ACUS48 KWNS 240900 SWOD48 SPC AC 240859 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Mon Aug 24 2026 Valid 271200Z - 011200Z ...DISCUSSION... A strong mid-level ridge will be centered over the Rockies on Thursday with a broad trough centered across the Great Lakes. The ridge will break down over the weekend with a more zonal flow with embedded shortwave troughs extending from the Northwest to the northern Plains and into the Northeast. Beyond this weekend, guidance differs on the evolution of the pattern with considerable uncertainty. ...D7/Sunday to D8/Monday - Northern Plains... Guidance continues to consolidate around an unseasonably strong mid-level shortwave trough across the northern Plains into the Upper Midwest on Sunday and Monday. There is still some spread around the timing of this trough and also the degree of destabilization ahead of it. However, despite these timing differences, a moderately strong signal for an increasing severe weather threat in this period appears to be emerging as a trough with a consistent convective signal is shown by the ECMWF and GFS and also by the AI-GFS and AI-ECMWF. Ensemble guidance shows a flattened ridge with a mid-level jet streak across this region during the same timeframe. Surprisingly, AI/ML guidance shows very little signal for a severe threat across this region. Analysis of individual ensemble members suggests this is likely reflective of the uncertainty in timing and location of this trough and greater spread among the ensemble guidance. Nonetheless, the potential for an organized severe weather threat across the northern Plains and/or Upper Midwest late this weekend into early next week appears to be increasing. If guidance continues to consolidate with decreasing spread about the timing of the trough, severe weather probabilities may eventually be needed. ..Bentley.. 08/24/2026