696
ACUS11 KWNS 252154
SWOMCD
SPC MCD 252154
ILZ000-WIZ000-IAZ000-MOZ000-KSZ000-NEZ000-252330-

Mesoscale Discussion 1413
NWS Storm Prediction Center Norman OK
0454 PM CDT Tue Jun 25 2024

Areas affected...Southern Iowa...far northern Illinois...far eastern
NE...and far northern Missouri

Concerning...Severe potential...Watch likely

Valid 252154Z - 252330Z

Probability of Watch Issuance...80 percent

SUMMARY...Scattered thunderstorms will continue to develop along a
cold front across the southern half of IA, far northern IL, and
eventually move into northern MO this evening. Large hail up to
1.5-2.5" in diameter and damaging wind gusts near 60-70 mph will be
possible as the thunderstorms mature early this evening.

DISCUSSION...Diurnal heating ahead of a cold front combined with a
very moist boundary layer beneath steep mid-level lapse rates has
contributed to a moderately to extremely unstable air mass this
afternoon. Surface convergence along the front has already lead to
thunderstorm initiation. Subtle height falls over the next several
hours associated with an upper trough to the north will continue to
aid in scattered thunderstorm development. Although mid to
upper-level flow is modest, sufficient deep layer effective shear
around 30-35 kt will support storm organization and some discrete
supercell potential before storms interact further south later this
evening. Any stronger thunderstorms across northern IL may be short
lived as they encounter a less favorable air mass/cold pool from an
earlier convective complex to the south and east.

Large hail will initially accompany the more robust updrafts through
early evening. Thereafter, storm mergers and clusters with deepening
outflow may result in a favored area of damaging wind gusts across
far southern IA and northern MO. A severe thunderstorm watch will be
needed soon.

..Barnes/Gleason.. 06/25/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LOT...MKX...LSX...DVN...DMX...EAX...OAX...TOP...

LAT...LON   41808763 42548782 42488986 42429030 42259072 42259072
            42089149 41919232 41909323 41879475 41789546 42039743
            41269713 40709649 39519505 39569269 40029164 40919098
            41498977 41668839 41808763