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
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