Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Thu Apr 23 2026 Valid 231300Z - 241200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATER THIS AFTERNOON/EVENING FOR EASTERN KANSAS INTO EXTREME NORTHERN OKLAHOMA... ...SUMMARY... Severe thunderstorms are expected to develop this afternoon and evening from the southern and central Plains into the lower to mid Missouri Valley, and upper Mississippi Valley. Tornadoes, large hail and severe wind gusts will be possible. ...MN/IA to KS/northern OK this afternoon into tonight... The interaction of a southeastward moving midlevel trough over southern BC/AB and a northeastward moving trough over the western Dakotas will lead to the formation of a deep closed low over southern SK. An associated, occluding surface cyclone will weaken across southern MB by this evening, as a trailing cold front moves across MN/IA/KS/MO and northern OK. Low-level moisture will spread northward across IA/MN in advance of the cold front, beneath the northeast edge of an elevated mixed layer. Surface heating and the degree of buoyancy may be limited by extensive clouds from IA into MN, and forecast wind profiles show complex/messy hodographs structures (stronger low-level shear lingering across IA). Mixed convective modes are expected along and ahead of the front this afternoon, which could produce occasional wind damage, large hail and perhaps a couple of tornadoes. The more substantial severe threat is expected late this afternoon through late evening from eastern KS into far northern OK, near and just northeast of a cold front/dryline triple point and weak secondary cyclone. A midlevel speed max near the Four Corners will progress eastward to the TX Panhandle by this evening, with ascent in the left exit region of the jet coincident with the triple point near or just north of the KS/OK border. An influx of mid 60s boundary-layer dewpoints beneath steep midlevel lapse rates will contribute to MLCAPE of 2000-3000 J/kg, with weakening convective inhibition across KS by mid afternoon. Storm development is expected along the cold front in KS by mid afternoon, with storms expected to develop southward to near the triple point. The large buoyancy, steep midlevel lapse rates and deep-layer shear sufficient for supercells will favor very large hail (2-3 inches in diameter) with the initial/more discrete storms. The tornado threat will peak this evening as low-level shear/hodograph curvature increase near the KS/OK border - there will be strong tornado potential with the anchor/southern supercells near the triple point. Upscale storm growth and cold pool development will favor a more linear convective mode with occasional wind damage as the outflow/effective cold front spreads southeastward into northeast OK and southwest MO overnight. ...OK dryline this evening... Storm development along the dryline in OK is uncertain late this afternoon/evening. Forecast soundings suggest that the degree of surface heating/mixing along the dryline and residence time in the dryline circulation will be close to supporting deep convection. If storms do form, the environment will conditionally favor very large hail initially, and the possibility of an evening tornado threat with any sustained storm. ..Thompson/Bentley.. 04/23/2026Read more