SPC AC 090555

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1255 AM CDT Tue Apr 09 2019

   Valid 101200Z - 111200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN
   KANSAS INTO SOUTHEASTERN NEBRASKA...

   ...SUMMARY...
   A few strong to severe storms with large hail and damaging wind will
   be possible Wednesday afternoon and evening from northern Kansas
   through southeast Nebraska and into western Iowa.

   ...Synopsis...
   Severe thunderstorm potential will likely be tied to a powerful,
   rapidly amplifying mid-level trough that will migrate from the
   central Rockies eastward to the central Plains through 12Z Thursday.
   A strong mid/upper jet will round the base of this trough and extend
   from southern New Mexico northeastward into southern Iowa.  At the
   surface, a rapidly deepening low over western Kansas will move
   eastward into central Kansas during the day before occluding and
   migrating toward southeastern Nebraska late in the period.

   ...Northern Kansas, southeastern Nebraska, and western Iowa...
   A stout elevated mixed layer will overspread much of the area
   beginning early in the period, with 8-9.5 deg C/km mid-level lapse
   rates persisting through much of the day.  A stout low-level jet
   axis will extend from northeastern Oklahoma into southern Iowa
   during the early morning.  Convergence on the nose of this jet and
   steep lapse rates suggest potential for elevated, hail-producing
   convection early across eastern Nebraska and western Iowa.  This
   risk should remain isolated and shift eastward toward the
   Mississippi River through midday.

   Later in the afternoon, forcing for ascent with the approach of the
   mid-level wave, lift within the left exit region of the
   strengthening mid-level jet, and steep lapse rates aloft will likely
   initiate storms over northwestern/north-central Kansas and vicinity.
   These storms may be slightly elevated atop a cold front initially,
   but will spread east-northeastward along the Kansas/Nebraska border
   area through the evening and overnight, eventually reaching western
   Iowa early Thursday. 

   The primary uncertainty for this forecast period will be the
   development of any surface-based convection south of the cold front
   and along/near the trailing dryline, which should extend southward
   from the surface low along the US281/81 corridor during peak heating
   hours.  Hail will be the dominant threat with any elevated
   convection, but storms that can manage to become surface-based will
   have a threat of significant hail, damaging wind gusts, and perhaps
   a tornado despite high bases and relatively low boundary-layer
   moisture content.  The spatio-temporal extent of the surface-based
   convective threat should be relatively focused and reside south of
   the KS/NE border toward the I-70 corridor from around 22-02Z. 
   Thereafter, nocturnal boundary-layer decoupling should result in
   mostly elevated hail potential through the overnight hours as storms
   spread toward western Iowa and vicinity.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:     15%     - Slight
   Hail:     15%     - Slight

   ..Cook.. 04/09/2019

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z