The Storm Prediction Center has flagged four consecutive days of severe weather from Saturday, April 11 through Tuesday, April 14, across the south-central United States. Sunday is the day to worry about. Dallas, Oklahoma City, Wichita, Tulsa and Joplin are in the primary threat corridor for two to three of those days, with tornadoes, large hail and damaging winds exceeding 60 mph all on the table. If you are driving I-35, I-44, I-40 or I-20 between Texas and Missouri this weekend, you need to either have a plan or pick a different departure date.
Four consecutive extended-range outlooks is not something the SPC does casually. At the Day 4-8 range, forecasters usually hedge because model confidence that far out is low. This time they are not hedging. The outlooks span all four days with what the SPC describes as a level of confidence seen only a couple of times per year. Model agreement is strong and the pattern driving the event is well-defined: a potent upper-level trough digging into the western U.S. this week, building a ridge over the East, then pushing a powerful surface frontal system through the Plains. Ahead of that front, moist southerly return flow from the Gulf will push surface dewpoints into the 60s across the southern and central Plains. That is textbook April severe weather fuel.
The Weather Prediction Center’s extended forecast discussion reads the same way: an amplified upper-level pattern this weekend into next week, a strong frontal system, heavy rainfall and severe weather potential across the south-central U.S.
The Setup
The synoptic picture is not complicated. An upper-level trough currently over the western U.S. ejects east across the central states over the weekend, dragging a strong surface cold front through the Plains. Deep Gulf moisture streams north ahead of the front and supplies the instability. Each afternoon, as surface temperatures climb and the cap erodes, thunderstorms fire along and ahead of the boundary. The threat corridor shifts northeast each day: west Texas on Saturday, central Oklahoma and north Texas on Sunday, the Midwest by Monday and Tuesday. None of that is unusual for mid-April in the Plains…