Areas affected…Much of South Dakota
Concerning…Tornado Watch 564…
Valid 092303Z – 100000Z
CORRECTED FOR OUTLINE COORDINATES
The severe weather threat for Tornado Watch 564 continues.
SUMMARY…The severe threat continues across WW 564.
DISCUSSION…A cluster of strong to severe storms continues across
central portions of South Dakota near 9V9 and around 40 miles north
of VTN. These storms have exhibited occasional rotation along with
hail and strong wind gusts, which isn’t surprising given the
moderate CAPE/strong low-level shear environment in place –
especially near the effective warm front. A tornado threat will
exist, though radar presentation of ongoing storms hasn’t been
consistent with classic supercellular/mesocyclonic tornadoes over
the last hour or so. In fact, storms appear to be congealing into a
small linear segment near Buffalo/Lyman Counties. This evolution is
consistent with recent high-resolution guidance/CAMs, which suggest
that this cluster will begin to migrate southeastward along the warm
front toward southeastern South Dakota over time.
Upstream, an isolated, hail and wind-producing cell has exhibited
supercellular structure over the past hour or so just northeast
through east of Rapid City. This cell will continue to pose a
severe risk for the next several hours and will approach western
portions of WW 564 during that time.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 43290163 43610168 44590173 45370164 45510137 45380030
45149834 44829783 43859761 43159763 42809782 42949973
43110120 43130138 43190160 43290163