SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Sat Jun 14 2025
Valid 142000Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MONTANA INTO
THE CENTRAL HIGH PLAINS...AND FROM SOUTHERN KANSAS INTO CENTRAL
OKLAHOMA...
...SUMMARY...
Scattered severe thunderstorms capable of producing large hail and
damaging wind gusts will be possible across parts of the northern
and central High Plains this afternoon and evening. Large hail and
damaging winds will also be possible this afternoon from eastern
Oklahoma into western Arkansas, and late tonight from southern
Kansas into central/northeast Oklahoma.
...20z Update...
The previous forecast largely remains on track with only minor
adjustments made to account for recent convective trends.
...Western Arkansas...
A loosely organized MCS continues to move across western AR, and
while GOES IR imagery continues to show deep/robust updraft
development, MRMS echo top imagery over the past couple of hours
reveals that these updrafts have been fairly transient, likely owing
to weak deep-layer wind shear. The MCS will likely continue to move
east/southeast towards southwestern AR through peak heating and may
be capable of damaging winds, but given the recent trends, 15%
wind/Slight risk probabilities have been removed from western AR.
...Oklahoma...
An outflow boundary is noted in visible imagery and surface
observations from south-central OK to western OK. This boundary is
sufficiently displaced from the upper cirrus associated with the MCS
to the east to yield surface temperatures in the 80s on the cool
side of the boundary. Consequently, a corridor of southeasterly
low-level flow and MLCAPE upwards of 2500-3000 J/kg is in place
across southwest/western OK and could be a preferential corridor for
a supercell or two later this evening. Latest CAM guidance has
hinted at this possibility, but solutions continue to vary.
Additional convection along and north of this boundary remains
likely later tonight as the nocturnal jet strengthens and isentropic
ascent increases. Continued re-development of elevated convection
across north-central OK casts some uncertainty on where initiation
later tonight is most likely, and may result in more focused
convection along and west of the I-35 corridor. Here again, CAM
solutions have not captured recent convective trends well and show
some variance in the exact evolution. Regardless, 15% hail/wind
probabilities have been shifted westward to account for these
trends.
...Central to Northern High Plains...
The early stages of convective initiation are underway across
central to eastern WY with further development and intensification
expected through the evening. See MCD #1286 for additional details.
..Moore.. 06/14/2025
.PREV DISCUSSION... /ISSUED 1125 AM CDT Sat Jun 14 2025/
...KS/OK/AR this afternoon through tonight...
Convection is ongoing this morning in several clusters from
southeast KS into central and eastern OK. The KS cluster had the
better defined cold pool and MCV this morning, but has weakened
while moving into the areas of rain-cooled air in the immediate wake
of the OK convection. The environment downstream into AR could
support some continuation of the eastern OK storms that have
intensified recently, with an attendant threat for occasional wind
damage and isolated large hail with multicell clusters.
The convectively-enhanced midlevel trough will remain over eastern
KS into tonight, when a southwesterly low-level jet is expected to
develop as the low levels recover in the wake of this morning's
storms. Related increases in low-level warm advection will support
new thunderstorm development tonight in roughly the same areas being
impacted by the weakening storms this morning, and an MCS could
evolve in this warm advection zone overnight. An environment with
steep midlevel lapse rates, large CAPE, and some enhancement to
low-midlevel vertical shear will favor the potential for large hail,
severe outflow gusts and a low chance for a couple of tornadoes.
...MT/central High Plains late this afternoon into late evening...
Subtle height rises are expected over the High Plains and MT, with
the stronger mid-upper flow confined mostly to MT. Forcing for
ascent will likewise be relatively weak, with some upslope flow
component along and east of a lee trough. At least widely scattered
thunderstorm development is expected east/northeast of the higher
terrain from eastern WY into northeast CO, and potentially along the
baroclinic zone across central MT. A few supercells will be
possible with large hail from MT into eastern WY, though storms with
southward extent will have more of a threat for severe outflow gusts
based on a tendency to grow upscale on merging outflow in an
environment with steep lapse rates and deep-layer vertical shear
that will be close to the lower margins for sustained supercells.
There will be some potential for a cluster or two to persist
overnight while spreading eastward over the High Plains.
...Mid-Atlantic to the southern Appalachians this afternoon...
Along and south of a stalled front from southern DE into northern
MD/VA, surface heating is ongoing in cloud breaks. As surface
temperatures warm into the 80s with 72-74 F dewpoints, MLCAPE will
increase to near 2000 J/kg this afternoon. Modest enhancement to
vertical shear (effective bulk shear of 25-30 kt) with subtle
perturbations crossing the Appalachians could allow for some
clustering of storms with the potential for isolated wind damage.
Scattered thunderstorms are expected farther southwest into the
southern Appalachians and vicinity, immediately east of the slowly
weakening midlevel trough over KY/TN. Moderate buoyancy, DCAPE
approaching 1000 J/kg and roughly 30 kt midlevel flow could be
sufficient for isolated downbursts with associated wind damage.
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