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Winter 2021/22 December Thread


AMZ8990
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Not a lot of changes overnight.  There is one trend which I don't like which is seeing the MJO loop into 8 and back into 7.  The GEFS switched from being very cold at 0z to quite warm at 6z.  Might be a blip and might not.  Looks like American modeling, CFSv2 included, has had something change between 0z and 6z.  Now, that is no uncommon but worth noting.  GEPS and EPS look very good.   However, I am wary of any blip on the GEFS in particular as it can grab a trend first.  I do think the NAO does its work.  

Addendum:  The GEFS at 6z weakens the -NAO more quickly.  This is a bias in American modeling which is to break down high latitude blocking too quickly.  I don't discount it though quite yet.  Let's see what other modeling does.  

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Bring on the rain in NE TN, it is badly needed.  La Nina is doing the work here in terms of low rainfall.  I think remember that the Ohio Valley can get a lot of rain during La Ninas.  That might be helping middle TN.  Rain yesterday helped, but our urban streams are still quite low (as of last night).  Not even a trickle was going over the dam at Bays last week.  

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1 hour ago, Carvers Gap said:

That is wild.  With November being so cold, would have thought they would have recorded at least a trace.  Higher elevations here have recorded some.  

I believe “measurable” means 0.1” or more…so they may have recorded a trace already.
 

What’s even worse is that Chicago hasn’t had any measurable snow this season so far. :(
 

I enjoy following everyone’s comments in this sub-forum…keep it up :snowman:

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Boy, we had better hope the 6z and now 12z GEFS are not right.  12z GFS never went BN for the entire run.  12z GDPS looks great.  I don't think the American suite is handling the block well.  Crazy how the model sees it first, and then tries to break it down so quickly.  Once the block retrogrades into the Davis Straits and the model gets inside of d12....should see some more cooling in the model.  Though admittedly, this feels almost exactly like last winter without the Christmas cold snap.  But as Cosgrove mentions, at some point this pattern could send brutally cold air southward.

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20 minutes ago, Carvers Gap said:

Boy, we had better hope the 6z and now 12z GEFS are not right.  12z GFS never went BN for the entire run.  12z GDPS looks great.  I don't think the American suite is handling the block well.  Crazy how the model sees it first, and then tries to break it down so quickly.  Once the block retrogrades into the Davis Straits and the model gets inside of d12....should see some more cooling in the model.  Though admittedly, this feels almost exactly like last winter without the Christmas cold snap.  But as Cosgrove mentions, at some point this pattern could send brutally cold air southward.

Yeah im really trying to be patient but we have been burnt so many times im like well it is what it is.  There are signs there but this season feels so off already. Really weird pattern we have been stuck in.

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43 minutes ago, Met1985 said:

Yeah im really trying to be patient but we have been burnt so many times im like well it is what it is.  There are signs there but this season feels so off already. Really weird pattern we have been stuck in.

I hear ya.  This pattern is an extreme pattern.  Just tough to know if we have the bear or if the bear has us!  

I think we see some cold and snow...maybe a lot of it at times.  Warm Decembers usually lead to one of two outcomes - non-winters or big winters.  Looks like this is going to be a year when Canada is really cold.  I think we see maybe 1-2 severe surges of cold.  I suspect the MJO got wonky on the GFS at 6z.  CPC's MJO stuff is not available for some models(don't know if those are connected or just a tech issue for them).  

Saw where Robert had a new post on WxSouth.  Anyone have access to it?  Not looking for a repost, but just if he thought it might get cold.  It won't take but a small adjustment for it to get really cold here.  Oddly, I don't want to be in the bullseye for cold right now.  

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Looks like the GEFS/GEPS are accentuating the western Pac ridge.  Almost looks like a feedback error.  My guess is that modeling is not even close to having a solution for the first ten days of January.  Not good trends at 12z but a ways to go.  Seems like whichever area of blocking is accentuated(even in the slightest), it is moving the trough around by thousands and thousands of miles.  On the plus side, the CFSv2 is much colder this run.  I just think things are going be all over the place.  Reminds me A LOT of last winter.

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I fell way behind on this thread, but here is my still semi-bearish outlook.

If something can go wrong in the West Pac, it will. Typhoon is dying in the South China sea, no phase. Models have remnant low hooking up with a Japan system, but that's no phase. Per Carvers (my negative take at least) it just jacks up the +ABNA...

Which might hook up with the raging -NAO forecast by January. Except the damn -PNA is relentless. We've seen this rodeo before. Models will struggle much worse than normal (both directions) as Arctic air enters the central US.

Now the -NAO is amped up on tilt both CFS and GFS weeklies, with some handoff to West Coast / Southwest ridge; however, we've also seen those false alarms before. I simply don't believe it.

SER remains stubborn, and it jives with a locked in -PNA. Worse yet, MJO convection wants to reset over that dreadful Maritime Subcontinent. 

Color me skeptical of a cold pattern change. 

My interpretation of the West Pac satellite image 

bearish.PNG.b7851938e3e9d85f9b75a3a259cd3023.PNG

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If looking for positives, the end of the 12z EPS run looks plausible.   I still like the Dec 20-30 as a transition time frame, especially at high latitudes.  Jan 1-10 looks cold-ish though I am less confident after the 12z suite.  Warm-up third week of Jan, and then maybe we see true winter later in January.  Again, similar to last winter for those just to my west.  Almost looks like the EPS didn't flip warm as much as it delayed the cold by 48 hours.  I can hear the eye roll and understandably so as I share the same concern - cold pushed back again and I agree.  But, not uncommon for that to occur.  I like the timeframe around New Year's for a transition to seasonal cold with some warm interludes for sure.  As Jeff notes, the SER is going to fight all winter.  I also agree that the NAO at some point will hook into the wester Pac ridge.  I think that is when we score a decent pattern.  The EPS has this late.  

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42 minutes ago, Mr. Kevin said:

If the cold pattern keeps getting delayed, it probably wont happen imo. May be a winter we have to unfortunately punt and start thinking about next winter. I will hold on into mid January, which is usually my cutoff, but if no changes by then, time to give up imo.

That was what was said last winter....always safer to go warm.  Last winter saw historic cold and snow in western parts of the forum area.  I think we will be ok.

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Wild run by the 18z GFS underway just in terms of how cold it is to the previous run.  Again, it doesn't hurt to repeat that the ultra cold air in this pattern is playing havoc in concert with two very strong anomalous blocking regimes.  Could be a wild next month of weather in terms of extremes in both North America and our forum area.

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When you see a ridge over the mid-latitudes(especially over eastern NA) hook-up with a -NAO....we have seen this for several years, and it nearly always precedes major changes in stratospheric anomalies.  The consequence of that coupling is model mayhem and extreme cold dropping into either EurAsia or NA.  That is all I have on that.  Let's see if that trend continues.  

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18 minutes ago, Carvers Gap said:

When you see a ridge over the mid-latitudes(especially over eastern NA) hook-up with a -NAO....we have seen this for several years, and it nearly always precedes major changes in stratospheric anomalies.  The consequence of that coupling is model mayhem and extreme cold dropping into either EurAsia or NA.  That is all I have on that.  Let's see if that trend continues.  

Webberweather posted the -enso phase 7 example of the mjo  and it was pretty chilly for January. 

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The 18z is the ying to the 12z's yang.  If you watch the global wind pattern at 200-300mb, you can see each deepening of the western trough is progressively eastward.  Why is that important if true?  That means the pattern is progressing eastward.  The 18z features a monster GOA positive height anomaly late in the run.  No idea where this is headed, but models are all over the place.  Likely culprits are a strat warm(no necessarily a split) and also bitterly cold air over the western Canada(likely a feedback problem).  Been a wild day of model watching!!!!

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3 minutes ago, Mr. Kevin said:

Webberweather posted the -enso phase 7 example of the mjo  and it was pretty chilly for January. 

7 is tricky for January.  I hear it is slightly different for La Nina.  The CPC map is cold for 7 when the three month time frame is centered during December, but gets warmer for January.  Again, Nina may well be slightly different.  Major reshuffle in modeling.  No idea where this ends-up.  So, 12z flipped warm and 18z flipped crazy wild with a huge EPO ridge.  Pattern shake-up likely under way...again, no idea where this heads but it could get wild.  Have a good one.  If you get a good tweet, feel free to share.  Not much to talk about at present as we get ready to ride out a warm-spell after Christmas.

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2 minutes ago, Carvers Gap said:

The 18z is the ying to the 12z's yang.  If you watch the global wind pattern at 200-300mb, you can see each deepening of the western trough is progressively eastward.  Why is that important if true?  That means the pattern is progressing eastward.  The 18z features a monster GOA positive height anomaly late in the run.  No idea where this is headed, but models are all over the place.  Likely culprits are a strat warm(no necessarily a split) and also bitterly cold air over the western Canada(likely a feedback problem).  Been a wild day of model watching!!!!

It may not mean anything, but alot of talk about some kind of warming in the stratosphere on Twitter. Also, john homenuk, also known as earth light on American weather, said a 1059mb high pressure is retrograding into Greenland. Thought I would point that out

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7 minutes ago, Mr. Kevin said:

Was the 18z gefs ensembles colder than 12z? I usually dont focus on 18z ,especially past 240hrs. 

GEFS is still running.  Looks like both blocking areas are less strong.  We will see where that leads.  Pac is substantially less strong.  Honestly, modeling is just going to be nuts for a few days.  I thought it would settle down once the typhoon dissipated.  Nope.

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16 minutes ago, Carvers Gap said:

7 is tricky for January.  I hear it is slightly different for La Nina.  The CPC map is cold for 7 when the three month time frame is centered during December, but gets warmer for January.  Again, Nina may well be slightly different.  Major reshuffle in modeling.  No idea where this ends-up.  So, 12z flipped warm and 18z flipped crazy wild with a huge EPO ridge.  Pattern shake-up likely under way...again, no idea where this heads but it could get wild.  Have a good one.  If you get a good tweet, feel free to share.  Not much to talk about at present as we get ready to ride out a warm-spell after Christmas.

 

If you look at the GAWX post, it's all about the amplitude. Lower in Phase 7 was the coldest in January of all MJO phases for Atlanta. They normally get cold via the same way we do except for very extreme CAD.

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1 minute ago, John1122 said:

 

If you look at the GAWX post, it's all about the amplitude. Lower in Phase 7 was the coldest in January of all MJO phases for Atlanta. They normally get cold via the same way we do except for very extreme CAD.

Webberweather posted the phase 7 mjo chart earlier on southern.wx for January 

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2 minutes ago, John1122 said:

 

If you look at the GAWX post, it's all about the amplitude. Lower in Phase 7 was the coldest in January of all MJO phases for Atlanta. They normally get cold via the same way we do except for very extreme CAD.

Thanks, it was your previous post I remember that from.....knew I had read that somewhere.  Any thoughts on the models bouncing around?  I do believe this year we see a repeat of November.  Fall was warm during the first half and then the cold pattern of November slammed the door shut on that.  Almost seems like that is repeating.  

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1 minute ago, Carvers Gap said:

Thanks, it was your previous post I remember that from.....knew I had read that somewhere.  Any thoughts on the models bouncing around?  I do believe this year we see a repeat of November.  Fall was warm during the first half and then the cold pattern of November slammed the door shut on that.  Almost seems like that is repeating.  

 

Modeling run to run beyond D8 is rarely stable, I'm surprised it's not been more volatile to be honest. Small things have big consequences down the road that far so it's not shocking at all to see them moving around a lot. 

 

Yes, phase 7 low amp was -4 in Atlanta. 8-2 were something like -1 or -2. In low amp, around the COD, even 6 was BN.

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21 minutes ago, Mr. Kevin said:

Was the 18z gefs ensembles colder than 12z? I usually dont focus on 18z ,especially past 240hrs. 

I don't sweat temps(LOL) after d10.  Pretty much just look at the trends at 500.  Out to about 294, the -NAO is the dominant feature with the are of AN heights in the Pac being weakened.  Hints of AN heights in Alaska which is a big change.  

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3 minutes ago, Carvers Gap said:

I don't sweat temps(LOL) after d10.  Pretty much just look at the trends at 500.  Out to about 294, the -NAO is the dominant feature with the are of AN heights in the Pac being weakened.  Hints of AN heights in Alaska which is a big change.  

If AN heights in Alaska happens, then game on for sure. If not game off lol. The Pacific is so important in sensible weather. Alutian ridging is the big thorn for sure so far imo

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Just now, Mr. Kevin said:

If AN heights in Alaska happens, then game on for sure. If not game off lol. The Pacific is so important in sensible weather. Alutian ridging is the big thorn for sure so far imo

Models have no idea how to handle those two areas of blocking at this range.   If the -NAO is stronger, the Pacific is likely weaker.  Flip that around and the NAO is weaker.  The 18z GEFS definitely accentuated the NAO this run, and temps are much cooler.  Actually, the 18z would work really well.   One thing that we have to consider is that there is some likely feedback over the West.  I

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