RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat May 16 2026
Valid 161630Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL HIGH PLAINS AND CENTRAL PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...
...SUMMARY...
Severe thunderstorms capable of producing large to very large hail,
severe/damaging winds (some 75+ mph), and a few tornadoes should
occur this afternoon and evening across parts of the central Plains
into Iowa.
...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.
..Mosier/Bunting.. 05/16/2026
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SPC 2000Z Day 1 Outlook
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.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 PM CDT Sat May 16 2026
Valid 171200Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR
NORTHEAST COLORADO...PORTIONS OF NEBRASKA...SOUTHEAST SOUTH
DAKOTA...FAR SOUTHWEST MINNESOTA...AND NORTHWEST IA...
...SUMMARY...
Severe storms are expected Sunday afternoon into Sunday night from
portions of the central Plains into the Upper Midwest. Supercells
with very large hail and strong tornadoes are possible, before one
or more linear bands of storms leads to an increase in the wind
damage risk.
...Synopsis...
A strong upper trough will dig across the western U.S. and pivot
east toward the Rockies/Four Corners vicinity on Sunday into early
Monday. Meanwhile, an early day upper shortwave impulse is expected
to be located over MN/IA. This feature will lift northeast across
the Upper Midwest/Great Lakes through Saturday evening. Enhanced
southwesterly deep layer flow will overspread the central High
Plains to the Upper Midwest while mid to upper 60s F dewpoints
spread north across portions of the southern/central Plains to the
Mid-MO/MS Valley and as far north as southern MN/WI.
At the surface, a lee low will deepen across southeast CO into
western KS. A sharp dryline is expected to extend southward across
west-central KS into far western OK/TX. Meanwhile, a cold front will
extend from eastern SD/central NE into northeast CO by afternoon,
while a warm front extends west to east across southern MN/WI and
into Lower MI. These boundaries will be focus for severe
thunderstorm development during the afternoon/evening.
...Northeast CO into NE/SD/MN/IA...
A volatile environment is expected to develop Sunday afternoon,
particularly across parts of NE/SD/MN/IA. Initial thunderstorm
development is expected across northeast CO into southwest NE within
an upslope flow regime ahead of the approaching synoptic cold front.
Low-level capping and weaker boundary layer moisture is expected
across this area. However, even elevated convection atop the
cooler/drier boundary layer will pose a risk for large to very large
hail given very steep lapse rates, strong vertical shear and
elongated/straight hodographs.
With time, additional convection is expected to develop further east
within the warm sector across parts of eastern NE and southeast SD
near the triple point and on the nose of the dry slot as a subtle
lead shortwave impulse overspreads the region. While some morning
cloudiness and showers could be ongoing across parts of the area
this activity is expected to quickly shift northeast and allow for
clearing. As a result,stronger heating of the moistening airmass
will result in a narrow corridor of strong destabilization (MLCAPE
2500-3500 J/kg). Forecast soundings indicate supercell wind
profiles, with effective shear greater than 40 kt across the region.
Backed low-level winds within the warm sector, veering with height,
will contribute to increasing low-level SRH and favorably curved
low-level hodographs. While the corridor for discrete supercells
will be narrow, partly due to capping and modest large-scale ascent
and partly due to the advancing cold front resulting in upscale
growth, the expectation is for a few supercells capable of producing
strong tornadoes and large to very large hail across northeast
NE/far southeast SD/southwest MN and northwest IA.
With time, one or more linear/bowing segments is expected to develop
near the east/southeast-advancing cold front and as the low-level
jet increases during the evening. An attendant risk of severe wind
gusts will accompany this activity. The severe risk will diminish
with time and eastward extent during the nighttime hours as
instability weakens and capping increases.
...KS/OK vicinity...
A more conditional risk is expected across KS into the southern
Plains vicinity. Capping and weak large-scale ascent will likely
inhibit convection. Nevertheless, a favorable thermodynamic and
kinematic environment will reside along the surface dryline from
west-central KS into western OK and eastern parts of the TX
Panhandle toward western north TX. Hot conditions behind the dryline
and moderate low-level convergence, particularly across the
northwest OK vicinity, may support sufficient mixing/deeper dryline
circulations such that a few storms develop. If these storms
develop, they will likely be higher based. Given very steep low to
midlevel lapse rates, moderate instability, and supercell wind
profiles, large to very large hail and strong/severe wind gusts will
be possible. Any storms that develop may struggle to move off the
dryline, and the corridor for severe potential will likely remain
confined.
...Lower MI...
Isolated thunderstorm are possible Sunday afternoon as a warm front
lifts northward and a weak upper shortwave impulse overspreads the
region. Weak to moderate destabilization is forecast as low-level
moisture increases beneath modest midlevel lapse rates. While
low-level winds will be light, vertically veering wind profiles and
increasing southwesterly mid/upper level flow will support organized
updrafts. Isolated gusty winds or small hail could occur with any
surface-based storms that occur into the evening hours.
..Leitman.. 05/16/2026
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Sat May 16 2026
Valid 181200Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
OKLAHOMA...CENTRAL/EASTERN KANSAS...SOUTHEAST NEBRASKA...PARTS OF
IOWA...AND NORTHWEST MISSOURI...
...SUMMARY...
Numerous strong thunderstorms are expected to develop Monday along a
cold front and dryline extending from the Great Lakes into the
central/southern Plains. Supercells capable of all hazards
(including very large hail and strong to intense tornadoes) will be
possible across central Kansas into southeastern Nebraska.
...Synopsis...
An upper trough is forecast to extend from MT to the Four Corners
Monday morning. An upper shortwave trough emanating from the base of
the larger-scale western U.S. trough is forecast to lift northeast
across the central Plains to the Upper Midwest through the period.
As this occurs, a belt of strong southwesterly midlevel flow will
overspread OK/KS into IA and the Great Lakes vicinity. Beneath
enhanced southwesterly deep layer flow, rich Gulf moisture will
spread north/northeast from the southern Plains into the Mid-MS
Valley and Great Lakes. Meanwhile, a cold front will reside from the
Upper MS Valley to a surface low over central KS during the
afternoon. A dryline will extend southward from the KS surface low
into western OK/west-central TX. A volatile environment is expected
across parts of the warm sector, particularly across KS into IA,
where significant all-hazards severe storms are expected.
...Central KS into southeast NE/southwest IA/northwest MO...
Upper 60s to low 70s F dewpoints are forecast ahead of the dryline
and cold front. This area should remain mostly free from convective
contamination from any continuing convection from late in the Day
2/Sunday period. Strong heating and very steep midlevel lapse rates
will contribute to strong destabilization. Supercell wind profiles
are expected, with backed low-level winds veering with height, while
also increasing in speed. Southerly 850-700 mb flow is forecast to
strengthen in the 21-00z time frame as large-scale ascent also
increases. This will allow for enlarged low-level hodograph
curvature and increasing 0-1 km SRH. Robust convection will develop
within the warm sector and supercell capable of very large hail (2-4
inch diameter), strong to intense tornadoes, and damaging wind gusts
will be possible.
With time, convection will likely grow upscale as the surface cold
front begins to develop southeast through the evening/nighttime
hours.
...Central IA into portions of IL/WI/IN/Lower MI...
Uncertainty is greater with northeast extent on Monday. Ongoing
convection and cloud cover is possible across parts of IA into WI
Monday morning. Regardless, a moist airmass will be in place.
Depending on location and extent of morning convection, airmass
recovery is possible. Furthermore, downstream destabilization into
parts of northern IL/IN and Lower MI seems more likely. This could
result in re-intensification of any morning convection as it spreads
east. While convective evolution remains uncertain, a damaging wind
and hail risk appears possible.
...OK/TX...
A more conditional severe risk exists further south across OK/TX.
Large-scale ascent will remain weaker further south. However, strong
instability within the very moist warm sector will exist. Deep layer
flow will be somewhat less compared to further north, but still
sufficient for supercells. If storms can develop, a risk for large
to very large hail will exist.
..Leitman.. 05/16/2026
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