ACUS11 KWNS 092311
SWOMCD
SPC MCD 092310=20
MOZ000-ARZ000-OKZ000-100115-

Mesoscale Discussion 1923
NWS Storm Prediction Center Norman OK
0610 PM CDT Wed Aug 09 2023

Areas affected...Eastern Oklahoma...northwest Arkansas...and
southwest Missouri

Concerning...Tornado Watch 618...

Valid 092310Z - 100115Z

The severe weather threat for Tornado Watch 618 continues.

SUMMARY...The threat for all severe hazards continues across WW 618.
The severe threat will be greatest in the near-term across southwest
Missouri where storms continue to mature, but destabilization across
western Arkansas is increasing the potential for severe storms later
this evening.

DISCUSSION...Convective clusters continue to mature across southwest
MO into far northeast OK. This activity has remained fairly benign
so far, likely due to unfavorable deep-layer shear and storm motion orientations relative to the initiating boundary that are fostering
storm interactions and upscale growth. However, MRMS vertically
integrated ice and lightning trends have shown steady, though
gradual, intensification. Further upscale growth into a
semi-organized line appears probable in the coming hours, but any
discrete cells that can become established just ahead of the line
will pose a tornado risk if they can achieve east/southeast storm
motions (which will maximize low-level SRH). Lingering inhibition
downstream is apparent in visible imagery in the form of billow
clouds along the AR/MO border. Consequently, the threat for severe
wind/hail (and perhaps a tornado) will be limited to southwest MO
for the next hour or so where temperatures are warming into the
upper 70s/low 80s.

Further south across eastern OK to western AR, surface temperatures
continue to climb into the low/mid 80s amid broken cloud cover.
Recent forecast soundings suggest that temperatures in the mid-80s
are required to erode lingering inhibition and support surface-based
convective initiation. These temperatures are currently being
observed on the western fringe of WW 618 over central to eastern OK
where a few attempts at convective initiation have been observed
over the past 30 minutes in visible imagery. While forcing for
ascent over this region has been meager up to this point, the
approach of the upper trough from the west should increase the
probability of convective initiation within the next couple of
hours. Strong low-level shear is noted on the KSRX VWP where
easterly winds through the AR River Valley are supporting 0-1 km SRH
values around 350 m2/s2. This shear will likely diminish somewhat as boundary-layer mixing increases amid continued warming, but the
combination of strong deep-layer shear, favorable low-level SRH, and
increasing buoyancy will support severe convection capable of all
hazards through heading into the evening hours.

..Moore.. 08/09/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7dIpH9W-dbIm4iIVltkOvFCPFC4N8zjNBM2U1NaZfB5IAr29gDVxDT0SkPM13MenP01WGqf-9= NQfEZtbnZXU9KooqQw$ for graphic product...

ATTN...WFO...LZK...SGF...TSA...

LAT...LON 34879443 34829481 35259576 35719578 36729468 37309367
37349284 37149224 36909212 36539224 35459343 34879443=20


=3D =3D =3D
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