Valid 301200Z – 311200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN AND CENTRAL PLAINS…HIGH PLAINS AND OHIO VALLEY…
…SUMMARY…
Scattered storms, some producing severe wind gusts, are possible
over southern Kansas into Oklahoma and the Texas Panhandle today.
Storms with marginally severe wind gusts will also be possible in
the Ohio Valley. Other storms capable of mainly hail are expected
near the Front Range.
…Southern and Central Plains…
West to northwest mid-level flow will be in place today across the
central U.S. as a shortwave trough moves southeastward into the
Ozarks. An MCS associated with marginally severe wind gusts should
be located in eastern Oklahoma and northwestern Arkansas at the
beginning of the period. At the surface, a cold front is forecast to
move southward into the central Oklahoma and the Texas Panhandle.
Along and south of the front, surface dewpoints in the upper 60s and
lower 70s F should result in a pocket of moderate instability by
afternoon. This combined with increasing low-level convergence along
the front will result in isolated to scattered thunderstorm
development. In spite of the instability in place, NAM forecast
soundings have 0-6 km shear values across Oklahoma and the Texas
Panhandle generally less than 25 kt. This should keep any severe
threat isolated. The stronger multicells may have potential for
marginally severe wind gusts and hail.
…Ohio Valley…
A shortwave trough will move across the mid Mississippi Valley
today. At the surface, a cold front will advance southward into the
Ohio Valley. Surface dewpoints in the upper 60s F will likely result
in a pocket of moderate instability along and just south of the
front by afternoon. Thunderstorms are forecast to initiate along the
front in southern Illinois and southern Indiana during the mid to
late afternoon as the shortwave trough approaches. This activity
should spread eastward into southern Ohio and northern Kentucky by
early evening. Steep low-level lapse rates combined with the
moderate instability may be enough for marginally severe wind gusts
with the stronger multicells.
…High Plains…
West northwest mid-level flow will be in place across the central
High Plains today. At the surface, upslope easterly flow will push
low-level moisture into the foothills. As surface temperatures warm,
destabilization will result in isolated thunderstorm development in
the higher terrain. This convection is forecast to move
southeastward into the eastern Plains of Colorado. Although moderate
deep-layer shear should be in place, instability should be weak
enough to keep any hail threat marginal.
..Broyles/Squitieri.. 08/30/2019
$$