04/26/2026
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0841 AM CDT Sun Apr 26 2026
Valid 261300Z - 271200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ...
CORRECTED FOR SUMMARY WORDING
...SUMMARY...
Scattered severe thunderstorms with large to very large hail,
damaging winds and tornadoes are expected this afternoon through
tonight across parts of the southern/central Plains. A couple of
strong tornadoes and hailstones up to 2-3 inches in diameter are
possible.
...Southern/Central Plains to the Mid Mississippi Valley...
Fairly substantial changes have been made to the outlook based on
latest observational and guidance trends. Namely, the Enhanced Risk
has been expanded into northern OK to account for the potential of
both surface-based supercells this afternoon, and elevated
supercells this evening/tonight. The Slight Risk has been expanded
southward into north-central TX for a somewhat more
conditional/uncertain supercell threat. The eastern extent of severe
probabilities have also been expanded in MO to account for a
potential cluster producing severe/damaging winds occurring late
tonight into early Monday morning.
A weak lead mid-level vorticity maximum over the central High Plains
this morning should continue to aid elevated thunderstorm
development across KS through the afternoon. Increasing MUCAPE with
persistent low-level warm/moist advection and steepening mid-level
lapse rates combined with strong deep-layer shear will support
organized updrafts, including the potential for supercells. This
convection will probably tend to remain elevated to the north of a
front as it spreads east-northeastward over the central Plains, but
scattered large hail may occur given the overall favorable
environment. Isolated 2+ inch diameter hail also appears possible
with the strongest cores. Eventually, this activity may pose a
greater threat for damaging winds across eastern KS into western MO
by late afternoon/early evening, if it can become truly surface
based.
A more notable mid-level shortwave trough is expected to eject
northeastward across the Southwest and southern/central High Plans
today, accompanied by a 50-60 kt southwesterly mid-level jet. Weak
lee cyclogenesis is forecast to occur across the southeast
CO/northeast NM vicinity in response, with the surface low
developing into the OK Panhandle and southwest KS by this evening.
Strong to locally extreme instability is once again forecast to
develop to the east of a sharpening dryline across western/central
OK as daytime heating of a moist airmass occurs. There is still a
fair amount of uncertainty with the placement of an effective warm
front by late afternoon/early evening, but current expectations are
for this boundary to be draped somewhere near north-central OK by
peak afternoon heating. The surface triple point may serve as a
focus for convective initiation today, although better large-scale
ascent associated with the mid-level shortwave trough overspreading
the warm sector will be delayed until this evening and past peak
diurnal heating.
Greater than average uncertainty exists regarding the potential for
surface-based convective initiation today in OK/north TX. Still, it
appears possible that multiple supercells may develop with gradual
erosion of lingering MLCIN and weak ascent preceding the ejecting
shortwave trough. Any supercells that can root and ingest the ample
low-level moisture will be capable of producing very large hail
(2-3+ inches in diameter) given a overall rather favorable
environment. The tornado potential is less clear through the day,
but a southerly low-level jet will quickly strengthen this evening
and aid curved/elongated hodographs with strong effective SRH. A
somewhat conditional/uncertain threat for a couple of strong
tornadoes remains apparent, especially if any supercells that can
form this afternoon persist into the evening.
Additional, somewhat elevated supercells may form this evening into
tonight along/north of the warm front from northwest OK near the
triple point into KS. This activity will also pose a threat for
large to very large hail. Some guidance suggests a cluster
eventually evolves from this convection across eastern KS into MO
late tonight/early Monday morning. If this occurs, then a greater
threat for severe/damaging winds would exist.
Farther south into TX, the forcing for ascent will remain
weak/nebulous along the dryline. Still, some potential for a few
supercells is apparent across north-central TX where the greatest
heating and minimal MLCIN is forecast to exist. Large to very large
hail should be the main threat with any splitting supercells that
can develop this afternoon along/east of the dryline and be
sustained.
...ArkLaTex/Lower Mississippi Valley/Central Gulf Coast...
A small cluster will continue tracking southeastward this morning
from southern MS to the central Gulf Coast. With sufficient
low-level moisture and instability in place ahead of this
convection, isolated damaging winds may occur. A pair of supercells
across northeast TX have fluctuated in intensity over the past
couple of hours. The potential for additional thunderstorms to form
on the western flank/outflow of this morning convection remains
unclear given weak large-scale forcing and the low-level jet
forecast to weaken further through the morning. If any additional
convection can form, it would pose an isolated severe hail and
damaging wind threat.
..Gleason/Thompson.. 04/26/2026
