687
FXUS63 KARX 280537
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1237 AM CDT Sat Jun 28 2025

.KEY MESSAGES...

- Dense fog possible tonight.

- Several lines of storms will move through the area this
  weekend (Saturday morning, Saturday night, and Sunday
  afternoon and evening). The second and third lines may produce
  some damaging winds.

&&

.DISCUSSION...
Issued at 238 PM CDT Fri Jun 27 2025

This afternoon

A weak surface trough will move east across western Wisconsin
this afternoon. With surface-based CAPES up to 200 J/kg and
weak shear along and ahead of this boundary, only expecting
isolated to scattered showers and maybe an isolated storm or two.

Tonight

The ridge axis will be overhead. With light winds and clearing
skies, there will be the possibility of dense fog. Early this
morning, this ridge axis was located over the Northern Plains
and it produced dense fog there.

Saturday Morning

The CAMs are in general agreement that a weakening mesoscale
convective complex will southeast through the area. While there
is in agreement that this will likely occur, the timing is
uncertain ranging as early as 28.11z (NAM 4km) to 28.14z (HRRR).
ML CAPES will generally range from 250 to maybe 750 J/kg. With
this convective complex being linear, winds will be the primary
threat with this line. At this time, expecting wind gusts of
30-40 mph.

Saturday Afternoon and Night

With mostly to partly sunny skies, most unstable CAPES will
climb into the 1500 to 3000 J/kg during the afternoon. The 0-6
km hodographs are favorable for supercells across the eastern
Dakotas and west-central and southwest Minnesota during the mid
to late afternoon. As these cold pools coalesce, this convection
will become more linear and move southeast toward the area.
With this system moving into a less shear environment and the
MU CAPES weakening, there should be a gradual decrease in
intensity. SPC currently has a slight (threat level 2 out of 5)
risk across parts of southeast Minnesota and northeast Iowa. The
main threat would be damaging winds.

Sunday Afternoon and Night

A remnant outflow boundary will be located somewhere near the
Interstate 90 corridor. As surface heating develops, there
should be intensifying deformation heating band developing. The
models suggest weak convergence along this boundary and this
should result in the development of isolated to scattered
convection. With weak shear, not anticipating any severe
weather in our area. Meanwhile, further west additional showers
and storms are expected to develop along a cold front. As the
front moves east, the convergence will increase along this
front. A line of storms is expected to move through the Upper
Mississippi River Valley during the late afternoon and evening.
The main threat with this line will be damaging winds.

Wednesday through Thursday

An upper level ridge will build across the Central Plains and
possibly the Northern Plains. During the afternoons and
evenings, scattered supercells are expected to develop in the
Dakotas and then as their cold pools coalesce, this will result
in a forward propagating mesoscale convective complexes. The
main question is where these systems will track across the Upper
or Mid Mississippi River Valleys. The operational GFS and many
of its ensembles suggest these convective systems will track
southeast across the Upper Mississippi River Valley. Meanwhile,
the operational ECMWF continues to track these convective
systems will track across southwest Minnesota, and western and
southern Iowa.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1236 AM CDT Sat Jun 28 2025

Pockets of MVFR to VFR clouds around 2.5-3.5kft persist through
the overnight hours leading to SCTvBKN conditions, primarily at
LSE and areas east of the Mississippi River. Mist/fog is
possible during the early morning for areas east of the
Mississippi River given ample low level moisture, but some
uncertainty in this development exists given the aforementioned
low cloud cover and cirrus streaming in from the west. However,
continued to carry some restricted visibilities at LSE this
morning, with visibilities of 1-3SM possible towards central
Wisconsin. A line of storms currently moving into western
Minnesota may make their way into our region this morning, but
confidence is not high on when/if this would occur as they are
expected to decay as they move east. Southerly winds across the
region today, gusting 20-25KT west of the Mississippi River
this afternoon.

&&

.HYDROLOGY...
Issued at 135 PM CDT Fri Jun 27 2025

An areal flood warning remains in effect along the La Crosse
River and its tributaries from just east of Sparta to La
Crosse. This was due to around 5 inches of rain this week. This
has resulted in moderate flooding. This flooding is expected to
continue into Sunday morning.

Minor flooding continues along the Cedar River in Austin and
Black River at Black River Falls. However, these rivers are
expected to fall below flood stage either late this afternoon or
early evening.

Minor flooding is expected to occur in the Charles City area by
Saturday evening.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...Boyne
AVIATION...Falkinham
HYDROLOGY...Boyne