ACUS11 KWNS 251706
SWOMCD
SPC MCD 251705=20
ARZ000-OKZ000-251830-

Mesoscale Discussion 1253
NWS Storm Prediction Center Norman OK
1205 PM CDT Sun Jun 25 2023

Areas affected...portions of eastern Oklahoma into western Arkansas

Concerning...Severe potential...Severe Thunderstorm Watch likely=20

Valid 251705Z - 251830Z

Probability of Watch Issuance...95 percent

SUMMARY...The severe threat is increasing across portions of eastern
OK into western AR. Severe hail and wind are the main threats, with
2+ inch diameter stones and 65+ kt gusts possible. A Severe
Thunderstorm Watch issuance will be needed.

DISCUSSION...Clear skies have allowed for mixing and destabilization
of the boundary layer ahead of the surface cold front across eastern
portions of OK into west-northwest AR. Visible satellite indicates
increasing cumulus ahead of the surface cold front, with
mesoanalysis showing convective inhibition gradually eroding across
eastern OK/western AR. Convective initiation may occur sooner than
what the more recent CAM guidance suggested. Surface temperatures
are warming into the 90s F, that combined with mid 70s F dewpoints
overspread by 7.5+ C/km mid-level lapse rates, is contributing to
over 4000 J/kg of SBCAPE/MUCAPE. Furthermore, gradual veering winds
in the surface-700 mb layer, and unidirectional speed shear above
700 mb, are supporting modestly curved but elongated hodographs over
the warm sector, with effective bulk shear exceeding 40 kts in some
locales.=20

The current thinking is that rapid, intense multicellular or
transient supercellular development is likely in the next few hours,
with large hail (some 2+ inches) the main concern initially. After a
couple of hours, rapid upscale growth via merging cold pools should
support the development of an intense MCS/possible southeastward
propagating bow echo. While severe hail cannot be ruled out with
this mode of convection, severe winds should become the dominant
concern, with 65+ kt gusts possible. A Severe Thunderstorm Watch
will be needed within the next 1-2 hours to address the impending
severe threat.

..Squitieri/Grams.. 06/25/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7_e2GlALuSRJwF63VFCFPUTFNJt5IAgdYuP77l9N9XvpyvaVg6OkDlmgml47ukVOg0Fbyoyww= 4pd_nnLb7IMFHHXnjA$ for graphic product...

ATTN...WFO...MEG...LZK...SHV...TSA...

LAT...LON 34259514 34559563 35039586 35489579 35969482 36189300
36249148 36129084 35899051 35389041 34869076 34429200
34199348 34259514=20


=3D =3D =3D
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