SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Thu Oct 23 2025 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN GREAT PLAINS... ...SUMMARY... Isolated severe storms are expected this afternoon into the overnight hours across the southern Great Plains. ...Southern Great Plains... Southern CA upper low is advancing east in line with latest model guidance. Early morning water-vapor imagery depicts a well-defined circulation approaching the lower CO River Valley. This feature is forecast to progress into the southern Rockies by 24/00z, and shift slowly east during the overnight hours. As the trough moves east, LLJ will begin to increase across the southern Great Plains, especially during the evening when speeds should exceed 40kt across west TX into the TX Panhandle. While lee cyclogenesis is not expected to be particularly focused/intense, low-level warm advection will focus across the southern Plains and an extended convective event is expected, especially during the latter half of the period extending into the day2 period. Low-level trajectories are becoming a bit more favorable for Gulf moisture to advance across south TX into the High Plains. 70s dew points are currently noted across deep South TX while 60F dew points are noted as far north as Kimble Count. PW values will increase markedly over the next 24-36hr across TX into OK and this will contribute to destabilization ahead of the approaching trough. Models suggest a southwest-northeast oriented boundary will extend from the TX South Plains into southwest OK by mid afternoon. Strongest boundary-layer heating will be just south of this wind shift and modest 0-3km lapse rates should aid buoyancy by peak heating as temperatures warm into the low-mid 80s. This boundary will prove instrumental in convective development as midlevel flow begins to increase ahead of the trough. Forecast soundings suggest supercells are possible and hail is likely the primary concern. However, as moisture increases near the boundary conditions may become a bit more favorable for a tornado or two. Severe risk will likely linger well into the overnight hours as the primary corridor of deep convection will not move appreciably across the southern Plains. Upstream, isolated robust convection should develop within cool/steep lapse rate environment across the southern Rockies. This activity should be diurnally driven and some risk for marginally severe hail/wind is possible. ..Darrow/Thornton.. 10/23/2025
