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January 2021 Medium/Longterm Pattern Discussion.


AMZ8990
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I think a system between the Feb 4 and 7 ends up being Jax's squall line and we finally get to apply the thunder in the mts rule. 6z GFS suggests that a flex of the -NAO could keep those suppressed, but the Euro Control still amplifies them. 

 

Still looks like a big anticyclone gets broken off in the N. Pac and rolls back towards Siberia, dislodging some cold.

6z GFS offers a glimpse at how that could turn out. 

giphy.gif

 

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Again, I think we potentially may see a major trough amplification around or just after the 5th.  The 0z GEPS has a monster EPO ridge moving forward in time on its 0z run.  If the air in front of that sharp trough is warm enough, could be fireworks for sure.  The 0z EPS is not far behind but its Pacific ridge is displaced further west.  As Webber noted the other day, there is a super fine line between torch and major league cold.  Modeling is now moving up in time that Feb 5th timeframe.  This is the first winter in a while where I don't remember tracking at least some severe wx, so a big amplifying trough with warm air in front is definitely a good recipe. Almost has a "flooding and then snow" look.  Again, I look for the coldest air to go into the front range of the Rockies and surge eastward 2-3 times in February.  Only concern would be a repeat of November....

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Two thoughts...

1.  I think NE TN, SW VA, and SE KY are going to have to keep an eye on the system just after 100.  The 6z GFS and 0z CMC both pop a lee side low or inland runner after energy transfer up the Piedmont/Coastal Plain.  Now, I am not a huge fan of energy transfer, but if the energy transfer were to occur far enough to the southeast, one could see rain changing to snow in the aforementioned areas.  Bit of a long shot but it has been my experience that these types of handoffs tend to run a snow axis from Bristol to DC.

2.  MJO.  Some modeling stalls the MJO around 6-7.  However, wanted to share a couple from this morning (ECMWF and CA-LLR) which actually move the MJO along.  Some MJO modeling actually produces another wave off of Eastern Africa and rolls it eastward.  If that happens, that means the MJO rolls through phases 1, 2, and 3.  You can see on the CHI map that very wave beginning just after d5.  

ECMWF(notice it head towards 8)

1942919002_ScreenShot2021-01-23at10_12_04AM.png.b2d68e3d57c510a4e96b3e6ccb3d6974.png

 

CLA is about perfect...

1195295641_ScreenShot2021-01-23at10_12_47AM.png.11668536af42912cb4898d60f815a097.png

CHI Propagation Map from yesterday as today is not updated for this yet(look specifically for the way around Africa move to the central IO....that is MJO 1-3 which is cold for JFM)

1932681446_ScreenShot2021-01-23at10_25_19AM.png.a6e3b4b4fd6d854acd3a6c5e1ebef2d4.png

That is one window for potential cold.  It is on modeling and there seems to be some moderate agreement among MJO modeling.  FTR, I think the MJO is now driving the boat in terms of temps.  The -NAO seems to be driving the storm track.  So, the 0z GEPS and 6z DFSv2, which pop significant EPO ridges are showing the cold potential(as opposed to the very real warm potential scenario) for just after the 5th.  Could it be a mirage?  Sure, but I don't need to provide all of the caveats.  The above is a great example of why modeling is struggling.  I tend to think we see the cold move East...so I am tentatively rolling with cold pushing East around the 5th(likely gets pushed back a few days as cold often can), but that is my current thinking.  

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10 hours ago, Carvers Gap said:

Again, I think we potentially may see a major trough amplification around or just after the 5th.  The 0z GEPS has a monster EPO ridge moving forward in time on its 0z run.  If the air in front of that sharp trough is warm enough, could be fireworks for sure.  The 0z EPS is not far behind but its Pacific ridge is displaced further west.  As Webber noted the other day, there is a super fine line between torch and major league cold.  Modeling is now moving up in time that Feb 5th timeframe.  This is the first winter in a while where I don't remember tracking at least some severe wx, so a big amplifying trough with warm air in front is definitely a good recipe. Almost has a "flooding and then snow" look.  Again, I look for the coldest air to go into the front range of the Rockies and surge eastward 2-3 times in February.  Only concern would be a repeat of November....

Hopefully blocking will be persistent and be prevalent thereby preventing a Nov. repeat.

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6 minutes ago, snowmaker said:

What trend do we need to get us more in the game with this storm. I have been watching the carolina folks looking at this one for days. Seems to be trending better now for ky and tn. Hope it continues now that we are getting closer in the timeframe.

A low track further south with better HP overhead. 

The models have slowly been shifting south with it. They were cutting it straight to a block then transferring it at one point. That's what got NC in the big snow window. Still transferring but the low isn't transferring from WVA now. 

 

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