SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Thu Oct 16 2025 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms associated with marginally severe hail will be possible on Thursday in the late afternoon across parts of the central High Plains. ...Synopsis and Discussion... Broad upper troughing over the western CONUS will move gradually eastward today as an embedded upper low progresses northeastward from eastern UT through the western Dakotas. Moderate to strong mid-level flow will extend through the eastern periphery of this low, spreading from southern/central Rockies northeastward through the northern/central Plains and Upper Midwest. Primary surface low associated with this system will also track northeastward, beginning the period over the western NE/SD border vicinity and likely ending the period occluded over the north-central ND/south-central MB vicinity. This progression will push a cold front eastward across the Dakotas and western NE, and southeastward across northeast/east-central CO, and far northwest KS. The cold front is forecast to move through western NE, northeast CO, and far northwest KS around peak heating. Low-level moisture will be modest (i.e. dewpoints generally in the low 50s), but strong boundary-layer mixing will result in steep low-level lapse rates and temperatures in upper 70s/low 80s. These conditions should be sufficient for modest buoyancy, despite the limited low-level moisture. Thunderstorms are expected near the front as a combination of large-scale forcing for ascent and lift along the front interact with the modest buoyancy. Moderate to strong (i.e. 50 to 60 kt) effective bulk shear is expected to be in place, supporting the potential for some more organized storms. Hail is the primary severe risk, but a few strong gusts are possible as well. Southerly to perhaps even southeasterly surface winds will result in some low-level curvature near the front in northeast CO, northwest KS, and southwest NE, to east/northeast of a secondary surface low over eastern CO. A low-probability tornado threat will result, but front-parallel shear suggests a mostly linear mode as well as tendency for undercutting by the cold front. As such, any tornado threat should remain low. Farther north, elevated instability will be maintained across the northern Plains due to a broad area of 30-50 kt south/southwesterly low-level jet. Colder temperatures aloft over the northern High Plains could support small hail at times as activity develops ahead of the approaching upper low. ..Mosier/Weinman.. 10/16/2025
