SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1013 AM CST Thu Dec 26 2024 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR SOUTHEAST TX... ...SUMMARY... Several tornadoes, including a strong (potentially EF2+) tornado or two, will be possible this afternoon/evening across southeast Texas. Damaging gusts of 60-70 mph and large hail of 1-1.75" in diameter will also be possible from east Texas this afternoon into Louisiana, southern Arkansas and far west central Mississippi overnight. ...East TX/LA/southern AR through tonight... Elevated convection has already formed over north central TX this morning in a band of ascent preceding a midlevel shortwave trough moving eastward. New thunderstorm development is expected through the afternoon farther to the south and east across east/southeast TX, as the warm sector spreads northward in advance of a weak surface cyclone. Boundary-layer dewpoints in the mid-upper 60s beneath midlevel lapse rates near 8 C/km will drive MLCAPE ranging from 500 J/kg a little south of I-20 to 1500-2000 J/kg across southeast TX by late afternoon, where surface-based storms are likely with small breaks in the stratus. Vertical shear profiles will be characterized by sufficiently long hodographs (effective bulk shear in excess of 45 kt) and low-level hodograph curvature (effective SRH in excess of 200 m2/s2) for supercells. The initial storms will be more cellular across southeast TX with a gradual transition to a mixed mode/band of storms this evening into tonight as the storms spread eastward/northeastward across LA/southern AR. The surface-based supercells in southeast TX will be capable of producing tornadoes from early afternoon into late evening (including a strong/EF2+ tornado or two), along with isolated large hail (1-1.75 inches in diameter). With the gradual change in storms to a more linear mode, the potential for wind damage (and embedded tornadoes) will persist into tonight. ..Thompson/Moore.. 12/26/2024