There is some concern that an isolated severe weather threat may develop in Southeast Texas this afternoon. Isolated storms have shown an intensification trend over the last hour. The strongest storms may produce large hail, localized damaging winds, and potentially a tornado. Widespread severe weather is not expected until tonight in Arkansas and Louisiana. A localized threat could develop in East Texas and Southeast Texas through the evening hours.
Mesoscale Discussion 0368 NWS Storm Prediction Center Norman OK 0131 PM CDT Wed Mar 29 2017 Areas affected...Southeast Texas into western Louisiana Concerning...Severe potential...Watch possible Valid 291831Z - 292100Z Probability of Watch Issuance...60 percent SUMMARY...Storms may strengthen later today into the evening with a tornado risk along with locally damaging winds. A watch could be required later this afternoon. DISCUSSION...A leading line of cells approaching the Sabine river is currently weakening, while new cells continue to evolve to the west near dying/mixing outflow boundaries. Here, the cap is locally weaker as well as compared to points east, although the 18Z LCH sounding shows a dramatic increase in low-level moisture and weakened capping inversion. Strong southwesterly flow aloft will continue to overspread the area, with main surface low well to the north. Southerly 850 mb flow around 25-35 kt will be maintained, and change little through 00Z. As the trough approaches, a boost to low-level convergence will occur and help to eventually push this cluster of cells eastward across LA. In the short term, it appears the severe threat will be driven by the storm scale, with merging cells eventually becoming supercells as gradual destabilization occurs and meso lows form, also locally backing surface winds and maintaining favorable low-level shear. Indeed VWPs show better backing at 850 mb in closer proximity to the storm cluster, with less favorable shear farther east into LA. The air mass remains very moist, with impressive lapse rates aloft. Although widespread severe is not expected, a small corridor may certainly develop a supercell tornado risk this afternoon through evening.