Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
620 ACUS02 KWNS 050509 SWODY2 SPC AC 050507 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1207 AM CDT Tue May 05 2026 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST TX TO THE LOWER MS AND TN VALLEYS... ...SUMMARY... Scattered strong to severe thunderstorms are expected Wednesday afternoon and evening across portions of Texas into the lower Mississippi and Tennessee Valleys/southern Appalachians. Damaging winds, large hail, and a couple of tornadoes will be possible. ...Synopsis... A positive-tilt large-scale upper trough will extend from the Upper Great Lakes to the Southwest early Wednesday. The southern extent of the trough will develop east toward the southern High Plains to northwest Mexico by Thursday morning. Strong mid/upper southwesterly flow ahead of the trough will overspread much of the southern and eastern U.S. At the surface, a cold front will extend from the upper Ohio Valley to central TX during the morning. The front is expected to develop south/southeast through the period, becoming oriented from the southern Mid-Atlantic to South TX by Thursday morning. Ahead of the front, rich Gulf moisture will be in place across TX into the Lower MS and TN Valleys, decreasing with northeast extent into parts of the southern Appalachians. ...Northern TN Valley and southern Appalachians... Forecast guidance varies, but some showers/thunderstorms may be ongoing Wednesday morning across parts of AR into northern parts of the TN Valley within a warm advection regime on the nose a gradually weakening low-level jet. This activity will likely play some role in destabilization later in the day across parts of the TN Valley into the southern Appalachians vicinity. Nevertheless, strong deep-layer shear and a moist boundary layer will be sufficient for at least some severe risk, including damaging wind gusts and perhaps hail. Some tornado risk could also materialize given favorable low-level shear and 0-1 km SRH increasing to greater than 250 m2/s2 during the afternoon/evening. However, this is less certain given aforementioned instability issues and later storm timing into the southern Appalachians. ...TX to MS/AL... Further south from northeast TX into MS/AL, strong destabilization is forecast where deep boundary layer moisture and stronger daytime heating occurs. MLCAPE in the 2000-3000 J/kg range appear possible in particular across northern LA into MS. Midlevel southwesterly flow is expected to increase by late afternoon into the evening as early capping will be overcome as the surface front begins to develop south/southeast. Convection along the cold front may quickly transition to linear/bowing segments given deep shear parallel to the surface boundary. However, low-level flow in latest model guidance does not appear to be overly veered, especially near northern LA into MS. Forecast hodographs indicate enlarged, favorably curved hodographs across this area. If open warm sector supercells develop, a risk for tornadoes (perhaps a couple strong tornadoes) will be possible. Furthermore, steepening midlevel lapse rates are evident in forecast soundings, along with elongated/straight hodographs and 45+ kt effective shear magnitudes. This indicates any semi-discrete supercells could pose a risk for large to very large hail. With time during the evening/nighttime hours, convection should generally congeal into a line or bowing MCS and spread eastward across the TN Valley toward the southern Appalachians, posing a risk for damaging gusts. Higher tornado and hail probabilities were considered across parts of the Lower MS Valley, however, given uncertainty in storm mode and coverage of discrete supercells, will hold at level 2 (Slight) risk for now. Across portions of central TX overnight, some guidance suggests convection may develop within low-level warm advection as the western extent of the surface cold front dives southward across the Edward Plateau vicinity. If storms develop, they would likely be elevated. Nevertheless, a hail risk could materialize within the conditional scenario late in the forecast period. ..Leitman.. 05/05/2026 $$