ACUS02 KWNS 160546
SWODY2
SPC AC 160545

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1245 AM CDT Wed Apr 16 2025

Valid 171200Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
CORN BELT STATES...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible, mainly from
late afternoon Thursday into the evening, across parts of the Corn
Belt States. Large to very large hail, a couple tornadoes, and
localized damaging winds may occur.

...Synopsis...
A longwave trough, consisting of multiple embedded shortwave
impulses, will drift east from the southern Prairie Provinces to the
Lower CO Valley. A lee surface cyclone will be anchored over the
central High Plains. Minor, triple-point surface waves are expected
along the baroclinic zone in far northeast KS and southern MN on
Thursday afternoon.

...Corn Belt States...
Along the leading edge of a stout EML and 700-mb warm front,
isolated to scattered elevated convection should be ongoing at 12Z
Thursday across parts of the lower MO Valley. This activity may pose
a threat for isolated severe hail before weakening towards midday.

Neutral mid-level height change is anticipated in its wake along the aforementioned baroclinic zone. Low-level warm theta-e advection and convergence along the front will be primary drivers of convective
potential from late afternoon into Thursday night. Guidance spread
is quite large for a D2 forecast with the thermodynamic setup ahead
of the front, especially across IA to the northeast of the
triple-point dryline intersection in northeast KS. The 00Z NAM is
around 20 F cooler with surface temps at peak heating relative to
the bulk of guidance that have very warm and well-mixed boundary
layers. This has substantial impact on the spatial extent and
amplitude of MLCAPE/MLCIN ahead of the front. It seems probable that
mid to upper 50s surface dew points will spread as far north as
southern MN. With a lean towards the more well-mixed guidance, this
should support a corridor of moderate buoyancy with MLCAPE from
1500-2500 J/kg.

The most probable signal for late-afternoon storm development is
along the baroclinic zone from southeast NE into southern MN,
coincident with supercell wind profiles. Weak low-level winds
initially in the southeast NE region could support a long-track
supercell capable of producing a very large hail swath. Otherwise,
severe to sporadic significant severe hail seems plausible with late
afternoon to early evening storms, along with localized severe gusts
and a low-confidence tornado threat.

Coverage of elevated storms may remain subdued on Thursday night.
Despite a strong low-level jet across OK/KS to the Mid-MS Valley, restrengthening of the EML may inhibit sustained storms.
Conditionally, the environment will support elevated supercells with
a primary threat of large hail.

..Grams.. 04/16/2025

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)