Chase Log 5-24-08; Darren Clabo

 

Chasers:

            Vehicle 1: Darren Clabo, Shawn Honomichl, Kathleen Carroll

            Vehicle 2: Shawn Jacobs, Joanna George, Butch (the dog)

            Vehicle 3: John Wetenkamp, Matt Bunkers

 

The morning started with comprehensive review of the 12Z soundings/upper air data and a surface analysis. A 500mb cutoff low was centered over east central WY with a surface low over northeast WY. A warm front extended ESE from the surface low through SD and into northeast NE. Considering the proximity of the surface low to the cutoff 500mb low, we immediately identified the day as a “cold-core” type chase day. We wanted to play the warm front as near to the surface low as possible.

 

After consulting the RUC forecast soundings for the afternoon, we decided our best option was to head north out of Sturgis. We figured the CAPE was marginal at best for the day, but low-level shear profiles (0-1km) were very good. The RUC showed the best forecast hodographs at 18Z north of Sturgis, at 21Z near Faith, and at 00Z near Mobridge. We decided this ‘route’ was our best option. We left Rapid about noon and headed north.

 

Convection fired early south of the warm front over the northern Black Hills. This convection moved north and we intercepted it near Maurine, SD. This storm was weak and disorganized at best and exhibited outflow at the surface everywhere. After sitting on it for about an hour or so (and deciding it was going nowhere), we (vehicle 1) decided to break from it and run east towards a developing storm north of Philip.

 

At this point the Philip storm became severe warned with penny size hail. We knew the storm was still south of the warm front but if it were to interact with the warm front, it would most likely begin to rotate. As we neared Faith, a tornado warning was issued by NWS-RAP for areas near Cherry Creek. At this point, vehicles 2&3 began running east towards the storm. As we neared Dupree, we could see extensive mammatus and a crisp, vertical updraft to the south. Continuing towards the storm, we finally intercepted it 9 mi south of Eagle Butte on highway 63. Hail upwards of half dollars was falling and drifting to near 6 inches in the roadway. As soon as we broke through the hail core, we could see the base of the updraft and a very distinct, rotating wall cloud.

 

Soon after we arrived, vehicles 2&3 arrived at the same local. Upon their arrival (~4pm), the first tornado briefly touched down approximately 5 miles east of our location. Another ‘needle’ type tornado soon touched down given us two very distinct funnels. Considering the muddy easterly road, only vehicle 3 was able to manage it. At this point all three cars split up and surrounded the storm. Each saw upwards of 7 tornadoes, one lasting nearly 12 minutes and approximately ¼ mile wide, from the one distinct updraft. All vehicles sampled 2 inch hail with vehicle 1 receiving moderate hail damage to the car. It was estimated that these stones were near 2.5 inches. As the storm passed Eagle Butte, it ceased to produce tornadoes but did produce prolific funnel clouds and was rotating as it passed Ridgeview. The storm then began to lose supercellular characteristics and the chase was broken off. All cars returned safely to Rapid City around 10pm local time.

 

Summary:

     Features seen: ~7 tornadoes, 2in+ hailstones

     Miles traveled: ~400

     Notes: ~6in hail drifts on roadway, extensive hail fog observed

    

Pictures from Joanna George: