Texas Winter 2020-2021

[Ntxw]

At the same time the Ukmet was showing snow last night, the ICON has moderate to heavy precip moving through DFW and below freezing. On the ICON that is freezing rain and or sleet for DFW this Thursday.

[Iceresistance]

The Euro does have support from the EPS, so ignore it at your own peril. The low for Saturday the 13th on the last 4 EPS runs - 20F, 23F, 24F, 31F. The EPS is increasingly favoring an extension of the Pacific jet that undercuts the cold air, making it harder for it to surge southward. We need wave breaking out ahead of the extension to pop a ridge into the EPO region and force the cold south. The trend has been towards a flatter jet with no mechanism to really force the cold air south. Not saying that is what will happen, but just one of the wrinkles that is showing up on the Euro/EPS.

What is the EPO looking like in the next several days?

Ensembles show it going somewhat negative before next weekend and then back positive. The pure EPO teleconnection calculation might not be the best thing for tracking this, as only some of the CMC runs show a true big -EPO. So what we are looking for is ridging into the area that might not actually register as a true -EPO.

This is going to be a diffcult forecast for the EPO . . .

[rwfromkansas]

Betting on the Euro is usually right. Will we get robbed again? Will see. It does get things wrong.

[Ntxw]

Betting on the Euro is usually right. Will we get robbed again? Will see. It does get things wrong.

Euro is not much better if you are soloing it. It's not had a consistent forecast either (20s to 70s?). Sure you can count that as a trend if you look over multiple runs but that to me is not consistency. The winner is usually the middle ground between all of the guidance.

[cheezyWXguy]

Betting on the Euro is usually right. Will we get robbed again? Will see. It does get things wrong.

The euro is the best global model, but it’s only one tool in the arsenal and doesn’t outweigh a consensus, should one form. Its forecasting debacle regarding the genesis of hurricane laura, as well as many other storms last season, made this very clear to me.

[orangeblood]

At the same time the Ukmet was showing snow last night, the ICON has moderate to heavy precip moving through DFW and below freezing. On the ICON that is freezing rain and or sleet for DFW this Thursday.

https://i.imgur.com/uLVLxsU.png

https://i.imgur.com/zYxUUoI.png

That's a nasty ice storm...almost half inch QPF with temps in upper 20's. Also, ICON much colder than prior run last night. Starting to get in a decent strike zone of 120 hrs for most of these models

[txtwister78]

When one model (Euro) goes from temps in the 20's & 30"s to temps in the 70"s in a span of 24 hours you have to consider how "reliable" that is (yes even the Euro). If that trend continues (warmer) on future model runs than I think it's important to weigh the setup it has compared to the other models that still show a different solution. Right now it still remains the outlier and so we wait.

Looking at why it could be right is important as well however and I think Bubba's post illustrates that. As others have mentioned, a delayed (multiple shots of cold) are probably your best outcome if you want more precip (frozen) as opposed to one big blast of air that dries us out and removes potential for precip.

[bubba hotep]

12z UKMET is primed at 144 with what is likely a massive winter storm getting cranked up.

00z delivers, making the UKMET pretty consistent. Also, the placement of the TPV is much more in line with climo than the other models showing it farther west. They can and do rotate down towards Montana when being transported into the mid lats but a trip through N. Minn and toward the Great Lakes is much more common.

[rwfromkansas]

Sure hope some devastating ice storm doesn’t occur. I don’t mind a small one up to .20 accumulation. Enough to cause people to pause for a bit and you get a pretty glaze or sleet but with minimal power issues. More than that, and it gets bad.

[Iceresistance]

Raining pretty good outside right now at my house

[Ntxw]

GFS is trying to get to that ice storm scenario, it doesn't quite connect yet, temps are hovering on the GFS. What prevents is it forecasts a warmup slightly on Wednesday to just barely above freezing then back down.



The cold is coming after that on the run.

[Yukon Cornelius]

Extreme cold still expected or nah?

[Iceresistance]

GFS is trying to get to that ice storm scenario, it doesn't quite connect yet, temps are hovering on the GFS. What prevents is it forecasts a warmup slightly on Wednesday to just barely above freezing then back down.

https://i.imgur.com/h2ynkgU.gif

The cold is coming after that on the run.

MSLP of 474 near Minnesota on +144 & +150 hours

The PV is trending stronger

[Ntxw]

Extreme cold still expected or nah?

If you count the Euro as an outlier run, probably expect the coldest temps since 2018. This morning there was a large area of -20s moving into the northern tier states from Canada and it is currently frigid further north. A slight ripple can make a model go from extremely cold to just very cold.

[orangeblood]

Man, the 12Z GFS Op run at 500mb is textbook for extreme cold/multiple shots at winter storms across the southern plains...defining extreme cold as 20 F or below high temps for DFW, Austin 25 F or below

[txtwister78]

GFS says..."what's the Euro"? Lol

[bubba hotep]

Man, the 12Z GFS Op run at 500mb is textbook for extreme cold/multiple shots at winter storms across the southern plains...defining extreme cold as 20 F or below high temps for DFW, Austin 25 F or below

Shows lows across N. TX in the teens on Saturday but those are probably held up by increasing cloud cover from the incoming s/w that triggers some snow.

[bubba hotep]

That's one hell of a reinforcing cold shot coming down lol

[Ntxw]

Wxman57 is famous for telling us about source region. Well lets have a look shall we? Almost the entirety of West-Central and Central Canada is -20C or lower, -40C or lower is expansive. Consider pressures up there right now are in the high 1030s and low 1040s. What does that say? It says the air mass is much colder than what you would point it to be given the pressure pattern. The magic of blocking. Basically the air mass is COLD. We've seen these pressures earlier in the season and it was much warmer at the surface.

Anecdotally so what can one assume? That despite a "so so" pressure pattern one would expect it to be colder than what you interpret in a similar pattern.

[Iceresistance]

That's one hell of a reinforcing cold shot coming down lol

https://www.tropicaltidbits.com/analysis/models/gfs/2021020612/gfs_T2m_us_33.png

First Arctic Blast: PREPARE FOR TROUBLE!
2nd Reinforcing Blast: Make it Double