ZCZC SPCSWOMCD ALL ACUS11 KWNS 211854 SPC MCD 211854 TXZ000-212130- Mesoscale Discussion 0276 NWS Storm Prediction Center Norman OK 0154 PM CDT Thu Mar 21 2024 Areas affected...Parts of north and central Texas Concerning...Severe potential...Watch unlikely Valid 211854Z - 212130Z Probability of Watch Issuance...20 percent SUMMARY...Strong to severe thunderstorm development is expected over the next couple hours. Isolated large hail and locally severe gusts are the primary concerns. A watch is not currently expected. DISCUSSION...Boundary-layer cumulus is gradually deepening in the vicinity of a mesoscale low over northwest TX, where steep low-level lapse rates are impinging on middle/upper 50s surface dewpoints. Isolated convective initiation is underway in this area of focused mesoscale ascent. Farther south, cumulus is more shallow along the dryline (owing to weak low-level convergence), though deepening cumulus is developing west of the dryline in a well-mixed/destabilizing boundary layer. Aided by gradually strengthening DCVA preceding a midlevel shortwave trough crossing west TX, initial thunderstorms will develop/intensify along/south of the mesoscale low, where low-level convergence is maximized. Around 35 kt of effective shear (characterized by a mostly straight hodograph) will support initially discrete cells, with an isolated hail risk (potentially up to 1.5 inches with the stronger storms) and locally strong/severe gusts. Farther south, thunderstorms should evolve out of the steep low-level lapse rate plume, with a similar risk of isolated hail and slightly greater severe-wind risk, given the steeper low-level lapse rates and stronger deep-layer shear. With time, these storms should increase in coverage and spread eastward, as the large-scale ascent continues to overspread the region. This will promote localized upscale growth into several loosely organized clusters, though the strongest deep-layer shear may be displaced to the south of this activity -- potentially limiting convective organization and favoring outflow dominant storms. Nevertheless, strong to severe gusts (generally 50-60 mph) will become the main concern, though isolated large hail will remain possible with the more discrete activity. Current thinking is that the severe hail/wind risk may remain too isolated/marginal for a watch, though convective trends will be monitored through the afternoon. ..Weinman/Goss.. 03/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...EWX...SJT...LUB... LAT...LON 29909915 29939967 30149991 30600021 31770040 32650038 33380016 33839983 34029939 34089897 34029836 33799780 33399747 32239759 30449798 29959857 29909915 NNNN