RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Sun Apr 12 2026
Valid 121200Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
CENTRAL AND SOUTHERN TEXAS...
...SUMMARY...
Isolated to scattered severe thunderstorms are possible this
afternoon and evening across parts of the southern High Plains. More
isolated severe storms will be possible across portions of the Upper
Great Lakes and northern Rockies.
...Synopsis...
Early-morning surface observations reveal a surface low developing
across the northern High Plains with a broad fetch of southerly flow
from the western Gulf into the Plains and Midwest. This broad warm
sector characterized by mid 50s to low/mid 60s dewpoints will
largely remain in place through the day as the surface low
translates east across the Plains into the Great Lakes region
tonight. The greatest potential for strong/severe thunderstorms will
reside within this warm sector where regional forcing for ascent
will support a chance for deep convection.
...Southern Plains...
Latest 00z HREF/REFS guidance, as well as more recent CAM solutions,
all show considerable variability in the evolution of an ongoing MCS
through late morning across southern/southeast TX. While most
solutions depict a steady weakening trend, others - notably the
WRF-ARW - hint at some continued wind threat across the TX Coastal
Plain this morning. Regardless, this activity is forecast to
diminish by late morning/early afternoon, and will likely leave an
outflow boundary on the western periphery of the cold pool in its
wake.
Dewpoints in the low to mid 60s will quickly return northward in the
wake of the MCS with ensemble guidance depicting a plume of MLCAPE
values between 1500-2000 J/kg from central TX into western OK by
mid-afternoon. Thunderstorm development appears possible along any
residual outflow boundaries across central TX given weak capping
depicted in forecast soundings, though confidence in precisely where
this will occur or how widespread storm coverage will be remains
fairly uncertain. Thunderstorm initiation off the Sierra Del Carmen
mountains in northern Mexico and along a weak dryline across
southern KS southward into western OK/TX appears more probable,
though again, storm coverage will likely remain fairly isolated
given weak forcing for ascent and some degree of synoptic-scale
subsidence in the wake of the upper disturbance currently passing
over the region.
Convection that can develop within this buoyant and weakly capped
environment could become fairly intense given favorable
thermodynamic profiles. Despite some mid-level backing in forecast
hodographs, effective bulk shear values appear sufficient for a
large, to perhaps very large hail threat. However, given the
aforementioned uncertainties in thunderstorm coverage, 15% hail
probabilities have been confined to where ensemble guidance depicts
the best overall convective signal.
...Minnesota...
A lee cyclone evident in recent surface observations over the
northern High Plains will migrate eastward along the U.S./Canaidan
border through the day, reaching northern MN by around peak heating.
A narrow tongue of returning moisture may support a corridor of
sufficient ascent and buoyancy for deep convection. While latest
guidance remains somewhat mixed on thunderstorm coverage, forecast
soundings suggest elevated convection may support a threat for large
hail. Furthermore, several high-res forecast soundings depict an
environment favorable for surface-based supercells along the frontal
zone where dewpoints may reach into the mid/upper 50s. While this
potential appears very low per recent ensemble guidance, some
tornado threat could materialize along the front where STP values of
1-2 may emerge.
...Northern Rockies...
A plume of mid-level moisture (PWATs between 0.4 to 0.5 inches) was
recently observed in regional 00z RAOBs across the Great Basin
region. This air mass will largely remain in place over the next 24
hours ahead of an approaching upper low out of northern CA. This
mid-level moisture will support another day of fairly modest
surface-based buoyancy (around 250-500 J/kg SBCAPE), but persistent
30-40 knot flow within the CAPE-bearing layer combined with somewhat
deep boundary-layer mixing (LCLs forecast to be around 2 km) may
support another day of strong to severe downburst winds with the
more robust convective cells.
..Moore/Halbert.. 04/12/2026
Read more
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Sun Apr 12 2026
Valid 131200Z - 141200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST AND ACROSS PARTS OF THE SOUTHERN PLAINS...
...SUMMARY...
Severe thunderstorms are possible across the Upper Mississippi
Valley and Great Lakes region, and across portions of the southern
Plains on Monday.
...Synopsis...
The persistent/stagnant 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. Meanwhile, 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...
Strengthening southerly low-level flow will transport low to mid 60s
F dewpoints northward toward southern MN and southern/central WI.
Meanwhile, a plume of steep midlevel lapse rates will overspread the
region. Capping will likely suppress thunderstorm activity for much
of the day as the shortwave upper ridge moves across the region. By
late afternoon/early evening, height falls are forecast to
overspread the area and thunderstorms are expected to develop as a
strengthening low-level jet overspreads the warm front ahead of an
eastward-progressing surface low. Initial thunderstorm activity may
be, or quickly become, elevated to the cool side of the warm front
given northeast storm motion. Nevertheless, supercell wind profiles,
cool temperatures/steep lapse rates aloft, and moderate to strong
instability will support large hail potential.
If surface-based warm sector storms can develop, supercells capable
of all hazards will be possible. While this evolution is uncertain,
it appears most probable from southeast MN toward
south/south-central WI. Convection will spread eastward with time
into MI, continuing to pose a risk for hail overnight.
...Southern Plains...
A conditional supercell environment will exist along/east of the
surface dryline from portions of western/central OK toward the TX
Big Bend. Given a lack of height falls across the region, capping
will likely suppress convection. However, strong heating along the
dryline will promote mixing. Confluence low-level flow along the
dryline coupled with strong instability and mixing may be sufficient
for a couple of storms during the late afternoon/evening as a modest
low-level jet develops. While conditional, if a storm can develop,
supercell wind profiles suggest large hail, strong gusts and perhaps
a tornado will be possible.
..Leitman.. 04/12/2026
Read more
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0218 AM 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...
Southwesterly deep-layer flow will persist from the southern Plains
to the Great Lakes on Tuesday. An upper trough over the western U.S.
will slowly pivot eastward, emerging over the central/southern High
Plains by Sunday morning. Surface low pressure will remain centered
over the central Plains, with troughing extending southwestward into
west TX. A cold front will slowly sag southward across portions of
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 vicinity...
Convection may be ongoing across portions of the region Tuesday
morning. This activity should spread east, and persistent warm
advection should allow for airmass recovery during the afternoon.
Steep midlevel lapse rates will overspread mid 60s F dewpoints, and
moderate to strong destabilization is forecast. 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. Supercell
wind profiles are evident in forecast soundings, suggesting an
all-hazards risk. Given uncertainty related to potential airmass
contamination from early day convection and cloud cover, and
potential capping concerns, will maintain Slight risk (level 2 of
5). However, a rather volatile thermodynamic and kinematic
environment will exist across portions of the region, and higher
probabilities may be needed in subsequent outlooks depending on
forecast trends and mesoscale details.
...Southern Plains vicinity...
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 at least isolated storm development
by around 00z. Steep midlevel lapse rates and mid/upper 60s F
dewpoints will support strong destabilization amid supercell wind
profiles. Large to very large hail will be possible in addition to
strong wind gusts and a tornado or two.
..Leitman.. 04/12/2026
Read more
