[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 181820
SWOMCD
SPC MCD 181820
TNZ000-ALZ000-MSZ000-182045-

Mesoscale Discussion 1553
NWS Storm Prediction Center Norman OK
0120 PM CDT Wed Aug 18 2021

Areas affected...Northern Mississippi into northwest Alabama and
southwest Tennessee

Concerning...Severe potential...Watch unlikely

Valid 181820Z - 182045Z

Probability of Watch Issuance...5 percent

SUMMARY...Scattered thunderstorms may produce sporadic damaging
winds through the afternoon hours across parts of northern MS,
northwest AL, and southern TN.

DISCUSSION...A cluster of thunderstorms has shown signs of growth
and intensification over the past hour in the form of increased
lightning activity and cloud top cooling. While this activity is
rather disorganized, the downstream environment is destabilizing as
temperatures warm into the low 90s with dewpoints in the mid 70s.
MLCAPE values have already increased to 1000-1500 J/kg and may
increase further to near 2000 J/kg through the afternoon. Deep-layer
shear is modest over the region and will limit storm organization,
but amalgamating cold pools within the cluster and persistent ascent
associated with a weak shortwave trough over the region will likely
maintain thunderstorms into the early evening. Additional
thunderstorm development is possible along a weak confluence axis
noted in surface observations across the region. The combination of
moderate MLCAPE and somewhat steep low-level lapse rates (near 7
C/km) will support a damaging wind potential through the afternoon
and early evening both with the developing cluster and with any
stronger, more isolated cells. The overall severe potential is
expected to remain sporadic, so a watch is not anticipated at this
time.

..Moore/Dial.. 08/18/2021

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

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...

LAT...LON   34899025 35428941 35908828 35958707 35648645 35218622
            34478682 34028801 33828896 33728976 33779036 34089066
            34899025
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