Saturday: Severe storms will be widespread along the frontal zone from Iowa to Texas and Louisiana, but there remain questions about how the day will evolve. Models are suggesting that morning thunderstorms could develop from Oklahoma into Missouri, and any rain-cooled air from these storms may reduce instability later in the day along the lagging frontal zone. Still, it appears that Saturday afternoon will likely bring a renewed round of severe weather in eastern Oklahoma and eastern Kansas, eventually morphing into a squall line stretching from Iowa to Louisiana that should reach the Mississippi River overnight Saturday night. One or more corridors of persistent training storms may develop along the front from eastern Kansas to Wisconsin.

Sunday: Sunday should be the quietest of the next several days, although strong winds could occur with thunderstorms along the leading cold front as it pushes across Illinois into Michigan and Indiana. Late on Sunday night, the next big impulse from the upper low will begin moving into west Texas, and intense overnight storms could develop depending on how quickly low-level moisture returns to the area.

Monday: A major outbreak of severe weather, including significant tornadoes, looks quite possible as an especially potent upper-level impulse heads into the southern Plains. The strong winds and cold air aloft will lead to a widespread zone of favorable wind shear and high instability. The storms will likely be most intense and concentrated from southern Kansas to north and northwest Texas, especially across Oklahoma. Model agreement on this scenario is reflected in the fact that SPC has consistently highlighted the elevated risk on this day ever since last Tuesday. Because conditions will be favorable for supercells well ahead of the front/dry line, potentially tornadic storms could range across a broad area.

The other serious concern for Monday is a band of intense upward motion and torrential rain expected to develop with the upper impulse as it heads from Oklahoma across southeast Kansas into Missouri. GFS model output suggests that 3” – 6” totals could fall in a short period across already-saturated soils, and local amounts could be higher.

Depending on how the western trough evolves, more severe weather may erupt later in the week across the Plains and Midwest, and more heavy rain may fall. Flood concerns are likely to mount as we approach Memorial Day weekend.
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