Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 12 2024 17:35:29 ACUS02 KWNS 121735 SWODY2 SPC AC 121733 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Tue Mar 12 2024 Valid 131200Z - 141200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE LOWER MISSOURI VALLEY... ....SUMMARY... Severe thunderstorms capable of large to very large hail and a tornado or two are possible across the Lower Missouri Valley from Wednesday afternoon through Wednesday night. ....Synopsis... A large-scale upper trough will amplify over the Interior West during the period with a downstream ridge over the MS Valley shifting east into the OH Valley/Appalachians. A shortwave trough is forecast to eject northeast from the Sangre de Cristos into the lower MO Valley through the mid evening. A belt of stronger mid to upper-level southwesterly flow will overspread the TX Panhandle and OK during the afternoon and eventually nose into the lower MO Valley overnight. In the low levels, a cyclone over the KS vicinity during much of the day 2 period will feature a warm front advancing north through portions of the lower MO Valley and a dryline extending southward into OK and north TX. ....KS and NE eastward into the mid MS Valley... Strong low-level moisture advection into the region will occur as surface dewpoints are forecast to rise into the 50s deg F. Large-scale ascent attendant to the approaching shortwave trough coupled with low-level convergence near the surface low and warm front are expected to provide the lift needed for convective initiation. Storm coverage prior to sunset remains uncertain but thunderstorm coverage will likely increase during the evening near the warm front over northern KS eastward into the northern half of MO during the evening into the overnight. Steep mid-level lapse rates and strong deep-layer shear will support a storm environment in which the stronger storms will be capable of large to very large hail. If moisture quality is locally higher near the warm frontal zone and a supercellular mode is maintained, a tornado risk could develop due to enlarged hodographs. Storm coverage will likely increase into the overnight as warm-air advection strengthens in tandem with a LLJ. Primarily elevated storms capable of a large-hail threat may extend as far east as northeast MO into west-central IL. ....OK and north TX... Greater uncertainty on thunderstorm development will exist southward along the dryline and into eastern portions of OK and perhaps north TX beginning late Wednesday afternoon into Wednesday night. Model guidance varies considerably on the magnitude of low-level moisture with NAM exhibiting a more moisture-rich setup compared to model ensembles (HREF, SREF) and considerably drier solutions like the 15z RAP and latest GFS. Forecaster experience with these early season moisture return setups suggest a median to slightly drier solution is most probable. Moisture is the primary and likely consequential ingredient that will dictate severe thunderstorm risk across this corridor late Wednesday afternoon into the evening. With those concerns stated, cool mid-level temperatures in the -16 to -17 deg C range will result in steep lapse rates and contribute to moderate buoyancy (MLCAPE 1000-2000 J/kg). Clockwise-curved and elongated hodographs would favor supercells if a sustained storm can root in the boundary layer. Given the low probability (currently depicted in ensemble CAM guidance) for storm development, will maintain a categorical 1 (Marginal) risk. ...Smith.. 03/12/2024 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .