SPC AC 141249

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0749 AM CDT Mon Apr 14 2025

   Valid 141300Z - 151200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   INTO EARLY TONIGHT FROM EASTERN KENTUCKY ACROSS WEST VIRGINIA INTO
   CENTRAL VIRGINIA...

   ...SUMMARY...
   Scattered strong to severe storms are expected this afternoon
   through early tonight from the Upper Ohio Valley eastward to the
   Mid-Atlantic. Large hail, severe wind gusts, and a couple of
   tornadoes will be possible.

   ...Upper OH Valley this afternoon into VA early tonight...
   An initial shortwave trough and surface cyclone will occlude by
   tonight between Lake Superior and James Bay, as an upstream
   shortwave trough digs southeastward from the northern Plains toward
   the OH Valley.  An associated surface cold front will move
   southeastward across the OH Valley today, while a corridor of
   moisture return occurs ahead of the front from the Mid-South to WV. 
   Surface heating in cloud breaks will drive temperatures into the 70s
   by early-mid afternoon, coincident with northeastward advection of
   55-60 F boundary-layer dewpoints beneath the northeastward extent of
   an elevated mixed layer.  Though the upstream moisture source is
   rather modest by mid April standards, recent green up and unusually
   moist ground across the OH Valley will augment evapotranspiration. 
   These processes will result in MLCAPE of 1000-1500 J/kg with minimal
   convective inhibition as low-level ascent focuses along the front.

   Thunderstorm development is expected by mid afternoon in a broken
   band along the cold front from northern KY into southern OH, and
   storms subsequently expand in coverage while spreading
   east-southeastward across WV into VA through early tonight.  The
   moderate buoyancy and long hodographs will support supercells
   capable of producing large hail of 1-2 inches in diameter, and
   damaging winds of 60-75 mph are also expected, especially with any
   upscale growth into bowing segments.  Low-level shear/hodograph
   curvature will be sufficient for some tornado threat, though this
   will be modulated by the degree of low-level moistening. 
   Clusters/line segments will persist east of the Appalachians into VA
   through early tonight, though the severe threat will diminish with
   eastward extent and after 03z. 

   ...SD to IA this afternoon/evening...
   Despite limited low-level moisture, surface heating beneath cooling
   midlevel temperatures will support weak surface-based buoyancy and
   the potential for low-topped thunderstorms from SD into IA (in
   advance of the digging shortwave trough now over western ND/eastern
   MT).  Relatively cold temperature profiles will favor some threat
   for small hail, while steep low-level lapse rates and 30+ kt flow
   through the mixed layer favor gusty outflow winds of 40-50 mph.

   ..Thompson/Dean.. 04/14/2025

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z