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Wintry January 23rd-27th 2026

Ethan80963 said:
I’ve definitely heard from AmericanWX about the ICONs “warm bias” but it was probably a coopium thing because it came in worse. I’m pretty sure I’ve also seen it struggles a lot with P-Type depictions though.
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Thanks. I try not to speak in too many absolutes with things I'm not sure of. That is why I posed it as a question.
 
If the freezing rain near atl has a period of normal rain like being depicted will it just melt it all fast or does it stick around?
 
For Raleigh area...and Raleigh area only...this has been the theme on some of the globals and the NAM. Pushing that overrunning precip NW...on one hand it's 50 miles from 1" or 50 miles from less than 0.3" QPF. This precip through Sunday night is Raleigh's time to score sleet. The passing band after I think could be just rain or mix of freezing rain/rain but that's another argument until we get closer.

12z GFS AI

gfs-ai-carolinas-total_precip_inch-1769083200-1769385600-1769385600-20.gif


Then the big band pulls through and temps will warm...for Raleigh this will either be cold rain or freezing rain.



gfs-ai-carolinas-precip_12hr_inch-9428800.png
 
CaryWx said:
Was sure I read it but maybe I'm confusing it with another model. I'll have to go back and look at which ones trend more towards a "warmer thermal look" than actual proven fruition. For goodness sakes don't canonize a general comment like that. Certainly not on this forum anyway.
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absolutely not something directed at you, i just try to clean up things as much as i see them. i'm actually not great at remembering model biases. i just treat everything with a blank slate. i lean more towards run to run volatility or the unscientific "that don't really look right" when discounting models lol. there's a football podcaster i listen to (chris long) that described "every football game as a totally new story" and i keep a mindset like that with every unique storm
 
I don't know. I still think the Euro/Euro Ens will lead the way on this, I lean toward the cutter just exploding the CAD, eroding a good portion of it (last NAM just showed it too). With such an amped cutter going so west and with such a warm warm nose, most precip looks west of us. So it's not a nuisance, but historically bad in my mind is not likely. Looks more like a cold front than anything else for MBY. I just do not trust the ICON and the GFS at all.

But, perhaps with the last tick south, maybe the Euro continues trending south and Miller B's further south. That's the big change that may lead to more sleet for MBY that I'm curious about. Absent of that I think this keeps amping west moving most action to our north.
 
tempo47 said:
If the freezing rain near atl has a period of normal rain like being depicted will it just melt it all fast or does it stick around?
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Well considering 2m temps briefly rise into the mid 30s during this period off the GFS, I wouldn't bet on a ton of it just washing away unless the glaze was very light to begin with. The other big issue is the deep freeze following the heavy precip by only 3-6 hours, and any ponding on roadways (which is very likely in spots due to high QPF) is going to freeze solid. Whatever doesn't melt from the ZR is getting preserved with the cold coming in behind.
 
Ross said:
absolutely not something directed at you, i just try to clean up things as much as i see them. i'm actually not great at remembering model biases. i just treat everything with a blank slate. i lean more towards run to run volatility or the unscientific "that don't really look right" when discounting models lol. there's a football podcaster i listen to (chris long) that described "every football game as a totally new story" and i keep a mindset like that with every unique storm
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It may also be that a few years ago, the legend of warm bias ICON has been corrected by a model update. As Larry stated earlier, if anything, I've noticed a cold bias with 2m temps. IDK how it handles CAD in the recent past. It has been so long since a true non-in situ CAD has affected my area that I can't look to the past for the model's performance in this situation.
 
KyloG said:
Thanks and good point. I have no idea where these ideas come from...but it's spoken alot about the ICON for some reason.
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Not to belabor this as we could analyze every model for discrepancies and I doubt that is what this particular thread is for

Here's our AI friend's take on the ICON. It's warm bias's are found only in particular details. Which don't seem to apply specifically here imho. (grain of salt and all that).

Yes, research indicates that the ICON weather model can exhibit warm thermal biases in specific contexts, although it is generally considered a highly accurate model, especially for European and mountain weather.
Key findings regarding ICON temperature biases include:
  • Regional and Situational Warm Bias: Studies have identified significant positive temperature biases (too warm) in specific regions, such as over the Southern Ocean.
  • Boundary Layer Issues: In specific scenarios, such as the modeling of cold air pools (CAP), ICON has shown a significant warm bias below the top of the inversion.
  • Urban Heat Island Effect: While high-resolution configurations (ICON-CLM) can improve representations of urban heat islands, they can still produce warm nocturnal biases in urban areas.
  • Comparison to Other Models: While it has shown cold biases in some regional climate simulations, it has also shown better performance (less bias) than older models like COSMO or GME in certain scenarios.
It is important to note that ICON is frequently updated and developed, and different configurations (global, regional, climate) may exhibit different bias characteristics.
 
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Been gone from here with classes but I still think a really good front end thump can occur for my area. I like the RGEM and Canadian a lot but it might be taking in account high precipitation rates as "dynamic cooling" even up at the 700 mb area which does not really make sense. NAM probably makes a lot more sense but the last few CAD front end thump storms I have encountered has trended the front end thump further south than what the NAM had. So its really up in the air. Still thinking 3-6 inches of snow + sleet. If sleet is much more prevalent than freezing rain then maybe bump that to 4 to 8.
 
KyloG said:
Thanks and good point. I have no idea where these ideas come from...but it's spoken alot about the ICON for some reason.
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I will say I made my comment about from memory of us tracking the 2022 CAD storm and was meaning a warm bias more from a CAD standpoint. That said I also know that GaWx does great research for this board and I trust what he finds
 
CltNative90 said:
Sleet has saved the day more often than not in Charlotte since 2002. I’m hoping and praying that’s the case this time around, or we get dry slotted. My family living in what some would consider the inner city, there are repercussions of long term power outages that probably aren’t even being considered at the moment, similar to when a hurricane hits a major city (looting, etc.) This could get bad on many levels.
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Yes. I wouldn’t expect any power until midweek. It will take a long time to restore power and recovery will likely be very slow. Snow, you can just clear it off the road and travel is safe within 36 hours of the precip ending. Ice, you just have to wait for it to melt
 
HailCore said:
Well considering 2m temps briefly rise into the mid 30s during this period off the GFS, I wouldn't bet on a ton of it just washing away unless the glaze was very light to begin with. The other big issue is the deep freeze following the heavy precip by only 3-6 hours, and any ponding on roadways (which is very likely in spots due to high QPF) is going to freeze solid. Whatever doesn't melt from the ZR is getting preserved with the cold coming in behind.
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I noticed that the brief rise in surface temperatures depicted on some models for the Atlanta-Athens area comes after dark on Sunday. Very little will melt before the reinforcing Arctic front blows in overnight.
 
FallsLake said:
Yeah, the GFS would be a big storm. Specifically, from Charlotte to Raleigh, it looks like ~1.1" of mostly sleet (good). Then it switches to freezing rain for ~.7"(bad). Total ~1.8" for both. Funny how the types and QPF lined up perfectly.
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The saving grace is that if the .7" of ZR is with heavy rates, accretion on things such as powerlines, trees, ect. won't be as effective.
 
KyloG said:
Thanks and good point. I have no idea where these ideas come from...but it's spoken alot about the ICON for some reason.
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You know how it goes. Speak incorrect info enough times and many people start assuming it is true even with no evidence. Unfortunately, it’s human nature to an extent. So, my goal in these cases is to try my hardest to do my part in attempting to reduce the spread of misinfo along with my own objective evidence if I’m able to post it.

More on ICON precip types that have been mentioned. It on WxBell keeps on showing snowfall on Sunday for Columbia, Augusta, and Charlotte, but 850s are well above freezing! This is a common problem with WxBell Icon snow maps going back a ways:
IMG_7449.gif

850s at start: +4 to +9 in these cities
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850s at end of period: +10 to +12
IMG_7448.png
 
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