


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
771 ACUS02 KWNS 151738 SWODY2 SPC AC 151736 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1236 PM CDT Sun Jun 15 2025 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF MINNESOTA INTO NEBRASKA... ...SUMMARY... Scattered severe storms with areas of damaging winds and hail are forecast on Monday from the north-central High Plains into the upper Mississippi Valley. ...Synopsis... An early shortwave trough associated with an MCS will move east out of ND across northern MN during the day, with modest westerlies aloft behind it over the central Plains to northern Rockies. Height falls will occur behind the northern wave as it breaks down the antecedent ridge. Midlevel temperatures will generally be cool with around -10 C at 500 mb. At the surface, a trough will exist from northern MN near the convective system southwestward across NE. Sufficient moisture will exist behind this boundary across MT and WY for afternoon storms, with a nocturnal low-level jet aiding overnight development further across much of NE. ...MN/IA/SD... An MCS is likely to be ongoing Monday morning from ND into northern MN, with associated midlevel wave. As this feature continues east during the day, a conditional threat of supercells will develop along the southern periphery, even if only an MCV by afternoon. Here, a low-level lapse rate plume will develop out of the southwest. A couple tornadoes may occur along with large hail. Additional isolated cells will be possible trailing southwestward across southern MN, northern IA, and perhaps southeast SD and northeast NE. In favor of large hail potential will be strong instability with > 3000 J/kg MUCAPE, however, deep-layer shear appears less than optimal, suggesting more of a localized sig hail threat. Otherwise, enhanced low-level shear near along the southern periphery of the MCS/MCV influence may yield tornado potential. ...MT/WY/NE... Strong heating and gradual cooling aloft will steepen lapse rates and favor scattered cells capable of hail and wind from southern MT across much of eastern WY during the afternoon. Additional cells may develop over the Black Hills. With time, an MCS is likely to develop, with strong to severe gusts over much of western into central NE. A deep boundary layer and hot temperatures preceding the MCS will likely aid evaporation/downdraft potential, with southwest 850 mb wind favoring propagation. ..Jewell.. 06/15/2025 $$