Mid to Long Term Discussion 2018

[AfewUniversesBelowNormal]

It's kind of sad that we can't get past basically ENSO climatology, all these years later.. I think December is cold and February is warm.

[Waiting on snow]

7 hours ago, mackerel_sky said:

I hate a premature evacuation, but I’m looking over the cliff right now, and I only got one good shoe on... the other is a furry Croc! Atleast this week is going to be a little below normal!! Winning

I hope to be able to do a lot of cliff diving this winter!!! Wouldn't be fun to have wall to wall cold and snow. I like adversity!!

[mackerel_sky]

9 minutes ago, Waiting on snow said:

I hope to be able to do a lot of cliff diving this winter!!! Wouldn't be fun to have wall to wall cold and snow. I like adversity!!

If anybody chooses to cliff dive in December, looks like it’ll be warm enough for a speedo!

[Iceagewhereartthou]

3 hours ago, mackerel_sky said:

If anybody chooses to cliff dive in December, looks like it’ll be warm enough for a speedo!

Well living in the upstate we spend a lot of time at the bottom of the cliff!

[Solak]

Wonder how often we'll see this this Winter? AFD for the upcoming weekend.

The upper trough will really swing around and drive the low
northward by Saturday afternoon and there is some signal for a
Carolina split where we would not get a lot of the moisture.

[Poimen]

A little glimmer of hope in the LR. Both the EC and GFS want to build a PNA ridge and -AO by day 10. GFS has a potent s/w and a potential SE winter threat a few days thereafter. Something to keep our eyes on at least. 

[Jonathan]

23 hours ago, Cold Rain said:

It's a cutter pattern.  Trough axis is mainly in the west and tilted back toward the SW.  You have a decent look for AOB normal temps in the SE, but if a storm forms, it's a cutter.  No confluence in the NE, no blocking, main trough too far west, etc.  GFS actually looks a little better at D10.  What you would want to see in this pattern is a trailing wave after a rainer which develops on the tail end of the front.  Then, we could get a little something.

Regarding the general pattern progression, there really isn't anything that suggests December is going to go warm in the means or feature a complete lack of winter weather chances.  Most forecasts that I saw called for the month to be warmer than normal.  So this notion that winter forecasts are busting all over the place doesn't really hold water.  If there is anyone expecting December to be cold and snowy all through the month, then their expectations are way out of whack.  There isn't anything that suggests an overly cold or warm month right now.  And I haven't seen any patterns yet show up in the models that are of the torch variety and that can't be pretty easily fixed.  Sometimes, every variable is wrong.  That takes a long time to work out of.  That is certainly not the case at this point.  December should be variable, with maybe a slight lean toward cooler than normal.  That's my guess.

Thanks, CR. Think a lot of us (me lol) needed to hear this! WxTwitter is a scary place. :lol: 

[Thor]

[WinstonSalemArlington]

53 minutes ago, Thor said:

Come North!

 

[BIG FROSTY]

1 hour ago, Thor said:

That's got to come north, it jackpot's over Mack's house!! 

[mackerel_sky]

29 minutes ago, BIG FROSTY said:

That's got to come north, it jackpot's over Mack's house!! 

I approve this message!! The new GFSv3 was close to something 

[mackerel_sky]

31 minutes ago, BIG FROSTY said:

That's got to come north, it jackpot's over Mack's house!! 

If I got 4” and Roxboro blanked, I’d be glad to call it a winter!! Just don’t see where the cold air is gonna come from!

[Orangeburgwx]

2 hours ago, Thor said:

Come south about 75 miles!!!

[WarmNose]

1 hour ago, mackerel_sky said:

If I got 4” and Roxboro blanked, I’d be glad to call it a winter!! Just don’t see where the cold air is gonna come from!

It will make its own cold air!

[JoshM]

56 minutes ago, Orangeburgwx said:

Come south about 75 miles!!!

By 0z, the GFS will wish our storm back into the corn field!

[mackerel_sky]

2 hours ago, JoshM said:

By 0z, the GFS will wish our storm back into the corn field!

Done!

[mackerel_sky]

The GFS taketh away, the GFS v3, giveth!!

[Isopycnic]

5 hours ago, mackerel_sky said:

The GFS taketh away, the GFS v3, giveth!!

Congrats to Florence

[Orangeburgwx]

1 hour ago, Isopycnic said:

Congrats to Florence

6z is back to all rain... Damn you NW trend!!!

[BornAgain13]

I like....

 

 

[Thor]

Wake gradient, must be right

[Orangeburgwx]

2 hours ago, Thor said:

Wake gradient, must be right

Models always underestimate CAD... A LOT of areas further south and east of the current chart that will get a dusting at a minimum, and areas inside that zone are going to be higher.

The GFS 850/2m split for me during that time is 36/38, so with a stronger CAD than shown (which is a guaranteed rule of thumb) it is going to be a mess

[FallsLake]

Way too early to talk about a potential storm. We got to get this inside day 9/8. Tons of changes upcoming (positive and/or negative).   

[griteater]

So the going theme on the GFS and Euro Ensembles is this...

Possible wintry threat there in the Dec 8-9 timeframe with a split flow wave entering California - GEFS has a colder and more suppressed look compared to EPS.

After Dec 10th, zonal flow breaks out with NE PAC / AK trough, and warm anomalies spread out east of the Rockies.  EPS is on the aggressive side with the warming.  GEFS has it too, but it's not as aggressive

[SnowNiner]

11 minutes ago, griteater said:

So the going theme on the GFS and Euro Ensembles is this...

Possible wintry threat there in the Dec 8-9 timeframe with a split flow wave entering California - GEFS has a colder and more suppressed look compared to EPS.

After Dec 10th, zonal flow breaks out with NE PAC / AK trough, and warm anomalies spread out east of the Rockies.  EPS is on the aggressive side with the warming.  GEFS has it too, but it's not as aggressive

Yep, thanks Grit.  Surprised there's not a bit more chatter about Dec 8-9.  It's 10 days away I know, but both ensembles are showing at least a long lead threat to discuss.  Potentially not cold enough, but something to play with and talk about. 

Afterward the Pacific is bad.  Aleutian Ridge and Alaska trough is the opposite of what we need.  Hopefully it doesn't materialize or if it does it's transient.  Many times December can be the pattern that shows up the rest of the winter.  If that pattern materializes and has staying power, it could be a rough winter. 

[griteater]

3 minutes ago, SnowNiner said:

Yep, thanks Grit.  Surprised there's not a bit more chatter about Dec 8-9.  It's 10 days away I know, but both ensembles are showing at least a long lead threat to discuss.  Potentially not cold enough, but something to play with and talk about. 

Afterward the Pacific is bad.  Aleutian Ridge and Alaska trough is the opposite of what we need.  Hopefully it doesn't materialize or if it does it's transient.  Many times December can be the pattern that shows up the rest of the winter.  If that pattern materializes and has staying power, it could be a rough winter. 

The tropical forcing is so active right now (has been since late Sep) that variability isn't surprising to see on the modeling, so I personally wouldn't be too concerned with getting into a stuck pattern here in early winter.

[Jonathan]

5 hours ago, griteater said:

The tropical forcing is so active right now (has been since late Sep) that variability isn't surprising to see on the modeling, so I personally wouldn't be too concerned with getting into a stuck pattern here in early winter.

grit, question: I see the term "tropical forcing" a lot (here, twitter, etc) what exactly does that term mean?

[WeatherHawk]

1 hour ago, Jonathan said:

grit, question: I see the term "tropical forcing" a lot (here, twitter, etc) what exactly does that term mean?

Ask Rossby–Haurwitz they can tell you...it's super wordy and I can't even explain it myself...maybe a red label here can explain it

[griteater]

2 hours ago, Jonathan said:

grit, question: I see the term "tropical forcing" a lot (here, twitter, etc) what exactly does that term mean?

It's just the MJO really, but instead of the MJO phase chart, I prefer viewing it on a VP (Velocity Potential) map or on a hovmoller chart.

The chart below is the EPS VP Forecast (courtesy of a Mike Ventrice tweet).  The blues and pinks are -VP anomalies indicating upper level divergence which aids in rising motion and acts to enhance tropical convection more than normal.  The yellows and reds are +VP anomalies indicating upper level convergence which aids in sinking motion and acts to suppress tropical convection more than normal.  The location of the enhanced / suppressed areas of tropical convection have a large influence on the 500mb pattern over the Pacific and North America.

El Nino like is when you have +VP anomalies in the Maritime Continent and -VP anomalies in the central and eastern Pacific.  La Nina like is the opposite, -VP anomalies in the Maritime Continent and +VP anomalies in the central and eastern Pacific.  Typically, the stronger the ENSO phase (stronger El Ninos / stronger La Ninas), the more locked-in these VP anomalies become as opposed to cycling around the earth.

Here in late Nov into early Dec we are going thru an El Nino like period.  The building warmth on the EPS in mid-December is tied to the -VP anomalies moving east and reaching the Indian Ocean and the Maritime Continent (La Nina like).  The 500mb pattern for El Nino like vs. La Nina like varies some based on the month, and even the time of the month (it can be different for early Dec vs. late Dec)...but that's a topic for another day.

 

When I say that the MJO has been active since late Sep, you can see that on this hovmoller chart below.  CHI200 on this chart = VP anomalies (at upper levels - 200mb).  This chart is showing VP anomalies along the equator from 15S latitude to 15N latitude over a time period (from early Sep to late Nov, with the CFS forecast beyond into Dec).  The black lines show the movement of the MJO.  This shows how the MJO has been very active since late Sep (active cycling of alternating solid and dashed black lines).  If you just go down the chart from Sep to Nov along 120E longitude (location of the Maritime Continent), you can see how over time the Maritime Continent has alternated between -VP anomalies (green, which is La Nina like) and +VP anomalies (brown, which is El Nino like). 

What we would typically want to see for an established El Nino is a low frequency signal that is El Nino like (i.e. +VP in Maritime Continent and -VP in C & E Pacific) - in other words, we would want to see that type of pattern be predominate in the hovmoller chart over time, but with some level of MJO activity mixed in to enhance / suppress the overall low frequency signal.  Instead, what we have seen since late Sep is a lot of MJO variability (also referred to as inter-annual variability).  So, that's why I made the comment here that I would favor pattern variability that is higher than normal for early winter - https://twitter.com/griteater/status/1064557377050025984

 

Lastly, Mike Ventrice has a nice product that shows the VP movement in real-time here (via loop): http://www.atmos.albany.edu/student/ventrice/real_time/maps/mjo/global_analyses.html

[Orangeburgwx]

Swing and a miss on the 9th Storm... Great Lakes low #next