Aug 31, 2020 0100 UTC Day 1 Convective Outlook
Updated: Mon Aug 31 01:01:26 UTC 2020 (20200831 0100Z Day 1 shapefile | 20200831 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200831 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 79,837 1,539,753 Sioux Falls, SD...Wichita Falls, TX...Lawton, OK...Grand Island, NE...Kearney, NE...
MARGINAL 218,245 10,590,989 Memphis, TN...Oklahoma City, OK...Omaha, NE...Lincoln, NE...Little Rock, AR...
Probabilistic Tornado Graphic
20200831 0100 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 48,840 787,341 Sioux Falls, SD...Kearney, NE...Norfolk, NE...Aberdeen, SD...Watertown, SD...
Probabilistic Damaging Wind Graphic
20200831 0100 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 67,556 1,463,764 Sioux Falls, SD...Wichita Falls, TX...Lawton, OK...Grand Island, NE...Kearney, NE...
5 % 231,500 10,663,562 Memphis, TN...Oklahoma City, OK...Omaha, NE...Lincoln, NE...Little Rock, AR...
Probabilistic Large Hail Graphic
20200831 0100 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 17,846 262,631 Grand Island, NE...Kearney, NE...Hastings, NE...Lexington, NE...
15 % 69,539 1,178,432 Sioux Falls, SD...Grand Island, NE...Kearney, NE...Norfolk, NE...Aberdeen, SD...
5 % 192,291 8,234,653 Oklahoma City, OK...Lincoln, NE...Little Rock, AR...Amarillo, TX...Topeka, KS...
   SPC AC 310101

   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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