Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Apr 08 2024 05:52:00 ACUS01 KWNS 080551 SWODY1 SPC AC 080550 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Apr 08 2024 Valid 081200Z - 091200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF NORTHWEST TEXAS INTO NORTH-CENTRAL TEXAS... ....SUMMARY... Multiple rounds of severe thunderstorms should develop from early afternoon today through Tuesday morning across a large portion of the southern Plains into the Mississippi Delta region. Large to very large hail is the main threat (potentially up to 4 inches), especially over northwest Texas, though a few tornadoes and severe wind gusts will also be possible. ....Synopsis... A positively-tilted mid-level trough will amplify as it moves across the Southwest and northern Mexico today. Ahead of this trough, a broad region of moderate mid-level southwesterly flow will overspread the southern Plains and into the lower-Mississippi Valley. A weak surface cyclone will develop in West Texas and deepen through the period. As this occurs, the remnant front across southeast Texas early this morning will start to lift north as a warm front through the day. Mid-60s dewpoints are expected as far north as the Red River by 00Z. A cold front moving south through the central Plains this morning will meet this warm front near the Red River by late afternoon/early evening and become mostly stationary and mark the northward extent of significant destabilization and thus severe risk. ....Northwest Texas into north-central Texas... Storms are expected to rapidly form on the northwestern periphery of moisture return in a region of pressure falls across northwest Texas this afternoon. 40 to 45 knots of effective shear should support supercell organization. These storms will initially be high-based with limited moisture with large to very large hail as the primary threat. Low-level flow is forecast to be mostly weak, but there will be strong low-level veering which may be sufficient for some low-level updraft organization. Storms will move into better low-level moisture late in the afternoon and into the evening, which may increase the potential for a tornado or two. ....East Texas into the ArkLaTex... Moderate to strong instability is expected to develop across east Texas and into western Louisiana this afternoon as upper 60s to near 70s dewpoints advect northward. Despite a rare total solar eclipse across this region, its impact on the overall severe weather threat will likely remain minimal. Only moderate warming will be sufficient to erode inhibition across the region with the strengthening low-level jet and isentropic ascent as the primary focus for storm development later in the afternoon. Therefore, most guidance shows storms developing between 20Z and 22Z as the low-level jet strengthens, even the RAP/HRRR which account for eclipse-related radiation effects. Strong instability and shear is expected which will support supercells capable of large to very large hail. However, there are some concerns about storm interference and updraft longevity. Initially, a warm nose around 700mb is evident on NAM/RAP forecast soundings which may limit more robust updraft development. This warm nose is forecast to erode by 23/00Z. However, by that time, widespread shower/thunderstorm development may be underway which could be a limiting factor to updraft longevity and a greater tornado/large hail threat. Some guidance suggests a MCS may develop out of the northwest/north-central Texas convection and move through northeast Texas during the overnight hours. This solution will greatly depend on the evolution of earlier convection and position of the convectively enhanced warm front by late evening. ....Texas Hill Country overnight... Monday night, height falls will overspread much of Texas with a secondary low-level jet max strengthening into portions of central Texas. After 06Z, a very favorable environment will be present with NAM/RAP forecast soundings showing 2500 to 3000 J/kg MUCAPE and over 60 knots of effective shear. Therefore, there is a conditional threat for strong supercells with a threat for large to very large hail if isentropic ascent is sufficient for storm development into central Texas. ....West Texas early Tuesday... The dryline is expected to retreat into West Texas overnight with strong instability building back to near Midland early Tuesday morning. As forcing overspreads this region Tuesday morning, storms are expected to develop in a very unstable and strongly sheared environment. Therefore, supercells are possible with large to very large hail as the primary threat. ...Bentley.. 04/08/2024 $$ = = = 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) .