Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Fri May 01 2026 Valid 041200Z - 091200Z ...DISCUSSION... ...Days 4-6/Mon-Wed -- Southern Plains...Mid/Lower MS Valley...Southeast... An upper trough will develop southward across the northern Plains and Upper Midwest on Monday. At the same time, another upper trough will be oriented over southern CA and offshore over the Pacific. In response to modest height falls and increasing westerly flow across the Rockies, a lee low will develop over the central/southern High Plains. Increasing southerly low-level flow will allow modified Gulf moisture to return northward ahead of a dryline across the southern Plains, and to the south of a cold front developing southward across the central Plains and Upper MS Valley. Isolated strong to severe thunderstorms will be possible within the narrow moist/warm sector ahead of these surface boundaries, particularly the cold front across parts of the MO/Mid-MS Valley, as capping may persist further south across the Southern Plains. Given modest boundary moisture with north and east extent across the Midwest, it is uncertain how robust convection may be and where the most favorable area for severe storms may develop, precluding 15 percent probabilities at this time for Day 4/Mon. By Day 5/Tue, the jet associated with the eastward advancing Southwest U.S. trough will being to phase with the upper trough over the north-central U.S. This will bring strengthening southwesterly flow to portions of the southern Plains and Mid-South vicinity while southwesterly low-level flow continues to transport Gulf moisture north/northeast ahead of a southeastward-advancing surface cold front. The warm sector will become increasingly narrow toward the Lower Ohio Valley, and any strong to severe thunderstorm potential would likely focus from parts of Texas into Arkansas/far western TN/KY. However, model guidance varies with regard to placement and extent of potential convection ongoing Tuesday morning, which will have implications for severe potential through the rest of the day. Differences in the location of the surface front also add uncertainty, precluding a 15 percent delineation. Some strong to severe thunderstorm potential could persist into Day 6/Wed across parts of the Lower MS Valley and southeastern U.S. This remains uncertain and will be influenced by convective evolution in the days prior. ...Days 7-8/Thu-Fri... The surface cold front is expected to move offshore the East Coast on Day 7/Thu. Thunderstorm potential will continue ahead of the front across the Southeast to the Mid-Atlantic, but severe potential is uncertain as destabilization may be limited by widespread rainfall and cloud cover. On Day 8/Fri, most of the CONUS will be stable/dry behind the cold frontal passage. However, guidance suggests a shortwave upper trough will approach the southern Rockies/northern Mexico and surface cyclogenesis will maintain a moist airmass across TX. If this occurs, some severe potential could develop across parts of TX.Read more
