Mankato, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

878
FXUS63 KMPX 280731
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
231 AM CDT Sat Jun 28 2025

.KEY MESSAGES...

- A line of strong to maybe severe storms is tracking across
  Minnesota this morning with chances for hail and wind.

- Hot and humid today with heat index values in the 90s.

- Another chance for severe storms this afternoon into evening.
  All modes of severe are possible: tornado, wind, and hail.

&&

.DISCUSSION...
Issued at 231 AM CDT Sat Jun 28 2025

This weekend... A line of thunderstorms has developed across
western Minnesota early this morning. This line is in an area of
higher instability which has allowed for the rapid development
of convection as the low level jet has picked up. However as
these storms continue to the east the instability falls off
significantly. So long lived storms will require more upscale
growth into a full MCS. CAMs have not had a good show so far
this morning with almost every HRRR run being wrong. The RRFS
has shown some skill in determining the convective modes and
overall picture even if the CI timing has been off. Overall
going to have to depend more on conceptual models and
observations with this poor CAM showing. Based on the trends in
current observations the line continues to build itself and grow
upscale. It just comes down to if it can grow enough before it
outruns the best instability. How far east theses storms can get
will have in influence on the environment later today. A large
MCS moving across the whole state will make it hard for the
environment to regenerate into a more convectively favorable
one. However we still have the warm and moist air continuing to
advect into the Upper Midwest. This will bring heat index values
into the 90s across southern Minnesota and parts of western
Wisconsin. It will not get as warm in central Minnesota, more
upper 80s. Thinking back to the ingredients for thunderstorms
we will have lift from the warm front moving across Minnesota,
ample instability, tons of moisture with precipitable water
values over 1.5", and the one parameter with some doubt is
shear. This could be explosive amounts of instability like we
had a week ago, the difference this time is much less CIN. This
could lead to quick development of storms this afternoon. There
should be an initial discrete mode with supercells possible, but
it could quickly become more multicell in nature. The greatest
risk will be during this chance for supercells when all severe
modes will be in play. The tornado risk will be lesser in the
more multicell mode. Much of the rain chances today will be
convective in nature. So the temporal amount of the day
impacted by rain will not be as great as the forecast makes it
look. It is more a factor of uncertainty in when the rain will
occur. When it does occur it will be heavier thunderstorm rain
rather than what we had a few days ago with more widespread rain
that laster for longer periods. Moving into Sunday a cold front
will move in and bring some relief. However in the
afternoon/evening time frame storms will fire along the front.
Positioning of the front by this point will give most of us a
chance for more rain showers or weak thunderstorms. The area
that will be far enough ahead of the front for a chance a
stronger storms will be parts of western Wisconsin like Eau
Claire.

Next week... Great summer days to start the week Monday and
Tuesday with highs in the upper 70s to lower 80s and a break
from the rain and storm chances. By Wednesday a frontal passage
will provide the next chance for some more active weather.
Still quite the spread in global ensembles so PoPs remain low. A
generally more unsettled period continues into the later part
of the week, but with continued spread in the ensembles. So the
forecast shows low PoPs throughout this period. As we get closer
the forecast envelope will shrink and these PoPs will be fine
tuned to be higher for smaller periods of time. What is more
certain though is no huge temperature swings expected with
seasonable temperatures continuing into the mid to late week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1235 AM CDT Sat Jun 28 2025

Confidence has generally decreased over the past 6 hours with
TSRA chances. The most widespread convection is over the
southeast corner of NoDak, approaching western Minnesota over
the next 1-2 hours. Hi-res models had been consistently taking
this MCS down the the I-94 corridor, riding the gradient of
building instability. Two areas of convection over SoDak were
not captured as well, and may play a role in keeping the NoDak
storms on an eastward trajectory rather SE-ward. Expect changes
to the forecast as the storms continue to evolve this morning.
The PROB30s generally account for the two possible scenarios of
the either the NoDak storms traveling SE towards the Twin
Cities metro and weakening, or the SoDak storms traveling
through south-central MN and no storms across the rest of
central Minnesota.

With the uncertainty of storm evolution this morning, the exact
extent and persistence of storms later today remains lower
confidence as well. The most likely storm initiation is around
22-00z, and a somewhat messy, multicellular storm mode is
favored. Winds shift more southerly throughout the day, and
become gusty during afternoon especially in southern Minnesota.

KMSP...Adjusted the TEMPO from 11-14z back to a PROB30 due to
the aforementioned decrease in confidence. The useful aspect of
this setup is that storms are already ongoing, so we`ll be able
to see them coming should they turn southeast and continue
towards KMSP later this morning. If you don`t see them turn
over the next few hours, the probability for storms will
drastically decrease. Expect frequent updates to the forecast.

/OUTLOOK FOR KMSP/
SUN...MVFR/RA likely, chc TSRA/IFR. Wind SW 5-10 kts.
MON...VFR. Wind NW 10-15 kts.
TUE...VFR. Wind NW 10-15 kts.

&&

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

&&

$$

DISCUSSION...NDC
AVIATION...BED