Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0307 AM CDT Thu Oct 09 2025 Valid 121200Z - 171200Z ...DISCUSSION... An upper anticyclone is forecast to remain over TX for much of the Day 4-8 period, with attendant upper ridging oscillating between the Plains and the MS Valley. An upper shortwave trough over the Rockies on Day 4/Sun will lift northeast across the northern Plains into Canada, along with a deepening surface low. As this occurs, a cold front will sweep east across the northern/central Plains and the Upper Midwest through Day 5/Mon. Modest boundary layer moisture ahead of the front will support at least weak instability and thunderstorm potential. However, severe thunderstorm chances appear low given richer boundary layer moisture will remain offset from stronger shear/large-scale ascent. Another upper shortwave trough is expected to move from the Rockies into portions of the Plains late in the forecast period. As this occurs, lee cyclogenesis is likely to occur, and southerly low-level flow may transport modest Gulf moisture northward into the central Plains to the MO Valley. Some increase in severe thunderstorm potential could develop around Day 7 or 8/Wed or Thu, from the southern/central Plains toward the MO Valley. However, confidence is too low to include severe probabilities at this time given poor run-to-run model consistency.
