SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0241 AM CDT Mon Mar 31 2025
Valid 021200Z - 031200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
GREAT LAKES THROUGH THE MID MISSISSIPPI VALLEY AND THE ARKLATEX...
...SUMMARY...
An outbreak of severe storms is possible Wednesday and Wednesday
night from the Lower Great Lakes, the Mid MS Valley and the
ArkLaTex. Severe wind gusts, very large hail, and significant
tornadoes are expected.
...Synopsis...
A powerful, negative tilt, upper trough will move out of the Plains,
over the Midwest and into the Great Lakes Wednesday. Accompanied by
a 100+ kt jet streak, very strong forcing for ascent will overspread
a large unstable warm sector from the Great Lakes, OH Valley and MS
Valley. A strong cold front will sweep eastward with widespread to
numerous thunderstorms expected.
An outbreak of widespread severe storms including: significant
tornadoes, severe wind gusts and very large hail is possible
Wednesday and Wednesday night.
...Midwest to the lower Great Lakes and OH Valley...
Early in the forecast period, one or more clusters of thunderstorms
are likely to be ongoing across portions of KS/MO into the upper MS
Valley. Very strong synoptic ascent at the exit region of the H5 jet
may allow these storms to persist through the morning as the air
mass downstream slowly destabilizes. Re-intensification is possible
as storms move farther northeast into the lower Great Lakes by early
to mid afternoon. Depending on the timing, these storms may also
outrun the warm sector. This could limit the severe potential to
points farther south if the airmass is unable to recover.
Regardless, very strong effective shear (60-80 kt) and large
hodographs would support organized storms capable of significant
damaging winds, and a tornado risk.
...Mid MS Valley...
Immediately southeast of the primary upper low track, more subtle
forcing for ascent will overspread a rapidly moistening air mass
across the Ozarks, eastern OK and the Mid MS Valley. The air mass
will rapidly destabilize and become uncapped with MLCAPE of
1500-2500 J/kg likely by mid to late morning. Storms are likely to
form by midday as ascent overspreads a pre-frontal trough/diffuse
dryline. Some boundary parallel flow is likely suggesting a mixed
mode of cellular and bowing segments. However, the very strong
troposphereic shear profiles, courtesy of a 50+ kt low-level jet,
favor significant supercells as the primary storm mode. A secondary
surface low will serve to further back low-level flow and expand
very large hodographs from the late afternoon into the evening
hours. Very large hail, significant tornadoes and damaging winds all
appear likely. The severe threat will continue overnight with some
upscale growth across the Mid MS/TN Valley within the broadly
unstable air mass.
Consideration was given to higher severe probabilities across parts
of the Mid MS Valley for the potential for multiple long-lived
significant supercells. However, confidence in the exact storm mode
and location of maximum threat remains unclear given some potential
for morning convection and model timing variance.
...ArkLaTX...
Displaced south of the primary wave, forcing for ascent is somewhat
weaker than farther north. Isolated to scattered convection is
expected along the advancing Pacific front/surface trough from mid
to late afternoon from northeast TX, into northern LA and southern
AR. Upper 60s F dewpoints and elongated hodographs suggest
supercells with all hazards will be possible as they spread east
into the lower MS valley overnight.
Later in the evening, a second round of convection may evolve near
the Red River as low-level warm advection increases. The Pacific
front should gradually lift north as a warm front, allowing some
elevated thunderstorms to develop across southern OK and north TX.
Moderate buoyancy and continued strong flow aloft would likely
support a risk for hail.
..Lyons/Goss.. 03/31/2025
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