ACUS02 KWNS 170602
SWODY2
SPC AC 170600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Sun May 17 2026

Valid 181200Z - 191200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS PORTIONS OF
CENTRAL AND NORTHEASTERN KANSAS INTO FAR SOUTHEASTERN NEBRASKA...

...SUMMARY...
Numerous severe thunderstorms are expected to develop Monday along a
cold front and dryline extending from the Great Lakes into the
central/southern Plains. Supercells capable of all hazards
(including very large hail and strong to intense tornadoes) will
likely occur across central Kansas into southeastern Nebraska.

...Synopsis...
On Monday, a mid-level trough will deepen and lift out of the Four
Corners into the central Plains as a belt of enhanced westerly flow
moves within the mean flow. As this westerly flow overspreads the
Rockies, deepening of a surface cyclone across eastern Colorado is
expected, with strengthening of southerly surface flow across the
southern/central Plains. Convection is likely to be ongoing in the
vicinity of a lead shortwave across portions of Iowa into Wisconsin
at the start of the D2/Monday period.

A front will extend from the surface low in eastern Colorado
northward across southeast NE/IA/WI. A surface dryline will be
located across central Kansas extending southward into western
Oklahoma and southwestern Texas. Mid 60s to 70s dew points will be
common east of the dryline and northward ahead of the cold front
into the Great Lakes. Numerous severe thunderstorms are expected to
develop along the cold front southward to the dryline by the
afternoon. A corridor of enhanced severe potential will exist across
central KS/southeastern NE/southwest IA/northwest MO.

...Central KS into southeast NE/southwest IA/northwest MO...

Near the triple point of the surface low/dryline/cold front across
central Kansas, a more favorable corridor of severe potential will
exist Monday afternoon. Morning cloud cover should erode across
central Kansas by the afternoon allowing for strong daytime heating
and warming. Temperatures ahead of the dryline will approach the mid
to upper 80s, with dew points in the upper 60s to 70s. This will
yield and axis of moderate to strong MLCAPE around 3500-4500 J/kg
extending from central Kansas into southeastern Nebraska. MLCIN will
erode through the afternoon by around 18-20z with initiation
expected along the dryline and cold front to the north by around
20-21z. Forecast soundings indicate favorable kinematics to support
organized supercells, given deep layer shear around 40-50 kts.
Initial supercells will be capable of large to giant hail (2-4+
inch) given steep low to mid-level lapse rates around 7-8 C/km. Hail
probabilities were increased with this outlook to support this potential.

The southerly low-level jet is progged to increase as large scale
ascent spreads eastward through the afternoon, peaking around 40-50
kts by the 00-03z across northern OK into central KS. Strengthening
flow in the 850-700 mb layer will elongate low-level hodographs with
broad clockwise curvature in the 0-2 km layer and rapidly increasing
low-level SRH. Forecast soundings indicate 0-1 km SRH will approach
250-300 m2/s2 across portions of central/eastern KS. This in
combination with the volatile thermodynamic environment will support
an increase in tornado potential through the evening. Should
discrete supercells be maintained, strong to intense tornadoes will
be possible primarily from central to northeastern KS into
southeastern NE. Given southwesterly deep layer shear is oriented
somewhat parallel to the southwest to northeast cold front, storms
near the front may cluster and grow upscale. Better potential exists
for a more semi-discrete supercell across central Kansas ahead of
the dryline. A few HREF members do support potential for this
scenario, with long UH tracks across KS into southern Nebraska.
Tornado probabilities were increased from east-central KS into
southeastern NE/southern IA/northwestern MS.

...Central IA into portions of IL/KY/WI/IN/Lower MI...

Elevated thunderstorm activity will be likely at the beginning of
the period across portions of Iowa/Wisconsin. This will pose some
risk for a few instances of severe hail. Guidance suggests that
recovery will occur by the afternoon across this region with
thunderstorms redeveloping along the cold front and re-intensifying
of downstream convection the into the afternoon. Initial morning
convection may pose some wind/hail risk into IL/IN/western KY.
Additional development by the evening along the cold front to the
north will pose some wind/hail risk across portions of the upper Midwest.

 ...OK/TX...

A more conditional severe risk exists further south across OK/TX.
Large-scale ascent will remain weaker further south. However, strong
instability within the very moist warm sector will exist. Deep layer
flow will be somewhat less compared to further north, but still
sufficient for supercells. If storms can develop, a risk for large
to very large hail and perhaps a tornado will exist.

..Thornton.. 05/17/2026

$$
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 * Origin: Capitol City Online (618:250/10)