SPC Aug 31, 2020 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0801 PM CDT Sun Aug 30 2020

Valid 310100Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
THE CENTRAL AND NORTHERN PLAINS AS WELL AS A PORTION OF THE SOUTHERN
PLAINS...

...SUMMARY...
Severe thunderstorms capable of very large hail, damaging winds, and
a tornado or two remain possible from South Dakota into central
Nebraska for the next few hours. Other strong to severe storms are
possible over portions of Texas Panhandle tonight, spreading east/
southeast into southern Oklahoma this evening.

...01Z Update...

...Northern/Central Plains...
Severe thunderstorms are expected to continue along the cold front
from far southeast ND through central/eastern NE for at least the
next several hours. Steep mid-level lapse rates will continue to
support strong buoyancy, even as low-level stabilize with nocturnal
cooling. Vertical shear is sufficient for organized storm structures
and the potential for large hail and damaging wind gusts. Isolated
significant hail remains possible. Moderate southeasterly surface
winds are also contributing to veering low-level wind profiles
supportive of tornadogenesis. Recent KFSD VAD sampled over 130 m2/s2
of 0-1 km storm-relative helicity. In contrast, linear forcing and
predominantly outflow-dominant storm mode are not supportive of
tornadogenesis. Given all of these factors, a low probability risk
of a tornado or two exists. 

...Southern Plains...
Shortwave trough ejecting out of the southern High Plains is
expected to continue eastward tonight, potentially providing the
impetus needed for thunderstorm development from the TX Panhandle
across OK into AR. However, cloud cover has persisted across the
southern TX Panhandle, limiting destabilization across that area.
00Z AMA sounding sampled a well-mixed air mass, but the sounding
also sample a deep layer of warm and dry air in the mid-levels. Even
with the ascent from approaching shortwave trough, convective
initiation may be impeded by the warm and dry layer. Even so, the
conditional severe risk remains so will maintain 15% probabilities
introduced in the previous outlook.

Moderate to strong instability exists farther east across OK. The
expectation is for thunderstorms to develop ahead of the potential
cluster coming out of the TX Panhandle and/or as a result of
increased warm-air advection. Isolated hail and damaging wind gusts
could occur with the strongest storms.

..Mosier.. 08/31/2020

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from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_0100.html