SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Sun Jun 01 2025 Valid 021200Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL/SOUTHERN HIGH PLAINS TO THE NORTHERN GREAT PLAINS... ...SUMMARY... Scattered severe thunderstorms are possible from the central and southern High Plains into the northern Great Plains during the late afternoon and evening on Monday. Severe gusts and large hail are the expected hazards. ...Synopsis... An upper-level split flow regime on Monday will be characterized by a northern stream shortwave trough moving from the northern Rockies to the northern Plains, while a southern stream shortwave trough develops east from the Southwest into the southern/central High Plains. At the surface, an elongated area of low pressure will modestly deepen over the central Plains, with a lee trough extending southward across the southern High Plains. A cold front also will be oriented northeast to southwest from northern MN into northeast CO by 00z. The front will develop southeast into Tuesday morning across the Upper Midwest and central Plains. Both the surface cold front and the southern High Plains lee trough will focus thunderstorm activity during the afternoon/evening. ...NE/CO/WY border area to western MN... Moderate to strong instability is expected to develop along a somewhat narrow corridor ahead of the southeast-advancing cold front during the afternoon. Southwesterly flow aloft will modestly increase into the evening as height falls overspread the region. Strong heating will promote a deeply mixed boundary amid low to mid 60s F dewpoints ahead of the front (lower dewpoints expected further west across CO/WY/NE border area). Initial thunderstorms are likely to develop in an upslope flow regime across the CO/WY/NE border vicinity. High-based supercells capable of severe gusts and hail will be possible. Additional storm development is likely later in the afternoon into the evening along the cold front from central NE into MN. The stronger southwesterly flow aloft is forecast to lag behind the front, and developing convection may quickly move to the cool side of the boundary given boundary-parallel wind profiles. This will likely result in multicell clusters/linear segments capable of producing damaging gusts and large hail in stronger embedded cores. Instability will decrease with increasing inhibition with eastward extent during the evening and severe potential should wane after 03-06z. ...KS to the southern High Plains... Widespread thunderstorm activity is expected to develop over NM/CO in a drier and modestly unstable airmass compared to further east, but aided by steep lapse rates and several impulses ejecting across the southern Rockies ahead of the main upper shortwave trough. Strong outflow winds and hail may occur with this activity as it spreads east across the High Plains. This activity will encounter a corridor of deeper boundary-layer moisture and strong instability from western KS into parts of the Panhandles and western OK toward late afternoon/early evening. At the same time, a low-level jet will be increasing over the southern Plains. As a result, some organization/consolidation of thunderstorm clusters into bowing segments will be possible. This may result in a short window of increased severe gust potential across portions of western KS into western OK. The eastward extent of severe potential will likely be limited across central KS/OK and points east due to modest vertical shear, and as inhibition increases in the 03-06z time frame. ..Leitman.. 06/01/2025