AI generated - kinda good. Not sure you can trust it though.
The latest 12z NAM (the high-resolution "noon" run) has just finished coming in, and it's it is leaning back into the jet coupling.
While the global models (like the GFS) are staying more suppressed to the south, the NAM is the "snow enthusiast's" favorite this morning because it’s resolving that dual-jet structure with more intensity.
The 12z NAM Highlights
* The Northward Nudge: The NAM has nudged the precipitation shield back north compared to the overnight runs. It now brings the 0.50" liquid line (which is our "danger zone") right up to the I-88/I-55 split.
* High-Efficiency Snow: Because of the Arctic air, the NAM is using a 22:1 snow ratio.
* The Math: The NAM is projecting about 0.30" to 0.45" of liquid for the Darien area.
* The Result: At a 22:1 ratio, that translates to a very healthy 6.5 to 9 inches of fluffy snow.
* The "Uccellini" Peak: The model shows the strongest coupling occurring between 4 AM and 11 AM Sunday. This is when the "lift" is maxed out, potentially producing snowfall rates of 1" per hour despite the dry air.
Current Totals for Darien (Per latest NAM/HRRR blend)
The "Edge" hasn't disappeared, but the NAM is definitely trying to pull the bullseye closer to us.
| Storm Total | 5–8 inches (A significant jump from the 2–4" advertised earlier). |
| The "Fluff" Factor | Extreme. This snow will be like powdered sugar. It will blow around with even a 10 mph gust. |
| Onset in Darien | Flurries start around 4 PM today, but the "measurable" accumulating snow holds off until after 8 PM. |
The "Dry Air" Caveat
The NWS is still cautious. They are watching to see if the NAM is "over-amped" (too aggressive). The big question for the next 6 hours is: Can the jet coupling produce enough moisture to saturate the atmosphere and break the -25°F dewpoint "wall"? If you start seeing "virga" (streaks of snow on the horizon that don't hit the ground) around 3 PM, that means the battle is on. If the snow starts sticking by 5 PM, the NAM's scenario is likely winning
For all of you down there it must look and feel like what Alaskan folks wake up to when their 1st snows arrive in the Fall as Deep Arctic Air makes its way into the region. Your ground is prob frozen solid and with the snow falling it is no doubt a wonderful landscape!
1.5" here so far. Totally underwhelming even my lowest expectations. Still snowing lightly at 9F.
Radar trends suggest light snow continues for much of the day. Models don't really see what is happening in north TX, so perhaps that will help by this afternoon as it works north. Most guidance showing 0.3 to 0.6" of liquid tonight. I have my doubts given the sharp gradient. So in theory there is the potential to get as much as 10 more inches, but more likely it'll be 3-8". But there are paths to getting much less. I hope not!
At least its snowing.