Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Apr 27 2026
Valid 271200Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
MID-MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY AND PARTS OF THE
MID-SOUTH...
...SUMMARY...
Widespread strong to severe thunderstorm development appears
probable across the middle Mississippi into lower Ohio Valleys this
afternoon through this evening, accompanied by potential for a few
strong tornadoes, damaging wind gusts and large hail.
...Synopsis...
Water vapor imagery shows a prominent shortwave trough promoting
elevated strong to severe convection across central and eastern
Kansas. This activity is expected to move north and eastward through
Iowa/Missouri/Wisconsin/northern Illinois into daybreak and perhaps
part of the afternoon for some areas. The outflow from this
convection should act to limit the northern extent of greater
destabilization during the afternoon and thus the greatest severe
threat. A surface low will track northeastward along the parent
shortwave. Though this low has trended downward in intensity in
recent model runs, strong low-level wind fields are expected within
the warm sector throughout the day and into the evening. Areas of
pre-frontal convergence and a cold front will be the focus for
convective development along with more strongly forced convection
tied to the shortwave trough. The front will be draped south and
westward into the Ozarks and the southern Plains.
...Mid-Mississippi Valley/Lower Ohio Valley...
As mentioned, surface based buoyancy will be limited by early day
activity. The current expectation is for parts of central/eastern
Missouri into central/southern Illinois and western Kentucky to see
greater destabilization. There is activity ongoing within central
Missouri early this morning that may have some impact, however. This
is the source of greatest uncertainty for these regions. The
kinematic environment will certainly be favorable for supercells.
The moderate to strong 850 mb jet will also lead to potential for
several tornadoes, some of which could be strong. Lapse rates at
mid-levels will be rather steep. Large to very-large hail potential
is evident given the long hodographs. Some upscale growth into one
or more linear segments is expected to occur. This will increase
the threat for damaging winds. An increase in tornado probabilities
was considered. Given the questions regarding early day convection
and where favorable convergence zones/outflow boundaries might be
located reduces confidence. Convective trends into daybreak will
need to be closely monitored.
...Mid-South...
Models indicate potential for supercells along the cold front and
even potentially ahead of it. Forcing for ascent will be weaker, but
this may help to keep activity cellular longer. Some of this
activity could develop after 00Z. Mid-level lapse rates are expected
to be steep enough and mid-level flow strong enough to support large
to potentially very large hail and damaging winds. The tornado
threat will likely be lower given the time of day and tendency for
storms to be at least slightly elevated.
...Upper Midwest...
Observational and model trends suggest destabilization will be more
limited on account of convection at daybreak and beyond. Even so,
strong low-level and effective shear will still allow storms to be
organized and capable of large hail, damaging winds and a couple
tornadoes. There will be potential for both convection at daybreak
and also during the afternoon. The greatest potential for afternoon
supercells would be in parts of eastern Iowa along with the surface
low and colder air aloft.
...Western/central Texas...
As moisture returns westward during the evening, some model guidance
suggest convection might try to develop along the retreating
dryline. Buoyancy and shear would support a threat for large hail
and perhaps severe winds. However, mid-level ascent will be very
weak and models generally do not sustain these convective attempts.
Severe probabilities may be needed if confidence in development
increases.
..Wendt/Moore.. 04/27/2026
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