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January 24-25th Potential Winter Weather Event


dmc76

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Historically, synoptic scale models have always had a bias in being

too progressive aloft and near the surface in moderating

temperatures on the heels of an arctic outbreak.  Given the coarser

vertical resolution in these models, they typically do not capture

low-level cold air all that well...and I think they are starting to

catch on to this.  By Thursday, the large scale guidance shows

another trough that will be dropping into the eastern US and

re-enforcing the cold air.  As this trough gets carved out, there is

a separate wave that will be approaching from within the southern

stream on the southern periphery of the antecedent Arctic airmass.

The operational GFS and Canadian GEM both overpower the northern

stream (known model biases) and allows a surface low to cut from the

Ozarks northeastward into the Great Lakes.  On the other hand, the

last few runs of the GFS ensemble and the latest 19/12Z Euro keep

the systems more separate and weaker which results in the system

passing to our south.  Given the model biases here of warming things

up too quickly and overpowering the northern jet, we are not going

to use the operational GFS and Canadian for this forecast.  Instead

we will be trending the forecast much closer to the GFS Ensemble and

Euro blend.

 

LMK riding the southern solution. 

 

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With regard to the LMK post. There's has been several times though this winter that the northern stream has had a good deal of the energy and kept most of the action in the upper Midwest. I could go either way imo. ... or both branches could phase.

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With regard to the LMK post. There's has been several times though this winter that the northern stream has had a good deal of the energy and kept most of the action in the upper Midwest. I could go either way imo. ... or both branches could phase.

 

Yeah I don't buy what LMK is selling, this is a Northern stream dominant system, if it phases with the Southern stream that still favors a Northern solution as well.

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different scenario...this is hardly a major negatively tilted storm.

 

Should be strengthening as it approaches the region. Plus the Euro ensembles don't agree with the op at all, the mean tracks trough Southern Ohio. GFS ensembles for the most part are Northern stream dominant or are too progressive and have no system. None of them have a low through Georgia. By all means though put all your eggs in one basket of one Euro run that shifted 500 miles.

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Should be strengthening as it approaches the region. Plus the Euro ensembles don't agree with the op at all, the mean tracks trough Southern Ohio. GFS ensembles for the most part are Northern stream dominant or are too progressive and have no system. None of them have a low through Georgia. By all means though put all your eggs in one basket of one Euro run that shifted 500 miles.

 

12z Euro ensembles aren't crazy different from the op, as you seemingly allude to. They aren't starting that far apart at 120 hours. The op run at 144 hours, of course has a primary in E TN. Euro ENS mean is WV. This isn't cutting over IND or CMH, if it does become southern wave focused...I'll tell ya that. 

 

I've lived through a lot of arctic outbreaks in my 55 years, and the models have always seemed to push the cold air out too quickly. However, this seems to be a different world the past couple of years where warm wins. Right now I'd forecast a blend.

 

This isn't a mamby pamby airmass we're talking about though. The last winter and a half is a moot point right now. 

 

Yeah, figured it was time for me to reappear.   

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Sure it can cut over Ohio. The more southern focused, the more south/north in progression it will come pushing heights upward.

 

Obviously anythings possible, but this thing isn't going neutral/negative west of OH. If anything it'll be one or the other...northern stream blahness or southern stream ESE slider. It ain't cutting over OH from the south.

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Lets see. Aging Arctic airmass, -PNA, Slightly +NAO? Not the greatest snowcover in the world either. Yeah i am skeptical of the southern solutions.

 

Let's be clear here, this is a northern dominant vs southern dominant deal, isn't it? But aging arctic airmass doesn't jive with me. There's a refresher quickly following.

 

12zecmwfens850mbTSLPUS120.gif

 

12zecmwfens850mbTSLPUS144.gif

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YES a argument can be made for the aging Arctic airmass but still there is the other issues i mentioned.

 

compare.pn.png

 

 

Let's be clear here, this is a northern dominant vs southern dominant deal, isn't it? But aging arctic airmass doesn't jive with me. There's a refresher quickly following.

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Lets see. Aging Arctic airmass, -PNA, Slightly +NAO? Not the greatest snowcover in the world either. Yeah i am skeptical of the southern solutions.

 

Good points. Especially the NAO and snowcover issue. Lake effect snowcover won't really count.

 

Will be in between two periods of colder air masses at that time.

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Anyways AGAIN i am not making a call. Just stating that there is a few things going against the southern route. Models could as well be off with the PNA/NAO predictions as well. This is STILL over 120hrs out and it is bound to change a few more times.

 

It's all good. Real discussion with reasoning is what's its all about IMO. Sorely lacking lately. I will "argue" that brief PNA rise and then fall (as those charts showed) during the storm is pretty typical, no?

 

There's no definitive decisions to made at this point. We'll see how it plays out in the coming days.

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Good points. Especially the NAO and snowcover issue. Lake effect snowcover won't really count.

 

Will be in between two periods of colder air masses at that time.

 

There is valid points on both sides of the argument. I would wait and see what we have in a day or so. As mentioned above this thing is still 5+ days out.

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It's all good. Real discussion with reasoning is what's its all about IMO. Sorely lacking lately. I will "argue" that brief PNA rise and then fall (as those charts showed) during the storm is pretty typical, no?

 

There's no definitive decisions to made at this point. We'll see how it plays out in the coming days.

 

Agree about the reasoning part. I think you meant the NAO? Amazing how hard it seems to get and keep the PNA+..  I will note though that the other site is not as agressive with the -PNA/+NAO.. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

That actually has the PNA more on the +positive side. Go figure. :unsure:

 

But yeah give it a day or two and then see what we have. I remember these models a few days back advertising a clipper for Monday and that vanished once it got inside of day 5.. Why i always prefer to wait till we are inside of day 5/120hrs before starting a storm potential thread. Thats me though.

 

Oh and wow has the winds picked up here.

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Agree about the reasoning part. I think you meant the NAO? Amazing how hard it seems to get and keep the PNA+..  I will note though that the other site is not as agressive with the -PNA/+NAO.. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

That actually has the PNA more on the +positive side. Go figure. :unsure:

 

But yeah give it a day or two and then see what we have. I remember these models a few days back advertising a clipper for Monday and that vanished once it got inside of day 5.. Why i always prefer to wait till we are inside of day 5/120hrs before starting a storm potential thread. Thats me though.

 

Oh and wow has the winds picked up here.

 

No I was talking PNA. If the system in question is for the 24-25th, the chart you posted was positive right up before the system on the 23rd, then falls thereafter. Of course it's vice versa with respect to the NAO. Eh, indices. Still much time left to let this all shake out. It'd be nice if this took a turn for the historic and went all Jan 1978 on us, or something. 35th year anniversary is quickly approaching. ;) 

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No I was talking PNA. If the system in question is for the 24-25th, the chart you posted was positive right up before the system on the 23rd, then falls thereafter. Of course it's vice versa with respect to the NAO. Eh, indices. Still much time left to let this all shake out. It'd be nice if this took a turn for the historic and went all Jan 1978 on us, or something. 35th year anniversary is quickly approaching. ;)

 

We can atleast still dream. And wow on it now being 35yrs. Ugh i am getting old. :(

 

I see the 00z GFS has gone the euro route.

 

Now watch the euro switch back. lol Anything to torture people more. :yikes: Nothing ever comes easy.

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No I was talking PNA. If the system in question is for the 24-25th, the chart you posted was positive right up before the system on the 23rd, then falls thereafter. Of course it's vice versa with respect to the NAO. Eh, indices. Still much time left to let this all shake out. It'd be nice if this took a turn for the historic and went all Jan 1978 on us, or something. 35th year anniversary is quickly approaching. ;)

Yeah, I mentioned the 35th anniversary yesterday. What would have to happen to get the two systems to phase? Is that even possible at this point?
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We can atleast still dream. And wow on it now being 35yrs. Ugh i am getting old. :(

 

I see the 00z GFS has gone the euro route.

 

Now watch the euro switch back. lol Anything to torture people more. :yikes: Nothing ever comes easy.

 

I was two months shy of 3 years old for that one. 

 

Quite the shift on the models the past couple of days. I fear filtered sun much more than I do 36º and rain. Just sayin... 

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