Pattern January 2020 - Operation Thaw Alaska

[Webberweather53]

The CMC ens has been colder than the other two for several days. Unfortunately, it carries the strongest cold bias for the E US of the 3 major ensembles. So, this may be a function of bias.

This isn't a function of its cold bias, the Canadian just simply has a better Pacific pattern than the other 2 model suites w/ a deeper more extensive trough over eastern Russia that nudges the GOA ridge eastward. It's important to look a little beyond these stereotypical biases to assess why "x" model is producing "y" solution. Could you argue this cold bias is a function of a more intrinsic model bias such as one that produces weaker GOA ridges and stronger Kamchatka lows? Maybe, but again that requires more in depth analysis than sweeping the model under the rug because it usually is "x" biased.

 

[SnowNiner]

Even with its cold bais...nice changes from just 12 hrs ago...

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I think the cmc has a "it's always wrong bias", no matter what it shows. If we're depending on the cmc, our winter is in pretty bad shape, imo.

 

[KyloG]

To me the CMC-E and the GEFS have similar weight with regards to pattern accuracy in the extended. If you are looking at day 10-15 2m temps on either model you are bound to be disappointed with it's accuracy.

 

[whatalife]

I think the cmc has a "it's always wrong bias", no matter what it shows. If we're depending on the cmc, our winter is in pretty bad shape, imo.

There is no doubt this winter has been bad so far and just trying to find any positive I can at this point. I put most of my chips on whatever the EPS says.

 

[Webberweather53]

Pacific pattern definitely looks a lot better on this EPS run out to day 12, attempts to knock out the Gulf of Alaska ridge, at least temporarily.

 

[KyloG]

I agree, with the NPAC ridge where it's at, if it can wobble east over AK from time to time it will dump cold HP into the conus.

Makes me cringe looking at the evolution of the GEFS though...the pacific sure looks stable but with a building Scandinavian ridge. Reminiscent of Feb 2018 and 2019. Maybe this is our dominant winter pattern and we have to make the most of it.

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After watching the EPS come in....Now I wish I had waited an hour to look at the EPS before I posted this.

 

[Webberweather53]

The GEFS is pretty much on an island here trying to blow up the Aleutian ridge again ~300 hrs. The EPS supports the Canadian ensembles more in this regard & thus the pattern starts breaking down by ~ Jan 20th to something far less hostile but still not terribly favorable for wintry weather. There's more to this than "x" model suite is cold biased more than "y" suite.

 

[Webberweather53]

After watching the EPS come in....Now I wish I had waited an hour to look at the EPS before I posted this.

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I suspect this could be some manifestation of the GEFS's long-range -EPO bias which is likely tied to how it handles waves that interact with the Himalayas, now just shifted equatorward & westward instead of over Alaska.

 

[Rain Cold]

The GEFS is pretty much on an island here trying to blow up the Aleutian ridge again ~300 hrs. The EPS supports the Canadian ensembles more in this regard & thus the pattern starts breaking down by ~ Jan 20th to something far less hostile but still not terribly favorable for wintry weather. There's more to this than "x" model suite is cold biased more than "y" suite.

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This is a much better progression and something I hope we keep seeing steps toward. It's still probably going to have that Pacific-air-mass-influenced feel to it, but it will hopefully more easily lead to better things down road.

 

[NCSNOW]

the Canadian just simply has a better Pacific pattern than the other 2 model suites w/ a deeper more extensive trough over eastern Russia that nudges the GOA ridge eastward

Webber EPS and especially Canadian have way better GOA ridge placement and orientation. All will be boil down to exactly where the GOA sets up shop. Funny the GEFS and Canadian have the same MJO forecast. So what exactly is causing the forecasted placement of the GOA on the Canadian to be more east based ?

 

[Webberweather53]

This is a much better progression and something I hope we keep seeing steps toward. It's still probably going to have that Pacific-air-mass-influenced feel to it, but it will hopefully more easily lead to better things down road.

I think the EPS MJO forecast into phase 6 is too weak & thus also wrong when compared w/ other NWP models which partially explains the discrepancies between it and the GEFS, but I also think the GEFS is overselling the extent & amplitude of the Aleutian ridge beyond day 10 as it often does w/ North Pacific anticyclones.

 

[whatalife]

Well this is just a subtle difference...

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[GaWx]

This isn't a function of its cold bias, the Canadian just simply has a better Pacific pattern than the other 2 model suites w/ a deeper more extensive trough over eastern Russia that nudges the GOA ridge eastward. It's important to look a little beyond these stereotypical biases to assess why "x" model is producing "y" solution.

Part of that cold bias is a cold pattern bias just as is the case for the GEFS cold bias. My educated guess is that that is playing a role in this. The CMC ens has been colder for days. We'll see if it scores here. I'm not betting on it right now, but I hope it is right for a change.

Meanwhile, the EPS is colder than its last run and it has been stuck on hour 318 for 20 minutes.

 

[Webberweather53]

Part of that cold bias is a cold pattern bias just as is the case for the GEFS cold bias. My educated guess is that that is playing a role in this. The CMC ens has been colder for days. We'll see if it scores here. I'm not betting on it right now, but I hope it is right for a change.

Meanwhile, the EPS is colder than its last run and it has been stuck on hour 318 for 20 minutes.

Well every case is different and it’s important to understand how said bias plays into each case rather than broadbrush very general biases, I.e model biases are state dependent to a large extent. The GEFS has a LR cold bias but already shows a torch in the SE US, based on that logic we should automatically assume an even warmer pattern but that’s not how this works. The EPS is basically showing a similar pattern to the CMC ensemble so I would not immediately brush it under the rug. As far as I’m concerned the gefs and geps verification rates are similar in the extended, the one that agrees with the EPS (geps) is more likely to be right

 

[GaWx]

12Z EPS: Colder to the end of the run!

 

[Webberweather53]

Finally... a +PNA

 

[KyloG]

Finally... a +PNA

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There's going to be no living with JB after this run.

 

[Webberweather53]

Easy to see why the EPS looks so much better than the GEFS. North pacific ridge finally backs away to the International Dateline and is suppressed, whereas its amplified & over the Aleutians on the GEFS.

North Pacific blocking is great so long as either we have a very mature, poleward -EPO w/ ridging breaking into the Pacific-Arctic or if this ridge is confined to the Western North Pacific (near or west of the dateline), anything in between usually invites disaster (-PNA)

 

[John1122]

I hope it's not a headfake. Seems like the Euro had a +pna look several runs ago that it quickly lost. Anything is better than seeing that blue blob over BC and Washington. I'll always take an EPO in the GOA extending up into the Arctic that acts as a pseudo +PNA or a +PNA. They can work around the lack of a cooperative Atlantic. The Atlantic itself can't get it done when the Pacific is a disaster.

 

[BufordWX]

One thing we can be pretty certain of for the next 10 days is that we certainly won’t be lacking in rainfall.

Both the Gfs and the Euro are showing some pretty hefty totals for parts of the southeast especially Northern Alabama and Georgia. I have also noticed some consistency to them as well.

Euro has a solid 4-8 inches of rain from about Central Mississippi to the Appalachians over the next 10 days.


Gfs has even more rainfall with totals in the 5-9 inch range in Georgia and Alabama and some pockets over 10 inches in the next 10 days


All in all, looks like at the very least we will have a lot of rain to deal with until hopefully we get a pattern change later in the month. At least we wont be dealing with a drought again for a while.