Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Apr 03 2023 19:55:27 ACUS01 KWNS 031955 SWODY1 SPC AC 031953 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Mon Apr 03 2023 Valid 032000Z - 041200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES AND OVER PORTIONS OF CENTRAL TO NORTHERN TEXAS... ....SUMMARY... Isolated strong to severe thunderstorms may occur across parts of the Southeast and Texas this afternoon and evening. Damaging winds will be the primary concern, but a few instances of severe hail, and perhaps a tornado, are possible. ....Southern Georgia/northern Florida... A cluster of thunderstorms continues to propagate to the east/southeast along a diffuse warm frontal zone/surface theta-e gradient across southern GA into northern FL. Although several damaging wind reports have been noted with this activity, IR cloud top temperatures have shown a steady warming trend over the past 1-2 hours, and an undercutting outflow boundary is noted ahead of most of the deeper cells in the line, implying gradual weakening of the system. The expectation is for this line/cluster to continue to pose an isolated damaging wind risk into northern FL over the next several hours, but the threat for scattered damaging/severe winds appears sufficiently low to warrant a reduction in probabilities. ....Central/north Texas... Recent visible imagery shows a growing cumulus field along a diffuse dryline across central TX. While a few towers within the field show increasing vertical development, convergence along the dryline remains weak and a nearby ACARS sounding sampled residual capping over the region. These observations are in line with recent HRRR/RAP guidance, which shows little to no convective precipitation signal and continues to cast uncertainty into the probability for robust convective initiation. Given these concerns, the Marginal risk is maintained for this update. However, the environment over the region remains highly favorable for organized supercells if a mature storm or two can become established late this afternoon/evening. ...Moore/Gleason.. 04/03/2023 ..PREV DISCUSSION... /ISSUED 1128 AM CDT Mon Apr 03 2023/ ....Southeast... Water-vapor satellite imagery shows a low-amplitude shortwave trough centered over portions of the Southeast late this morning. This trough will move eastward off the NC/SC Coast by this evening. An ongoing cluster of thunderstorms over southeast AL and southwest GA will develop east-southeastward along/near a surface warm front which will attempt to advance northeast from the Gulf Coast. This will result in the cluster becoming gradually separated from the low-amplitude wave. Still, some tornado threat should continue into the afternoon with this activity until the low-level flow slowly weakens and veers. Damaging winds will also be possible farther east into southern GA and north FL as at least modest destabilization and filtered daytime heating occur ahead of the ongoing cluster. In the wake of this activity, a couple of thunderstorms may redevelop along residual convective outflow or the northward-developing warm front during the late afternoon to early evening across eastern MS and southern/central AL. Minimal large-scale ascent results in low confidence in this scenario occurring. But, if convection becomes sustained, a strongly sheared and destabilizing warm sector may support severe hail and/or damaging winds. ....North/Central Texas... Moderate to strong buoyancy and 50+ kt of deep-layer shear will support a conditionally favorable supercell environment along/just ahead of a dryline late this afternoon and early evening over parts of north/central TX. Near-neutral mid-level heights with minor downstream ridging is expected across the dryline. This area will also be well removed from a deepening upper trough across the western CONUS. Low-level convergence along the dryline should remain weak, but could be relatively maximized in the early evening across central TX as the dryline starts to retreat. Some 12Z convection-allowing models suggest a thunderstorm or two may briefly develop. However, uncertainty remains high regarding a particular location. Any sustained supercell would pose a conditional risk of all severe hazards, but large hail is likely if a thunderstorm can form and be sustained. Given the uncertainty in whether any convection will initiate given the negligible large-scale ascent, will maintain low severe probabilities with this update. But, observational and short-term model trends will be closely monitored for a possible upgrade to Slight Risk at 20Z, if warranted. ....Illinois/Indiana... Gradual destabilization this afternoon will occur south of a quasi-stationary front that bisects MO to central IL and northern IN. However, a building mid-level ridge along with the expansion of a stout EML suggest the chance for surface-based development today is low. Still, modest lift to the cool side of the front may support a few stronger elevated updrafts this evening through tonight. A weak combination of buoyancy/shear and warm-advection-related ascent suggests that small hail should be the most likely hazard. $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. 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