Oct 23, 2020 0600 UTC Day 1 Convective Outlook
Updated: Fri Oct 23 05:29:42 UTC 2020 (20201023 1200Z Day 1 shapefile | 20201023 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20201023 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 26,759 7,850,689 Detroit, MI...Toledo, OH...Fort Wayne, IN...Warren, MI...Sterling Heights, MI...
MARGINAL 141,267 23,142,253 Indianapolis, IN...Columbus, OH...Memphis, TN...Nashville, TN...Cleveland, OH...
Probabilistic Tornado Graphic
20201023 1200 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
5 % 12,739 6,313,863 Detroit, MI...Fort Wayne, IN...Warren, MI...Sterling Heights, MI...Flint, MI...
2 % 19,803 2,396,958 Toledo, OH...Lansing, MI...Muncie, IN...East Lansing, MI...Kokomo, IN...
Probabilistic Damaging Wind Graphic
20201023 1200 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 % 27,106 7,886,147 Detroit, MI...Toledo, OH...Fort Wayne, IN...Warren, MI...Sterling Heights, MI...
5 % 141,378 23,157,371 Indianapolis, IN...Columbus, OH...Memphis, TN...Nashville, TN...Cleveland, OH...
Probabilistic Large Hail Graphic
20201023 1200 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
15 % 27,144 7,880,229 Detroit, MI...Toledo, OH...Fort Wayne, IN...Warren, MI...Sterling Heights, MI...
5 % 112,635 15,843,325 Indianapolis, IN...Memphis, TN...Cincinnati, OH...Louisville, KY...Dayton, OH...
   SPC AC 230529

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 AM CDT Fri Oct 23 2020

   Valid 231200Z - 241200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
   THE LOWER GREAT LAKES INTO THE OHIO VALLEY...

   ...SUMMARY...
   Threat for a few severe storms capable of damaging wind, hail and
   perhaps a tornado or two will exist this afternoon into the early
   evening over a portion of the lower Great Lakes and Ohio Valley.

   ...Lower Great Lakes and Ohio Valley region...

   A mid-upper speed max situated within the base of a synoptic trough
   will move through the Great Lakes today. Accompanying weak surface
   low will develop northeastward through the Great Lakes this morning
   with a moist warm sector (low to mid 60s F dewpoints) advecting into
   the southern portion of lower MI. Cold front trailing from the low
   will reach Lake Erie southwestward into the lower MS Valley by early
   evening. Diabatic warming of the surface layer and modest mid level
   lapse rates will promote moderate instability in pre-frontal warm
   sector with 1500-2000 J/kg MLCAPE possible. Vertical shear will
   strengthen as the upper jet advances through the Great Lakes with
   40-45 kt effective bulk shear along with 200-300 m2/s2 0-1 km storm
   relative helicity, especially from northern IN into southern lower
   MI. Elevated storms should be ongoing in post-frontal region during
   the morning. However, surface-based storms are expected to develop
   along the cold front from southern lower MI into IN as it encounters
   an increasingly unstable boundary layer this afternoon. Vertical
   wind profiles will be sufficient for organized structures,
   especially with storms that can be sustained for a while along the
   advancing cold front before potentially being undercut. Damaging
   wind and hail are the primary threats, but a tornado or two will
   also be possible.

   ..Dial/Cook.. 10/23/2020

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