A good surface low in central South Dakota with a lifting
warm from extended off to the east over northeastern
South Dakota into central Minnesota looked to be the
focus for severe storms and possible tornadoes.
However, an outflow boundary crashing to the south
from earlier convection was the monkey wrench.
Surface maps from about 20Z (3 pm) showing the location of the low, the warm front (which had stalled for the most part by then) and the obs
showing the ridiculous 70-something dew points in place.
My original target was Summit, SD. I should have stopped and quit at Willmar, MN on my way out as the entire warm front was going to go off at
once as the TCu was exploding from west to east as that outflow boundary was putting the squeeze play on. The air has to go up as it sure can't
go down. Kept going west though and jumped on a couple of cells southwest of Appleton, MN. The west cell had a nice hook and couplet along
with really good inflow and the eastern cell was rapidly intensifying. Then it happened. Outflow. Like serious 73° outflow. 90° to the south of the
cells, but northerly winds. GAME OVER. This was taken a little east of Milan MN. Despite the awesome motion on the right side, this thing was
I dropped a little south to see if I could find southerly surface inflow but no luck. As the entire warm front was now forming a precip shield a
typhoon would be proud out, I started to make my way back east and home out of the rain. Note the bend in the antenna from the outflow.
Pretty nice scud bomb out in Chippewa county west of Willmar and northeast of Montevideo. I was waiting for the spotters to start going nuts
on this one as even structure vs location it is pretty convincing. Time was 5:31pm.
|Scud bomb with a satellite scud bomb.
By this time I just wanted to get home and quit thinking about missing the nice tornado up in North Dakota a few days earlier. I dropped down to
MN 7 and headed east. When I got to Cosmos MN I finally escaped the outflow and hit the warm air again. Instant fog and condensation on
everything. That never gets old. There were some cool LP-ish cells just south of Hutchinson I took a look at but photogenically there wasn't
much there so I continued on and headed north towards home just ahead of the line and torrential rain which was following. Just south of Howard
Lake MN John Wetter called from MPX and wanted me to take a look at a suspicious area between Cokato and Howard Lake as the line had
developed a notch. Well, here is the notch and the only time it had inflow. Note the direction the trees are blowing (left to right). This quickly got
cut off by cold outflow also as I headed for home just making it in the door as the flash flood warnings came out.