SPC MD 740

MD 0740 CONCERNING SEVERE POTENTIAL…SEVERE THUNDERSTORM WATCH LIKELY FOR THE MID MISSISSIPPI VALLEY TO THE SOUTHERN APPALACHIANS

Mesoscale Discussion 0740
NWS Storm Prediction Center Norman OK
1110 AM CDT Thu May 08 2025

Areas affected...the Mid Mississippi Valley to the Southern
Appalachians

Concerning...Severe potential...Severe Thunderstorm Watch likely 

Valid 081610Z - 081745Z

Probability of Watch Issuance...80 percent

SUMMARY...Widespread thunderstorm development is expected this
afternoon with a threat for large hail and damaging wind gusts.

DISCUSSION...Cold temperatures aloft, associated with an eastward
meandering upper low, will provide a focus for widespread
thunderstorm development this afternoon from the Mid Mississippi
Valley to the southern Appalachians. Beneath this cold air aloft,
surface dewpoints are mostly in the mid 60s. This moisture will be
sufficient for moderate instability this afternoon (~1500 J/kg
MLCAPE) as temperatures warm into the mid 70s. A belt of moderate
(40 to 45 knots) of mid-level flow exists south of this upper low
and was apparent on the 12Z RAOB from KBNA and KLZK. This will
provide a sufficiently sheared environment for organized storms
including the potential for some rotating updrafts. This cold air
aloft, yielding moderately steep mid-level lapse rates, and
potential for some supercells will support a threat for large hail,
some of which could be 2+ inches. A remnant EML and dry air aloft,
combined with steep low-level lapse rates will also support a
damaging wind threat. In addition, the expectation for many storms
within the already uncapped airmass should promote storm clustering
which will also increase the damaging wind threat within those
corridors which clustering/bowing segments occur.

The 12Z BNA RAOB showed a convective temperature of 73F which has
nearly been reached as of 16Z. As such, a few storms have already
developed over southeast Missouri and northwest Tennessee where
cooler temperatures aloft are likely supporting a lower convective
temperature. As the boundary layer warms and mid-level temperatures
continue to cool, expect additional strong storm development within
the next 1 to 2 hours. Multiple severe thunderstorm watches will be
needed to address the threat from this development.

..Bentley/Gleason.. 05/08/2025

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

ATTN...WFO...MRX...JKL...LMK...OHX...HUN...PAH...MEG...

LAT...LON   35029014 36878979 37328902 37338742 37418598 37158449
            37028343 36648324 36288332 35098447 35028552 34548760
            34068914 34118994 35029014 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

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