SPC AC 180100

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0800 PM CDT Wed Apr 17 2024

   Valid 180100Z - 181200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE UPPER OHIO VALLEY AND FROM NORTHEAST KANSAS INTO WESTERN
   MISSOURI...

   ...SUMMARY...
   Thunderstorms capable of large hail and wind damage will be possible
   over the next couple of hours in the upper Ohio Valley.  Marginally
   severe storms will be possible this evening in parts of the central
   Appalachians and Rio Grande Valley. Very large hail may occur late
   this evening into the overnight period across parts of the central
   Plains and Ozarks.

   ...Upper Ohio Valley/Central Appalachians...
   A line of strong to severe storms, arching from western Pennsylvania
   into southern Ohio, will continue to move eastward this evening into
   the higher terrain of the central Appalachians. The storms are
   located along an axis of instability, where the RAP has MLCAPE in
   the 500 to 1000 J/kg range. In addition to the instability, a
   vorticity max over eastern Ohio is supporting convective development
   along the line. The HRRR suggests that the line will continue to
   hold together for a few more hours as it moves into the central
   Appalachians. RAP forecast soundings ahead of the line from
   southeast of Pittsburgh, PA to Charleston, WV have 0-6 km shear near
   40 knots, with 0-3 km lapse rates near 7.5 C/km. This environment
   should continue to support a wind-damage threat with the stronger
   cells embedded in the line. Isolated large hail could also accompany
   the stronger cells that rotate. The severe threat should become
   increasingly marginal as the evening progresses.

   ...Central Plains/Ozarks...
   An upper-level trough, and an associated 60 to 80 knot mid-level
   jet, will move through the central and northern Plains tonight. In
   response, a 40 to 50 knot low-level jet will strengthen across
   Kansas this evening. Elevated thunderstorms are expected to develop
   along the northern edge of the low-level jet this evening in
   southern Nebraska. Additional storms are expected to initiate in
   southeast Kansas. This activity will spread northeastward into
   northeast Kansas by late evening, where a warm front will be in
   place from west-northwest to east-southeast. RAP forecast soundings
   near and just south of the front by 06Z have MUCAPE near 2000 J/kg,
   with effective shear near 40 knots. Also, 700-500 mb lapse rates are
   forecast to be near 7.5 C/km. This will be favorable environment for
   supercells with large hail. The strongest of storms could produce
   hailstones greater than 2 inches in diameter. The storms are
   expected to move into northwest Missouri and far southeast Nebraska
   around or just after midnight.

   ...Rio Grande Valley...
   At the surface, a trough is located across west-central Texas
   extending southward into the Rio Grande Valley. Near the surface
   trough, widely scattered thunderstorms have developed along and near
   an axis of moderate instability. The RAP has MLCAPE along the
   instability axis in the 1500 to 2500 J/kg range. In addition, the
   RAP has 700-500 mb lapse rates near 7.5 C/km range, with 0-6 km
   shear generally in the 50 to 60 knot range. This will continue to
   support isolated supercell development for a few more hours this
   evening. Isolated large hail and marginally severe wind gusts will
   be the primary threats.

   ..Broyles.. 04/18/2024

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