Mesoscale Discussion 1878
NWS Storm Prediction Center Norman OK
0933 AM CDT Mon Aug 07 2023
Areas affected...Portions of Tennessee Valley
Concerning...Severe potential...Watch likely
Valid 071433Z - 071630Z
Probability of Watch Issuance...80 percent
SUMMARY...The threat for severe/damaging winds will increase over
the next few hours. Tornadoes are also possible, particularly for
more discrete storms across Tennessee. A watch is likely with timing
probable by late morning.
DISCUSSION...Convection is ongoing from Arkansas into western
Tennessee. Given the speed and radar character of this suggests this
activity is currently elevated in nature, especially farther west.
However, modifying the 12Z observed OHX sounding for current surface
conditions suggests that MLCIN is eroding rather quickly and
strong/severe surface gusts may become more common in the next
couple of hours. Wind profiles are strong for this time of year and
2000-2500 J/kg MLCAPE is already present into the Tennessee Valley. Furthermore, low-level shear is certainly sufficient for low-level
rotation. Aside from a threat for severe/damaging wind gusts, there
is also potential for tornadoes. The main question will be storm
mode. Forcing for ascent may be enough to drive a more linear mode
than discrete. Convection in western Tennessee is showing some
stronger velocities on KNQA imagery. A watch is likely, but the
exact timing of the increase in storm intensity is uncertain.
Observations and guidance would suggest this could occur by late
morning.