195
ACUS02 KWNS 141731
SWODY2
SPC AC 141729

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1229 PM CDT Fri Jun 14 2024

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE MID-MO
VALLEY AND NORTHERN GREAT PLAINS...

...SUMMARY...
Scattered severe thunderstorms with damaging winds and large hail
are possible from the late afternoon into the evening Saturday,
across the Mid-Missouri Valley and in eastern Montana to central
North Dakota. A couple tornadic storms may occur in eastern Nebraska
to western Iowa, with isolated severe significant severe hail and
wind possible in the northern Great Plains.

...Mid-MO Valley...
A southern-stream shortwave trough currently centered near the Four
Corners will progress northeast into parts of the central Great
Plains to Upper Midwest by Saturday afternoon. This trough should
contain multiple embedded impulses that are convectively enhanced
from D1 convection over the High Plains. The greatest severe threat
will likely emanate out of one such MCV as it progresses towards the
Mid-MO Valley towards peak heating. While mid-level lapse rates will
be weaker in vicinity of the MCV, ample low-level flow should be
relatively strong ahead of the broader trough. A confined corridor
of moderate to large buoyancy (MLCAPE of 2000-3000 J/kg), aided by
greater low-level moisture along a residual frontal zone, should
develop from the Ozark Plateau northwest into the Mid-MO Valley.
Isolated to scattered thunderstorms are expected ahead of the MCV.
At least a few of these should develop into supercells given the
enhanced low-level SRH. Potential for a couple tornadic storms along
with a risk for severe wind/hail should develop during the late
afternoon through about dusk. This corridor will probably remain
focused on the mesoscale as highlighted by a relatively confined
level 2-SLGT. Strong low-level shear will exist with northeast
extent in the Upper Midwest, but forecast soundings indicate
convection will largely remain elevated, suggesting a more marginal
severe hail/wind threat Saturday night.

...Northern Great Plains...
A shortwave trough will move northeast across the Pacific Northwest
into the southern SK vicinity by early Sunday. A pair of lee
cyclones should develop near the Canadian Rockies and over the
northern High Plains before tracking eastward into MB to the central
Dakotas as a pronounced cold front accelerates eastward Saturday
night. Multiple corridors of thunderstorms will likely develop
during the late afternoon along the cold front and a lee trough,
over southern to eastern MT and the western Dakotas.

The degree of buoyancy with western extent into MT is somewhat
uncertain where large-scale ascent will initially be greatest. But a
plume of MLCAPE from 1500-2500 J/kg amid very steep mid-level lapse
rates should develop from the central/western Dakotas into a part of
eastern MT. Strengthening mid to upper-level flow with the
approaching shortwave trough will yield potential for high-based
supercells, conditionally favoring very large hail. 12Z HREF
guidance signals convection largely forming west of the larger
buoyancy plume and impinging on it during the evening. This suggests
that a cluster to linear mode may occur relatively quickly with cold
pools spreading east-northeast in the western to central Dakotas.
Small-scale bowing structures may develop, locally enhancing severe
wind intensity during the evening. Have expanded both level
1-2/MRGL-SLGT risks south and east to account for greater confidence
in a mixed severe hail/wind threat occurring.

..Grams.. 06/14/2024

$$