Good day all,
Finally got some pictures and a brief chase report up for June 7, 2009 from NE Kansas / SE Nebraska and into NW Missouri. Three supercells were intercepted, the first being a storm near Summerfield, Kansas near the Nebraska border, then another one farther southest into extreme NW Missouri near Oregon producing TREMEMNDOUS hail, and finally a supercell well after dark with a tornado near Cameron (illuminated by lightning).
Above: Stout updraft goes up on storm developing near two intersecting boundaries near Summerfield, Kansas.
Above: Rapidly rotating portion of first supercell southeast of Pawney, Nebraska.
1). June 7, 5:30 PM</B> - Observation and indirect penetration of an extremely severe, and possibly tornadic thunderstorm along and near the Kansas / Nebraska border / Highway 99 from near Summerfield, Kansas in Marshall County and eastward towards Du Bois, Nebraska near Highways 8 and 50 in Pawnee County. The storm was a classic supercell thunderstorm that was observed from initiation west of Summerfield and followed to its point of weakening to an LP storm (due to its inflow being cut-off from another supercell to the SE). The storm came very close to producing a tornado with excellent rotation and rain wrap during its most intense phase. An unconfirmed report of a tornado was associated with this storm, but only a rapidly rotating wall cloud was observed south of Humboldt. The storm had hail up to softball-sized (4"), but the core was avoided and not penetrated. Winds near 40 MPH (inflow / outflow) were observed along with moderate rain, small hail, and frequent lightning with some close hits. Conditions producing the storms were surface heating, intersecting boundaries (triple point), low pressure area, and upper trough. Documentation was still digital photos and HD video. A 2009 Chevy HHR was used to chase the storms. A tornado watch was also in effect for the area until 11 PM CDT.
Above: Explosive development of second supercell storm viewed from Falls City, Nebraska looking east into NW Missouri.
Above: Close up of hailstone (melted) collected west of Maysville, MO - Hail over 4" was found earlier near Oregon, MO.
Above: Interesting rotating area of the supercell storm east of Maysville, MO before weakening and moving towards I-35.
2). June 7, 8:00 PM</B> - Observation and indirect penetration of another extremely severe, and possibly tornadic thunderstorm from near Falls City, Nebraska in Richardson County, across the Missouri River through Oregon, Missouri along Highway 159 / 59, and into Daviess County near Altamonte, MO and Interstate 35. This dangerous classic to HP supercell storm developed southeast of the original supercell storm earlier in Marshall County, KS and had little "competition" from nearby storms (southernmost "Tail-End Charley" cell). The storm core, near Oregon, Missouri, consistently was producing incredible hail approaching, if not exceeding 5" (one chaser report was 5.25")! Hail at least grapefruit sized was observed on the backside of the storm passing through Oregon, with the VORTEX II teams / other chasers creating a massive chaser caravan. The storm produced many rapidly rotating wall clouds / funnels with a powerful (60 MPH+) RFD. Of course, the core was not penetrated, but still winds to 60 MPH, frequent lightning with close hits, torrential rains, and large hail (largest observed falling was quarter sized as the storm weakened later). A large funnel / possible brief tornado was observed with this storm near Maysville in DeKalb County from near Highway 6.
Above: This was south of DeKalb / Caldwell County looking north towards Cameraon, MO at about 10:45 PM CDT when storm spotter were reporting a large tornado with another supercell well after dark.
3). June 7, 10:30 PM</B> - Observation and direct penetration of a very severe, tornadic thunderstorm from near Clinton and DeKalb counties in Missouri, near and west of I-35 and south of Cameron and Osborne. The storm was an HP supercell storm, and hail up to golfball-sized (with isolated pieces to half-dollar) as 1.5" to 2" was encountered with 60-70 MPH winds, torrential rains, and continuous lightning with numerous close hits. A wind shift from strong easterly to strong westerly was encountered when exiting the storm core to the south (mesocyclone). Once clear of precipitation, the storm updraft region was observed from the south at a distance of 5 miles or so, illuminated by the frequent lightning. A large wall cloud, and subsequently, a large silhouette of a tornado became visible for several minutes. Spotter reports confirmed this, putting the tornado in southern DeKalb County over open farmland. The storm weakened and evolved to multicell afterwards.
I am also working on a chase log for June 5 and June 7 and it is available below...
http://www.sky-chaser.com/mwcl2009.htm