Jesse Risley
Staff member
Since no one else started a discussion yet, I'll post some brief thoughts after perusing the previous few model runs.
A fairly classic, potent SVR weather episode looks to be shaping up for Saturday for the ARKLATEX region, in particular. By early Saturday, models are indicating a system taking on a more negative tilt as a stalwart mid-level perturbation begins to overspread the western Gulf region. A surface low is progged to deepen, and while not a substantially compact cyclone per se, as it tracks proximal to the Interstate 30 corridor, ample moisture this time around should yield more than adequate surface instability AOA 2000 J/KG across the warm sector ahead of the approach of large scale forcing for ascent. Short-range models are yielding particularly favorable surface flow and ample directional shear for a heightened tornadic risk. CIN begins to erode across the open warm sector after 15z, as the main surface forcing begins to move into EC Texas as the surface low peregrinates NNE.
While there were and may still be some early concerns about CIN eroding too quickly given ample WAA and ongoing ascent, allowing too much convection, models seem to be indicating some convective initiation in the late morning and early afternoon across far E TX, WC LA and far S AR in areas of greatest destabilization with increasingly favorable 0-6km shear values. Ongoing convection in the warm sector, as depicted by most CAMs for several days, may also molest the northward extent of the surface warm frontal placement, perhaps further south than indicated by the 12z/12 HRRR and NAM runs. Several bands of convection appear likely, including a squall line INVO of the main surface forcing, following initial, possibly discrete supercellular activity. Mid-level lapse rates and ambient shear values will also support an attendant threat of some large hail and damaging winds with this activity, and there is also another, secondary interest of tornadic potential with initial, discrete storms that interact with the warm front itself, including some initial development indicated on the HRRR across far W Mississippi, as well as embedded mesovortices within the main line given the ample 0-1 km SRH values that increase with time as the LLJ strengthens. The only other caveat I noted on the recent two runs of the short-range models, particularly the NAM, was a limited scope of more widespread, favorable low and mid-level lapse rates, though it would appear there will at least be a narrow corridor where ingredients across the warm sector do want to align for heightened tornadic potential, particularly east of US 59, south of I-30 (or wherever the surface WF chooses to lay sprawled), and west of the Mississippi River.
A fairly classic, potent SVR weather episode looks to be shaping up for Saturday for the ARKLATEX region, in particular. By early Saturday, models are indicating a system taking on a more negative tilt as a stalwart mid-level perturbation begins to overspread the western Gulf region. A surface low is progged to deepen, and while not a substantially compact cyclone per se, as it tracks proximal to the Interstate 30 corridor, ample moisture this time around should yield more than adequate surface instability AOA 2000 J/KG across the warm sector ahead of the approach of large scale forcing for ascent. Short-range models are yielding particularly favorable surface flow and ample directional shear for a heightened tornadic risk. CIN begins to erode across the open warm sector after 15z, as the main surface forcing begins to move into EC Texas as the surface low peregrinates NNE.
While there were and may still be some early concerns about CIN eroding too quickly given ample WAA and ongoing ascent, allowing too much convection, models seem to be indicating some convective initiation in the late morning and early afternoon across far E TX, WC LA and far S AR in areas of greatest destabilization with increasingly favorable 0-6km shear values. Ongoing convection in the warm sector, as depicted by most CAMs for several days, may also molest the northward extent of the surface warm frontal placement, perhaps further south than indicated by the 12z/12 HRRR and NAM runs. Several bands of convection appear likely, including a squall line INVO of the main surface forcing, following initial, possibly discrete supercellular activity. Mid-level lapse rates and ambient shear values will also support an attendant threat of some large hail and damaging winds with this activity, and there is also another, secondary interest of tornadic potential with initial, discrete storms that interact with the warm front itself, including some initial development indicated on the HRRR across far W Mississippi, as well as embedded mesovortices within the main line given the ample 0-1 km SRH values that increase with time as the LLJ strengthens. The only other caveat I noted on the recent two runs of the short-range models, particularly the NAM, was a limited scope of more widespread, favorable low and mid-level lapse rates, though it would appear there will at least be a narrow corridor where ingredients across the warm sector do want to align for heightened tornadic potential, particularly east of US 59, south of I-30 (or wherever the surface WF chooses to lay sprawled), and west of the Mississippi River.
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