ACUS03 KWNS 170832
SWODY3
SPC AC 170831

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 AM CST Tue Feb 17 2026

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON
INTO EARLY EVENING ACROSS PARTS OF CENTRAL AND SOUTHERN
ILLINOIS...SOUTHERN INDIANA...WESTERN/NORTHERN KENTUCKY...AND
SOUTHWESTERN OHIO...

...SUMMARY...
Severe thunderstorms with potential to produce a few tornadoes and
damaging wind gusts are possible across parts of the middle
Mississippi into lower Ohio Valleys Thursday afternoon into early evening.

...Discussion...
Considerable spread persists within latest model output concerning
short wave developments within the evolving pattern across North
America through this period. In general, though, guidance indicates
that larger-scale mid-level troughing will slowly begin to shift
inland of the Pacific coast Thursday through Thursday night, while
being maintained downstream across the Rockies, Great Plains and
Mississippi Valley, and slowly developing toward the lower Great
Lakes and Appalachians vicinity. The center of a subtropical high
is likely to shift from the Gulf Basin into the Bahamas/Caribbean,
with its northern periphery maintaining an influence across parts of
the Southeast.

One or two short wave perturbations emerging from the Intermountain
West may be in the process of progressing into and across the
central Great Plains and lower Missouri Valley vicinity at the
outset of the period. The lower amplitude lead perturbation may
continue into and across the Ohio Valley during the day, as the
stronger upstream perturbation pivots across the mid to lower
Missouri Valley toward the Great Lakes region. This appears a bit
to the north, and at somewhat lower amplitudes, than what prior runs
of at least some model output has been indicating. However, this is
still likely to be accompanied by a sub-1000 mb surface cyclone,
which may undergo one or two periods of additional deepening while
migrating northeast of the lower Missouri Valley toward the Great
Lakes region Thursday through Thursday night.

...Middle Mississippi/Lower Ohio Valley...
Latest model output continues to indicate better low-level moisture
return (but still marginal for severe convective development) to
portions of the warm sector of the developing cyclone as it migrates
across and northeast of the lower Missouri Valley Thursday
afternoon. It appears that this may include a corridor of mid 50s
to near 60F surface dew points advecting northeast and east of the
confluence of the Mississippi and Ohio Rivers. However, it now
appears that much of this moistening may occur beneath relatively
warm mid/upper levels, associated with subsidence to the south of
the upper jet axis.

This is not reflected in the latest RRFS forecast soundings, which
indicate rather potent thermodynamic profiles evolving by Thursday
afternoon across the lower Ohio Valley vicinity, in terms of both
conditional and convective instability. A general consensus of
other model output suggests the development of much more modest
CAPE. This includes NAM forecast soundings, which depict CAPE at or
below 500 J/kg where the low-level moistening occurs, mostly due to
low equilibrium levels below the 500 mb level. It remains unclear
if this environment will become supportive of convection capable of
producing lightning.

Even so, NAM forecast soundings still depict boundary-layer based
CAPE supportive of low-topped convection which could acquire
supercellular structure in the presence of strong cloud bearing
shear. Aided by the evolution of sizable clockwise-curved low-level
hodographs beneath 30-50 kt southerly 850 mb flow, and a relatively
moist boundary-layer with steep lapse rates, a few tornadoes appear
possible, in addition to small to marginally severe hail. The
evolution of a small organizing cluster may still not be out of the
question, which probably would be accompanied by better potential
for damaging surface gusts.

..Kerr.. 02/17/2026

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