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Pattern The Great December Dump

Once again, the longer-term doesn't look quite as warm on the EPS, lots of southern stream systems are undercutting the block over east-SE Canada, keeping us at least seasonable. This active southern jet is almost certainly not going away anytime soon either especially once the MJO enters the Western Pacific, it'll probably become even stronger if anything as result of the added westerly momentum afforded by the West-Central Pac convection.

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How much worse/better can this get between now and December 31st? I don’t necessarily hate the angle of cold (trough) or lack thereofFDDE968D-3802-4B44-9DE4-F804D76C4275.png
 
Webberweather53 said:
Once again, the longer-term doesn't look quite as warm on the EPS, lots of southern stream systems are undercutting the block over east-SE Canada, keeping us at least seasonable. This active southern jet is almost certainly not going away anytime soon either especially once the MJO enters the Western Pacific, it'll probably become even stronger if anything as result of the added westerly momentum afforded by the West-Central Pac convection.

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This West-Central Pacific MJO event is going to be strongly coupled to & feeding back on the underlying ocean that's continuing to lean evermore towards El Nino. If we can get the -EPO/+TNH pattern we've seen countless times the last several years and have the TPV descend towards south-central Canada in early-mid January which seems at least probable this far out, we'll put ourselves into an amazing position to crank out a storm in that general time frame. Details will remain unresolved for the foreseeable future.Screen Shot 2019-12-18 at 10.01.24 AM.png
 
Webberweather53 said:
Once again, the longer-term doesn't look quite as warm on the EPS, lots of southern stream systems are undercutting the block over east-SE Canada, keeping us at least seasonable. This active southern jet is almost certainly not going away anytime soon either especially once the MJO enters the Western Pacific, it'll probably become even stronger if anything as result of the added westerly momentum afforded by the West-Central Pac convection.

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That pattern right there could bring a surprise or two. Right track at the right time and modified Pacific air can bring a surprise or two. I really like the 558dm line being pretty far south.
 
Webberweather53 said:
This West-Central Pacific MJO event is going to be strongly coupled to & feeding back on the underlying ocean that's continuing to lean evermore towards El Nino. If we can get the -EPO/+TNH pattern we've seen countless times the last several years and have the TPV descend towards south-central Canada in early-mid January which seems at least probable this far out, we'll put ourselves into an amazing position to crank out a storm in that general time frame. Details will remain unresolved for the foreseeable future.View attachment 28505
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Eric, the euro and eps dont get the mjo past phase 6, and it heads back toward the COD if I'm reading it correctly off the RMM charts. Perhaps they haven't caught on to what your referring to currently. I heard somewhere that the eastern IO convection is firing up stronger in January. Don't think we want that.
 
59 degree high forecast on Christmas day. That blows. Sorry we are having to look at January now. EPS looks OK sometime late week two looking at members. We just need to get something to hold.
 
I'm not sure about other's, but I'm watching New Years Eve/day time window for frozen precip. There are possibilities all across the board.

The system that's showing up during the 28th/29th window may cut or it may not. The latest GEFS is indicating that the system will get held back. If this system does cut, a baroclinic wave may form on the tail end of the boundary from the cutting system between the 29th - 31st window. Or, if the system don't cut, the S/W may kick out just in time to impact the Southeastern US by New Years Eve/Day. If that were the case, a full blown winter storm could be possible. Either way, I do think there will be a window of opportunity for frozen precip during the New Years Eve/day time window. The GFS OP (should be taken lightly, especially the long range of course) but it's showing another ULL dropping down into the southwest by Jan. 1st. The GEFS does not have that feature. So, who knows at this point, there could be several opportunities of frozen precip through early Jan.

I do think the late month system will cut though, because that's the pattern transitioning storm system. The pattern is looking like it will transition to a colder pattern across the east, including the southeastern US. During the transition, that's when the stage could be setting up for a possible winter event. As always, we'll see how it plays out. I've noticed the models haven't had good consistency with anything in the 7 day window. It seems like they have been changing something drastically in the near term. So, I would advise to expect to see some unexpected projections from these models - even in the short term.
 
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Jimmy Hypocracy said:
Not sure how/when or what the progression is crawling out of this big +AO being modeled. How long does it take to recover from something like this? Such bad timing
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If it ends up being as bad as modeled going into January then at least the first 3 weeks of January is toast. Ridiculous having to deal with this every year.
 
Myfrotho704_ said:
I know it’s a OP model, and LR at that, but geez the changes on the GFS hurts your eyes when you look at it for a time View attachment 28542
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I think the GFS struggles late because it likes to dump a wave in the southwest and just leave it there for 200 hours. So it’s literally impossible to figure out what the pacific pattern is going to be, which is the determining factor on where and how far south arctic air will make it thus determining whether or not a winter storm is even a possibility around here
 
Jimmy Hypocracy said:
I think the GFS struggles late because it likes to dump a wave in the southwest and just leave it there for 200 hours. So it’s literally impossible to figure out what the pacific pattern is going to be, which is the determining factor on where and how far south arctic air will make it thus determining whether or not a winter storm is even a possibility around here
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Yep, we’ve seen it time to time, creating those monstrous SW shortwaves, which creates either lots of rain in the SW/ south or crazy mid south ice storms, if there’s one thing that has been spotty but showing up on the GFS, it’s that SE Canada vortex
 
LOL, finally found the pic to go with this thread. Also congrats to the SE ridge/580+dm/heat lovers...again.

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tennessee storm said:
Daylight already 3 minutes longer than it was first of December ... spring can’t be far behind ... can it ? Lol
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When you say daylight you are talking about afternoon daylight ? Because overall daylight has decreased since early December. Our daylight will reach its annual minimum in 2.5 days.
 
Jimmy Hypocracy said:
Not sure how/when or what the progression is crawling out of this big +AO being modeled. How long does it take to recover from something like this? Such bad timing
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terrific.

cyclogent said:
LOL, finally found the pic to go with this thread. Also congrats to the SE ridge/580+dm/heat lovers...again.

View attachment 28556


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why do the unfavorable/unlikely for snow predictions pan out more than the opposite. Not saying that will for sure happen this time, but seems like that’s always the case. Winter in the south sux
 
Remember when we were supposed to have a torch first week of December and cold last half?

Instead we are at near normal for the first week and torching the last half....no matter the number of analogs and composites you have, nature finds a way to do what she wants.


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Jon said:
Remember when we were supposed to have a torch first week of December and cold last half?

Instead we are at near normal for the first week and torching the last half....no matter the number of analogs and composites you have, nature finds a way to do what she wants.


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Dang...that was a sobering post. And yeah, I agree with you.
 
The irritating part is looking at the Euro/EPS and I bet we get another nice southern stream system close to the end of the year, but that blasted Canada heat dome.
 
Jon said:
Remember when we were supposed to have a torch first week of December and cold last half?

Instead we are at near normal for the first week and torching the last half....no matter the number of analogs and composites you have, nature finds a way to do what she wants.


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Hmm definitely don't remember at least myself supporting this idea. My general call for us locally in NC (as noted on twitter) was for ~+3F ish this month and that the pattern change was probably coming around early January & not in Dec, I basically laid out this idea in the middle of November. It's certainly possible though that competing circulation signals emerge in the coming week or two and the CCKW over the central Pacific attenuates while a new CCKW over the East Indian Ocean & Maritime Continent takes over. We have to keep a close eye on this because it has the potential to spoil our chances for cold/snow in the first week or so of January, which will likely be predominated by a SER at the onset. This also could meansthe pattern change I've been alluding to in early january to occur ~January 5-10 ish has a chance to get pushed back

Nov 18:
"Timing wise if this SSWE being forecast in the longer term is successful, we'd be generally falling right in line w/ 1965-66's evolution timing-wise anyways. Looks like the pattern in that particular winter flipped sometime in early January & then the bottom fell out in mid-late January in eastern North America. Anticipating a pattern change somewhere in this timeframe seems to fit w/ tropical subseasonal forcing evolution, which I anticipate will return to the "favorable" phases (central Pacific & western hemisphere) again around early January..."
http://southernwx.com/community/threads/nippy-november.639/page-72#post-211254

As for the latter part:
"...we'll see a reinforcement of the tropospheric precursor pattern in the meantime that should deliver the final blow to the polar vortex if it already hasn't happened."

There's a legitimate chance this also comes to fruition over the coming weeks although my confidence isn't exactly high in this happening




I've been far from perfect this winter in the long-range & the break I thought we would see later this month hasn't been anywhere near as bad as I thought it could be.
 
Storm5 said:
If you like cutters and warm rain the 12z gfs is for you


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Thankfully Costco will let me return the sled I purchased in 2014.

I’m not sure these models have shown much of anything to hang our hats on for days. Not even a board wide fantasy snow.


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Webberweather53 said:
Hmm definitely don't remember at least myself supporting this idea. My general call for us locally in NC (as noted on twitter) was for ~+3F ish this month and that the pattern change was probably coming around early January & not in Dec, I basically laid out this idea in the middle of November. It's certainly possible though that competing circulation signals emerge in the coming week or two and the CCKW over the central Pacific attenuates while a new CCKW over the East Indian Ocean & Maritime Continent takes over. We have to keep a close eye on this because it has the potential to spoil our chances for cold/snow in the first week or so of January, which will likely be predominated by a SER at the onset. This also could meansthe pattern change I've been alluding to in early january to occur ~January 5-10 ish has a chance to get pushed back

Nov 18:
"Timing wise if this SSWE being forecast in the longer term is successful, we'd be generally falling right in line w/ 1965-66's evolution timing-wise anyways. Looks like the pattern in that particular winter flipped sometime in early January & then the bottom fell out in mid-late January in eastern North America. Anticipating a pattern change somewhere in this timeframe seems to fit w/ tropical subseasonal forcing evolution, which I anticipate will return to the "favorable" phases (central Pacific & western hemisphere) again around early January..."
http://southernwx.com/community/threads/nippy-november.639/page-72#post-211254

As for the latter part:
"...we'll see a reinforcement of the tropospheric precursor pattern in the meantime that should deliver the final blow to the polar vortex if it already hasn't happened."

There's a legitimate chance this also comes to fruition over the coming weeks although my confidence isn't exactly high in this happening




I've been far from perfect this winter in the long-range & the break I thought we would see later this month hasn't been anywhere near as bad as I thought it could be.
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Webber, if that CCKW don't pan out and it takes over in the maritime continent, like your alluding to, its probably game set and match for winter because it will take a long time to get out of those if we ever do.
 
Mr. Golf said:
Webber, if that CCKW don't pan out and it takes over in the maritime continent, like your alluding to, its probably game set and match for winter because it will take a long time to get out of those if we ever do.
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CCKWs circumnavigate the global tropics in span of 2-3 weeks, while the MJO takes 2-3 months, this would be far from game, set, match for winter.
 
GaWx said:
We already know it has a +PNA/-EPO bias. So, what you’re showing happens quite often with the GEFS. Nothing new here and it says practically nothing about how January will be.
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+AO bias too? dang
 
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