Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0700 AM CDT Tue Apr 28 2026
Valid 281300Z - 291200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY AND
MID-SOUTH...
...SUMMARY...
Multiple rounds of severe thunderstorms will occur across parts of
the southern Plains into the lower Mississippi/Tennessee Valleys and
Southeast through this evening. Very large to giant hail (2-4+
inches), swaths of severe/damaging winds, and a few tornadoes are
all possible.
...Southern Plains into the Lower Mississippi Valley/Southeast...
With large-scale upper troughing anchored over the Plains and
central Canada, an embedded mid-level shortwave trough will eject
eastward across the southern/central Plains to the lower/mid MS
Valleys by this evening. Rich low-level moisture continues to spread
northward from TX into southern OK this morning in tandem with a
low-level jet, and this trend should continue downstream into the
lower MS Valley through the day as a warm front lifts northward to a
weak surface low across the Ozarks. Another surface low will remain
over northwest TX, with a dryline extending southwestward to the Big
Bend region.
A strongly unstable airmass exists across the southern Plains to the
ArkLaTex, along and near a slowly retreating/northward-returning
warm front. Elevated supercells are ongoing across western north TX.
This activity is being aided by lift and strong deep-layer shear
associated with the ejecting mid-level shortwave trough, and
low-level warm/moist advection. Current expectations are for these
supercells to continue posing a threat for mainly large to very
large hail through the rest of the morning as they spread
east-northeastward across north TX/southern OK. But, eventual
clustering and a greater damaging wind threat may materialize into
the afternoon as this convection crosses the front and accesses
greater instability across AR and the Ozarks.
Additional surface-based convective development is forecast near the
triple point in north-central TX towards the ArkLaTex this
afternoon, where extreme instability (4000+ J/kg MLCAPE) and very
strong deep-layer shear (50-60+ kt) will support the potential for
multiple intense supercells. Very large to giant hail (2-4+ inches)
may occur with the strongest supercells given the overall very
favorable environment and presence of steep mid-level lapse rates.
Some tornado threat may also exist with these supercells, even
though low-level shear is not forecast to be overly strong.
Numerous to widespread convection across the Mid-South to southern
Appalachians has generally diminished in intensity this morning. In
its wake, airmass recovery is anticipated today across the lower MS
Valley and Mid-South. A convectively reinforced front/outflow
boundary from the morning thunderstorms should attempt to lift
northward some through the day, with the greater instability
forecast across the lower MS Valley where steep mid-level lapse
rates are in place. Convective evolution across these areas through
the evening remains unclear, but multiple rounds of supercells and
multicell clusters capable of producing large hail, scattered to
numerous damaging winds, and perhaps a few tornadoes appear likely.
Less instability is forecast to the north of the ongoing convection
across the TN Valley, but some airmass recovery and severe threat
still appears possible by late afternoon/early evening.
..Gleason/Jewell.. 04/28/2026
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