Mesoscale Discussion 1521

Issued

Jul 3, 2024, 1:45 PM CDT (18:45 UTC)

Expired

Jul 3, 2024, 3:45 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

The Paducah radar (KPAH), 175 km from the middle of the area, began a volume at 18:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

544 
ACUS11 KWNS 031846
SWOMCD
SPC MCD 031845 
KYZ000-ILZ000-TNZ000-MOZ000-ARZ000-032045-

Mesoscale Discussion 1521
NWS Storm Prediction Center Norman OK
0145 PM CDT Wed Jul 03 2024

Areas affected...South-Central/Southeast MO...Far Southern IL...Far
Western KY...Far Northeast AR...Extreme Northwest TN

Concerning...Severe potential...Watch possible 

Valid 031845Z - 032045Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorm development is expected this afternoon from
the Ozark Plateau into the Lower OH Valley. Strong to severe storms
capable of damaging gusts are possible, and convective trends will
be monitored for potential watch issuance.

DISCUSSION...Visible satellite imagery shows that the outflow
associated with antecedent storms currently extends from about 40
miles east-southeast of TBN (in south-central MO) eastward to the
MO/KY border vicinity. Southward progress of this boundary has
slowed significantly over the past hour, with current indications
suggesting that the western portion of this boundary has stalled.
Strong heating and low-level moisture advection will likely result
in this boundary becoming increasingly diffuse with time, although
there is some potential it returns northward as an effective warm
front (particularly the western end). 

Cumulus continues to deepen south of the outflow boundary, where
temperatures are now in the low 90s and dewpoints are in the low to
mid 70s. These warm and moist conditions are fostering an uncapped
environment with moderate to strong buoyancy. Recent mesoanalysis
estimates MLCAPE is around 2000 to 3000 J/kg. Vertical shear is
modest, with 0-6 km bulk shear currently around 25 to 30 kt. This
may increase somewhat as slightly stronger mid-level flow attendant
to a subtle convectively augmented vorticity maximum moves into the
region. 

Current expectation is for thunderstorm coverage to increase this
afternoon, supported by both ascent attendant to the convectively
augmented vorticity maximum moving through the central Plains and
low-level convergence. Strong buoyancy will support robust updrafts,
but the lack of stronger shear will likely limit organization,
promoting a predominantly multicellular mode. Even so, scattered
coverage of these strong updrafts and resulting potential for
damaging gusts may require the need for a watch.

..Mosier/Gleason.. 07/03/2024

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

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...

LAT...LON   36269294 37139249 37819035 37888841 37138809 36408864
            35779189 36269294

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.