Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
960 ACUS02 KWNS 300530 SWODY2 SPC AC 300528 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CDT Thu Jul 30 2026 Valid 311200Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM IOWA SOUTHWARD INTO THE OZARK PLATEAU...AND OVER THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... At least isolated severe storms appear possible from Iowa southward into the Ozark Plateau, and over the central and southern High Plains Friday afternoon and evening. Sporadic occurrences of damaging wind and large hail will be the primary hazards with a conditional risk for a few tornadoes, mainly in Missouri. ...Synopsis... A short-wave trough from the upper Midwest into mid MO Valley Friday morning will translate into the mid MS Valley with a belt of 30-35 kt winds forecast within the western through southern periphery of that feature. At the surface, an area of low pressure is expected to undergo slight deepening while developing from northwest or central IA at the start of the period into southern IL by late Friday night. Meanwhile, a trailing cold front will advance south/southeast into the southern Plains and Ozark Plateau. ...Lower Missouri and mid Mississippi Valleys into the Ozark Plateau... Mainly elevated showers and thunderstorms are expected to be ongoing at 12Z Friday across portions of IA and MO within a zone of forcing for ascent ahead of the mid-level system, and warm advection and moisture transport along a 30-40 kt low-level jet. Those mechanisms are likely to sustain deep convection through the morning into afternoon east of the surface low, mainly across IL. In the wake of the early-day storms and where cloud breaks can occur, daytime heating combined with boundary-layer dewpoints in the low to mid 70s is expected to yield a relatively narrow axis of moderate instability with MLCAPE of 1000-2500+ J/kg. Additional surface-based storms are expected to develop by early- to mid afternoon initially near the surface low in south-central or southeast IA with subsequent southward development along or ahead of the front across MO. The 00Z CAMs suggest that the initial storm mode will be semi-discrete, which is consistent with model forecasts of 30-35 kt deep-layer shear vectors oriented largely perpendicular to the initiating boundary. While some marginally severe hail is possible with any supercell structures, warm mid-level temperatures will contribute to considerable melting, potentially limiting that threat. Damaging wind potential may be limited by storm mode with a more substantial threat being dependent on upscale growth into clusters or a cold-pool-driven MCS. Tornado potential remains unclear as the models suggest the strongest low-level shear will remain displaced to the east of the primary instability axis. That being said, a conditional threat for a few tornadoes appears possible with: 1) storms forming near or to the south of the surface low, should modest low-level CAPE develop in the presence of locally enhanced vertical vorticity, and 2) any supercells that can form in the warm sector and move east into the stronger low-level shear forecast across eastern MO during the late afternoon into evening. Given the above uncertainties, a level 1/Marginal Risk will be maintained with this forecast. ...Colorado and New Mexico... Initially northerly, post-frontal winds Friday morning are expected to switch to northeast and then east by afternoon into evening, supporting isolated to widely scattered thunderstorms along favored terrain. MLCAPE on the order of 1000-2000 J/kg will coincide with 30-35 kt of deep-layer shear, suggesting the potential for at least transient supercell structures capable of large hail. With time, storms may grow upscale into clusters with a relatively deep, well-mixed boundary layer enhancing the potential for locally severe wind gusts. This is especially the case across parts of eastern NM Friday evening where the merging of the terrain-induced storms and cold-frontal storms could organize a more substantial cold pool. ..Mead.. 07/30/2026 $$