ACUS01 KWNS 061259
SWODY1
SPC AC 061258
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0658 AM CST Fri Mar 06 2026
Valid 061300Z - 071200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS INTO WESTERN ARKANSAS/MISSOURI AND
SOUTHERN IOWA...
...SUMMARY...
Scattered severe thunderstorms are expected from mid afternoon
through tonight from parts of the southern/central Plains to the
Ozarks and Midwest. The greatest potential for a few strong
tornadoes and very large hail should exist across eastern portions
of Oklahoma/Kansas/Nebraska into western Arkansas/Missouri and
southern Iowa.
...Synopsis...
Upper troughing over the western CONUS this morning will evolve into
more of a split flow pattern through the period, as a lead mid-level
shortwave trough ejects northeastward across the central
Plains/Upper Midwest, and a closed low develops over the southern CA
vicinity. A surface lee cyclone has moved into northwest KS early
this morning, and is forecast to develop towards IA by this evening,
while a secondary low shifts eastward along the KS/OK border. A cold
front attendant to the primary surface low will surge
east-southeastward across the southern/central Plains and adjacent
portions of the Midwest through the period, and will likely provide
a focus for organized severe convection later today. A warm front
will develop northward through tonight across parts of the Upper
Midwest/Great Lakes. This boundary should serve as a northern limit
to the severe threat from surface-based convection. A dryline will
also extend southward from the secondary surface low across
western/central OK into TX by late afternoon.
...Central Plains into the Midwest/Great Lakes...
Strong low-level warm/moist advection ahead of the lead mid-level
shortwave trough will continue to support scattered to numerous
thunderstorms this morning across eastern KS/NE into northern MO and
IA/IL. This activity will tend to remain elevated, but could pose an
isolated hail threat. In the wake of this convection, low-level
moisture is expected to continue streaming northward today ahead of
the cold front, with upper 50s to low 60s surface dewpoints common
by mid afternoon. Cold temperatures aloft and steepened mid-level
lapse rates will support the development of at least 1000-1500 J/kg
of MLCAPE with daytime heating. More instability should exist
farther south into KS where greater low-level moisture will be in
place.
Current expectations are for scattered robust thunderstorms to
develop around mid afternoon (20-22Z) across southeast NE/northern
KS and vicinity, in close proximity to the surface low and ejecting
shortwave trough. Additional convection may also form farther south
into central/eastern KS. Strong deep-layer shear associated with a
50-70+ kt mid-level jet will easily support organized updrafts,
including multiple supercells initially. This activity will pose a
risk for large to very large hail, but fairly quick upscale growth
into one or more bowing clusters with a wind damage threat seems
probable along/ahead of the cold front as convection spreads into
IA/MO through the evening. Some risk for at least isolated
severe/damaging winds may persist late tonight into early Saturday
morning across WI/IL and perhaps even Lower MI if one of these
clusters can maintain intensity, although instability is forecast to
become more limited with eastward extent across these areas.
A few tornadoes may occur with sustained supercells or embedded QLCS circulations across the central Plains/Midwest along/south of the
warm front given favorable low-level shear and enlarged/curved
hodographs. A strong tornado appears possible with any supercells
this evening as low-level shear strengthens in tandem with a south-southwesterly low-level jet. The Enhanced Risk has been
expanded a little north/westward in northeast KS, southeast NE, and
southwest IA to account for the very large hail potential with
initial supercell development. Some consideration was also given to
greater severe wind probabilities in IA, but confidence in a more
concentrated corridor of damaging winds is low given the weaker
instability forecast with eastward extent across the Midwest.
...Southern Plains into the Ozarks...
Convective initiation along the length of the dryline in OK/TX
remains highly uncertain this afternoon/evening, as low-level
convergence will be weak and stronger large-scale ascent associated
with the ejecting shortwave trough will remain mostly displaced to
the north of these areas. Still, recent HRRR/RAP/NAM guidance
suggests that MLCIN will be minimal by peak afternoon heating, with
moderate instability in place along/east of the dryline. If any
cells can form and be sustained, they would likely become severe and
pose a threat for very large hail given the presence of steep
mid-level lapse rates noted on the 12Z OUN observed sounding, along
with around 35-45 kt of deep-layer shear aiding updraft
organization. The tornado threat would also increase this evening
with any persistent supercells as low-level shear gradually
strengthens. Regardless, the chance for convective initiation still
appears highly uncertain/conditional this afternoon. A better chance
for robust thunderstorm development remains apparent later this
evening/tonight as the cold front advances southward. Both large
hail and damaging winds may occur with this overnight activity
through the end of the period.
Most guidance also continues to show a somewhat separate area of
thunderstorms developing farther east across eastern OK/western AR
and vicinity this afternoon into early evening. This activity might
be aided by a very weak mid-level perturbation moving northeastward
today across central/northeast TX. If this convection develops, then
it would pose a threat for all hazards, including large hail,
damaging winds, and tornadoes (some of which could be strong). No
changes have been made to the Enhanced Risk across the southern
Plains/Ozarks with this update.
..Gleason/Dean.. 03/06/2026
$$
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