SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Jun 13 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MONTANA INTO THE CENTRAL HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of large hail and damaging wind gusts will be possible across parts of the central and northern High Plains Saturday afternoon and evening. Additional severe storms will also be possible in parts of southern and central Plains. ...Synopsis... The upper-level trough in the eastern U.S. will weaken during the day on Saturday. Ridging will become more prevalent within the Plains and Southwest. Within the Northwest and northern Rockies, troughing will remain in place. A moist airmass will be in place underneath the upper ridge and will continue to move north and westward given the presence of lee troughing. ...Montana into central High Plains... With the upper-level trough remaining situated within the Northwest/eastern Pacific, moderate mid-level winds and surface troughing will remain in these regions. Moisture should continue to advect into the High Plains/central Montana. Effective shear of 40-55 kts will again support supercell development/maintenance at least early in the convective cycle. Large to very large hail and severe winds will be possible. One or more clusters may also evolve through the afternoon and into the evening. With the low-level jet focusing into Nebraska/South Dakota, clusters could persist a bit farther east in these locations. Severe gusts would be the primary threat with that activity. ...Central/southern Plains... The overall evolution of convection is less certain in these areas. Some guidance continues to show some potential for activity from overnight Friday to continue into Saturday. Whether this activity could reinvigorate as the very moist airmass destabilizes during the day is not clear. With shear decreasing with eastward extent, such a scenario would largely be dependent on mesoscale cold pool dynamics. For now, marginal severe wind probabilities will be maintained over much of Kansas/Oklahoma in order to account for this conditional outcome. Storms are more likely to initiate within the higher terrain or surface lee trough during the afternoon. However, weaker mid-level ascent with southern extent suggests storm coverage will be more isolated in the southern High Plains/Trans-Pecos/Big Bend. Isolated severe gusts and large hail are possible with these cells/clusters. ...Eastern South Dakota/far western Minnesota... A modest increase in the low-level jet during the evening/overnight may promote widely scattered to scattered storms along a boundary. Marginal deep-layer shear and steep mid-level lapse rates would support some risk for marginally severe hail. ...Southeast into Mid-Atlantic... A nebulous upper-level trough will continue to slowly progress east. This feature will likely weaken with time. The moist airmass across these areas may support pockets of larger MLCAPE (from around 1500 J/kg farther east, increasing to near 3000 farther west). With poor lapse rates, ongoing precipitation/cloud cover, and weak mid-level winds, organized severe storms do not appear likely. Isolated wind damage may occur where locally greater surface heating occurs. ..Wendt.. 06/13/2025
