Mankato, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

363
FXUS63 KMPX 130355
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1055 PM CDT Tue Aug 12 2025

.KEY MESSAGES...

- An additional round of near surface wildfire smoke is forecast to
  arrive late tonight and stick around through tomorrow.

- The pattern will become more active late week into early next
  week. A stalled front will support multiple rounds of showers
  and thunderstorms, capable of heavy rainfall totals.

&&

.DISCUSSION...
Issued at 256 PM CDT Tue Aug 12 2025

TODAY/WEDNESDAY...Water vapor satellite imagery displays an upper-
low spinning over central Ontario early this afternoon. This feature
and its associated surface low near Hudson Bay will continue to
serve as the primary drivers of our weather in the short term.
Surface analysis depicts a cold front extending south of the
surface low through W WI into SE MN. Significant improvements
to the air quality were observed following the frontal passage
earlier today. The rest of the afternoon looks great, with only
diurnal Cu in the sky and a light breeze out of the west-
northwest. Afternoon highs top out in the mid 70s to low 80s.
Diurnal Cu will dissipate this evening and very light winds will
prevail. Suspect that we`ll see another round of ground fog as
temperatures cool towards the dew point tonight, owing to the
clear skies and light winds. Any fog that develops is forecast
to erode shortly after daybreak Wednesday.

Focus will then shift to the potential brief return of degraded air
quality due to a narrow plume of wildfire smoke. A secondary
cold front trailing the aforementioned Hudson Bay surface low is
currently draped from west to east across Manitoba. Latest
observations ahead of the front at Brandon AP (Manitoba) and
Cavalier AP (ND) indicate visibility reductions due to smoke.
This secondary cold front is forecast to sag south towards
central MN over the next 12 to 24 hours and hi-res models
continue to suggest that a high concentration of near surface
smoke will accompany the frontal passage. The latest from MPCA
is the issuance of an AQA through tomorrow for counties along
and north of the MPX/DLH CWA line (Todd to Kanabec). Smoke
scenario is forecast to improve as a warm front lifts through
the region through tomorrow night.

THURSDAY ONWARD...The next feature of interest is currently spinning
over the north Pacific west of British Columbia. Guidance displays
this feature at the base of a shortwave trough which is progged to
translate east and become negatively tilted over central Canada. In
response, surface cyclogenesis is forecast to occur over Saskatchewan
tomorrow, with an eventual ENE track towards the Hudson Bay.
While the core of this system will be well to the the north of
the Upper Midwest, we do expect the return of a more active
pattern as the system traverses across Canada. I previously
mentioned a warm front pushing the smoke concerns out of the
picture tomorrow night. This warm front will lift north in
response to strengthening warm advection across the central
CONUS, which is ultimately tied to the cyclogenesis across
central Canada. The passage of the warm front will position a
40-50kt low-level jet from western KS northeast into SW MN
tomorrow night. The approach of the shortwave is forecast to
spawn convection across the Dakotas tomorrow, which will pose
some severe weather threat. However, we are not currently
expecting these storms to maintain peak intensity into SW MN
tomorrow night given limited instability. Nonetheless, the low-
level jet should allow for increasing coverage of showers/storms
over night into Thursday morning. Latest NBM PoPs between
30-40% (over western MN/moving into central MN) seem reasonable,
with localized heavy rain serving as the primary concern with
this convection.

Could see a few airmass showers/storms Thursday afternoon as the
region remains within the warm advective regime. However, the
greater forcing will be the system`s cold front, which will be the
focus for deeper convection across ND/NW MN Thursday afternoon &
evening. Confidence remains medium to high that the primary
severe weather risk during the Thursday night/Friday morning
period will remain to the northwest of our forecast area. That
being said, the approach of the cold front should promote an
uptick in shower/storm coverage heading into Friday morning,
which is again reflected by 30-40% PoPs in the latest NBM.

The forecast begins to take on a different look from Friday midday
through early next week. The aforementioned cold front is forecast
to stall near the MN/IA border and remain in the position through at
least Monday given little forcing amid zonal flow aloft. Upper
ridging will be the dominating feature over the Ohio Valley,
with several disturbances set to ride the ridge and intersect
the stationary boundary across the Upper Midwest. This setup
sets the stage for daily thunderstorm chances (30-50%) through
Monday. While strong to severe convection is possible, the
greater threat will be more on the hydro side. A persistent low-
level jet will support a moisture rich atmosphere, reflected by
PWATs in excess of 2 inches. In addition to heavy rainfall
rates, the setup bears watching for training/backbuilding
convection. This pattern supports an on/off nature to the
rounds of thunderstorms, likely due to capping, such that
nocturnal period is more likely to see the development and
occurrence of training thunderstorms. Confidence is low in
where the heaviest precipitation bands will be and that will
likely be more of day by day analysis once we enter the hi-res
CAM windows. The big picture idea supports the latest trends
from the global ensembles which advertise multi-day QPF totals
in excess of 3-4" across south central MN/western WI. Not
everyone will see that much rain given the convective nature of
this setup, however, it should be noted that locations that do
observe the heaviest of the rain could exceed 4" over the 4-day
period. As such, the threat for flooding will increase and
become our primary concern over the weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 637 PM CDT Tue Aug 12 2025

Main concern overnight is patchy fog. Areas that do see fog
could have IFR conditions early Wednesday morning, while areas
that remain clear will be VFR. This fog should burn off, with
VFR conditions and light winds expected for Wednesday into
Wednesday evening.

KMSP...VFR conditions throughout. There is a small chance for
overnight/early morning fog, but for now did not include a
mention in the TAFs. Winds will be light, out of the northwest,
but should take on a southeast direction on Wednesday evening.

/OUTLOOK FOR KMSP/
THU...VFR. Chc -TSRA. Wind SE 10-15 kts.
FRI...VFR. Chc MVFR/-TSRA. Wind S 10-15 kts.
SAT...VFR. Chc MVFR/-TSRA. Wind E 10-15 kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...JRB