...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THE ARKLATEX INTO WESTERN ARKANSAS...
...SUMMARY...
Several clusters of strong to severe storms are possible from central Texas across the ArkLaTex and into the lower Ohio Valley Friday and Friday night. The greatest threat for tornadoes, large hail and damaging winds will be from the ArkLaTex across western Arkansas, including potential for strong to potentially intense tornadoes.
...Synopsis...
A mid-level trough, centered across the Southwest and northern New Mexico, will start to shift east on Friday. As this occurs a broad, strong low-level jet will develop across eastern Texas and into Louisiana, Arkansas, and Mississippi. This strengthening lower tropospheric flow will aid in the northward advancement of a warm front, located from central Texas to the Mid-Mississippi Valley at the beginning of the period, to eastern Oklahoma an near the MO/AR border by 00Z Sat. This reorientation of the frontal boundary should be favorable for supercells with the potential for large hail (some 2+ inch), damaging wind gusts, and tornadoes (some potentially EF3+).
...ArkLatex to Western Arkansas...
As a warm front lifts north across Arkansas through the day, a very unstable environment (2500-4000 J/kg MLCAPE) will develop from the ArkLaTex into western Arkansas as temperatures warm into the mid 80s with dewpoints in the low 70s. Some weak convection may maintain along the frontal zone in eastern Oklahoma during the morning and early afternoon. However, more robust convective development is not anticipated until mid-afternoon when height falls start to overspread the region, and the influence of the entrance region of the upper-level jet increases ascent. In addition, most high resolution guidance indicates a local area of low pressure may traverse the frontal zone to near northwest Arkansas by 21Z. The combination of these factors, which have decent agreement among 12Z guidance, points toward multiple supercells along the frontal zone during the mid to late afternoon and into the evening. These supercells, in an environment featuring 2500-3500 J/kg MLCAPE and 0-1km SRH ~400 m2/s2, will support the potential for strong to intense tornadoes. Messy storm mode could limit the longevity of any of these supercells/tornadoes, but even with limited duration, the environment supports a tornado threat. A more conditional long-track tornado threat, which would also bring greater opportunity for EF3+ tornadoes, exists east of the frontal boundary. Synoptic forcing ahead of the boundary is relatively weak, but very strong instability (3000-4000 J/kg MLCAPE) is forecast with minimal inhibition across the warm sector. Therefore, more discrete, open warm-sector supercell development is possible, but will be more dependent on mesoscale details which will become more clear in the Day 1 timeframe.
