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Jan. 17-18, 2026 SE Winter Weather Threat

@jackendrickwx or @bouncycorn or anyone else that has access to Weathernext2 (the Google AI model), is there a more detailed map of accumulations and more regional? Really looked like it was very similar to what the Euro AI was showing
Watching the 12z roll in now on stormvista. @bouncycorn has greater capabilities than me for this. I am not a model whiz.

Something I will note about whatever it shows at 12z (or any z) is that it is a pretty coarse, 64 member ensemble. It is good, but I am not going to be trusting its 2m temps verbatim. I don't trust its snow maps either necessarily, i just don't know if it can resolve a borderline dynamic cooling scenario like this. Maybe it can, we'll see
 
Watching the 12z roll in now on stormvista. @bouncycorn has greater capabilities than me for this. I am not a model whiz.

Something I will note about whatever it shows at 12z (or any z) is that it is a pretty coarse, 64 member ensemble. It is good, but I am not going to be trusting its 2m temps verbatim. I don't trust its snow maps either necessarily, i just don't know if it can resolve a borderline dynamic cooling scenario like this. Maybe it can, we'll see
Yeah not looking for specifics but a better look at the footprint which it and the Euro AI seem to be similar. Will be a great test of how it handles 2m temps in this scenario and if it's off, since it's AI, one would think it would "learn" and resolve that going forward.
 
A remarkably similar northwestern jump to the AIFS from the Weathernext at 12z. New on top

View attachment 183847

View attachment 183848

I should note that the 850s do progress eastward with the ensuing frames. Just trying to show the QPF jump, I know the thermos are bleh in general

Starting to look more amped like the GFS from yesterday tho not as cold obviously
 
The AI models are great at 5h, but I haven't seen any data saying they are the best in the world at predicting overrunning/WAA precip totals. Just keep that in mind.

Both can be true... AI models nailed 5h... and we have more precip than they've been showing from overrunning.
That's the right take here I think. And they can still shift further inland with the rest of them. The ECMWF is the stickler right now
 
The AI models are great at 5h, but I haven't seen any data saying they are the best in the world at predicting overrunning/WAA precip totals. Just keep that in mind.

Both can be true... AI models nailed 5h... and we have more precip than they've been showing from overrunning.
The AI models are great at precip. In fact, the purple line on this error chart "FGN" is the Weathernext2 model. Beats IFS HRES and IFS-EPS.
(lower is better)
1768503750894.png
 
The AI models are great at precip. In fact, the purple line on this error chart "FGN" is the Weathernext2 model. Beats IFS HRES and IFS-EPS.
(lower is better)
View attachment 183850
light overrunning precip at mid-lattidudes? Or all precip in the Northern Hemisphere?

We will find out for this setup I guess. Though I think we've already sort of found out with the big NW jump they just had in qpf. (undetermined if there's more adjusting left to do).
 
The AI models are great at 5h, but I haven't seen any data saying they are the best in the world at predicting overrunning/WAA precip totals. Just keep that in mind.

Both can be true... AI models nailed 5h... and we have more precip than they've been showing from overrunning.
Always something to keep in mind with verification scores, too (which tend to be at h5). Something can be the best at h5 and not necessarily be the top dog translating that to the surface (and vice versa). Of course, all else being equal, being right in the mid / upper atmosphere should translate to being right at the surface, but all else is not necessarily equal.
 
A nice increase on the snow map for the 12z WxNext. Now explicitly showing a 1-2" swath along a similar path to several EPS member

View attachment 183851

The big jump NW by the two major AI models is interesting. I think trend wise those are the models to pay attention to imo. They are not infallible but the other models seem to be a cycle or 2 behind in terms of trends. If these trends keep up in next couple cycles it’s possible we get something closer to amped gfs solution maybe less extreme though. Columbia and CLT squeak out a couple inches of snow maybe? I’m in Hickory area so need big NW trend back this way. Obviously more NW equals warm nose issues pretty quickly.


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The AI models are great at precip. In fact, the purple line on this error chart "FGN" is the Weathernext2 model. Beats IFS HRES and IFS-EPS.
(lower is better)
View attachment 183850

Well predicting precipitation in general across the board is not the same as predicting precipitation in specific waa/overrunning setups like this one. These broad brushed model skill analyses do not tell us anything about how they handle specific situations as these skill scores and biases are likely state dependent to some degree.

My hunch is if you re-ran these models for the overrunning events we’ve had since the mid-20th century, they would still undervalue the waa aloft at this range

Thus far, I am not impressed with how the AI models are handling this setup. They’re really just correcting to the more amped GFS/GEFS solutions from yesterday which a lot of people scoffed at because they were “bad” models.

These suites thus far have been struggling just as much as most other models, tho I think they are an improvement over the traditional euro which is stubbornly (& likely wrongly) too far south & east.
 
A nice increase on the snow map for the 12z WxNext. Now explicitly showing a 1-2" swath along a similar path to several EPS member

View attachment 183851

@bouncycorn this is already like a hundred mile+ jump from the previous WeatherNext solution... earlier you were saying that this kind of jump just doesn't happen within 80 hours on WeatherNext/AIFS -- is this event maybe the kind of outlier scenario that these models can struggle with and this is just as surprising to you? Or does this fit with your thinking still?

Just seems totally not what I expected based on your earlier comments.
 
@bouncycorn this is already like a hundred mile+ jump from the previous WeatherNext solution... earlier you were saying that this kind of jump just doesn't happen within 80 hours on WeatherNext/AIFS -- is this scenario maybe the kind of outlier case that these models are struggling with and this is just as surprising to you?

In all fairness, you do have to give credit that they did stick to their guns for as long as they did, and even their precipitation banding moved only by perhaps 25 miles to the NW.

With all of that said though, just because models are superior track-record wise does not mean it will perform to the best. ALL must be considered unless it's a blatant throwaway model run. The GFS (and definitely its ensemble counterpart) definitely had a DA or overcorrection issue at 00z which is what led to the outlier amped run last night, as all other runs remain similar. Just got to keep in mind what is good towards forecastability and the bad.
 
Well predicting precipitation in general across the board is not the same as predicting precipitation in specific waa/overrunning setups like this one. These broad brushed model skill analyses do not tell us anything about how they handle specific situations as these skill scores and biases are likely state dependent to some degree.

My hunch is if you re-ran these models for the overrunning events we’ve had since the mid-20th century, they would still undervalue the waa aloft at this range

Thus far, I am not impressed with how the AI models are handling this setup. They’re really just correcting to the more amped GFS/GEFS solutions from yesterday which a lot of people scoffed at because they were “bad” models.

These suites thus far have been struggling just as much as most other models, tho I think they are an improvement over the traditional euro which is stubbornly (& likely wrongly) too far south & east.
Yeah I definitely agree there. On top of this, EPS has been shifting north as well so I don't think it's too much longer until Euro OP folds.
 
considering 2017 and 2014 are our top analogs, I absolutely love where I am currently in Atlanta it will tick nw
 
considering 2017 and 2014 are our top analogs, I absolutely love where I am currently in Atlanta it will tick nw

Being in Macon, I figure we'll be alright if the ticks still continue. Temps shouldnt be the worst in the world; better than the coastal situation at the moment.

The AI model suites also appear to have a very smoothed out temperature gradient which doesn't exactly indicate it's handling something smaller-scale well.
 
also just want to say that given we can go from everything to nothing like last night, i don't think its smart to rule areas further north getting stuff
 
I just dabble here but seems like these models are good with severe weather but every time I’m lurking during winter threats the models are always so far out of agreement it’s insane.
 
I just dabble here but seems like these models are good with severe weather but every time I’m lurking during winter threats the models are always so far out of agreement it’s insane.

I believe it's due to winter weather threats overall relying on many other factors that aren't modeled or represented/measured nearly as well. Hidden small-scale air masses may tip the scales in some people's (dis)favor while severe weather often requires just "few" (relatively) things.
 
also just want to say that given we can go from everything to nothing like last night, i don't think its smart to rule areas further north getting stuff
As of now, this is a Deep South storm, but with this NW trend happening and especially now with the Euro then I wouldn’t rule out snow in areas further north. Let’s wait and see.
 
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