Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sat May 16 2026
Valid 162000Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL HIGH
AND CENTRAL PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
LOWER OHIO VALLEY...
...SUMMARY...
Severe thunderstorms capable of producing large to very large hail,
severe/damaging winds (some 75+ mph), and a few tornadoes remain
likely this afternoon and evening across parts of the central Plains
into Iowa.
...20z Update OH valley/Midwest...
Ahead of several MCVs and outflow from prior convection, ample
heating is supporting destabilization amid mid to upper 60s F
surface dewpoints. Scattered thunderstorm development is likely
across over southern IL/IN into northern KY through this evening.
Moderate buoyancy and ~30 kt of deep-layer shear will promote a mix
of organized multicell structures capable of damaging gusts and some
hail. A tornado or two also remains possible with any stronger
linear clusters or transient supercells able to become established.
See MCD#735 for short term information.
...Central High Plains to the Mid MO Valley...
Several foci for strong to severe convection remain apparent this
afternoon along a broad frontal zone from the Rockies/High Plains to
the Mid MO Valley. Scattered severe storms are expected this
afternoon and evening near the intersection of the surface trough
and stalled front across the mid MO Valley. Moderate to strong
destabilization and 40+ kt of westerly deep-layer shear will support
supercell structures with large hail and damaging winds over te mid
MO Valley. A locally greater tornado risk may develop with any
sustained supercells across parts of eastern NE and southern IA into
northern MO where baked low-level flow near a modifying outflow
boundary intersects with the stalled front.
Initial convective development within the broad upslope regime
across the higher terrain of the central Rockies and adjacent High
Plains should continue to intensify as it moves eastward this
afternoon/evening encountering progressively stronger buoyancy and
shear. This will support supercells with large to very large hail,
damaging gusts and a tornado or two from northeastern CO and
southwest NE into northwest KS. Upscale growth into one or more
clusters with a continued severe threat is expected tonight along
and north of the stationary front across the central Plains. See
MCD#736 for more information.
...Southern Plains...
A conditional risk for strong thunderstorms remains apparent along
the dryline late this afternoon/evening across portions of the
eastern TX Panhandle and western OK. Displaced from the stronger
deep-layer shear, and likely high based owing the strong low-level
mixing, predominately multi cell storms are possible amid steep
mid-level lapse rates and moderate buoyancy (1500-2000 J/kg MLCAPE).
Confidence in convective initiation remains low but a risk for
damaging gusts and hail remains possible.
..Lyons.. 05/16/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sat May 16 2026/
...Central High Plains into Mid MO Valley...
Recent surface analysis placed a low over southwest KS, with a warm
front extending through a low over far southeast NE to a third low
over southern WI. The low over southwest KS is forecast to fill
while another low develops back farther west across southeast CO
today. As it does, low-level moisture advection will persist across
the central Plains, while a deeper upper trough traverses the
Intermountain West. Combination of low-level convergence east and
north of the surface low and increasing large-scale ascent will
favor thunderstorm development during the late afternoon/early
evening across northeast CO. This initial activity is expected to be
supercellular, with large to very large hail as the primary risk.
This initial activity should be high-based, with strong downdrafts
resulting in a quick transition to a linear mode. Even so, some
tornado risk is still apparent, particularly with the southernmost
supercells that persist through the early evening when a
strengthening low-level jet will lengthen low-level hodographs
considerably.
Most guidance continues to suggest that an intense bowing cluster,
with significant wind gusts over 75 mph possible, will develop and
spread eastward along/near the warm front from along the southern
NE/northern KS border vicinity through the evening. Given the
organized nature of this line, it should persist throughout most of
the night, and an eastward expansion has been made to the Enhanced
Risk to account for increased probability of strong gusts into more
of southeast NE.
A separate area of intense thunderstorms is anticipated farther east
this afternoon/evening along/near the warm front. Given the ongoing
thunderstorms across northern MO, there is some question to where
the front consolidates this afternoon. Consensus within the guidance
places it from far southeast NE across southern IA, but there is
some chance it ends up a bit farther south in far northern MO.
Robust thunderstorm development is expected along this boundary this
afternoon amid strong low-level moisture advection and heating, and
persistent low-level convergence. Environmental conditions support
supercells capable of all severe hazards, including large to very
large hail (isolated 2"+ inches in diameter) and tornadoes, but a
messy convective mode and related storm interference could disrupt
updrafts and may limit discreteness. Tornado risk will be focused
along/near the front where backed low-level easterly winds may
locally enhance 0-1 km SRH. Some clustering is possible, with an
attendant threat for more damaging gusts wherever this clustering
occurs.
...Mid Mississippi Valley into the Midwest/Ohio Valley...
With the primary shortwave trough well west of the region, mesoscale
features will dominate the severe potential across the region today.
One such feature is the MCV currently moving through southeast MO.
This feature is expected to result in a localized increase in
mid-level flow along its eastern periphery as it progresses
eastward/northeastward along the OH River vicinity. Filtered heating
and/or outflow from the ongoing showers and thunderstorms could
result in a baroclinic zone ahead of this vorticity maximum from
north-central KY into far southern IN. Expectation is that ascent
attendant to the MCS coupled with low-level convergence along this
boundary will result in additional thunderstorm development this
afternoon.
The locally enhanced mid-level flow coupled with modest low-level
southerly flow should result in moderate vertical shear, with
effective bulk shear values from 30 to 40 kt. This is sufficient for
updraft organization, but the mixed boundary layer will likely
support strong downdrafts. The general expectation is for an early
mostly multicell/isolated supercell mode to transition quickly to a
more linear mode with one or more bowing line segments. Isolated
hail is possible early in the convective cycle, with a trend towards
more damaging gusts with time. Given the modest and veered low-level
flow, the tornado potential will be low, but the presence of a
boundary suggests that there remains a low-probability tornado risk.
...Southern High Plains...
Isolated thunderstorms may initiate this afternoon along the surface
dryline from southwest KS into the eastern OK/TX Panhandles and
western OK. While deep-layer shear will be weaker with southward
extent across the southern High Plains, a narrow zone of minimal
MLCIN along/east of the dryline may support isolated convection
capable of producing both locally severe hail and wind gusts.
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