Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
986 ACUS02 KWNS 260541 SWODY2 SPC AC 260540 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sun Jul 26 2026 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE GREAT LAKES INTO PARTS OF THE OHIO VALLEY... ...SUMMARY... Severe storms capable of mainly damaging winds and large hail are possible across the Great Lakes into the Ohio Valley Monday into Monday night. More sporadic occurrences of damaging wind appear possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. ...Synopsis... Within the northeast periphery of an upper high centered over the southern High Plains, a low-amplitude short-wave trough and associated mid-level jet streak will move through the Great Lakes. At the surface, an area of low pressure over WI Monday morning is forecast to develop either south or southeast along a cold front advancing south through the Great Lakes. The western extension of that boundary is expected to stall over the mid MO Valley into central High Plains. ...Great Lakes into the Tennessee Valley and central Appalachians... Latest model data indicate the potential for multiple storm clusters to be ongoing at 12Z Monday from northern MN into the Midwest within a broad zone of warm advection and moisture transport centered around 850 mb. The duration and extent of any early-day storms will have implications on the subsequent air mass destabilization later in the day ahead of the synoptic cold front. Where stronger heating can occur, the presence of boundary-layer dewpoints in the 60s to low/mid 70s beneath the eastern edge of an EML plume will yield MLCAPE as high as 2500-3500+ J/kg. As alluded to above, there is considerable model spread in location of storm initiation and subsequent evolution Monday afternoon into night. That being said, storm development appears most probable along the cold front in WI and lower MI Monday afternoon or evening within a zone of strengthening forcing for ascent preceding the short-wave trough. The presence of 40-50+ kt effective bulk shear magnitudes will support organized storm modes, including supercells initially with an associated large hail threat. The extent of any tornado threat will be dependent on semi-discrete supercells being maintained within a zone of stronger low-level shear from southeast WI and southern lower MI into northern IL and IN, and perhaps western OH Monday afternoon and evening. Damaging-wind potential is expected to increase Monday evening into night as storms coalesce into one or multiple cold-pool-driven MCSs. The preferred corridor for that occurrence still appears to be from lower MI into IN and OH, and perhaps KY, where an upgrade to a level-3/Enhanced Risk may become necessary in later outlooks. Storm clusters capable of damaging winds could reach as far south and east as the TN Valley through Cumberland Plateau and Allegheny Mountains Monday night, owing to modestly strong north/northwest steering winds. ...Mid-Atlantic... A southeastward extension of stronger, mid/upper-level winds is forecast to overspread the region Monday afternoon into night with effective bulk shear approaching 30 kt in some areas during the peak of the diurnal heating cycle. Scattered storms appear possible along a lee trough Monday afternoon within a moist and moderately unstable air mass with MLCAPE up to 1000-2000 J/kg. Steepening low-level lapse rates will enhance damaging wind potential, especially in areas of stronger shear where some cold-pool organization is possible. ...Central High Plains... Aided by a weak mid-level disturbance rotating around the upper high, widely scattered thunderstorms appear possible within a moist and moderately unstable upslope regime Monday afternoon into evening. Forecast soundings indicate a well-mixed boundary layer with sizable temperature-dewpoint spreads, suggesting the potential for a few severe wind gusts with the strongest storms. ...Southeast Arizona... Model soundings indicate some enhancement of easterly mid-level flow across the region Monday with effective bulk shear magnitudes up to 35 kt. The models indicate afternoon storm initiation along the higher terrain closer to the international border within a relatively deep and well-mixed boundary layer. Some cold-pool organization appears possible given the stronger vertical shear with an associated risk of severe wind gusts. ..Mead.. 07/26/2026 $$