SPC Day 1 Convective Outlook — 06Z Forecast Discussion on 1 April 2024

SPC AC 010606 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK  0106 AM CDT Mon Apr 01 2024 Valid 011200Z - 021200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS TO THE OZARKS AND INTO FAR WESTERN INDIANA....   ...SUMMARY... Severe weather is expected to occur over a broad region from the southern Plains, the Ozarks, portions of the Ohio Valley, and into a  small part of the Mid-Atlantic. Large to very large hail, damaging winds, and tornadoes (some strong) are possible. The severe threat will peak this afternoon/evening in the southern Plains with the greatest threat for the Ohio Valley vicinity being the evening/overnight period. ...Synopsis... A large, positively tilted upper-level trough will shift east from the Southwest to the central Plains today. A mid-level shortwave trough, currently rounding the base of the large scale trough, will advance quickly northeast through the day today within a strong mid-level jet. This strong flow will overspread a broad, very moist warm sector and lead to severe weather across a large portion of the Southern Plains into the Midwest. A surface low is present across eastern Colorado this morning with a  stationary front extending eastward across Kansas and Missouri and into the Ohio Valley. This surface low will drift slowly east through the day and the front is expected to lift north across Missouri as a warm front during the afternoon. ...North Texas, central and eastern Oklahoma, southeast Kansas, and the Ozarks... Mid 60s dewpoints are expected across much of the warm sector east of the dryline by mid-day today with temperatures warming into the 70s to low 80s. Moderate to strong instability is expected to  develop by the time ascent associated with the approaching trough overspreads the dryline. Once this occurs, expect rapid storm development along the dryline from southern Kansas to north Texas. Very strong shear, and mostly straight hodographs will support splitting supercells initially capable of large to potentially giant hail across a broad region from southwest Missouri to north Texas. Storm evolution off the dryline is still somewhat uncertain. Some guidance depicts more discrete development off the dryline and the potential for multiple rounds of supercells, while other CAM guidance waits until closer to 00Z to convect and leads to upscale growth and significant storm interaction within the first few hours. This evolution will have a significant impact on the longevity of  the giant hail threat, but even with a messy storm mode, very large hail will remain a threat. Low-level shear is expected to be very weak for much of the day, which will limit the tornado threat. However, by the evening, the low-level jet is expected to strengthen with the ejecting wave and low-level shear will improve. The most favorable hodographs are expected across northeast Oklahoma into southeast Kansas and southwest/central Missouri in a region where mature supercells will likely be ongoing. Therefore, a more favorable period for tornadoes and potentially strong tornadoes may exist from 23-03Z as the low-level shear improves. ...Eastern Missouri into southern Illinois... At least isolated supercells are expected to develop along the warm front from northern Missouri into central Illinois this afternoon and evening. Strong instability and very strong shear will support large to very large hail. In addition, storm motion is expected to  be parallel to the surface front. Therefore, any supercells which can latch onto the warm front will have a higher tornado threat. However, more isolated storm coverage and uncertainty regarding storm evolution preclude higher tornado probabilities in this region. Later in the evening and into the overnight hours, storms from the west will move into the region with a threat for large hail, a few tornadoes, and severe wind gusts. ...Ohio River Vicinity... Supercells from Illinois may continue east along the warm front into the evening across southern Indiana and potentially southern Ohio. Additional storms may also develop along this frontal zone with a  primary threat of large hail. Weaker instability/shear should limit the overall threat from these storms compared to farther west. However, moderate instability and strong shear will support a threat for large hail, damaging wind gusts, and perhaps a tornado. Overnight, a cluster of storms is expected to approach from the west. The overnight environment will continue to support a severe threat with 1500 J/kg MLCAPE and effective shear in excess of 50 knots. There is still considerable uncertainty how this cluster will evolve. A cluster of supercells would pose a threat for all severe weather hazards, while a more organized MCS may support a greater severe wind and QLCS tornado threat. ...Central Texas... Strong instability is expected to develop ahead of a dryline across central Texas this afternoon. Confluence along the dryline and weak height falls should provide ample support for isolated to scattered storm development. Any storms which develop will be capable of very large to giant hail, given very strong instability and shear an  expected supercellular storm mode. ..Bentley/Darrow.. 04/01/2024