SPC AC 290602

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0102 AM CDT Tue Apr 29 2025

   Valid 291200Z - 301200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
   WEST TX INTO SOUTHWEST OK...AND FOR PARTS OF THE OHIO VALLEY AND
   LOWER GREAT LAKES...

   ...SUMMARY...
   Scattered severe thunderstorms are possible within a broad swath
   from the Lower Great Lakes to the southern High Plains, mainly
   during the afternoon to evening on Tuesday. Corridors of greater
   threat are expected over the Upper Ohio Valley/Lower Great Lakes and
   in parts of west Texas into southwest Oklahoma.

   ...Synopsis...
   A deep mid/upper-level shortwave trough will move eastward across
   the Great Lakes into southeast Canada today. A deepening surface low
   will move across Quebec during the day, as an attendant cold front
   moves across the Great Lakes, Ohio Valley, and Northeast. To the
   west, a mid/upper-level trough and embedded midlevel cyclone will
   move very slowly eastward across the Four Corners/Southwest. A weak
   surface low is expected to remain nearly stationary near the TX
   Trans-Pecos region. A cold front initially moving southward into the
   southern Plains will tend to slow down with time, with its position
   becoming modulated by repeated rounds of convection. 

   ...Ohio Valley into the Lower Great Lakes...
   Some uncertainty remains regarding the evolution of overnight
   convection into the start of the D1/Tuesday period. However, most
   guidance suggests that, despite weakening midlevel lapse rates,
   moderate buoyancy will develop along/ahead of the front from the
   Ohio Valley into parts of the Lower Great Lakes. Any ongoing morning
   convection may intensify as it moves east-northeastward, with
   additional development expected along/ahead of the front this
   afternoon. 

   Strong low/midlevel flow will support development of organized storm
   clusters, along with some potential for discrete or embedded
   supercells. Scattered damaging winds will be possible, with some
   potential for swaths of more concentrated wind damage if any
   organized clusters or linear segments develop. 35-50 kt in the
   850-700 mb layer will support sufficient low-level shear for some
   supercell and/or line-embedded tornado threat. Isolated hail could
   also accompany any persistent supercell structures. 

   ...West TX into the Ozarks...
   Multiple rounds of thunderstorms are expected across the southern
   Plains in the vicinity of the surface front, with widely scattered
   diurnal development also possible along the southward trailing
   dryline into the Permian Basin vicinity. Strong midlevel flow east
   of the Southwest trough will provide sufficient deep-layer shear for
   storm organization, within a moderate to strongly unstable
   environment near/south of the front. Occasional supercells will be
   possible, with a threat of large to very large hail, severe gusts,
   and a few tornadoes. One or more clusters are likely to develop and
   spread eastward, which could provide localized swaths of more
   concentrated strong/severe gusts. The favored corridor of any such
   clusters remains somewhat uncertain, with the front expected to
   gradually sag south with time.

   ..Dean/Weinman.. 04/29/2025

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