Apr 9, 2019 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Tue Apr 9 07:19:43 UTC 2019 (20190409 0730Z Day 3 shapefile | 20190409 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190409 0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 29,470 3,032,115 Evansville, IN...Gary, IN...Hammond, IN...Champaign, IL...Lafayette, IN...
MARGINAL 45,790 13,083,812 Chicago, IL...Indianapolis, IN...Aurora, IL...Naperville, IL...Joliet, IL...
Probabilistic Graphic
20190409 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 % 29,499 2,987,279 Evansville, IN...Gary, IN...Hammond, IN...Champaign, IL...Lafayette, IN...
5 % 45,908 13,279,220 Chicago, IL...Indianapolis, IN...Aurora, IL...Naperville, IL...Joliet, IL...
   SPC AC 090719

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0219 AM CDT Tue Apr 09 2019

   Valid 111200Z - 121200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   ILLINOIS AND INDIANA...

   ...SUMMARY...
   Scattered thunderstorms capable of damaging wind gusts are possible
   in Illinois/Indiana and western Kentucky Thursday afternoon.

   ...Synopsis...
   A vigorous mid-level disturbance - initially centered over Nebraska
   at the start of the period - will maintain its intensity while
   lifting northward toward the western Great Lakes region Thursday. 
   On the southern and eastern periphery of this disturbance, a belt of
   very strong (80-100 kt) mid-level flow will shift eastward,
   overspreading portions of the Mississippi and Ohio River Valleys. 
   Meanwhile at the surface, a deeply occluded low will migrate from
   eastern Nebraska into southern Minnesota.  A low-level moist axis -
   characterized by 50s F dewpoints - will shift eastward just ahead of
   a cold front that should reach western Illinois, southeastern
   Missouri, and eastern Arkansas by the early evening.

   ...Portions of the Midwest southward to western Kentucky...
   The combination of strong forcing/ascent associated with the
   mid-level disturbance and cold front will likely result in evolution
   of a linear convective complex that should progress
   eastward/northeastward across the Marginal and Slight Risk areas
   Thursday afternoon.  Surface-based instability should be marginal
   owing to poor mid-level lapse rates, although very strong wind
   fields aloft (exceeding 90-100 kts above 650 mb across the region)
   will enhance convective downdraft potential and result in a risk of
   damaging wind gusts.  This threat should mainly be diurnally driven,
   with weakening buoyancy limiting the severe threat with eastward
   extent overnight.

   ..Cook.. 04/09/2019

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