2AM Day 3 Convective Outlook for Saturday, October 25. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EAST AND SOUTHEAST TEXAS INTO WESTERN LOUISIANA
SUMMARY
Scattered to numerous storms with isolated severe potential are likely over parts of southern and eastern Texas and western Louisiana Saturday.
Southern/eastern TX to western LA
The upper trough over the Rio Grande Valley will continue eastward Saturday, overspreading East TX and LA before reaching the lower MS Valley by early Sunday. Embedded within the broader trough, a shortwave feature will move out of northern Mexico and across the northwest Gulf coast with an accompanying basal speed max. A weak surface low over OK will drag a cold front eastward over central TX while strong ascent from the upper trough and cold front will overspread a plume of rich low-level moisture but modest lapse rates from the Gulf Coast to OK.
Widespread shower and thunderstorm activity is expected early Saturday as one or more convective complexes from the previous day will likely be ongoing over eastern TX/OK. Significant uncertainty remains with respect to diurnal destabilization and the resulting severe threat across northeast TX, southern OK and northwestern LA. Continued southeasterly low-level flow and the arrival of stronger forcing from the approaching trough suggests multiple rounds of thunderstorms are likely through Saturday evening. Relatively stronger heating on the southwestern flank of this activity over southern and coastal TX could allow for more robust surface-based buoyancy to develop by early afternoon. With sufficient veering for organized storms amid the strong low-level warm advection regime, at least an isolated severe risk is likely.
The primary uncertainty this outlook cycle is the potential for a messy convective mode and sagging outflow to limit the surface-based warm sector over southeast TX. Relatively strong low and mid-level shear ahead of the upper trough could support supercells or bowing clusters with damaging gust and tornado potential. Will introduce 5% severe probabilities for now given the uncertainty from antecedent convection. However, enlarging low-level hodographs (ESRH 150-200 m2/s2) and the potential for stronger destabilization may necessitate higher outlook probabilities in subsequent updates.