Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Tue Aug 05 2025
Valid 051300Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
NORTH AND SOUTH DAKOTA...
...SUMMARY...
Thunderstorms associated with a threat for severe gusts and large
hail will be possible across parts of the Dakotas today into this
evening.
...Northern Plains...
Warm-air advection showers and thunderstorms are ongoing this
morning across the western Dakotas, where the western edge of the
low-level jet overlaps the eastern edge of the steep mid-level lapse
rates. These storms will likely continue northeastward this morning,
perhaps even expanding in coverage, as the low-level jet persists
and large-scale ascent attendant to an approaching shortwave trough
strengthens. Occasionally strong updrafts could produce hail and a
damaging gust or two.
Cloud cover and outflow associated with these storms could result in
an effective warm front extending from a weak low over western SD
eastward across central and eastern SD. The exact location and
sharpness of this front remain uncertain. Given that the shortwave
trough will likely remain well west of the region, low-level
convergence near this boundary as well as the surface low should
both be areas where convective initiation is most likely this
afternoon. Ample buoyancy and vertical shear will be in place for
supercells with the initial development, with large hail and
damaging gusts as the primary risks. Stronger low to mid-level flow
may be in place across eastern SD, contributing to greater low-level
shear and relatively higher tornado potential. Primary concern
across eastern SD is whether or not the warmer low to mid-level
temperatures inhibit the development of mature updrafts.
One other scenario that seems plausible is for storms on southern
periphery the ongoing cluster to become increasingly surface based
as they move eastward/northeastward with time. Given current trends
and recent guidance, this would most likely occur along the eastern
ND/SD border after 20Z. As previously mentioned, hail is possible
within this cluster throughout the day, but the transition to a more
surface-based character could introduce the threat for stronger
gusts as well.
A strengthening low-level jet coupled with persistent mid-level
westerlies support the potential for upscale growth in a
east-southeastward progressing MCS. Damaging gusts will be possible
with this MCS, particularly over SD, but increasing low-level
stability should result in a gradually diminishing severe potential
with eastward/southeastward extend into northeast NE, northwest IA,
and southwest MN.
..Mosier/Bentley.. 08/05/2025
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