Mar 26, 2020 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Thu Mar 26 20:53:33 UTC 2020 (20200326 0730Z Day 3 shapefile | 20200326 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200326 0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 93,575 13,217,796 Indianapolis, IN...St. Louis, MO...Aurora, IL...Naperville, IL...Joliet, IL...
MARGINAL 295,247 42,305,916 Chicago, IL...Columbus, OH...Memphis, TN...Milwaukee, WI...Nashville, TN...
Probabilistic Graphic
20200326 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
15 % 93,114 13,039,988 Indianapolis, IN...St. Louis, MO...Aurora, IL...Naperville, IL...Joliet, IL...
5 % 295,836 42,624,964 Chicago, IL...Columbus, OH...Memphis, TN...Milwaukee, WI...Nashville, TN...
   SPC AC 262053

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0353 PM CDT Thu Mar 26 2020

   Valid 281200Z - 291200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MUCH OF
   IL/IN...AS WELL AS THE ARK-LA-MISS...

   ...SUMMARY...
   Scattered severe storms will be possible, mainly Saturday afternoon
   and evening, across much of the Mississippi and Ohio Valley regions.
   A few tornadoes, damaging winds, and large hail will all be
   possible.

   ...MS/OH Valley area...
   A deepening synoptic cyclone will move from northeast KS Saturday
   morning to WI by Saturday night, in advance of an
   ejecting/positive-tilt midlevel trough.  An elevated mixed layer in
   prior days should limit thunderstorm coverage in the warm sector,
   and allow low-level moisture to spread northward into IL and the OH
   Valley, beneath the remaining steep lapse rate plume through the day
   Saturday.  Elevated convection will be possible through the day into
   the northern half of the OH Valley in a warm advection regime, and
   also across IA/WI in the zone of strong ascent preceding the surface
   cyclone and midlevel trough.  Large hail will be the primary threat
   with the elevated storms.

   During the day, surface destabilization in advance of the cold front
   will contribute to an environment favorable for thunderstorm
   development along the front by early afternoon, roughly near the MS
   River.  Potentially moderate bouyancy (MLCAPE close to 1000 J/kg)
   and effective bulk shear in excess of 70 kt will favor supercells,
   with broken bands of cells expected given fast storm motions that
   will likely exceed the motion of the cold front.  Low-level shear
   and hodgraph curvature will be largest across the northern part of
   the warm sector, where a few tornadoes will be possible, in addition
   to damaging winds/large hail.  The frontal convection will spread
   eastward through the evening/overnight into the OH Valley, with some
   potential for isolated severe wind/hail and perhaps tornadoes.  

   There is some potential for increases in severe probabilities and
   some expansion of the northern Slight Risk area in later updates. 
   Areas of TN/KY will also be monitored for any increase in severe
   threat with convection developing northeastward overnight from the
   Mid South.  The southern Slight Risk area remains unchanged in this
   update, though there is uncertainty regarding the magnitude of the
   severe threat this far south.

   ..Thompson.. 03/26/2020

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