I left my place at 8:15 with the intent to head to Sioux City. Got to
Worthington around 12-12:30, looked at data, and at that point the dew
points in the mid 50s were already to Omaha. Low in SD/NE... things still
looked good. The 9 hour Ruc had Sioux City with LI to -8, CAPE over 1,000,
DP to ~55 with good moisture convergence, and low just to the west.
By 1:10 I was noticing some cells going up just to my east as I traveled
down to Sioux City near Le Mars. I was concerned with these storms given the
time and their position. With a little debate with myself I decided to let
them go, and fortunately they did not go severe. But they did produce a
boundary that storms would later feed off of.
By 2:15 I was in Sioux City... went to the south side of town and found an
Arby's parking lot to get some data. The look of the situation at that point
was to head NW. The dew point in Sioux City was
58, but the real nose of the moisture and heat was in eastern Nebraska into
SE SD. The frontal boundary just to the west of that. Staying in SUX would
be a longer wait for convection, and this area would be farther from the
lifting mechanism. I still couldn't find the warm front, but I didn't look
too hard. Decided to play the cold front/dryline which seemed to be as far
north as Nebraska. The Yankton area looked like there was a hint of a dry
intrusion stream. Very small, but enough to create a mesoscale boundary that
interested me. Peggy and Mel were also heading to Yankton and reading
Scott's email about being further north all swayed me.
So I headed to Yankton. When I got there, I had no digital signal so I
couldn't get data, and I couldn't get a hold of anyone to give me a bird's
eye view, so I went with visuals (OH NO!)... the better cumulus appeared to
be further to the north. Peggy had also called me just before then and said
that Tim Vasquez suggested the Mitchell, SD area where the cumulus looked
good. So I went north on 81.
When I got between Freeman and Bridgewater in McCook County (just west of
Sioux Falls, SD) at about 4:50 I had a real dilemma. The cumulus were REALLY
starting to look good, towers going up everywhere, a tornado watch just
issued, but it had appeared that I might have been better off farther south
again. A little showery cell got going just to my west. I was interested,
but the word from Rory (thanks for the help Rory) was that it looked weak on
Radar and I should head south...back where I just came from. Peggy and Mel
were now heading further south at this point, from their position in Sioux
Falls.
I decided to compromise. I left my target of Sioux City to drive up here,
and I wasn't going to drive all the way back again, so I went to the south
side of that multicellular-like cluster of showers and waited. It was not
much after I got to the SE side of the showers that they blew up into a huge
hail core and became what I believe was the first severe storm in South
Dakota... McCook county.
 | These initial showers were moving very slowly... even once the storm became
severe, it was just drifting to the east, so an hour later at 5:50, I was
still in McCook County. Eventually a lowering became visible. |
 | The storm had matured enough to produce 1.00" hail that covered the road.
I called this in to the NWS in FSD as 1" hail E of 81, E of Bridgewater. |
 | It was about this same time that I was able to see a beautiful lowering which really had me excited. It just had that look, but the lowering was not rotating and never did produce.
The photo doesn't give it justice, but what was really fun to see was this 1"
diameter hail shaft coming down right next to this lowering and seeing a
rain foot or hail foot extend directly beneath the lowering. |
 | There was also a rainbow that went from one side of the storm to the other right "in front" of the lowering, hail shaft and hail covered road. I didn't get a picture of all of this in one shot, but it was really cool
looking. I followed this storm through Sioux Falls, SD with a persistent wall cloud
right up until the end. It got over the Minnesota line and dissipated. |
 | There was a new cell just to the north of my storm, which had just gone severe per
a report of 1" diameter hail in Elkton, SD (home town of my pretty 2001
tornado), so I headed north to intercept that guy. |
 | By the time I got there it was below severe limits I believe. This is where I met up with Peggy and
Mel, and drove back to MSP with a ham radio conversation with them about the day. We were treated with a beautiful sunset to top off the chase. |