MD 0535 CONCERNING TORNADO WATCH 139… FOR EXTREME EAST-CENTRAL/SOUTHEAST MO INTO WEST-CENTRAL/SOUTHWEST IL
Mesoscale Discussion 0535
NWS Storm Prediction Center Norman OK
0650 PM CDT Sat Apr 15 2023
Areas affected...Extreme east-central/southeast MO into
west-central/southwest IL
Concerning...Tornado Watch 139...
Valid 152350Z - 160115Z
The severe weather threat for Tornado Watch 139 continues.
SUMMARY...The threat for damaging wind, hail, and a tornado or two
will spread east of the Mississippi River this evening.
DISCUSSION...A QLCS continues to evolve near the MS River this
evening. A supercell that earlier produced very large hail southwest
of St. Louis produced an apparent tornado as the larger-scale cold
pool overtook the storm. Multiple bowing segments are now
approaching the MS River, with strengthening velocities from the
KLSX radar suggesting the risk for damaging wind gusts is
increasing. Modestly curved low-level hodographs downstream with 0-1
km SRH near 100 m2/s2 will also support a threat of a line-embedded
tornado or two as these bowing segments surge eastward. The
increasingly linear mode should tend to reduce the hail risk with
time, though instability remains sufficient for at least isolated
hail with the strongest embedded updrafts.
Later this evening, ongoing convection will approach the eastern
edge of WW 139. Increasing MLCINH with time and eastward extent
renders the need for downstream watch issuance uncertain at this
time, and this may depend on the extent to which the ongoing bowing
segments can accelerate eastward prior to the onset of stronger
nocturnal cooling/stabilization.
..Dean/Bunting.. 04/15/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...ILX...LSX...SGF...
LAT...LON 39319056 39528925 39218856 38748839 38048838 37478862
36838907 36788965 36929053 37109105 37989039 38379035
38939053 39139061 39319056
