in its handling of the MJO are apparent...but I liked the run.

It’s nice to finally be upon peak climatology for wintry weather.  Been waiting a long time for it.  Hopefully the next 2 months don’t disappoint!!

[Carvers Gap]

Watching the hindcast Euro Weeklies roll right now.  They precede the main Weeklies by about thirty minutes.   You all may need to sit down if the main run is half as good as the hindcast run. 

[weathertree4u]

38 minutes ago, Carvers Gap said:

Watching the hindcast Euro Weeklies roll right now.  They precede the main Weeklies by about thirty minutes.   You all may need to sit down if the main run is half as good as the hindcast run. 

Such a tease

[Carvers Gap]

16 minutes ago, weathertree4u said:

Such a tease

LOL.  Sorry.  I was just waiting for the second half of Weeklies(first is hindcast...second is the normal run) to get finished.  Plus, my jaw hit the floor.  Still trying to gain composure.  LOL.  Sometimes they differ.  Easy explanation for this run.  Cold.  Weeks 2-7 are BN for temps....as a caveat, probably closer to the second half of week two.  The control has multiple Arctic outbreaks.   Basically just reloads a retrograding trough beginning in week 2.  Now, it is just one run...but that was impressive.  I suspect one of our folks will be kind enough to put the control and mean for snow.  If not, I will drop it in here later.  Me, after looking at the Weeklies...

 

[weathertree4u]

Just now, Carvers Gap said:

LOL.  Sorry.  I was just waiting for the second half of Weeklies(first is hindcast...second is the normal run) to get finished.  Plus, my jaw hit the floor.  Still trying to gain composure.  LOL.  Sometimes they differ.  Easy explanation for this run.  Cold.  Weeks 2-7 are BN for temps....as a caveat, probably closer to the second half of week two.  The control has multiple Arctic outbreaks.   Basically just reloads a retrograding trough beginning in week 2.  Now, it is just one run...but that was impressive.  I suspect one of our folks will be kind enough to put the control and mean for snow.  If not, I will drop it in here later.

Why wait pretty please lol

[Carvers Gap]

The control is crazy.  The mean is good.  Overall, the 500 pattern and 2m temps look the best.  I can only load one as my space is low.  If Holston hasn’t loaded them by 9:30 eastern, I will post them.

[Holston_River_Rambler]

Sorry, been out with peeps 

Control: 

 

Still can't find the US overall mean. Looking at individual cities, as Carver's said, definitely better than last run. Here's Elizabethton for some eye candy (and maybe hints at timing for pattern changes).

Being selfish for a bit, I'd say about half of the individual members look good (subjectively defined as 6"+) in Knoxville.  

[Holston_River_Rambler]

500 mb anomalies: 

 

This is made from the hindcast set of images (found on a different weather board), so not sure how different it is from the final run.

[Carvers Gap]

Snow mean...Now, this is a pretty big move by the Euro Weeklies, bit they for fit today’s EPS runs.  It could easily go back.  I need to see a couple of more runs before jumping on the bandwagon. The Arctic shots on the control are pretty impressive. 

[Carvers Gap]

The snow pack, if it were to verify, to our north would allow for cold air to reach us relatively unmodified.

[Holston_River_Rambler]

Nice to see the EPS mean and control aren't terribly far apart.

On a side note, I think I failed to purchase the model plan that gave me the weeklies. Or I haven't figured out where it is yet... 

[Carvers Gap]

So, I take tonight's Weeklies run w cautious optimism.  I think it unlikely that it will be 5.5 weeks of BN temps.  However, it does imply a return to a base cold pattern.  Is it right?  I don't know.  I like that the operational and ensembles from today agree with it.  However, it did miss this current warmup(strength and duration) initially.  So, I think we enjoy the run, and see if it repeats itself.  That said, the transition to the colder pattern begins shortly after the New Year.  The big question is whether the warmup in mid-Jan continues to be muted or absent.  I do like that the constant push back of the cold to later weeks "seems" to have stopped. 

[Carvers Gap]

Of note, John has begun our January pattern discussion thread....

As for our current December situation, a high wind warning remains in effect until the early afternoon for the mountains.  There are numerous flood advisories and warnings posted right now for N AL, E TN, the Plateau, SW VA, N GA, and W NC.  I have to drive into some of those warning areas this afternoon.  I will see if I can get some pics.  Maybe some of our northern Alabama posters can give us an update as I see plenty of flood warnings posted in that region.   TRI sits at +1.5 for temps and +1.5" for precip.  That precip number will most assuredly rise.  It has been pouring at my house as I type this.  That is an active dashboard right there.

 

[AMZ8990]

7 hours ago, *Flash* said:

Not sure I buy this despite an impressive 500 mb vort max (almost closes off @ 700 mb, albeit broad), a favorable surface low track position (weak low track seems off)...and the fact this sets up right over @AMZ8990. Usually I'm skeptical of systems reliant upon ULL CAA, but since we're not far from peak climo, perhaps it won't take much for western areas to get the job done. Overall, not a bad op run for the mid-term. Even if the NW trend continues, parts of our viewing area should have a sneaky system to track heading into the New Year. 

 

Nice, I hadn’t had a chance to look at the models today until I saw your post.  I’d take that look all day long, lol!!  I saw in the 18z where it tried to turn this into a CAD event so maybe we’re in for a week of tracking.  Time will tell, it’s nice to have some potential systems to look into now though.