Wednesday Severe Threat Incoming

The fall season is here! It’s time for a legitimate severe weather threat on Wednesday across the Southern Plains with a couple of tornadoes being possible thanks to strong shear.

Here’s how it comes together: an upper-level low and a 50-70 kt mid-level jet move from the southern Rockies into the southern High Plains. A surface low tracks into western Kansas, and a dryline sharpens from the far eastern TX Panhandle into West Texas. East of that dryline, upper 60s to low 70s dewpoints feed a pocket of moderate instability from West Texas into southwest Oklahoma by afternoon.

• Storm mode: Storms may start out discrete in the mid-to-late afternoon, then organize into a line moving east through the evening.
• Hail and wind: The latest ECMWF puts MLCAPE at 1,000-2,000 J/kg from east of Lubbock to near Lawton. With about 40 kt of 0-6 km shear, that supports supercells with wind damage and hail. Models still disagree on exactly where the instability axis sets up.
• Tornadoes: Low-level helicity climbs into the 200-250 m²/s² range in the early evening, supporting a tornado threat with rotating storms embedded in the line.
• Central Plains: Kansas has poor low-level lapse rates but about 1,000 J/kg MLCAPE and 50 kt of shear, enough for isolated severe wind and hail.

The threat holds into mid-to-late evening across central Oklahoma and central to southwest Texas.