ZCZC SPCSWOMCD ALL ACUS11 KWNS 281559 SPC MCD 281559 ARZ000-TXZ000-OKZ000-281730- Mesoscale Discussion 0135 NWS Storm Prediction Center Norman OK 0959 AM CST Sun Feb 28 2021 Areas affected...northeast Texas through southeast Oklahoma and southwest Arkansas Concerning...Severe potential...Watch likely Valid 281559Z - 281730Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms are expected to increase in coverage and intensity by late morning into the afternoon. Primary threats will be isolated large hail and damaging wind gusts, though a tornado or two will also be possible. A WW will likely be needed before 17Z. DISCUSSION...As of mid morning a cold front extends from eastern OK through north central and west central TX. An isolated thunderstorm with mid-level updraft rotation has developed on the front and is located just east of Gainesville with another isolated storm near Mineral Wells. The downstream warm sector is already moderately unstable with 1000-1500 J/kg MLCAPE supported by upper 60s F dewpoints and 7-7.5 C/km mid-level lapse rates. Further destabilization will occur, but will be limited to some degree by widespread multi-layer clouds. Weak, progressive impulses embedded within the southwesterly upper flow regime and forcing along the cold front will contribute to an increase in thunderstorm coverage later this morning as the boundary layer slowly warms. The primary low-level jet has shifted east of this region resulting in small 0-1 km hodographs. However, a belt of strong southwesterly winds increasing to around 70 kt at 500 mb resides above the warm sector and is contributing to 60+ kt effective bulk shear. Therefore, some storms should organize with supercells and bowing segments likely, eventually consolidating into a dominant linear mode. Large hail and isolated damaging wind will be the main threats. The small low-level hodographs should tend to limit overall tornado threat. However, a tornado or two cannot be ruled out. ..Dial/Hart.. 02/28/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SHV...TSA...FWD...OUN... LAT...LON 32559772 33599665 34899484 34329358 31909679 31859817 32559772 NNNN