Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Fri May 16 2025
Valid 161200Z - 171200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
KENTUCKY...NORTHERN AND WESTERN TENNESSEE...SOUTHEAST MISSOURI...FAR
SOUTHERN ILLINOIS...SOUTHERN INDIANA...FAR SOUTHWEST OHIO...
...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells associated with
tornadoes, large hail and wind damage. Several strong tornadoes are
expected, and a long-track high-end tornado will be possible. From
the evening into the overnight, a bowing line segment is expected to
form with potential for tornadoes and damaging winds, some possibly
greater than 75 mph.
...Mid Mississippi and Ohio Valley/Tennessee Valley...
A negatively-tilted mid-level trough will move through the Upper
Midwest and mid Mississippi Valley today, as an associated 75 to 90
knot mid-level jet translates northeastward into the Ozarks. At the
surface, a low will move into the western Great Lakes, as a cold
front advances eastward into the mid Mississippi Valley. A very
moist airmass will remain in place ahead of the front, extending
eastward into the Ohio and Tennessee Valleys. Across this airmass,
surface dewpoints will be in the upper 60s and lower 70s F. Warming
surface temperatures will result in moderate to strong
destabilization across much of the moist sector by afternoon. An
area of low-level convergence is expected to become increasingly
focused from the Ozarks into the mid Mississippi Valley. This will
result in the initiation of scattered strong to severe storms around
midday. Several convective clusters are expected to organize and
move eastward into the lower Ohio Valley during the afternoon. Storm
coverage will expand markedly during the late afternoon and early
evening as low-level flow increases across the region.
Concerning the thermodynamic environment, a pristine airmass is
expected to be in place by afternoon. Model forecasts are in good
agreement that MLCAPE will peak from 3000 to 4000 J/kg from parts of
the Ozarks eastward into the Ohio and Tennessee Valleys. As
instability increases, deep-layer shear and lift are also expected
to increase as a mid-level jet approaches from the west. Ahead of
this feature, an 850 mb jet is forecast to develop over the mid
Mississippi Valley. This jet will gradually increase in strength
into the 45 to 65 knot range, moving eastward into western Kentucky
by late afternoon. Near the axis of the low-level jet at Paducah,
RAP forecast soundings at 23Z have MLCAPE near 3500 J/kg, 0-6 km
shear around 60 knots, and low to mid-level lapse rates near 7 C/km.
0-3 km helicity is forecast to be between 225 and 250 m2/s2. This
environment will support supercells and tornadoes. Several strong
tornadoes appear likely, and a high-end long-track tornado will be
possible from far southeast Missouri, into southern Illinois and
southern Indiana, southward into western Kentucky and far northern
Tennessee.
During the late afternoon, storm coverage is expected to become
widespread across the moist sector. Several supercell clusters will
move eastward from the mid Mississippi Valley into the Ohio and
Tennessee Valleys. Steep mid-level lapse rates will promote large
hail development. The more intense cores may have hailstones between
2 and 4 inches in diameter. Supercells will also be capable of
producing damaging wind gusts. During the early evening, the
wind-damage threat is expected to increase as some of the convective
clusters gradually transition into more linear structures. Winds
could exceed 75 mph along the leading edge of these faster-moving
bowing line segments. During the evening, multiple bow echos are
expected to form that will result in extensive wind damage swaths.
Wind damage is expected across a broad area, including parts of the
mid Mississippi, Ohio and Tennessee Valleys into the central
Appalachian mountains.
...Ark-La-Tex/Lower Mississippi Valley...
A very moist airmass will be in place today across the Ark-La-Tex
and lower Mississippi Valley. Surface dewpoints in the lower to mid
70s F will result in moderate to strong destabilization across much
of this airmass. A capping inversion is expected to be in place for
much of the day, but should weaken late in the afternoon as a
mid-level jet moves eastward into the mid Mississippi Valley. The
southern edge of the jet will help to increase large-scale ascent,
aiding convective development. In response, a few clusters of storms
will form and move eastward into the lower Mississippi Valley during
the late afternoon and early evening. In areas that strongly
destabilize, storms could be capable of producing large hail and
wind damage. Hailstones greater than 2 inches in diameter will be
possible with intense supercell cores.
..Broyles/Weinman.. 05/16/2025
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