Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Sun Apr 26 2026
Valid 262000Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
CENTRAL AND EASTERN KANSAS INTO FAR NORTHERN OKLAHOMA AND FAR
WESTERN MISSOURI...
...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 to Lower
Missouri Valley. A couple of strong tornadoes and hailstones up to
2-3 inches in diameter are possible.
...20Z Update...
The forecast (see below) remains generally on track. The main
changes made to this outlook were to expand severe probabilities
farther to the east to account for an uptick in severe potential
later tonight, as depicted by some of the latest high-resolution
guidance.
Overall, uncertainties remain regarding precisely where the
strongest storms are going to occur. OK Mesonet data over the past
few hours have depicted some lowering of dewpoints in west-central
OK, with a slightly diminished CU field noted. However, several
guidance members depict supercellular development in the 02-06Z
period over northern OK, likely in part to the strengthening of a
low-level jet. Given impressive shear profiles and 8.5-9 C/km
mid-level lapse rates expected in this region overnight, it is
plausible that the strongest storms for the remainder of the period
(to 12Z Monday morning) may occur here, with 2+ inch diameter hail
and perhaps strong tornadoes. The primary uncertainty for
introducing higher tornado probabilities over northern OK is the
possible late storm initiation and associated boundary layer
stabilization, which may dampen the robustness of tornado production
with these storms.
Visible satellite imagery depicts more agitated CU centered over
Baylor County, TX, which may hint at locally higher/less conditional
severe threat across far north-central TX later this afternoon and
evening. However, synoptic forcing is weak, and if storms form, they
will likely be sparse, precluding the addition of higher severe
probabilities in this region at this time.
..Squitieri.. 04/26/2026
.PREV DISCUSSION... /ISSUED 1154 AM CDT Sun Apr 26 2026/
...Southern/Central Plains to the Mid Mississippi Valley...
Appreciable severe potential is still readily apparent especially
later this afternoon into tonight, although sub-regional details
remain quite complex, particularly regarding the southern extent of
deep convective initiation southward along the dryline.
A weak lead mid-level vorticity maximum over the central High Plains
early today will continue to aid elevated thunderstorm development
across Kansas through the afternoon. See Mesoscale Discussion 547
for short-term details. 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 Kansas into western
Missouri by late afternoon/early evening.
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
Colorado/northeast New Mexico vicinity in response, with the surface
low developing into the Oklahoma Panhandle and southwest Kansas by
this evening. Strong to locally extreme instability is forecast to
develop east of a sharpening dryline across western/central Oklahoma
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 Oklahoma by
peak afternoon heating. The surface triple point may serve as a
focus for convective initiation later today into this evening,
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 Oklahoma/north Texas,
but the volatile environment and ample conditional-type potential is
concerning. 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 northern Oklahoma near
the triple point into Kansas. This activity will also pose a threat
for large to very large hail and possibly an increasing
tornado/damaging wind risk.
Farther south into Texas, the forcing for ascent will remain
weak/nebulous along the dryline. Still, some potential for a few
supercells is apparent across north-central Texas 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.
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