Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1147 AM CDT Wed Mar 29 2017
Valid 291630Z - 301200Z
THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS/LOWER MO VALLEY SOUTHWARD TO LA/LOWER MS RIVER VALLEY...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS/LOWER MO VALLEY SOUTHWARD TO LA/LOWER MS RIVER VALLEY...
THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TX/SOUTH-CENTRAL PLAINS TO MS RIVER VALLEY...
SUMMARY... Severe thunderstorms are expected later today into tonight from parts of east Texas, eastern Oklahoma, and southeast Kansas into the lower and middle Mississippi Valley. Large hail, tornadoes, and damaging winds will be possible especially late this afternoon and tonight.
Ozarks/lower MO Valley to ArkLaTex/lower MS River Valley... The closed upper trough currently over the south-central Plains at late morning will continue a slow-general-northeastward advance toward the lower MO River Valley through late tonight and early Thursday. Ahead of this system, 12Z regional observed soundings reflected considerable lapse-rate-related impacts from the overnight/early morning squall line that continues to move generally east-northeastward and decay across the Ozarks and Ark-La-Tex vicinity. This may have ramifications on the extensiveness/likelihood of significant hail potential, for instance, although the air mass will recover/gradually moisten and destabilize to the south of a northward-moving warm front across the Ozarks/lower MO Valley, and ahead (east) of a slow-eastward-moving cold front.
Latest thinking is that surface-based storms will develop as early as mid-afternoon near the eastern KS surface low southward along the front, including far eastern portions of KS/OK into western portions of MO/AR. Moderate low-level hodograph curvature (beneath strong but somewhat backed mid-level southwesterly winds) and resultant strong low-level shear/SRH will support a tornado risk aside from large hail and evolving damaging wind risk into this evening.
Farther south, storms may diurnally be a bit more isolated across the remainder of the ArkLaTex vicinity, although an ongoing quasi-linear cluster across near-coastal southeast TX may persist east-northeastward into LA as it favors a zone of outflow-related weak boundary/zone of differential heating. This cluster and other peripheral development may pose a damaging wind/tornado risk through the afternoon and evening hours.
Later tonight, storms should increase in coverage/intensity initially across portions of AR/LA as forcing for ascent/DPVA increases related to an east/northeastward-ejecting vorticity maxima within the base of the larger-scale trough. Related mass response should result in increasingly strong low-level winds/confluence. A mixed mode of storms should be prevalent, with hail initially possible prior to a more common damaging wind/embedded tornado risk as storms toward/across the MS River late tonight.