MD 0729 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PORTIONS OF CENTRAL MISSOURI INTO CENTRAL ILLINOIS
Mesoscale Discussion 0729
NWS Storm Prediction Center Norman OK
0216 PM CDT Mon May 08 2023
Areas affected...portions of central Missouri into central Illinois
Concerning...Severe potential...Watch likely
Valid 081916Z - 082015Z
Probability of Watch Issuance...95 percent
SUMMARY...The severe threat is increasing across portions of the
mid-MS Valley. Large hail (some 2+ inches in diameter) will be the
primary threat initially, with severe gusts become the main threat
later on as storms congeal into an MCS. A Severe Thunderstorm Watch
will be needed in the next hour.
DISCUSSION...Strong surface heating along a baroclinic zone has
resulted in surface temperatures exceeding 80 F amid mid to upper
60s F dewpoints. With up to 8.5 C/km mid-level lapse rates
overspreading this heated airmass, SBCAPE has already reached 4500
J/kg in spots, that combined with 40-50 kts of effective bulk shear,
is promoting an environment favorable for rapid, intense
thunderstorm development (18Z mesoanalysis). RAP forecast soundings
show modestly elongated hodographs (mainly due to speed shear
influences) suggesting that initial storm mode will be multicellular
to perhaps transient supercellular. With near-saturation occurring
in the hail-growth zone above the effective inflow layer, efficient
hail production may lead to 2+ inch stones falling in some spots.
However, low-level shear is expected to remain weak, with storms
expected to quickly become outflow dominant. Cold pool mergers will
likely support MCS development, with severe wind gusts then becoming
the main concern. A Severe Thunderstorm Watch will be needed in the
next hour to address the growing severe threat.
..Squitieri/Guyer.. 05/08/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...LSX...SGF...
LAT...LON 37889459 38769100 39198983 39138910 38558896 37988894
37588918 37338982 37059100 37049257 37029333 37099397
37179449 37549473 37889459
