####018004132#### ACUS01 KWNS 012019 SWODY1 SPC AC 012017 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0317 PM CDT Mon Apr 01 2024 Valid 012000Z - 021200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL AND NORTHEASTERN OKLAHOMA...AND INTO FAR NORTH-CENTRAL TEXAS... ...SUMMARY... Severe thunderstorms with very large hail (2-3 inch diameter or greater), damaging gusts (60-80 mph) and a few tornadoes (potentially up to EF2) are expected this afternoon into tonight from north Texas and Oklahoma into the lower Ohio River Valley. ...Discussion... Current forecast reasoning and outlook areas remains generally in line with prior outlooks, with widespread/all-hazards severe risk from the southern Plains into the Ohio Valley. The main change in the current outlook update is a westward adjustment of thunder/severe probability lines across the Big Country and Concho Valley of Texas, where storms have initiated along a developing dryline a bit earlier, and farther west, than previously anticipated. Otherwise, the outlook remains largely unchanged at this time, aside from minor line tweaks to account for current convective evolution/development. ..Goss.. 04/01/2024 .PREV DISCUSSION... /ISSUED 1128 AM CDT Mon Apr 01 2024/ ...Synopsis... Embedded speed maxima (90-100+ kt 500 mb) from southern NM/far west TX to northwest Mexico will eject northeastward to OK this evening and MO overnight. An associated lee cyclone will deepen this afternoon across the TX South Plains and then progress into northwest OK this evening and the mid MS Valley by the end of the period. A broad/moist warm sector is in place from the southern Plains to the mid MS/lower OH Valleys, beneath a warm elevated mixed layer with 8-9 C/km midlevel lapse rates. The cap will weaken through the afternoon from the west, with thunderstorm initiation becoming likely by mid afternoon along a surface front from KS into MO/IL, and mid-late afternoon along the dryline from western/central OK into northwest TX. ...KS/MO/IL/IN through tonight... Scattered thunderstorm development is likely starting mid afternoon along the baroclinic zone from KS into MO, and storms will subsequently spread eastward along the warm front from MO into IL/IN. The environment will favor supercells capable of producing very large hail (2-3 inches in diameter) and a few tornadoes, with an isolated strong tornado possible. Storm mode will become messier into the overnight hours with upscale growth into clusters/line segments, with an increase in the threat for damaging winds (60-80 mph), and a continued threat for tornadoes (possibly up to EF2) with embedded/QLCS circulations. ...OK/TX this afternoon into early tonight... The elevated mixed layer and associated cap, along with widespread clouds, will tend to delay surface-based storm development until mid-late afternoon, when forcing for ascent increases from the southwest with the approach of the mid-upper jet streak. By about 21z, scattered thunderstorm development is expected along the dryline from northwest TX into western OK, and storms will spread quickly northeastward into central/eastern OK through this evening/early tonight. Steep midlevel lapse rates and boundary-layer dewpoints in the mid-upper 60s will contribute to MLCAPE of 2000-3000 J/kg, in an environment with very strong deep-layer shear/long hodographs favorable for multiple supercells with very large hail (3 inches in diameter or greater). The magnitude of the tornado threat is a bit less certain, given a weakness in the low-level shear until a more consolidated low-level jet response begins by late evening, when storm mergers and upscale growth become more probable into eastern OK/northwest AR/southwest MO early tonight. However, given the very strong flow and seasonably rich low-level moisture, there will be the potential for a couple of strong (roughly EF2) tornadoes late this afternoon into tonight. $$