11AM Day 2 Convective Outlook for Thursday, January 8. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS INTO THE LOWER/MID MS VALLEY
SUMMARY
Isolated severe storms are possible on Thursday from Oklahoma into parts of the Lower/Mid Mississippi Valley.
Southern Plains into the Lower/Mid MS Valley
Within a belt of broad/enhanced midlevel southwesterly flow, a negative-tilt shortwave trough and accompanying surface low will track northeastward from the southern Plains to the Great Lakes through the period.
Strongly forced thunderstorms will be ongoing/spreading east-northeastward across OK at the start of the period. While poor midlevel lapse rates and only partially modified Gulf moisture will limit buoyancy for these storms, 50-60 kt of effective shear will support a few organized clusters/line segments and perhaps transient supercell structures. Isolated large hail will be the primary concern, though locally damaging gusts and a brief tornado will be possible with any surface-based storms that can evolve.
This activity will spread/develop northeastward into the Ozarks and eventually the Lower OH Valley vicinity through the afternoon/evening, in tandem with the midlevel trough and surface low. Here, boundary-layer moisture and related buoyancy will become more limited with northward extent, though strengthening deep-layer flow/shear (to include a 50-kt low-level jet) will continue to support a risk of severe storms capable of damaging winds and possibly a brief tornado. Multiple rounds of storms will be possible through this corridor into the overnight hours ahead of an approaching front. Farther southeast, recent high-resolution guidance depicts a band of storms developing within broad/moist confluent low-level flow over the Lower MS Valley late in the period. While these storms will be on the eastern edge of the warm sector, strong low/deep-layer shear will yield a conditional severe risk.
Arizona
Thunderstorm potential is expected to increase through the day across parts of AZ, as a midlevel shortwave trough moves east-southeastward across the region. Gusty winds and/or small hail could occur with the strongest convection, though buoyancy is currently expected to remain too meager for an organized severe threat.