SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0725 PM CDT Tue Oct 21 2025 Valid 220100Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low tonight. ...01z Update... Strong midlevel height falls are spreading across the Mid-Atlantic early this evening. Latest water-vapor imagery depicts a progressive trough advancing into the upper OH Valley and along with it seasonally cold 500mb temperatures. This has contributed to steep 0-3km lapse rates and weak buoyancy north of the jet. However, boundary layer cooling will negate this to a large degree over the next few hours and convection should gradually weaken. Latest lightning data supports this with decreasing flashes evident across eastern OH. Even so, models appear to have underestimated buoyancy a bit across western/northern VA as updrafts have penetrated levels necessary for lightning. 00z sounding from IAD exhibited around 70 J/kg MUCAPE if lifting a parcel near 2km AGL - just adequate for lightning discharge. Have extended thunder probabilities into this portion of the Mid-Atlantic to account for ongoing thunderstorms, which should spread into southern PA over the next few hours. ..Darrow.. 10/22/2025
