Kds86z
Member
Something about his phone and also real busy.
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Severe Weather 4/17/26
- Thread starter N0mz
- Start date
Seasons of weather
Member
Beefy cell in southwestern/southern Wisconsin and strong looking QLCS with embedded tors possible east into Chicagoland and rest of southern Wisconsin on 18z HRRR run
The 18z NAM is a high end tornado event for WI and vicinity. Multiple supercells in an extremely favorable environment characterized by strong low level shear, very steep lapse rates, and plenty of low level instability.
CheeselandSkies
Member
IDK...looks like a linear mess to me. Even the Notorious Roofie-us does the same. Seems like these events always ride a knife's edge WRT convective mode especially in this neck of the woods. Tuesday had a shot for a cleaner supercell mode too, but it just didn't happen.
This setup is not the same as Tuesday. Also be very careful a) using the RRFS (lol) and b) interpreting its convective mode when it explicitly has problems with updrafts that are too intense/yielding too much precip.
speedbump305
Member
Always appreciate your analysis Andy!
And have to agree with you here. Tomorrow could be a particularly nasty day and I really wouldn’t be surprised to see an upgrade to a moderate risk.
jiharris0220
Member
It’s important to not lean in too much on the upscale growth along the coldfront, if that were the threat, we wouldn’t be at 10% risk (although perhaps not the most accurate statement considering line segments can produce tornado outbreaks on there own).
The threat that’s so concerning for tomorrow is the OWS convection out ahead of the cold front.
With the kinematics we’re dealing with, literally any sort of convection that manages to initiate out ahead of the line for any time interval beyond an hour likely will produce sig tors.
A concerning trend is that the 3km NAM despite its linear bias shows plenty of OWS convection well out ahead of the main line for up to 6 hours.
The threat that’s so concerning for tomorrow is the OWS convection out ahead of the cold front.
With the kinematics we’re dealing with, literally any sort of convection that manages to initiate out ahead of the line for any time interval beyond an hour likely will produce sig tors.
A concerning trend is that the 3km NAM despite its linear bias shows plenty of OWS convection well out ahead of the main line for up to 6 hours.
speedbump305
Member
Do you think it’s possible we see an upgrade? I’d say it’s likely. There’s plenty of OWS convection firing way ahead of the main line.
jiharris0220
Member
The environment is locked in at this point.
An upgrade would have to involve increasing consistency between the cam models in terms of storm mode and exact timing of coldfront progression.
If it trends any slower, and cams begin to all agree on widespread OWS activity out ahead of the main line, then a moderate risk I feel like anyways is guaranteed, not sure what else would prevent it if it came to that.
Kds86z
Member
Kds86z
Member
Kds86z
Member
CheeselandSkies
Member
Oh, of course. I'm just used to it also having a bias toward discrete, in addition to extremely intense, updrafts. As in routinely putting that memetastic HRRR run for 5/20/2019 to shame.
Kds86z
Member
TornadoFan
Member
Oh man, Oklahoma is gonna get it.
Kds86z
Member
CheeselandSkies
Member
That looks rather tame for Wisconsin given some of the other statements on here recently.
Kds86z
Member
Just a tad lol.
jiharris0220
Member
Nadocast cast has kinda lost its hold as an output to be taken seriously. As it’s the only output that has it this lukewarm.
It’s been off for quite a few years already though.
Meanwhile the hrrr continues the with the slower cold front and higher moisture return trend it’s been on for the past day and half.