337
ACUS02 KWNS 210602
SWODY2
SPC AC 210600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Jun 21 2024

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHERN
MO...CENTRAL/EASTERN IA...SOUTHEAST MN...CENTRAL/SOUTHERN
WI...NORTHWEST IL...

...SUMMARY...
Severe storms will be possible across the upper Mississippi Valley
and upper Midwest on Saturday. Damaging wind, isolated hail, and a
tornado or two are all possible.

...East-central Great Plains into the upper Midwest...
The Slight Risk has been shifted southward, based on the latest
guidance regarding the likely position of the primary surface
boundary during the afternoon and evening.

A convectively enhanced shortwave trough is forecast to move across
the upper Midwest on Saturday. In the wake of morning convection,
moderate to locally strong buoyancy is expected to develop from
eastern KS/southeast NE northeastward into parts of southern
WI/northern IL, along/south of an outflow-reinforced front.
Scattered thunderstorms are expected to develop along the front by
late afternoon and spread eastward into the evening. Effective shear
generally in the 30-40 kt range will support a few organized
cells/clusters. Relatively strong heating and large PW will support
strong/damaging gusts as the most likely hazard. Warm temperatures
aloft and weak midlevel lapse rates should limit the hail threat,
though isolated hail cannot be ruled out if any supercells can be
sustained. A tornado or two will also be possible, in the presence
of moderate low-level southwesterly flow and modestly enhanced SRH.

Farther east, intensification of morning convection and/or afternoon
redevelopment will be possible across parts of lower MI. While
instability will be weaker compared to areas father west, somewhat
enhanced low/midlevel flow will support a threat for isolated
damaging wind and possibly a brief tornado.

...Parts of the Northeast...
Widely scattered thunderstorms will be possible across parts of the
Northeast during the afternoon and evening, within a warm,
moderately unstable, and weakly capped environment along/south of a
cold front draped across parts of New England. Modest midlevel
west-southwesterly flow could support a few weakly organized
cells/clusters capable of locally damaging wind.

...Parts of ND...
A mid/upper-level shortwave trough is forecast to move across parts
of SK/MB on Saturday, with some influence of this shortwave expected
to extend into parts of ND. Isolated to widely scattered
thunderstorm development will be possible during the
afternoon/evening, with moderate buoyancy and sufficient deep-layer
shear supporting potential for a few organized storms capable of
isolated hail and strong/severe gusts.

..Dean.. 06/21/2024

$$