SUMMARY…Locally strong wind gusts and a brief tornado or two will be possible during the overnight to early morning hours across northeast Arkansas, far northern Mississippi, and into western Tennessee. Uncertainty in coverage of these severe-weather threats may preclude watch issuance, though convective trends will be monitored, with potential for spatial watch extension of WW 419.
DISCUSSION…Early overnight surface analyses showed an area of low pressure located over central AR which is expected to undergo further deepening, in response to strong height falls with the approaching upper trough. This surface low should reach northwest TN, near the KY border, by 12Z. Instability is much less with northward extent across the discussion area compared to locations farther south, though objective analyses indicated parcels are likely surface based, given minimal inhibition. Given the strength of deep-layer forcing for ascent spreading across this region, and further strengthening of wind fields/shear parameters, transient storm organization will be possible, even with scant buoyancy. Memphis VAD continues to show very large low-level hodograph curvature with 0-1-km SRH exceeding 500 m2/s2. The southerly low-level winds will maintain warm sector moisture/weak instability into much of western TN overnight. Thus, given the low CAPE/high shear environment, consideration for spatial extension of WW 419 is possible.
