Convective Outlook
— Day 4-8
Monday/Day 4 ?
A severe weather outbreak will be possible from Monday afternoon into the evening and overnight period. On Monday, the western trough will take on a negative tilt before ejecting across the central Plains, with strong southwesterly flow aloft overspreading the region. This will result in strong lee cyclone development across western Kansas. A surface cold front will extend northward to a secondary surface low across the upper Midwest. A dryline will extend southward across portions of western Kansas into western Oklahoma. Numerous thunderstorms are expected to develop along and ahead of the cold front and further south along the dryline Monday afternoon and evening from Nebraska into central Kansas. Given the volatile air mass ahead of these features, with moderate to strong instability and strengthening deep layer shear, initial development will likely be supercellular. Initial supercells will pose risk of all hazards including large to very large hail, damaging wind, and tornadoes. As the southwesterly low-level jet increases into the evening, large clockwise enhancement of low-level hodographs across portions of central Kansas into northern Oklahoma may lead to an increasing risk for strong to intense tornadoes. Additional thunderstorm development will spread in tandem with the cold front from the central Plains to the upper Midwest through the evening, with potential for more widespread damaging wind and a few tornadoes (some of which may be strong).
Tuesday/Day 5 To Thursday/Day 7 ?
Severe potential is expected to continue D5/Tuesday as the cold front extends from the upper Midwest to southern Plains. Strong to moderate instability ahead of the front will continue to support severe storms from the northern part of the southern Plains northeastward into the mid Mississippi Valley. Trends are for the front to shift eastward faster than originally expected, and as such probabilities were shifted eastward with this update. Strong to severe storms may extend further north into the northeast and Great Lakes Region.
On Wednesday and Thursday, the cold front is forecast to move southeastward across the southern Plains and mid Mississippi Valley, extending east-northeastward into the Mid-Atlantic. A severe threat could develop along and ahead of the front each afternoon and evening. However, uncertainty concerning the exact location of the front is substantial at this extended range.
000 ACUS48 KWNS 150903 SWOD48 SPC AC 150901 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0401 AM CDT Fri May 15 2026 Valid 181200Z - 231200Z ...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/MON... ...DISCUSSION... ...Monday/Day 4... A severe weather outbreak will be possible from Monday afternoon into the evening and overnight period. On Monday, the western trough will take on a negative tilt before ejecting across the central Plains, with strong southwesterly flow aloft overspreading the region. This will result in strong lee cyclone development across western Kansas. A surface cold front will extend northward to a secondary surface low across the upper Midwest. A dryline will extend southward across portions of western Kansas into western Oklahoma. Numerous thunderstorms are expected to develop along and ahead of the cold front and further south along the dryline Monday afternoon and evening from Nebraska into central Kansas. Given the volatile air mass ahead of these features, with moderate to strong instability and strengthening deep layer shear, initial development will likely be supercellular. Initial supercells will pose risk of all hazards including large to very large hail, damaging wind, and tornadoes. As the southwesterly low-level jet increases into the evening, large clockwise enhancement of low-level hodographs across portions of central Kansas into northern Oklahoma may lead to an increasing risk for strong to intense tornadoes. Additional thunderstorm development will spread in tandem with the cold front from the central Plains to the upper Midwest through the evening, with potential for more widespread damaging wind and a few tornadoes (some of which may be strong). ...Tuesday/Day 5 to Thursday/Day 7... Severe potential is expected to continue D5/Tuesday as the cold front extends from the upper Midwest to southern Plains. Strong to moderate instability ahead of the front will continue to support severe storms from the northern part of the southern Plains northeastward into the mid Mississippi Valley. Trends are for the front to shift eastward faster than originally expected, and as such probabilities were shifted eastward with this update. Strong to severe storms may extend further north into the northeast and Great Lakes Region. On Wednesday and Thursday, the cold front is forecast to move southeastward across the southern Plains and mid Mississippi Valley, extending east-northeastward into the Mid-Atlantic. A severe threat could develop along and ahead of the front each afternoon and evening. However, uncertainty concerning the exact location of the front is substantial at this extended range. ..Thornton.. 05/15/2026