SPC AC 300552

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1252 AM CDT Wed Oct 30 2024

   Valid 301200Z - 311200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
   EASTERN KANSAS INTO FAR NORTHEASTERN OKLAHOMA AND NORTHWESTERN
   MISSOURI...

   ...SUMMARY...
   Strong/severe thunderstorms, capable of producing large hail,
   damaging wind gusts, and a few tornadoes, are expected today into
   early tonight, particularly from the middle Missouri Valley area
   into the southern Plains.

   ...Synopsis...
   A pronounced mid-level trough will traverse the Plains and become
   negatively tilted as it impinges on the Upper MS Valley today.
   Surface lee-troughing will remain in place across the Plains,
   resulting in the northward transport of an appreciably moist
   low-level airmass. A surface low will develop along the KS/OK border
   this afternoon and track toward the MS Valley this evening. A cold
   front will be draped across the MS Valley into KS while a dryline,
   extending from the low, is poised to sweep eastward across OK and
   northern TX through the day. Deep-layer ascent along and ahead of
   the cold front and dryline will support at least scattered
   thunderstorm initiation by late afternoon across the Plains. These
   storms will progress eastward amid a buoyant and highly sheared
   airmass. Severe storms are likely ahead of the cold front and
   dryline, with all hazards possible.

   ...Upper MS Valley into the southern Plains...
   Thunderstorms are expected to first initiate along the cold front
   over northern KS into western IA by mid to late afternoon as
   stronger upper-level support from the impinging mid-level trough
   overspreads the terminus of a 50+ kt southerly low-level jet. 7+
   C/km mid-level lapse rates, overspreading rich low-level moisture
   (including mid-60s F surface dewpoints), should yield at least 1500
   J/kg SBCAPE. Strong southwesterly 500 mb flow overspreading the
   low-level jet will contribute to 50+ kts of effective bulk shear,
   but with vectors aligned roughly parallel with the front. Initial
   semi-discrete storm modes, capable of mainly severe wind/hail, will
   quickly merge to form a QLCS with embedded bowing segments and
   perhaps a few mesovortices. This initial band of storms should
   approach the MS Valley region by sunset, accompanied by mainly
   damaging gusts and perhaps an isolated tornado threat.

   Farther south into central KS/northern OK, more discrete
   thunderstorm development is expected by early evening. Surface
   temperatures in the upper 70s F, combined with mid to perhaps upper
   60s F dewpoints, will contribute to 1500-2000 J/kg MLCAPE just
   before sunset. Storms that can mature in this environment may
   benefit from over 50 kts of effective bulk shear, as well as an
   increase in low-level shear upon approaching the western periphery
   of the low-level jet. Forecast soundings depict overall curved
   low-level hodographs with mid-level elongation and 250-350 m2/s2
   effective SRH. As such, supercells should be the initial storm mode
   before storm mergers result in squall line development. While many
   forecast soundings depict a weakness in the 800-600 mb layer, the
   overall strength of the low-level shear suggests at least a few
   tornadoes are possible, and a strong tornado or two may occur,
   mainly after dark. The severe threat may transition to more of a
   damaging gust threat after the squall line forms, though
   line-embedded QLCS tornadoes remain possible.

   ..Squitieri/Lyons.. 10/30/2024

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