LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Sat May 30 2026
Valid 301200Z - 311200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
HIGH PLAINS INTO CENTRAL KANSAS AND NORTH-CENTRAL OKLAHOMA...
...SUMMARY...
Thunderstorms with large hail and severe wind gusts are expected on
this afternoon and evening from parts of the central High Plains
into central Kansas and north-central Oklahoma. Isolated severe
gusts and hail will also be possible in the northern High Plains,
and across parts of western Texas.
...Synopsis...
Latest GOES imagery depicts a pronounced mid-level low over southern
UT with a modest (25-35 knot) subtropical jet emanating from
northern Mexico into the southern Plains. Several shortwave
vorticity maximum are noted along the MS River Valley and across the
Southeast within a broad upper-level deformation zone. Over the next
12-24 hours, the low over southern UT will drift northeast, likely
overspreading the central High Plains by late afternoon/early
evening. As this occurs, more focused surface pressure falls and lee
cyclone development will become apparent across eastern WY/CO and
into portions of western KS/OK and the TX Panhandle.
00 UTC RAOBs across the central to southern Rockies sampled very
steep (8-9 C/km) lapse rates, which should advect eastward in the
wake of ongoing convection through this afternoon given the
southwesterly mid-level flow regime. Additionally, late-evening
surface observations across the central CONUS reveal an expansive
reservoir of rich low-level moisture with dewpoints in the upper 60s
to mid 70s spanning from central OK into the Southeast. This
moisture will advect west/northwest through the morning and
afternoon hours in response to the surface pressure
falls/cyclogenesis over the central High Plains.
The combination of destabilizing thermal profiles aloft and
increasing low-level moisture content will promote a broad swath of
moderate to very high buoyancy from the central High Plains
southward into the southern Plains. Thunderstorm development within
this unstable air mass appears likely as ascent increases through
the day along the surface trough/sharpening dryline.
...Central High Plains...
35-45 knot southerly mid-level flow across the central High Plains
will yield elongated hodographs with deep-layer shear vectors
oriented off the dryline/surface trough. This will result in
high-based supercell development initially across northeast
CO/western NE into western SD with an attendant threat for large
hail and strong outflow winds. With time, upscale growth is
anticipated as convection spreads north/northeast across NE and SD
with an increasing threat for severe winds.
...Central/Southern Plains...
Most guidance depicts a sharpening dryline across western/central
KS, western OK, and into western TX through the afternoon hours.
More focused forcing for ascent across central KS to northern OK
ahead of a subtle low-amplitude upper wave will likely favor
scattered thunderstorm coverage with more isolated thunderstorms
likely with southward extent into western TX. Although ample
buoyancy will be in place (MLCAPE values between 3500-4500 J/kg),
the primary limiting factor across the central/southern Plains will
be modest deep-layer wind shear. Consensus among forecast guidance
suggests effective bulk shear values on the order of 25-35 knots are
likely, which will promote a combination of supercells and
multicells. However, the steep lapse-rate environment coupled with
sufficient deep-layer wind shear will support the potential for
large hail along with severe wind gusts.
A focused corridor for a tornado threat may emerge across northern
OK to central KS where southeasterly low-level flow should support
effective SRH on the order of 150-200 m2/s2. However, the tornado
threat will likely be highly conditional on achieving a sustained
supercell with balanced inflow/outflow. Given the increased
convective signal across northern OK/KS, 15% hail/wind
probabilities, as well as 2% tornado probabilities, have been
introduced.
...Southwest Missouri into central Arkansas...
A zone of isentropic ascent near 850 mb will become established
across the Ozark Plateau by late afternoon. Isolated to scattered
thunderstorms are likely within this corridor given MUCAPE values
upwards of 3000 J/kg, and sufficient deep-layer wind shear should be
in place for a few organized cells capable of large hail and perhaps
strong/severe downburst winds.
..Moore/Marsh.. 05/30/2026
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