SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1030 AM CST Fri Nov 07 2025 Valid 071630Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MIDDLE TENNESSEE AND SOUTH-CENTRAL KENTUCKY... ...SUMMARY... Scattered severe thunderstorms are possible later this afternoon through the evening across parts of the Ohio and Tennessee Valleys. A few marginally severe storms could also develop in the central Gulf Coast states late this afternoon into the overnight period. ...Synopsis... Water-vapor imagery late this morning shows a mid-level shortwave trough over eastern NE/KS moving into southwest IA/MO. This upper feature will move into the OH Valley by mid evening and the central Appalachians by 08/12 UTC. Surface analysis indicates a cold front over the middle MS Valley. The front will sweep east-southeast across the OH/TN Valleys before reaching the Mid-Atlantic states and northern portions of the central Gulf Coast states by early morning Saturday. ...TN Valley into the southern Appalachians... South-southwesterly low-level flow will act to gradually advect richer moisture poleward within the warm conveyor and feature surface dewpoints rising into the 56-58 deg F range across KY and near 60 deg F across Middle TN by late afternoon. Perhaps equally consequential will be mid-level cold-air advection with 500-mb temperatures forecast to significantly cool (e.g., -12 deg C at 12 UTC per the Nashville, TN 12 UTC raob to -16 to -17 deg C by 00 UTC). As a result, weak destabilization is forecast with MLCAPE ranging from 200-500 J/kg over KY to 500-1000 J/kg across the TN Valley. Model guidance continues to show scattered cellular storms developing late this afternoon initially over the KY/TN border vicinity, with storms developing farther south near the AL/TN border during the evening. Forecast hodographs will support organized storms with the stronger updrafts, including the possibility for a few supercells. A tornado risk, in addition to the threat for damaging gusts and perhaps marginally severe hail may accompany the stronger storms. A mix of linear storm modes and supercells are expected through the early to mid evening as this activity moves east. Storms and the severe risk will probably lessen over the southern Appalachians before diminishing overnight. ...Central Gulf Coast... Greater low-level moisture is anticipated farther south across this region. However, overall forcing for ascent, both synoptically and along the front, will be weaker and mid-level temperature considerably warmer. The primary forcing across this region will likely be warm-air advection, which leads to greater uncertainty regarding convective initiation, particularly given the cloud cover expected. If an updraft is able to mature and persist, there will likely be enough low-level helicity to support a limited tornado risk. ..Smith/Leitman.. 11/07/2025
