805
FXUS63 KMPX 311939
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
239 PM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Quiet weather continues with patchy fog possible again tonight,
favoring western WI.

- Isolated storms in western MN on Monday, with a cold front
bringing widespread showers and a few storms Tuesday into Wednesday.

- Temperatures cool down significantly midweek, rebounding by
  next weekend.

&&

.DISCUSSION...
Issued at 239 PM CDT Sun Aug 31 2025

It would be difficult to imagine a better final day of August and
meteorological summer with temperatures in the low to mid 70s with
fair weather cumulus the only clouds in the sky. The expansive cu
field over southern Minnesota especially will gradually dwindle
after around 5-6pm, with our daylight hours being cut significantly
as it has been over 2 months since the summer solstice. We have lost
approximately 85 minutes of daylight over the course of August, and
can expect to lose a larger amount in September as the sun angle
continues to decrease as the Earth`s tilt migrates the sun towards
the equator by the Autumn equinox. For some additional context, in
the Twin Cities our average temperatures to start September are a
high of 78, low of 60, for an average of 69 degrees. By September
30th, those averages are 67/48/57 respectively, showing just how
significant the lowering sun angle and daylight hours are in terms
of temperature.

Circling back to the upcoming forecast, we can expect a few showers
and storms across western Minnesota Monday afternoon/evening on what
will otherwise be a relatively quiet day once again, as some
localized vorticity circulates around an upper level trough that
will be diving southwards towards the Great Lakes from the northern
jet in Canada. A surface low will develop as it digs southwards,
with a cold front forming and moving across the area Tuesday into
Wednesday. Unlike most of our synoptic level low pressure systems
this summer, there will be limited potential for northwards moisture
advection and warmth from the central plains, which will keep the
vast majority of activity as purely rain showers with some rumbles
of thunder. The lack of warm sector moisture will also keep PWATs
closer to 1 inch than the excessive 1.5+ inches we have seen from a
few systems this summer. In terms of percentiles for this time of
year, the 1-1.25`` PWATs are around the 90th for northern Minnesota
but within the 25th-75th expected range for the southern half of the
state and western Wisconsin. All of this is to say, widespread
showers and some rumbles of thunder are expected along the cold
front, but significant rainfall is not expected with amounts
generally ranging from 0.25-0.5 inches.

Temperatures cool down significantly Wednesday and Thursday with -5
to -7C below normal 850mb temperatures behind the cold front, with
our coldest day likely to be Thursday with morning temperatures in
the upper 30s to low 40s and highs struggling to break 60 depending
on lingering cloud cover. This cool spell will be a brief drop into
more fall-like weather, however temperatures will rebound back
towards the mid to upper 60s by the end of next weekend. Longer
range guidance continues to show less than 25% of ensemble
membership favoring any sort of shower activity beyond the 7 day
forecast, with relatively dry conditions expected to linger towards
the middle of September.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1221 PM CDT Sun Aug 31 2025

Scattered cumulus with bases around 5000 ft will dissipate
around sunset & then redevelop late tomorrow morning. Patchy fog
& mist is possible in rural & low-lying areas overnight, but any
impacts at terminals will likely be limited to EAU where fog &
visibility below 1SM looks likely early tomorrow morning.
Southeast winds between 5-10 kts this afternoon drop below 5 kts
overnight.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
TUE...VFR. -SHRA likely, chc -TSRA/MVFR. Wind SW 5-10kts bcmg
WNW 10-20 kts in evening.
WED...Chc MVFR/-shra. Wind NW 10-15G25 kts.
THU...VFR. Wind NW 10-20 kts.

&&

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

&&

$$

DISCUSSION...TDH
AVIATION...ETA