2025 Short Range Severe Weather Discussion

[CheeselandSkies]

Timelapse from our former chief engineer's webcam. At 1:31 the inflow band moves overhead and I think a second or two later the tornado spins up toward the right of the frame, he says it didn't form until just out of frame but I think it's just tough to see due to lack of contrast against the rain core from this angle. Then a dramatic RFD clear slot follows as the supercell pushes off to the northeast.
 

 

[WestMichigan]

10 hours ago, frostfern said:

GRR

In addition, at the MCV rotates east into Michigan we will see our
deep layer shear increase. Moisture (surface dew points in the
70s), instability (MUCAPE of 2,000-3,000 j/kg) and lift via the
MCV along with shear will all be in place this evening. We agree
with the slight risk area via SPC given the parameter space this
evening. The HREF 4 hour reflectivity max tells the story quite
well, in that our diurnal convection will fade into the evening
and the focus will shift to the incoming line. The lake is quite
warm and we do not expect a decrease in intensity as the lake may
actually give the convection as boost. The lift via the MCV will
help storms as well. So, bottom line...expecting a line of storms
this evening with wind being the main threat. An isolated tornado
like what has happened already this afternoon in Wisconsin is
certainly possible later this evening in a QLCS mode in areas
where flow backs to the southeast or east ahead of the line.
Showers and storms sweep out of the CWA by 2am-3am.

HREF was wrong.  The lake always seems to kill storms during peak heating hours.

I got enough drops of rain to leave a few water spots on the windshield, but the pavement was never wet.

[CheeselandSkies]

0Z Wednesday (7 PM CDT Tuesday) 3KM NAM valid for 22Z Wednesday (5 PM CDT). Placement of tornadic cells was almost spot-on, but the timing was about 4 hours slower than reality (and much closer to the time of day I would expect tornadic storms).

[frostfern]

4 hours ago, WestMichigan said:

I got enough drops of rain to leave a few water spots on the windshield, but the pavement was never wet.

I got .33” from early day shower, but it came so fast most of it ran into the storm drains without soaking in.  After that it was a few drops, then some rumbles off to the east as the line reformed.

There was 1500 j/kg CAPE over the lake (as opposed to 2500 j/kg inland), but it seems lower apparent temperature / higher density over the lake can slow down storm outflow to the point unstable parcels are no longer being lifted enough to reach free convection.  That and the line was way out ahead of the MCV / low which the CAMs got wrong somehow.