December and a Hint of January Pattern Discussion

[smokeybandit]

As long as that warm air is out of here for Christmas.  Nothing worse than a warm Christmas

[mitchnick]

As Bob says the GFS is much quicker with the front than the euro which actually has 3 really warm days culminating in a max of over 70 on SUnday.  That looks like an outlier but the euro ensembles have trended warmer in the past couple of days.   The euro esnembles suggest lots of uncertainty concerning the timing of the front.  To a lesser extent so does the GEFS ensembles which has a couple of slow frontal passage members.  If you're hoping for the clipper to yield, good luck.   The low goes to our north so our north so surface temps are likely to be a problem.   I haven't looked at the super ens mean as there seems to be enough differences in the euro and GEFS to make using them dangerous. 

GFS not as strong with the clipper but the NAM run is a quintessential reason why we feel envious of NE winters

[Bob Chill]

As Bob says the GFS is much quicker with the front than the euro which actually has 3 really warm days culminating in a max of over 70 on SUnday.  That looks like an outlier but the euro ensembles have trended warmer in the past couple of days.   The euro esnembles suggest lots of uncertainty concerning the timing of the front.  To a lesser extent so does the GEFS ensembles which has a couple of slow frontal passage members.  If you're hoping for the clipper to yield, good luck.   The low goes to our north so our north so surface temps are likely to be a problem.   I haven't looked at the super ens mean as there seems to be enough differences in the euro and GEFS to make using them dangerous. 

 

It's a very uncertain period for sure. But not all that promising irt to snow. I'm pretty sure you feel the same way. Would need the perfect evolution of boundary placement, entrenched cold air, and on the nw flank of a second wave if one even exists. It's just another period of interest with a lot of disagreement that needs to eventually agree. 

 

I'm kinda half trolling with the clipper. It's moved towards a better chance at some snow tv or a dusting. But the low track is a glaring flag. If I see some flakes fall again it's a win imo. 

[usedtobe]

It's a very uncertain period for sure. But not all that promising irt to snow. I'm pretty sure you feel the same way. Would need the perfect evolution of boundary placement, entrenched cold air, and on the nw flank of a second wave if one even exists. It's just another period of interest with a lot of disagreement that needs to eventually agree. 

 

I'm kinda half trolling with the clipper. It's moved towards a better chance at some snow tv or a dusting. But the low track is a glaring flag. If I see some flakes fall again it's a win imo. 

Clipper comes at night so it probably would be cold enough but with the low to our north we downslope so even if a model like the gfs has us in snow, i'd be hesitant to believe it.  I guess we can get a few flakes but our chances of accumulating snow are about the same as the skins chances of winning all the rest of their games. 

[Bob Chill]

I will name the clipper Kirk Cousins 6 and 10

[Ian]

Not to be a moderator but clipper is short term http://www.americanwx.com/bb/index.php/topic/41819-december-2013-obs-and-discussion/

[Bob Chill]

Gfs still faster with the front but has thrown a new unwanted wrinkle in the mix. The dreaded great lakes low...boo

[usedtobe]

Gfs still faster with the front but has thrown a new unwanted wrinkle in the mix. The dreaded great lakes low...boo

 

It probalby would have a more euro look to it if it didn't cut off the low way our west and leave it sitting there for so long.  The euro and its ensembles are more progressive with it.  Make that more progressive and you get some phasing with the northern stream so you get a low up into the lakes but you also never quite allow the northern stream to pull the front through us as quickly as the GFS does.  Quite a few GEFS members from last night had the lost cut off solution so either probably is in the works.  I sort fo favor the euro but not by much. 

[Bob Chill]

Wes, euro is more like the gfs now with timing. Kind of a messy fropa. It happens in steps like the gfs. Northern low pulls the boundary with a much more wsw-ene alignment than the last one. Not much of a hp to the n initially.

Interesting strong lp coming out of tx heading to wv and right overhead. Could happen but many many changes to come. Very tough forecast at this lead.

[mitchnick]

[Bob Chill]

Mitch, gefs definitely amplified Xmas week for a time. Another pretty cold airmass. Still progressive but prominent ridging in the west on the means.

Guidance is very mixed but nothing shows a bad pattern. I wish we could all donate and buy a block though. Atlantic is one hostile beeeyotch

I'm eager to hear Wes' thoughts this week. This is a complicated pattern. Way over my head to make any definitive weenie calls

[Scarlet Pimpernel]

Mitch, gefs definitely amplified Xmas week for a time. Another pretty cold airmass. Still progressive but prominent ridging in the west on the means.

Guidance is very mixed but nothing shows a bad pattern. I wish we could all donate and buy a block though. Atlantic is one hostile beeeyotch

 

It does look to get pretty amplified right around Christmas.  In looking at the day-to-day evolution (at least the ops GFS), it seems to occasionally want to relax and lift the flow more right near the end.  For example, see today's 00Z.  Not sure how much that means, really, in the grand scheme.  And yes, the Atlantic looks pretty bad.  We're lucky the Pac is keeping things decent, at least to some extent.

[Amped]

Hopefully we can hold onto the snowpack too our northeast for the remainder of winter. This will really help with boundary layer should we get a decent storm track.

[mitchnick]

Since the thread doesn't specify whether we're talking Dec., 2013 or 2014,....:  

http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/nino34Mon.gif

[mattie g]

Since the thread doesn't specify whether we're talking Dec., 2013 or 2014,....:

http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/nino34Mon.gif

As long as we get a consistent blocking pattern...

[Heisy]

Lock it in

[mdsnowlover]

Lock it in

lol.gif

GFS says that is freezing rain for NCentral md!!

[usedtobe]

Mitch, gefs definitely amplified Xmas week for a time. Another pretty cold airmass. Still progressive but prominent ridging in the west on the means.

Guidance is very mixed but nothing shows a bad pattern. I wish we could all donate and buy a block though. Atlantic is one hostile beeeyotch

I'm eager to hear Wes' thoughts this week. This is a complicated pattern. Way over my head to make any definitive weenie calls

 

Right now I don't have many thoughts.  The ens mean that Mitch posted didn't show any analog snowstorms.  I still don't like the pattern for getting a snowstorm for us unless it's a puny one despite the PNA look.  As you say, the Atlantic is still hostile.  We'd do better with a more split flow look.  We do have that in the dailies until the cut off low lifts by us.   It's more a clipper type pattern if we could get something to dive south of us. 

[Yeoman]

Get the Ark out for Xmas eve

 

[welbane]

Cold-dry / warm-wet. No change in sight.

[usedtobe]

Both the 06Z GFS and last night's Euro are slow getting the front through us. Both almost get it but and then lift it back north which torches Sunday....The euro has a max of over 70 and the GFS, around 65.  The pattern still looks hostile for snow lovers around DC.  I make no claims about the guys out west that snow when we rain or having a slop fest. 

[Ian]

Bring on 70!!

[aldie 22]

Bring on 70!!

No thanks

[WinterWxLuvr]

This thread keeps getting shorter. 

 

The GFS has now almost totally flipped from two days ago.  Then, its faster solution with the front was an outlier among its ens, and now its slow solution is going against the majority.

 

I like agreement better. 

[WinterWxLuvr]

Cold-dry / warm-wet. No change in sight.

It hasn't been either of those.

[Fozz]

Bring on 70!!

 

ugh

[clueless]

I guess I will take 70. I mean, why not? If it ain't gonna snow...

[Bob Chill]

Euro ensemble mean gets the front through basically on the 24th. 6z gefs a day earlier. It's becoming kinda clear that the entire fropa event will be wet for us and it's trending that way further north as well. The hp behind the front just isn't that impressive or strong. Yes, it's cold but not the beast we would need it to be. We'll see how it shakes out.

Post fropa has +'s and minus's from what I'm seeing over the last couple days of guidance. EPO ridge is still there but flattened quite a bit from what it's been. This will limit the ability for crazy cold hp's to build and enter the conus. But the pna looks to be + from xmas through the end of the run. Way too far out to draw any conclusions. We'll have to see how amplified things can get. Nothing impressive yet.

imo- snow chances post xmas will be limited to ns vorts. Maybe one digs far enough to tap the gulf. Who knows. I could easily see one getting under us if things shake out as is.

It's a below normal temp regime but not well below or frigid. Overall, I'm not that impressed with the trends.

[Scarlet Pimpernel]

Euro ensemble mean gets the front through basically on the 24th. 6z gefs a day earlier. It's becoming kinda clear that the entire fropa event will be wet for us and it's trending that way further north as well. The hp behind the front just isn't that impressive or strong. Yes, it's cold but not the beast we would need it to be. We'll see how it shakes out.

Post fropa has +'s and minus's from what I'm seeing over the last couple days of guidance. EPO ridge is still there but flattened quite a bit from what it's been. This will limit the ability for crazy cold hp's to build and enter the conus. But the pna looks to be + from xmas through the end of the run. Way too far out to draw any conclusions. We'll have to see how amplified things can get. Nothing impressive yet.

imo- snow chances post xmas will be limited to ns vorts. Maybe one digs far enough to tap the gulf. Who knows. I could easily see one getting under us if things shake out as is.

It's a below normal temp regime but not well below or frigid. Overall, I'm not that impressed with the trends.

 

Pretty much sums it up.  I'm not overly impressed with what I've seen in the trends, either, even if we're talking out toward la-la land.  Not that long ago, the period around Christmas week or so looked very cold around here with perhaps an event that could be supported in that pattern.  There was a pretty strong +PNA pattern and I swear I even saw the -10C 2-m temperature line getting south of the DC area at times.  Certainly some very cold 850s.  Now, the flow is a lot flatter it seems, not nearly as cold.  As you say, maybe somewhat below normal overall, but I don't see the level of big, cold highs coming in now.  This could all change, who knows, but the Atlantic is lousy.  It doesn't look like a torch except for the couple of days before the front passes prior to Christmas, but it doesn't look all that "wintry" either.

[WinterWxLuvr]

Pretty much sums it up.  I'm not overly impressed with what I've seen in the trends, either, even if we're talking out toward la-la land.  Not that long ago, the period around Christmas week or so looked very cold around here with perhaps an event that could be supported in that pattern.  There was a pretty strong +PNA pattern and I swear I even saw the -10C 2-m temperature line getting south of the DC area at times.  Certainly some very cold 850s.  Now, the flow is a lot flatter it seems, not nearly as cold.  As you say, maybe somewhat below normal overall, but I don't see the level of big, cold highs coming in now.  This could all change, who knows, but the Atlantic is lousy.  It doesn't look like a torch except for the couple of days before the front passes prior to Christmas, but it doesn't look all that "wintry" either.

Exactly.  And that's what everyone needs to remind themselves of every time the pattern doesn't look good.  The long range has done this several times this season already, yet, we've had no real warmups and have had some pretty decent early winter weather.