Jun 23, 2021 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Wed Jun 23 07:26:29 UTC 2021 (20210623 0730Z Day 3 shapefile | 20210623 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 329,155 36,091,886 Chicago, IL...Detroit, MI...Kansas City, MO...Omaha, NE...Colorado Springs, CO...
Probabilistic Graphic
20210623 0730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 329,137 36,091,571 Chicago, IL...Detroit, MI...Kansas City, MO...Omaha, NE...Colorado Springs, CO...
   SPC AC 230726

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0226 AM CDT Wed Jun 23 2021

   Valid 251200Z - 261200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHERN/CENTRAL PLAINS TO THE MIDWEST/GREAT LAKES...

   ...SUMMARY...
   Isolated strong to severe storms may occur Friday from portions of
   the southern/central Plains to the Midwest and southern Great Lakes.

   ...Southern/Central Plains to the Midwest...
   A positively tilted upper trough should advance slowly eastward
   across the northern/central Plains and Upper Midwest on Friday. A
   belt of modestly enhanced mid-level west-southwesterly flow should
   exist from parts of the southern/central High Plains to the
   Midwest/Great Lakes on the southern fringe of the upper trough. At
   the surface, a weak low may develop from parts of the Midwest to the
   southern Great Lakes by Friday evening, while a separate low remains
   over the central High Plains. A weak front should extend between
   these two surface lows across the central Plains and mid MS Valley.

   Any appreciable severe threat will mostly remain confined along and
   south of the weak front. There is considerable uncertainty in model
   guidance regarding the placement of this boundary Friday afternoon,
   as storms ongoing Friday morning may shunt the rich low-level
   moisture farther south along various outflow boundaries. Regardless,
   at least weak to locally moderate instability should develop south
   of the front where diurnal heating of the moist low-level airmass
   can occur. Mid-level winds are not forecast to be overly strong, but
   they should still be sufficient for some storm organization. A mix
   of multicell clusters and supercells appears possible, posing an
   isolated threat for both large hail and severe wind gusts.

   For now, a broad area of low severe probabilities has been included
   from parts of the southern/central High Plains to the Midwest and
   southern Great Lakes where there is some degree of confidence that
   surface-based storms may occur. Once confidence increases in the
   placement of storms that will likely be ongoing Friday morning, and
   when one or more corridors of greater destabilization can be
   ascertained, then greater severe probabilities will probably be
   needed.

   ..Gleason.. 06/23/2021

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z