December 2017 Mid-Long Range Disco 2

[Ralph Wiggum]

trough in the SW getting stronger....that won't help down the line on this run

Yep....looked ok up til day 10 then huge phasing system out in the SW really trying to establish and anchor in the mean trof and pump SER downstream.

[mitchnick]

1 minute ago, yoda said:

Nice CAD at 264... Day 11 ice ftw

if the weather is going to ruin Christmas, it better be for snow and not ice or sleet imho

[Bob Chill]

1 minute ago, mitchnick said:

the other issue is, will the system get squished while the trough is to our north and then come up the back side warm once the trough to the NE pulls out

IMHO- the 12z gfs sucks. Yea, shows some confluence/cad or whatever but the overall progression is spot on for a strong SE ridge problem. 

[SnowGoose69]

I’m guessing that all we see is a transient 2-4 day period of a SE ridge which will largely be the result of some sort of cutting system.  Even the GFS MJO forecast (which probably is wrong anyway) wouldn’t ordinarily telocconect to a SE ridge 

[mitchnick]

1 minute ago, SnowGoose69 said:

I’m guessing that all we see is a transient 2-4 day period of a SE ridge which will largely be the result of some sort of cutting system.  Even the GFS MJO forecast (which probably is wrong anyway) wouldn’t ordinarily telocconect to a SE ridge 

I'll feel better to get some model to support that. But we're not going to get any model to come up with the ultimate correct (or as correct as possible) solution until a week from today.

[WhiteoutWX]

Just to recap for anything by day 10 on this run to occur you need for all these things to be modeled correctly:

1. Enough Greenland ridging to occur to keep the heights over the eastern US supressed.

2. The trough in the southwest at 180 to cutoff. Not enough to completely detach itself from broader trough (otherwise it will be cold and dry) but enough to let northern portion of trough to head east and force the boundary into the Mid-Atlantic.

3. A near triple phaser to occur between multiple northern stream waves and the SW cutoff at hour 240 which completely blows up the downstream troughing over the east and allows the system to eject into the midwest. 

Long story short...it's safe to say this ain't happening. But I think the trends were positive up to day 8/9. That final phase at hour 240 is suspect to me. If that doesn't happen or happens a little differently I think we could have seen a better solution.

[BristowWx]

6 minutes ago, mitchnick said:

if the weather is going to ruin Christmas, it better be for snow and not ice or sleet imho

Better than ruining it with 65 and partly cloudy imho

[mitchnick]

2 minutes ago, BristowWx said:

Better than ruining it with 65 and partly cloudy imho

well, I was considering "ruining" as preventing people from traveling since most families get together

I'll take 65 over sleet/ice

[yoda]

GFS tries for a snowstorm again at the end of its run

[Bob Chill]

4 minutes ago, WhiteoutWX said:

Just to recap for anything by day 10 on this run to occur you need for all these things to be modeled correctly:

1. Enough Greenland ridging to occur to keep the heights over the eastern US supressed.

2. The trough in the southwest at 180 to cutoff. Not enough to completely detach itself from broader trough (otherwise it will be cold and dry) but enough to let northern portion of trough to head east and force the boundary into the Mid-Atlantic.

3. A near triple phaser to occur between multiple northern stream waves and the SW cutoff at hour 240 which completely blows up the downstream troughing over the east and allows the system to eject into the midwest. 

Long story short...it's safe to say this ain't happening. But I think the trends were positive up to day 8/9. That final phase at hour 240 is suspect to me. If that doesn't happen or happens a little differently I think we could have seen a better solution.

Excellent post. Thank you for this. I'm going to be skeptical of any op rushing things. Of course I hope the sw trough/se ridge is quick and transient...but I don't think it will play out like that. Not mad at the GL ridging allowing for some confluence/compressed flow north of us. That's a pretty typical way for us to get CAD going even with a SE ridge. Overall though, the gfs op run wasn't good for snowstorms in the east. Especially south of new england. 

[WhiteoutWX]

1 minute ago, Bob Chill said:

Excellent post. Thank you for this. I'm going to be skeptical of any op rushing things. Of course I hope the sw trough/se ridge is quick and transient...but I don't think it will play out like that. Not mad at the GL ridging allowing for some confluence/compressed flow north of us. That's a pretty typical way for us to get CAD going even with a SE ridge. Overall though, the gfs op run wasn't good for snowstorms in the east. Especially south of new england. 

I agree it for sure is not a classic east coast snowstorm pattern IMO, but it screams mixed bag/ice scenario possibilities. Which for some are less fun than others. To me, wintry weather is wintry weather so I'll take it. But I know most people don't like losing their power or having tree damage so I understand if most are unenthused. 

[Kmlwx]

Let's shoot for the Eskimo Joe - EMP-esque ice storm power outages or bust.

[mitchnick]

CMC says the he!! with the SW trough AND the SE Ridge thru day 10. Cold.

 

[Bob Chill]

12 minutes ago, WhiteoutWX said:

I agree it for sure is not a classic east coast snowstorm pattern IMO, but it screams mixed bag/ice scenario possibilities. Which for some are less fun than others. To me, wintry weather is wintry weather so I'll take it. But I know most people don't like losing their power or having tree damage so I understand if most are unenthused. 

Heck yea man. Same page here. Winter wx is winter wx. Period. End of discussion. lol. Especially in this area where we can get shut out of winter wx for the entire met winter. haha. A Christmas pellet/ice storm is completely acceptable. Damaging ice is rare here so I'm not worried about that. Unless we get a cold hp on roids moving across, I doubt a damaging ice storm is even in play. The middle of the country however seems to be pretty ripe for some sort of ice storm that could in fact be damaging. 

The CAD sig is real. Even the ens show it in the long range which is not very common at all. Who gets what is something that literally can't be answered for a week but any op or ens run that favors a CAD setup d8+ is a check mark in the win column. 

[BristowWx]

3 minutes ago, mitchnick said:

CMC says the he!! with the SW trough AND the SE Ridge thru day 10. Cold.

 

Let’s do this.  F*** the SER.  Yes it did look cold.  GEFS not completely finished yet.  

[yoda]

6 minutes ago, mitchnick said:

CMC says the he!! with the SW trough AND the SE Ridge thru day 10. Cold.

 

Yes indeed... also looks like some type of system may be developing near the GOM day 10 at hr 240

[Ralph Wiggum]

GEFS much better look irt to positioning of EPO ridge, SW trof axis, PV influence, and SER centered around days 10/11

[Ralph Wiggum]

GEFS has a much nicer Christmas Day look imo. Loving the sprawled HP with wave in GOM and along coast.

[Bob Chill]

Last 5 runs of the GEFS for Christmas. 12z sped things up for sure and lead times are closing. Too early to make any calls but for now the latest gefs isn't roasting us. 

[Conway7305]

Is there any site that can help me learn more about the weather patterns, upper level patterns?  I would really appreciate it.  I know the basics of reading the maps and models.  I know a little about how troughs and ridges Influence our weather. I don’t know about much about 500mb heights, stratospheric warming, cold air damming, MJO, low placements, high pressure placements, energy digging, and different maps you look at making your calculations.  Also what does EPO mean? Sorry to be a pain.  Just trying to learn. Thanks 

[BTRWx's Thanks Giving]

23 minutes ago, Ralph Wiggum said:

GEFS much better look irt to positioning of EPO ridge, SW trof axis, PV influence, and SER centered around days 10/11

 

See, I use the MJO to see through to that kind of thing.  I seriously believe ops follow ensembles follow teleconnections foolow MJO

[Bob Chill]

Very nice CAD sig leading into the holiday. Moisture streaming up from the SW to go along with it. 

 

[BTRWx's Thanks Giving]

4 minutes ago, Bob Chill said:

Very nice CAD sig leading into the holiday. Moisture streaming up from the SW to go along with it. 

 

Where?

eta: mslp != 850s

[Bob Chill]

I really hope the EPS trends the same way as the GEFS. Notable shift across the board to speed up the SW trough and knocking down the SE ridge. This 5 day mean is about as good as you can get around here for possible winter wx in the face of a +NAO. It's definitely a cold NA pattern as well but progressive flow so not a clean snow pattern. Completely acceptable though. 

 

 

 

 

[Kmlwx]

5 minutes ago, BTRWx's Thanks Giving said:

Where?

You don't see the buckling in the isobars/anomaly shading in the CAD signature pattern?

[BTRWx's Thanks Giving]

Just now, Kmlwx said:

You don't see the buckling in the isobars in the CAD signature pattern?

I had to fetch a different map layer to see it.

[Bob Chill]

3 minutes ago, BTRWx's Thanks Giving said:

I had to fetch a different map layer to see it.

The best way to identify CAD is MSLP plots. When you have stout HP centered between Toronto and Montreal it's going to push N-NE flow down the piedmont. For a ens mean pressure panel @ d8+, the one I posted is a really strong signal. 

[BTRWx's Thanks Giving]

Just now, Bob Chill said:

The best way to identify CAD is MSLP plots. When you have stout HP centered between Toronto and Montreal it's going to push N-NE flow down the piedmont. For a ens mean pressure panel @ d8+, the one I posted is a really strong signal. 

New to me. Thanks!

[Eskimo Joe]

1 hour ago, Kmlwx said:

Let's shoot for the Eskimo Joe - EMP-esque ice storm power outages or bust.

We don't do ice storms here.  They always fail.  Snow or bust.

[isohume]

1 hour ago, mitchnick said:

if the weather is going to ruin Christmas....

That's a big if.