894
ACUS03 KWNS 131931
SWODY3
SPC AC 131930

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Sun Jul 13 2025

Valid 151200Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MIDWEST TO THE CENTRAL HIGH PLAINS AND ACROSS THE MID MISSISSIPPI
VALLEY...

...SUMMARY...
Isolated strong to severe thunderstorms are possible Tuesday
afternoon and evening across portions of the central Plains to Upper
Midwest and Mid Mississippi Valley.

...Northern/Central Plains to the Upper Midwest...
A broad upper trough and multiple convectively enhanced shortwave
perturbations moving out of southern Canada should move
east/southeastward over the Northern Rockies Tuesday. A belt of
enhanced mid-level flow (30-40 kt) will also spread eastward,
overlapping with a sagging cold front from the western Great Lakes,
across the northern Plains and into the Rockies. Along and south of
the front, rich low-level moisture is expected with dewpoints in the
upper 60s to low 70s F contributing to 2500-3000 J/kg of MLCAPE.
Ascent from the approach trough and flow aloft will aid in deepening
a lee low across the central High Plains at the junction of the
front and a prominent lee trough. Convergence along these features,
should support scattered thunderstorms Tuesday afternoon and
evening.

With deep-layer shear increasing to 30-35 kt, scattered
thunderstorms organized into multicell clusters or supercell
structures is possible along the cold front from the eastern Dakotas
to the western Great Lakes and within the broader warm sector across
southern SD to central NE. More isolated storms will also be
possible along and east of the lee trough trailing the surface low
to the south. Steep low mid-level lapse rates of 8+ C/km will be
more than sufficient for isolated severe storms capable of damaging
gusts and some hail. Consideration was given to higher severe
probabilities given large forecast buoyancy and more focused forcing
along the front/triple point. However, variability in the timing of
the front and overnight convective influences at this range lend low
confidence to any one solution.

At least an isolated severe risk should also extend westward within
the post-front upslope regime across far southern MT and into
eastern WY and western SD. While buoyancy will be reduced, low-level
moist advection and upslope flow behind the front will support
isolated to widely scattered storms within enhanced mid-level flow.
Hail and isolated damaging gusts are possible.

...Mid MS Valley...
Multiple model solutions show a rather well-defined MCV moving out
of the southern Plains and Ozarks into the mid MS Valley by Tuesday
morning. A very warm and humid air mass will remain in place ahead
of this feature supporting sufficient buoyancy for scattered
thunderstorms. The exact placement and intensity of this feature
remains very uncertain owing to different mesoscale
solutions/convective influence in the coming days. Still, some
enhancement of the low/mid-level flow field could support some
organized clusters capable of damaging gusts.

..Lyons.. 07/13/2025

$$