SEVERE WEATHER OUTLOOK
Day 1 Convective Outlook
Forecast Discussion
SPC AC 120028 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0728 PM CDT Fri Sep 11 2026 Valid 120100Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER FAR EASTERN SOUTH DAKOTA INTO PORTIONS OF MINNESOTA... ...SUMMARY... Widely scattered severe thunderstorms capable of producing large hail up to two inches, damaging winds, and a couple of tornadoes will continue through the remainder of the evening into tonight from far eastern South Dakota into portions of Minnesota. Isolated occurrences of severe wind gusts and large hail remain possible over parts of the central Plains tonight. ...Upper Mississippi Valley into the central Plains... A broken band of thunderstorms has recently developed from far eastern SD into north-central MN within a relatively narrow instability axis preceding a surface cold front and dryline. The presence of steep mid-level lapse rates (per 00Z ABR sounding) atop boundary-layer dewpoints in the mid to upper 60s F is resulting in MLCAPE up to 1500-2000 J/kg. As mentioned above, the corridor of stronger instability and minimal capping is rather narrow longitudinally, which suggests the severe weather threat may remain somewhat limited spatially into tonight. The KFSD VWP is likely indicative of the ambient kinematic environment, which features 35-40 kt of deep-layer shear and relatively strong low-level shear, supportive of a supercell storm mode with the primary hazard being large hail up to two inches. Tornado potential will be conditional on the maintenance of semi-discrete supercells residing within the narrow axis of minimal convective inhibition. Damaging wind potential may tend to increase by late evening as thunderstorms evolve into line segments. Additional storms appear possible late this evening into tonight ahead of a southeastward-moving cold front over portions of eastern and central NE. Similar to locations to the north, a relatively narrow zone of minimal convective inhibition and moderate instability exists ahead of the front, which leads to uncertainty in the areal coverage and duration of the threat. Severe wind gusts will be the primary hazard with any surface-based storms that can become established, though isolated occurrences of large hail are also possible. ..Mead.. 09/12/2026 NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
Updated: Sat Sep 12 00:28:48 UTC 2026 (
Day 2 Convective Outlook
Forecast Discussion
SPC AC 111726 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Sep 11 2026 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL PLAINS...AND FROM OHIO/WEST VIRGINIA INTO PARTS OF WESTERN PENNSYLVANIA... ...SUMMARY... Widely scattered strong to severe storms may develop Saturday afternoon and evening over parts of the Central Plains. Isolated activity may also affect parts of the Upper Ohio Valley into western Pennsylvania. ...Central Plains... Substantial forecast uncertainty exists on Saturday given the subtle forcing mechanisms at play. In general, sporadic severe storms appear will be possible as instability becomes strong south of a cold front from eastern KS into northwest OK where temperatures will become hot with minimal CIN. Even near/north of the cold front (into southeast NE, southern IA, northern MO), elevated instability may favor large hail. Overall lapse rate profiles will be steep, favoring both hail and wind, with sufficient mid to high level winds and deep-layer shear. Low-level winds will remain weak, and may favor highly deviant storm/cluster motions through the evening. ...Eastern OH/WV into western PA... A weak midlevel wave is forecast to move across the region, with around 35 kt winds at 500 mb. Dry air will exist northeast of the region, but surface pressures will drop with increasing low-level moisture out of the south and mid to upper 60s F dewpoints developing. Storms are generally forecast to develop over OH and northeast KY, spread east across WV and western PA. Given the increasing wind speeds and somewhat favorable low-level shear, some of the storms could eventually produce damaging gusts, most likely as peak instability is achieved. ..Jewell.. 09/11/2026 NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
Updated: Fri Sep 11 17:26:54 UTC 2026 (
Day 3 Convective Outlook
Forecast Discussion
SPC AC 111921 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0221 PM CDT Fri Sep 11 2026 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEASTERN STATES...AND NORTHERN PLAINS... ...SUMMARY... Strong storms accompanied by at least some risk for severe weather may occur across parts of the Northeast, and across parts of the north central Great Plains Sunday into Sunday night. ...Ohio into the Northeast... A large upper low/trough will push across eastern Canada on Sunday, with a strong speed max aloft spreading across the Great Lakes late in the day. A cold front will push toward the OH Valley and Lower Great Lakes late in the day, with a moist and marginally unstable air mass ahead of it. Areas of heating and lift near the boundary should support scattered afternoon/evening storms, and deep-layer shear of 30 to perhaps 40 kt could support a degree of organization. Lapse rates aloft appear to be poor overall, suggesting only a Marginal Risk of damaging gusts or hail will exist. ...Northern Plains... High pressure will move from the northern Plains to the Upper Great Lakes as shortwave ridging occurs over the Plains during the day. A compact yet deep upper low is then forecast to move into the northern Rockies, with height falls increasing over the northern High Plains Sunday night. The steeper low-level lapse rates will be confined to the higher terrain from east-central WY to the Front Range in CO, with generally stable low levels to the east due to high pressure. After a days worth of heating, isolated surface-based storms may occur late over eastern WY, with additional activity developing within the warm advection regime as the low-level jet increases over the central Plains. The overall threat appear minimal, and likely in the form of marginal hail. ..Jewell.. 09/11/2026 NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
Updated: Fri Sep 11 19:21:14 UTC 2026 (
