Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Apr 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... An active severe weather pattern expected through at least this weekend, before predictability diminishes early next week. ...D4/Friday... Guidance remains consistent with a broad swath of strong mid-level southwesterlies from the southern High Plains to the Great Lakes, downstream of a longwave trough from northern ON to the Lower CO Valley. This will overlap a similarly oriented surface front. In response to increasing mid-level height falls, a surface cyclone should track across the central Great Lakes portion of the baroclinic zone during the day. Afternoon severe may be focused in this region with stronger low-level shear. Parts of this region may warrant higher probabilities in later outlooks. Farther southwest, a pronounced EML may delay the bulk of storm development along the front until evening. But given the strong deep-layer shear and moderate buoyancy, scattered severe storms appear possible. ...D5/Saturday... Amplification of an embedded northern-stream shortwave impulse over ON/QC should sustain an expansive swath of strong mid-level flow from the OH Valley northeastward. The northeast extent of appreciable instability overlapping with this regime becomes nebulous east of the Appalachians, but scattered severe storms seem possible from the Cumberland Plateau into the Mid-South on Saturday afternoon to evening. Over the southern Great Plains, lingering convection Saturday morning renders uncertainty along the largely stalling baroclinic zone that will undoubtedly be modified by convective outflow. But with greater consistency in guidance handling the pivot of the basal shortwave impulse across the Southwest, multiple rounds of strong to severe convection are plausible through Saturday night. ...D6/Sunday... Predictability lessens by this period with the evolution of compact shortwave trough ejecting onto the southern Great Plains. This yields substantial spread in the attendant synoptic cyclone. In addition, potentially extensive ongoing convection Sunday morning further lessens confidence in mesoscale details. But a belt of potentially very strong mid-level southwesterlies overlapping rich western Gulf moisture supports inclusion of a severe-area highlight in the South-Central States.