SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CDT Thu Mar 14 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SATURDAY THROUGH SATURDAY NIGHT ACROSS SOUTH CENTRAL AND SOUTHEASTERN TEXAS... ...SUMMARY... Strong storms may impact portions of south central and southeastern Texas Saturday through Saturday night, accompanied by at least some risk for severe weather. ...Synopsis... In general, models indicate further amplification of the large-scale flow across North America through this period, including the evolution of a high within prominent building mid/upper ridging across the Pacific Northwest through much of the western Canadian Provinces. Downstream of this ridging, large-scale troughing is forecast to continue to evolve across much of eastern Canada and the northern tier of the eastern U.S., with one significant short wave perturbation digging into the Upper Midwest/Red River Valley vicinity, in the wake of another accelerating across and east of the lower Great Lakes. To the south-southeast of the developing high, it appears that a mid/upper low will begin to weaken while remaining quasi-stationary across the Southwest. However, at least one notable embedded perturbation may gradually pivot around the southwestern through southern periphery of the circulation center, across the international border area by 12Z Sunday. At the same time, a short wave trough emerging from the subtropical eastern Pacific may progress through cyclonic flow to the south, across the Mexican Plateau into the Rio Grande Valley by late Saturday night, preceded by more subtle impulses progressing into and through the crest of low amplitude subtropical ridging across the Gulf coast vicinity. In lower-levels, a weak surface front, reinforced by convective outflow, appears likely to stall and weaken across the northeastern and north central Gulf coast vicinity, southwestward into the lower Rio Grande Valley, while a more significant cold front surges from the north Great Plains/Upper Midwest and Great Lakes into and through the Ohio and middle Mississippi Valleys. ...Southern Texas... Model spread, concerning some of the short wave developments through this period, continues to contribute to at least some uncertainty concerning convective potential for Saturday through Saturday night. Inhibition associated with elevated mixed-layer air may also continue to be a factor, particularly where a lingering moist unstable boundary becomes unstable with daytime heating, across parts of the lower Rio Grande Valley and coastal plain. However, guidance is suggestive that destabilization and lift along the leading edge of the warmer elevated mixed-layer air may contribute to vigorous thunderstorm development by midday Saturday, as it retreats back northeastward across south central Texas through the upper Texas coastal plain. Although this may be mostly rooted above stable near-surface lapse rates, steep lapse rates farther aloft may support sizable CAPE in the mid to upper levels, and promote a risk for large hail in the presence of strong convective layer shear. In the wake of this early day convection, at least some model output is suggestive that a corridor of stronger daytime heating may overcome inhibition and allow for a period of boundary-layer based thunderstorm development late Saturday afternoon and evening, roughly from around College Station into areas south of San Antonio. This could include one or two supercells accompanied by some risk for a tornado, in addition to large hail, before weakening, though low-level hodographs are forecast to remain relatively modest to weak. Thereafter, forcing for ascent associated with the subtropical short wave perturbation crossing the Mexican Plateau into Rio Grande Valley may contribute to renewed vigorous convective development late Saturday night across south central Texas. This activity will probably be elevated, rooted within ascent associated with lower/mid-tropospheric warm advection, but the environment may remain conducive to a risk for severe hail. ..Kerr.. 03/15/2024
