RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Sun Apr 12 2026
Valid 122000Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
CENTRAL TEXAS...
...SUMMARY...
Isolated to scattered severe thunderstorms remain possible today
into evening mainly across parts of Texas and perhaps other nearby
parts of the southern Plains. More isolated severe storms may occur
across portions of the Upper Great Lakes and northern Rockies.
...20z Update Central TX...
Filtered diurnal heating in the wake of earlier showers and storms
across much of central TX was supporting moderate destabilization
this afternoon. While mid-level lapse rates are generally poor,
sufficient destabilization should support a gradual uptick in
convective coverage this afternoon and evening. With moderate
deep-layer shear in place, some organization could support a risk
for damaging gusts, hail, and tornado or two.
...MN/WI...
The aforementioned warm front continues to surge north but has
slowed farther south than earlier guidance. Weak to moderate
destabilization along and just south of the boundary will remain
supportive of a conditions supercell risk this afternoon/evening.
Strong shear profiles east of the surface low and near the rapidly
modifying boundary could support a risk for hail and possibly a
tornado. Have shifted severe probabilities southward slightly to
better match the observed frontal positioning. See MCD #390 for the
latest information.
...OK/KS/TX Panhandle...
A conditional risk for a supercell or two remains evident this
afternoon across the dryline in the central and southern Plains.
Ample heating in the wake of an early morning MCS could allow for
isolated storm this afternoon or evening as the dryline is forecast
to mix eastward before eventually retreating. Forecast guidance
continues to show weak subsidence suppressing convective
development, but deepening cumulus evident over the southern TX
Panhandle could support an isolated storm this evening. All severe
hazards would be possible.
...Intermountain West...
Steep mid-level lapse rates beneath the cold core of the upper low
over the West will continue to support scattered high-based storms
this afternoon. With a relatively dry-sub cloud layer, somewhat deep
boundary-layer mixing will support strong to
severe downburst winds.
..Lyons.. 04/12/2026
.PREV DISCUSSION... /ISSUED 1129 AM CDT Sun Apr 12 2026/
...Synopsis...
Recent satellite imagery shows a pair of phased shortwave troughs
over the Plains, one moving through the Dakotas and another moving
through KS/OK. Both of these waves are forecast to continue
northeastward through the day, with the northern wave reaching
northwestern Ontario and the southern wave reaching the Great Lakes
region. This evolution will take these waves east/northeast of the
higher low-level moisture, which will remain in a corridor from the
southern Plains northeastward into the Upper Midwest. Showers and
thunderstorms are anticipated throughout much of this corridor
today, with highest thunderstorm chances across central/east TX and
from the Upper Midwest into the Great Lakes.
Farther west, an upper low is slowly drifting eastward across
northern CA. Guidance suggests this eastward drift will continue
today, with several shortwave troughs rotating quickly through the
base of this system and ejecting across the Great Basin and northern
Rockies. Large-scale ascent and modest mid-level moisture associated
with these waves will combine with cold temperatures aloft and
associated buoyancy to support thunderstorms today from northern CA
across the northern Great Basin and northern Rockies, and into the
northern Plains.
...Southern/Central Plains...
Much of this region will be displaced south and west of any notable
large-scale forcing for ascent. This limited ascent, combined with
the showers and isolated thunderstorms currently ongoing across
central and east TX, complicates the overall forecast today, with
mesoscale factors likely contributing significantly to when and
where storms develop this afternoon and evening. General expectation
is for development along the southern and western periphery on the
ongoing storms (i.e. from southeast/south-central TX into southwest
TX) later this afternoon and this evening. This redevelopment will
be supported by a combination of moist advection, modest heating,
and limited low-level convergence. Moderate to strong buoyancy amid
moderate vertical shear could support supercells if the mode remains
discrete. However, the weakness in the mid-level flow suggests
storms may tend to cluster, a scenario that is supported by most CAM
guidance. Buoyancy and shear are still strong enough to support
rotating updrafts and large hail early in the convective cycle, but
the trends towards a messy convective mode could limit the
persistence and coverage of robust updrafts. Damaging gusts are
possible even with the clustered storm mode, especially given there
is some potential for slightly more organized bowing segments over
time.
Farther west, mid-level height rises/subsidence are anticipated
coincident with the dryline from central Kansas south-southwestward
across western Oklahoma and west/southwest Texas. The environment,
characterized by 1500 to 2000 J/kg of MLCAPE and 30 to 40 kt of
westerly deep-layer shear, is conditionally supportive of supercells
capable of all severe hazards. However, the previously mentioned
height rises and subsidence, combined with modest convective
inhibition, are generally expected to preclude thunderstorm
development. Even so, given the conditional risk, Marginal risk
probabilities will be maintained.
...Minnesota/Wisconsin...
Recent surface analysis places a low just west of FAR, with a warm
front extending southwestward across central/southeast MN and
southern WI. This low is forecast to move eastward today, while the
warm front expands northward. A narrow corridor of surface-based
buoyancy could develop from north-central MN into far northwest WI
as dewpoints increase in the upper 50s (perhaps even low 60s).
Thunderstorm initiation appears possible along the cold front within
this corridor, although veered low-level flow and northward/westward
displacement of the better forcing casts doubt to whether updrafts
will be maintained. Any storms that do mature within this warm
sector should become supercells capable of all severe hazards,
including large hail and tornadoes. However, low confidence in storm
development and maturity precludes higher probabilities with this
outlook.
...Northern Rockies...
Mid-level moisture will support another day of modest surface-based
buoyancy ahead of the shortwave trough mentioned in the synopsis.
Persistent 30-40 knot flow within the CAPE-bearing layer combined
with somewhat deep boundary-layer mixing will support strong to
severe downburst winds with the more robust convective cells, mainly
this afternoon through early evening.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 PM CDT Sun Apr 12 2026
Valid 131200Z - 141200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF CENTRAL/EASTERN MINNESOTA INTO WESTERN/CENTRAL WISCONSIN...
...SUMMARY...
Severe thunderstorms are likely across the Upper Mississippi Valley
and Great Lakes region with potential for large to very large hail,
damaging wind, and tornadoes. A more conditional and isolated risk
for severe storms is possible across portions of the southern Plains
on Monday.
...Synopsis...
A southwesterly flow regime will continue from the southern Plains
to the Upper Midwest on Monday. Low-amplitude upper ridging will
move across the Upper Midwest during the day ahead of a shortwave
trough moving across the northern Plains. The shortwave will shift
east across the Great Lakes overnight. Meanwhile, an upper trough
from the northern Rockies to offshore the southern CA coast will
pivot eastward toward the Four Corners region. At the surface, low
pressure near the SD/NE border will develop east along the MN/IA
border to central WI. Lee troughing will persist across the Plains.
A dryline will extend southwest from the Mid-MO Valley into western
OK/TX, while a warm front extends from southern MN into
southern/central WI. These boundaries will become a focus for severe
thunderstorm development during the afternoon/evening.
...Upper Midwest...
Along and south of the surface warm front across MN into
southern/central WI, strong daytime heating will be occurring amid
dew points in the low to mid 60s. This will yield moderate to strong
instability with MLCAPE around 2000-3000 J/kg. A plume of steep low
to mid-level lapse rates will also impinge upon the region through
the afternoon. Capping will likely suppress thunderstorm activity
for much of the day as the shortwave upper ridge moves across the
region. By the late afternoon/early evening, a shortwave trough will
overspread the region with an increase in the low-level jet.
Thunderstorm activity is expected to develop, with initially
elevated supercells likely given strong deep layer shear and
thermodynamic profiles. These will be capable of large to very large
hail (some 2-3+ inches in diameter). Should any supercells be able
to anchor to the warm front and become surface based, the threat for
a tornado or two (possibly strong) will increase given large
clockwise curved hodographs indicative of favorable low-level shear.
An Enhanced Risk was included with this outlook driven by the hail
potential. Convection will spread eastward with time into MI,
continuing to pose a risk for hail overnight.
...Central/Southern Plains....
A conditional severe risk will extend further down the dryline into
the central/southern Plains for the afternoon/evening. Strong
daytime heating will yield very warm temperatures ahead of the
dryline but most convective temperatures are near or exceeding 90F.
Forecast soundings indicate strong capping in place across much of
the region through the afternoon with generally weak forcing for
ascent outside of the dryline circulation, which will likely inhibit
a more widespread severe risk. Nonetheless, moderate to strong
instability will overlap increasing deep layer shear as the
low-level jet increases through the evening. An isolated supercell
threat will be possible along the dryline, with greater confidence
along the Red River in northern TX/southwestern OK and further south
into Texas near the Rio Grande Valley. Should supercells develop,
the main risk will be for large to very large hail (some 2+ inches
in diameter).
..Thornton.. 04/12/2026
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Sun Apr 12 2026
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE SOUTHERN PLAINS TO THE GREAT LAKES...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected on Tuesday
and Tuesday night from the Southern Plains to the Great Lakes.
...Synopsis...
The western US trough will eject across the Rockies on Tuesday with
strengthening westerly flow overspreading the Plains into the Great
Lakes Region. A surface low will deepen across western KS/NE with a
warm front lifting across the Lower Missouri Valley into the Great
Lakes and sharpening dryline across the southern/central Plains. A
cold front will sag southward across the Upper Midwest/Great Lakes
vicinity. The surface trough/dryline and the boundary across the
Great Lakes will become a focus for thunderstorm activity through
the forecast period.
...Lower MO Valley to the Great Lakes...
Convective coverage will overlap the start of the period near 12z on
Tuesday across portions of the Midwest/Great Lakes Region. Trends
are for relatively quick clearing across portions of central Iowa
into Illinois. As the warm front lifts northward, strong daytime
heating is expected amid dew points in the low to mid 60s. It is
likely the air mass will recover with potential for moderate to
strong instability by the afternoon. Stronger height falls are not
expected across the region, as the main upper trough
will be focused well to the southwest. However, warm advection atop
a southward-sagging surface boundary should support isolated to
scattered storm development by late afternoon/evening. The primary
risk will be for large to very large hail ( some 2.5"+ in diameter)
and damaging wind.
By late afternoon/evening, 700 mb flow will strengthen (around 50-60
kts) with a plume of steep low to mid-level lapse rate nosing into
central Iowa/northern Illinois from the southwest. The 850 mb
low-level jet also increases, with large clockwise curved hodographs
developing with the resulting increase in low-level shear. If
supercells can develop and maintain residency along or south of the
warm front, a corridor of greater tornado risk (a couple of which
may be strong tornadoes) may present itself.
Consideration was given to a 30 percent area (primarily hail
driven). With some uncertainty remaining in morning convection and
coverage of storms in the afternoon/evening, the 15% was maintained
with this outlook until more information can be gleaned from hi-res
guidance.
...Southern Plains...
Ahead of the dryline across the Southern Plains, strong daytime
heating is expected. Large-scale ascent will begin overspreading the
region by late afternoon/evening as the western upper trough finally
begins to eject eastward. As this occurs, mixing and convergence
along a surface dryline should support storm development by around
00z. If little convective development occurs on D2/Monday, a
relatively undisturbed moist/very unstable air mass will be in
place. It is likely that rather robust thunderstorm development will
occur along the dryline, with the primary mode being supercelluar.
Large to very large hail (2 to locally 2.5+ inches in diameter),
damaging wind, and a couple of tornadoes will be possible. Given
that deep layer shear profiles have more of a parallel component to
the dryline, storm interactions may keep the period of more discrete
supercell thunderstorms short, with a shift to clusters of mix-mode
supercell and multi-cell storms.
..Thornton.. 04/12/2026
Read more
