630
FXUS63 KMPX 292308
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
608 PM CDT Tue Jul 29 2025

.KEY MESSAGES...

- Showers and storms expected overnight along the I-90 corridor in
  southern MN. Localized ponding or flooding is possible.

- Quiet weather for the rest of the week, with wildfire smoke
  from Canada returning. Next chance for showers Sunday into
  Monday.

&&

.DISCUSSION...
Issued at 212 PM CDT Tue Jul 29 2025

Fair weather cumulus is bubbling this afternoon with a bit of cirrus
in southern Minnesota from convective debris from storms in Iowa, as
most of the area will continue to see filtered sunshine as
temperatures settle in the mid to upper 80s this afternoon. Dew
points in the mid to upper 60s will make it feel somewhat humid for
one more day, ahead of an incoming ridge and surface high pressure
that will not only drop temperatures but also push the warmer dew
points off to the east. Model guidance today has started to push the
potential for showers and storms over southern Minnesota beginning
tonight and lasting through tomorrow morning before the Canadian
ridge drifts southwards with stagnant flow aloft allowing a rather
potent shortwave to move west to east across the northern plains.
Right now, the consensus is to push the best forcing through central
to northern Iowa and as far north as the Mankato area, however we
expect to see the majority of acitivity within the MPX CWA focused
along the I-90 corridor. Forecast soundings show a meager 500 or so
J/KG MUCAPE with effective shear below 25kts as well as poor low
level lapse rates, such that individual storm strength is expected
to be rather low. PWATs are on the top half of the scale from 1.6 to
1.8 inches, however this may be overdone as high-resolution guidance
is showing dew points that are probably 3-4 degrees too high
right now given our current conditions. The primary risk from
storms overnight will be localized flooding/ponding water over
roadways that haven`t recovered from multiple days of
thunderstorms since this weekend, with a small but non-zero
chance for a few strong to severe wind gusts. Given the forcing
and poor shear, we do not expect storms to be able to maintain
strength of individual updrafts long enough to produce large
hail, and poor 0-1km shear and relatively high LCLs should also
prevent a legitimate tornado threat.

The ridge will continue to slowly slide southwards with west to
northwesterly flow aloft and surface high pressure building over the
northern plains throughout Wednesday, with this surface high
pressure expected to dominate the local forecast through the rest of
the week before exiting the region to the east on Saturday. Mostly
sunny skies are expected with fair weather cumulus possible Wed-Fri,
and unfortunately with northwesterly flow aloft we are once again
likely to see periods of wildfire smoke entering the region. The
potential for near-surface smoke is uncertain for the southern half
of Minnesota and western Wisconsin, however there will likely be
times we reach at least orange if not red air quality ratings as
sunshine will enhance mixing in the lower levels. The next chance we
will see more scattered to widespread showers and potential
thunderstorms will arrive on the heels of the departing high
pressure on Sunday as southerly winds in the lower levels will bring
not only moisture rich air but also warm air advection to force
ascent. We will need to see how this threat evolves throughout the
course of the week, with diurnal storm chances expected to be
favored alongside potential nocturnal activity along the nose of the
low level jet whose position has yet to be determined. Stay tuned
for future updates, and for now we hope you enjoy the sunshine and
can avoid the worst of the smoke concerns for the rest of the
week!

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 600 PM CDT Tue Jul 29 2025

Only concern will be a chance for SHRA/TSRA in southern
Minnesota overnight into Wed AM, potentially impacting RWF and
MKT. In conjunction with the storms, high clouds will overspread
much of the region tonight and tomorrow. Winds will generally be
at or below 10 kts, becoming more northeasterly through the
period. FU may start to be a concern near the end of the period,
with increasing surface smoke likely through the end of the
week.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
THU...VFR. Wind E 5-10 kts.
FRI...VFR. Wind SE 5-10 kts.
SAT...VFR. Winds S 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.

&&

$$

DISCUSSION...TDH
AVIATION...BED