07-30-11 CHASE LOG: MINNESOTA This turned out to be a fantastic day that many, including myself, were thinking would be more of a straight line wind and hail threat and not worth the bother to chase. However, morning storms moved through central MN into WI by early afternoon and laid an outflow boundary right through central MN in the vicinity of Hwy 212. SPC issued a Severe Thunderstorm Watch along this outflow boundary at 1:30pm CT, while a supercell developed across western SD and was crossing over the border into western MN. The thinking was that more storms, along with this initial cell, would develop along the boundary. Well, low and behold, the supercell evaporated into thin air, likely due to the presence of strong capping along the boundary into MN.
The aforementioned watch box was soon cancelled, while additional development was forecast along and ahead of a cold front entering the eastern Dakotas into northwest MN later in the afternoon, and possibly along the remnant outflow boundary that was rapidly receding north towards the I-94 corridor. The airmass ahead of the cold front and along the outflow was characterized by dewpoints in the 70’s, MLCAPE of 2500-4500 J/KG, and 45 kts of Effective Shear. The one concern was the southwest surface winds that were developing, but considering the winds aloft were out of the northwest, there actually was favorable low level shear in place for supercells and low-end tornado threat.
Our course took us from Hutchinson northward on Hwy 22 and then west on Hwy 55 at Eden Valley. Storms began to develop along and ahead of the cold front to our northwest near the Fergus Falls area and were strengthening quickly upon moving east southeast, so we continued northwest towards the cells on Hwy 55. A new Severe Thunderstorm Watch was issued at 5:35pm CT that included all of central MN. As we approached Hwy 29 near Glenwood, we had to make a decision to keep going west on the storm near Elbow Lake, or continue north to the storm near Wadena. We chose the storm near Wadena as it looked like it was better organized and had a higher echo top compared to the western storm and appeared to be in just as good of an environment. Later we find out that the western storm produced a beautiful rope tornado near Collis, MN.
Upon reaching the storm near Parkers Prairie, we went east of town on Cty Rd 46 and set up the tripod to film a developing all cloud. This wall cloud looked very good for while with fairly rapid condensation, but you can see in the sped up video how the RFD comes around and the wall cloud occludes and eventually gusts out. We continued to follow on Cty Rd 71 and then south on Cty Rd 16 towards Rose City. Here the storm cycled with another wall cloud and came very close to producing a tornado. This wall cloud eventually wrapped up and we continued to follow on Cty Rd 1 and then east on Cty Rd 36 towards Long Prairie. Traveling south on Cty Rd 11 and east on Cty Rd 10, another tight wall cloud with rapid condensation formed with a strong RFD surge. Yet another opportunity for the storm to produce a tornado but it failed to do so. To the east of Gutches Grove on Cty Rd 10, I’m 75% sure we had an elephant trunk funnel that stuck around for only 10 seconds or so as the wall cloud was producing the most rapid condensation I had seen all day. Thereafter, the storm became outflow dominant with a photogenic shelf cloud as we traveled down towards Sauk Centre and eventually towards Belgrade where we called it a day after experiencing winds near 50 mph from the gust front.
Here is video from the day:
Fast condensation into a developing wall cloud east of Parkers Prairie, MN on Highway 46. This is the first wall cloud seen in the time lapse at the beginning of the video.
Wall cloud tightening up, I believe north of Rose City, MN on County Road 71. Notice the clear slot cutting in on the left side!
Shortly after the picture above. Condensating inflow tail into the wall cloud with nice bowl shape underneath.
Rapidly rotating and condensating wall cloud at this point near Gutches Grove, MN on Highway 11.
Another view of the wall cloud and associated inflow tail near Gutches Grove.
Had to really crank up the contrast here, but I am 75% sure that there is an elephant trunk funnel in the front center. This was at the point of the fastest condensation into a wall cloud that I had seen all day, and the area became tight, defined, and was rapidly rotating for about 10 seconds. This was southwest of Long Prairie on County Road 10. Video captured this much better.
Storm gusting out with a shelf cloud forming near Grey Eagle, MN.
Turbulent undulations on the cloud base in Sauk Centre, MN.
More photos from this day can be found here: http://www.flickr.com/photos/39991047@N02/sets/72157627327597494/
Base Reflectivity of cell near the time it had a rotating wall cloud and looked the best near Gutches Grove, MN.
Storm Relative Velocity of the storm, indicating at least some rotation, when a rotating wall cloud was witnessed near Gutches Grove, MN.