ZCZC SPCSWOMCD ALL ACUS11 KWNS 251720 SPC MCD 251720 LAZ000-ARZ000-TXZ000-252015- Mesoscale Discussion 0300 NWS Storm Prediction Center Norman OK 1220 PM CDT Mon Mar 25 2024 Areas affected...parts of western/northern Louisiana and adjacent southern Arkansas Concerning...Severe potential...Watch possible Valid 251720Z - 252015Z Probability of Watch Issuance...40 percent SUMMARY...Potential exists for one or two supercell storms to gradually develop this afternoon, particularly near/west of the Alexandria through Monroe vicinities by 3-4 PM CDT, if not earlier. This may be accompanied by increasing risk to produce tornadoes--perhaps a strong one. DISCUSSION...In advance of a pre-frontal low-level wind shift/confluence zone slowly advancing eastward across parts of western Arkansas and eastern Texas, new thunderstorm development has initiated across upper Texas and southwestern Louisiana coastal areas. This appears to be in response to low-level moistening and lift within a fairly strong warm advection regime, which may be maximized near or just above 850 mb. This is forecast to continue to shift north-northeastward toward north central Louisiana, near/west of Monroe, through 20-21Z, where somewhat weaker mid-level inhibition and increasing mid/upper forcing beneath more pronounced difluent flow aloft may support thunderstorm intensification. Given the strong deep-layer shear, and forecast of enlarging low-level hodographs beneath strengthening southerly 850 flow (to 50+ kt), the structure of the near-surface thermodynamic profiles remains the primary uncertainty concerning severe weather potential. For example, notable differences are evident between the NAM and Rapid Refresh forecast soundings, with the NAM soundings suggesting convection may remain elevated above a saturated but weakly stable profile from the surface through around 850 mb. Lapse rates within this layer in the Rapid Refresh forecast soundings appear at least somewhat more unstable, and perhaps supportive of convection rooted closer to the surface, where hodographs within the low-level inflow layer may be more conducive to the evolution of strong low-level mesocyclones. ..Kerr/Hart.. 03/25/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...JAN...LCH...SHV... LAT...LON 30549391 32379358 33199256 32489169 31259207 30369248 29969331 30549391 NNNN