Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri May 15 2026

Valid 151200Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
IOWA...

...SUMMARY...
Severe storms producing damaging winds and large hail are likely
from Iowa into northeast Kansas. Isolated hail or damaging wind
gusts are possible over a large area from western Texas into
Wisconsin and western Illinois.

...Synopsis...
Moderate westerly winds aloft will exist across the northern tier of
states today, with several waves from the Pacific Northwest to the
Great Lakes. The feature of interest will move across the Dakotas
and toward the upper MS Valley late in the day, aiding storm
development and severity from NE into WI. To the south, a weak
shortwave trough will move out of NM and into TX, with mid and high
level flow enhancement along with modest cooling aloft.

At the surface, low pressure will develop from southwest KS into the
TX Panhandle, with a front extending into NE, southern MN, and into
northern WI. Increasing southerly winds during the afternoon and
evening will bring 60s F dewpoints northward toward these
boundaries, with scattered severe storms likely late in the day and
centered near Iowa.

Farther south, very steep lapse rates and a subtle upper trough
should again result in widely scattered high-based storms producing
severe gusts over the southern High Plains.

...IA into eastern NE and northeast KS...
Southerly winds and daytime heating will support moderate
instability this afternoon near a surface trough which will extend
from eastern NE into southern MN and northern WI. Dewpoints are
expected to reach into the lower 60s F, and perhaps approach 65 F
during the early evening. Meanwhile, midlevel temperatures will be
cool, resulting in steep lapse rates and robust CAPE profiles.

Storms are most likely to initiate during the late afternoon near
the IA/SD border, and extending northeastward into WI and perhaps
the central MI Upper Peninsula. Large hail will be possible with the
initial cells, supported by 60 kt deep-layer shear. Hail to 2.00"
diameter will be possible even into WI.

Farther south into IA, the deeper theta-e plume and increasing
low-level jet will enhance the severe wind risk, with an MCS
expected to develop and move east/southeast across the region.
Damaging winds with a few gusts over 70 mph are expected. Additional
clusters of severe storms are expected from southeast NE into
northeast KS as well, firmly within the low-level theta-e plume with
maximally deepened moist layer to 700 mb. Shear will not be as
strong, but the initial development is expected to be robust with
large hail and damaging wind gusts.

...Southwest KS into western Texas...
Strong heating will yield very deep mixed layers near and south of
the Panhandles surface low, while midlevel temperatures remain cool
enough to support instability despite very low dewpoints. Meanwhile,
the aforementioned shortwave trough will enhance lift late in the
day. The result will be scattered high-based thunderstorms, with
severe wind gusts expected. Isolated gusts over 70 mph may occur.
Cells that develop into southwest TX may contain marginal hail as
well, with elongated hodographs in the mid to upper levels.

..Jewell/Squitieri.. 05/15/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1256 AM CDT Fri May 15 2026

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS...

...SUMMARY...
Severe storms capable of large to very large hail, wind damage and
perhaps a couple of tornadoes will be possible Saturday afternoon
and evening across parts of the central Plains. Scattered
thunderstorms will also pose potential for strong to severe winds
across the lower to mid- Missouri Valley.

...Synopsis...
A trough is expected to begin to deepen across the western US as
strengthening mid-level flow moves southward from the northern
Pacific Friday and Saturday. Downstream across the central US,
upper-level westerly flow will strengthen across the
central/northern Rockies with strengthening lee troughing across the
Plains. Persistent southerly flow through the southern and central
Plains should establish a broad warm sector across the Plains,
bounded to the west by a dryline and to the north by a diffuse warm
frontal zone. Scattered thunderstorm development is expected across
portions of the central high Plains near a developing surface low
and along the warm front, with additional thunderstorms possible
along the dryline from eastern Kansas to western Oklahoma. Scattered
thunderstorms will also be likely across portions of the lower to
mid Missouri Valley.

...Central Plains...
As a short-wave trough moves across the central Plains late Saturday
afternoon, scattered thunderstorms are expected to develop near the
deepening surface low and the warm front by the afternoon across
eastern CO, northwest KS, and western NE. A broad warm sector will
be in place across much of the central Plains, with low to mid 60s
dew points reaching as far north as southern Nebraska. MLCAPE around
2000-2500 J/kg will be common by the afternoon. Initially, strong
deep layer shear and largely linear hodographs will support
potential for supercells capable of large to very large hail,
damaging winds, and a tornado. As the low-level jet strengthens into
the evening, low-level shear will increase but storm mode will also
likely shift to become more linear, with broken clusters/bowing
segments likely. A few of the mid-range hi-res CAMs depict a
stronger bowing segment moving across southern Nebraska into the
evening in concert with the increasing of the low-level jet. This
may present a more focused corridor of significant wind potential.
Confidence at this time in the exact location of this remains low.
Higher probabilities may be needed in subsequent outlooks if trends
align. 

...Western Oklahoma/northwest Texas...
Much of western Oklahoma and northwest Texas near the dryline will
remain capped at the base of the EML. Strong daytime heating and
favorable residence time within the dryline circulation may promote
an isolated supercell or two with potential for large to very large
hail and damaging winds by the late afternoon. Signal for
development is most favorable near the Red River in southern
Oklahoma where CAM guidance suggests potential and HREF calibrated
thunder probabilities are highest.

...Midwest/OH Valleys...
A leading mid-level shortwave trough with an enhanced belt of 50 kts
winds aloft will promote widely scattered thunderstorm development
into the mid- to upper Missouri Valley Saturday afternoon. MUCAPE
values on the order of 1000-2000 J/kg should support deep
convection, and effective bulk shear values near 30 knots within the
warm frontal zone may allow for organized convection with an
attendant threat for damaging wind.

..Thornton.. 05/15/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0231 AM CDT Fri May 15 2026

Valid 171200Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Severe storms will be likely Sunday from portions of the central and
southern High Plains into the Upper Midwest. Supercells capable of
all hazards will be possible before upscale growth and an emerging
damaging wind risk continues into the evening.

...Synopsis...
An upper-level trough will begin to eject across the Intermountain
West on D3/Sunday with a more subtle shortwave trough moving across
the central Plains. As a result, deepening low pressure will develop
across eastern Colorado/western Kansas with strengthening southerly
flow and warm moist advection south of a warm front lifting
northward into the northern Plains and upper Midwest. Early in the
period, elevated storms will likely be ongoing across portions of
Iowa into southern Minnesota. Scattered severe storms capable of all
hazards will be expected to develop near the warm front/low across
eastern Colorado into Nebraska and across southern South Dakota
continuing into portions of the upper-Midwest along the cold front
through the evening. A more isolated and conditional threat for
severe storms will extend southward along the dryline from western
Kansas into western Oklahoma.

...Central Plains into the Upper Midwest...
Early day elevated convection is expected to move across portions of
Iowa into the upper-Midwest. This will pose some risk for severe
hail through the morning. Across the central Plains, strong daytime
heating is expected to yield moderate to strong instability across
much of the central Plains. This in combination with strong deep
layer shear suggests a rather volatile environment, particularly
across central Nebraska into southern South Dakota/northwestern
Iowa. Guidance suggests that thunderstorms will develop across
eastern Colorado into Nebraska by the afternoon. Initial
thunderstorm development will likely be supercellular and capable of
all hazards including large to very large hail, damaging wind, and
tornadoes. As the front sags southward through the evening, eventual
upscale growth into a squall line is expected by the evening. A
strong 50 kt low-level jet will ramp up into the evening, which may
support a continuing potential for tornadoes, some of which may be
strong. 

...Western Kansas into western Oklahoma...
A more conditional threat may extend southward along the dryline
into western Kansas and western Oklahoma. Guidance suggests some
signal for isolated supercells to develop along and east of the
dryline Sunday afternoon. The environment here will conditionally
favor large to very large hail, damaging wind, and perhaps a tornado
or two with the strengthening low-level jet in the evening.

..Thornton.. 05/15/2026