Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
298 ACUS02 KWNS 120519 SWODY2 SPC AC 120517 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1217 AM CDT Mon Oct 12 2026 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS INTO THE LOWER MISSOURI VALLEY... ...SUMMARY... Widely scattered severe storms capable of large hail and damaging winds appear possible over portions of the central and southern Plains into the lower Missouri Valley Tuesday afternoon into night. More isolated severe weather may occur from southwest Texas into the mid Mississippi Valley, and in parts of New York. ...Synopsis... An upper low will progress through the Great Basin toward the central Rockies/Four Corners with a downstream belt of enhanced mid/upper-level winds stretching from the southern Rockies through the Great Lakes into the Northeast. Within that airstream, a short-wave trough will progress from the Great Lakes into the Northeast, while a more subtle impulse translates from the southern Rockies into the Upper Midwest. At the surface, an area of low pressure will develop from the Great Lakes into the Northeast with a trailing front stretching through the southern Great Lakes and southern IA into central or southwest KS, where it will link with a secondary surface low. Dryline will extend south from the KS low to along the TX-NM border by late afternoon or early evening. ...Central and Southern Plains into the Mid-Mississippi Valley... Level-2/Slight Risk wind and hail probabilities have been extended to the St. Joseph and Kansas City, MO vicinities in this forecast update to account for greater severe storm potential in a favorable CAPE-shear parameter space. Southerly low-level winds will maintain a moist boundary layer within the warm sector with dewpoints in the mid 60s to low-mid 70s F. While midlevel lapse rates will not be particularly steep, the moist environment coupled with daytime heating will contribute to a moderately unstable air mass by afternoon with MLCAPE of 1000-2000 J/kg. Slight height falls aloft combined with daytime heating and convergence along the surface boundaries are expected to eliminate remaining capping, yielding thunderstorm development by mid afternoon initially from the TX and OK Panhandles into central KS. Subsequent storm development is anticipated by late afternoon into evening farther northeast along the front into the lower-MO Valley. A more isolated wind and hail threat could spread into portions of southern IA and IL Tuesday evening and night. Finally, a separate round of strong to severe storms appears possible Tuesday night into early Wednesday over portions of southwest TX and the Permian Basin. Within the level-2/Slight Risk area, vertically veering wind profiles with 40-50 kt of deep-layer shear will favor supercells as the initial storm mode with large hail being the primary hazard, both along and to the north of the front. There is some model signal that the KS segment of the front may tend to surge south during the afternoon into evening, which would suggest the potential for a relatively quick transition to a more outflow-dominant storm mode and an associated damaging wind threat. Tornado potential will be conditional on supercell storm modes persisting into evening when the low-level jet and associated near-ground shear increase. ...New York... Showers and thunderstorms may be ongoing at 12Z Tuesday within a zone of low-level warm advection and moisture transport preceding the short-wave trough and surface low. Lingering clouds and areas of precipitation are likely to inhibit air mass destabilization, especially with eastward extent into the Hudson Valley. However, where cloud breaks can occur, the presence of boundary-layer dewpoints in the low-mid 60s will contribute to modest MLCAPE up to 500-750 J/kg by afternoon. On the condition that surface-based storms can develop and become sustained, the existence of a strongly sheared kinematic environment (particularly in the low levels) would favor supercells capable of a tornado or two and damaging winds. This forecast update will maintain level-1/Marginal Risk probabilities due to uncertainties in the extent of air mass destabilization. ..Mead.. 10/12/2026 $$