11PM Day 1 Convective Outlook for Wednesday, January 7. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS
SUMMARY
Marginally severe storms are possible from late tonight into the early morning on Thursday from parts of west and northwest Texas northeastward into Oklahoma.
West and Northwest Texas/Oklahoma
A mid-level trough will move quickly east-northeastward from the eastern Pacific this morning to the southern Plains tonight. Ahead of the system, a lee surface trough will develop across the High Plains, as winds become south to southeasterly over much of the southern Plains. In response, moisture advection will increase over the southern Plains, as a moist airmass spreads northwestward into parts of west-central and north-central Texas by midnight. Along the northwestern edge of this airmass, low-level convergence is forecast to increase after midnight, which will aid scattered thunderstorm development during the overnight period. Instability along a southwest-to-northeast corridor is forecast to remain weak, with MLCAPE peaking around 500 J/kg. In addition, a low-level capping inversion just the east of the instability axis will keep much of the convection elevated. In spite of these negative factors, effective shear will be in the 40 to 50 knot range, and 700-500 mb lapse rates are forecast to be between 7.5 and 8 C/km. This environment could support a marginal severe threat with cells that rotate. Hail and isolated severe wind gusts will be possible, mainly in the 08Z to 12Z timeframe.