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Mesoscale Discussion 1748 |
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Mesoscale Discussion 1748
NWS Storm Prediction Center Norman OK
0351 PM CDT Thu Aug 15 2019
Areas affected...portions of central and eastern KS into far western
MO
Concerning...Severe potential...Watch likely
Valid 152051Z - 152245Z
Probability of Watch Issuance...95 percent
SUMMARY...Scattered severe storms are expected to develop over the
next few hours. These storms could produce very large hail, damaging
winds, and possibly a couple of tornadoes. A watch will be needed in
the next 1-2 hours.
DISCUSSION...Elevated convection continues this afternoon across far
southeast NE into northwest MO. These storms could pose a persistent
hail threat over the next several hours. An outflow boundary
associated with this convection is oriented roughly west to east
from near CNK in north-central KS to near Kansas City. Strong
heating to the south of this boundary has resulted in around 20-30
degrees temperatures difference across the boundary, with mid 80s to
near 90 degrees south and mid 60s to mid 70s north. Surface
dewpoints south of the boundary ranged from the upper 60s to low
70s, resulting in 2500-3500 J/kg MLCAPE and rapidly eroding
inhibition. Evidence of the weakening EML has been noted over the
last 30 minutes or so in GOES-16 1-minute visible imagery as the CU
field in the vicinity of the outflow boundary has showing increasing
vertical development.
As warm advection increases and a low level jet begins to strengthen
early this evening, convection is expected to develop near the
outflow boundary by 00z. Weak upper forcing will likely allow
discrete cells to persist initially before upscale growth become
more likely with the increasing south/southwesterly low level jet
between 00-03z. Effective shear greater than 40 kt and very steep
midlevel lapse rates will support supercells capable of very large
hail (some baseball or larger). Damaging wind gusts (some greater
than 65 kt) also appears likely given steep low level lapse rates
and midlevel dryness enhancing evaporative processing leading to
intense downdrafts. Somewhat more uncertain is tornado potential.
Backed low level flow in the vicinity of the outflow boundary will
enhanced 0-3 km SRH values. However, aforementioned downdraft
potential could be a mitigating factor in overall tornado potential.
Nevertheless, overall environmental parameters support at least some
tornado threat with any cells that remain discrete. A watch will
likely be needed for portions of the MCD area by 23z.
..Leitman/Grams.. 08/15/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SGF...EAX...TOP...ICT...GID...DDC...
LAT...LON 37139517 37039599 37049687 37199770 37779863 38459895
38929893 39549872 39709849 39799751 39799601 39689548
39309455 39109429 38709410 38169419 37449447 37139517
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