Mesoscale Discussion 1656
NWS Storm Prediction Center Norman OK
0334 PM CDT Mon Aug 31 2020
Areas affected...Southeast Kansas...the I-44 corridor in Oklahoma
and northern Texas
Concerning...Severe potential...Watch likely
Valid 312034Z - 312200Z
Probability of Watch Issuance...95 percent
SUMMARY...Thunderstorm development is expected along the front in
the next 1 to 2 hours. All severe hazards are possible and a watch
will likely be needed.
DISCUSSION...Temperatures have warmed into the low 80s with
dewpoints in the low to mid 70s along and ahead of a cold front
which extends from southeast Kansas across Oklahoma and into Texas
just south of Childress. This has yielded 2000 to 2500 J/kg MLCAPE.
Some elevated convection has persisted in south-central Oklahoma for
most of the morning and early afternoon, but has recently begun to
weaken. Surface obs only show minor influence from this convection,
and westerly mid-level flow should usher in steeper lapse rates
across the region once again. Therefore, do not expect this activity
to have much influence on the convection later this afternoon. SPC
mesoanalysis suggests MLCIN is now eroded along the front. The 18Z
LMN RAOB also showed a mostly eroded CAP. Therefore, expect storms
to form along the boundary in the next 1 to 2 hours. The first
evidence of this has started southeast of Childress. However, flow
is weaker in that area, and thus, expect storm organization to be a
slower/more difficult process.
Farther north, the KTLX VWP shows between 35 and 45 kts of mid-level
flow which should provide ample shear for storm organization,
including the potential for supercells. While storms will initially
be discrete, this is expected to quickly change as numerous storms
form along the front. The best chance for significant hail will be
in the first 1-2 hours after storm organization when storm mode is
more discrete with severe wind becoming the primary severe threat
thereafter.
Additionally, a tornado or two is possible, specifically in southern
and south-central Oklahoma where surface winds are backed. Low-level
flow is not that strong, but there is significant veering in the
lowest 1-km which may support a tornado threat.
..Bentley/Grams.. 08/31/2020
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