Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun Mar 29 2026 Valid 011200Z - 061200Z ...DISCUSSION... A more seasonal synoptic regime is expected over the CONUS through the upcoming week as long-wave troughing slowly becomes established over the western two-thirds of the country. This will favor lee cyclone development and poleward moisture return ahead of occasional frontal intrusions. In general, ensemble consensus is that a leading, low-amplitude upper disturbance will propagate across the central CONUS during the D4/Wednesday to D5/Thursday period before a more amplified upper trough migrates into the Plains during the D6/Friday to D7/Saturday time frame. While there is broad agreement in this pattern among most guidance, notable discrepancies and spread among solutions limits confidence in the location, timing, or magnitude of any severe threat. ...D4/Wednesday - Southern Plains... A cold front pushing east/southeast across the central U.S. on Tuesday is forecast to stall across the southern Plains into the OH Valley by Wednesday. Aloft, ascent associated with the leading upper disturbance will overspread TX/OK, leading to modest surface low development along the stalled frontal boundary. Continued moisture return coupled with easterly advection of steep mid-level lapse rates will likely yield a reservoir of buoyancy across portions of central/eastern TX/OK and into AR/LA. Thunderstorm development along the frontal zone appears probable by late afternoon, and 40-50 knot mid-level flow attendant to the wave should provide adequate wind shear for organized storms. However, guidance continues to show variability with frontal placement and is likely displaying a northward bias given the tendency for long-range guidance to underestimate low-level cold advection. Additionally, it is unclear whether storm motions and deep-layer shear vectors will be favorably oriented to the front to support discrete convection and a more robust severe threat. ...D6/Friday and D7/Saturday - Southern Plains to the Ohio Valley... More intense surface low development is anticipated across the southern Plains and Great Lakes region Friday into Saturday as an more amplified upper wave begins to migrate east. Northward moisture return will likely continue through Friday with thunderstorm development possible in vicinity to the deepening lee cyclone. Although model variability remains fairly high at this range, ensemble guidance does show a modest QPF signal across OK/KS where the probability for adequate SBCAPE and deep-layer shear for organized convection is reasonably high. On Saturday, the ejection of the upper wave into the Plains will result in the northeastward acceleration of the lee cyclone. Rapid moisture return within a strengthening low-level wind field is possible as the low reaches the Great Lakes region by late Saturday. Based on forecast soundings and ensemble QPF signals, some severe thunderstorm potential is noted along and ahead of a cold front attendant to the low. However, high variability among guidance over the past 24 hours and the potential for a sub-optimal displacement of the primary upper jet with the expanding warm sector casts considerable uncertainty on the overall severe threat.Read more
