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
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