419
FXUS63 KMPX 011200
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
700 AM CDT Tue Sep 1 2026

.KEY MESSAGES...

- Best chance of rain comes tonight, thunderstorms likely
  across southern Minnesota with some strong to severe.

- A low confidence precipitation forecast with multiple low
  chances for rain through early next week.

- Summer-like temperatures and humidity continue through Labor
  Day weekend.

&&

.DISCUSSION...
Issued at 219 AM CDT Tue Sep 1 2026

Welcome to meteorological fall! It will not feel much like fall
though with temperatures continuing to be warm (generally in the
80s) even for the peak of summer. In addition we also have a
chance for some strong to severe thunderstorms tonight and
almost daily chances for more rain/storms. Even though next
week is starting to look a little cooler, it will be a while
before we get fall weather.

Today and Tonight... Another morning of ample radiative cooling
and light winds is providing for some patchy fog. Some areas
could be locally dense, but it will not be widespread. The cold
front has now passed through all of the area, but it won`t be
much cooler today as the warm airmass remains over us. The
bigger difference with this frontal passage is a drop in dew
points. It will not be dry by any means, but not as high as what
we saw in the past two days. We could still see some dew points
approach 70 along the I-90 corridor as some of the moisture
across Iowa advects north. The main impact for today will come
overnight as a shortwave moves over the Upper Midwest.
Convection is expected to initiate to our west across South
Dakota associated with this synoptic feature. As this
convection heads east upscale growth into a MCS appears like
the most likely solution. MCS maintenance looks favorable as it
would be fed by the LLJ. The biggest question right now is how
far north will this be? Most of the CAM guidance favors the I-90
corridor, but some outliers get as far north as the southern
Twin Cities metro area. Conceptually though the southern
solution where most of the CAMs are make the most sense as this
would be where the best environment would be. MU CAPE still
looks close to 3000 J/kg and deep layer shear also looks strong.
Due to the anticipated storm mode damaging winds would be the
main risk for tonight.

Wednesday into the Weekend... The summer pattern will continue
into the holiday weekend. Wednesday looks to be a little cooler
with highs more in the lower 80s as we look to get a break from
the WAA. This won`t last long as the WAA comes back Wednesday
night into Thursday to both bring our next rain chance and
warmer temperatures. There will be some lift with the warm front
lifting north which should give us enough for another rain
chance. As we throughout this period have plenty of warm and
moist air to fill the other "ingredients" needed for rainfall.
So where we can get enough forcing there should be rain. Once
again the best chance for rain this period (Wednesday night) is
across southern Minnesota. This will also provide for a warming
trend with highs on Thursday in the upper 80s. This heat will
hold through Saturday before some cooler air advects back in
early next week. Thursday night looks like a similar setup with
a similar impact, just a little more spread in ensemble guidance.
What is less certain is who will see rain and storms as these
more mesoscale features are not apparent this far out and our
more synoptic models are too broad with QPF. Friday night into
the weekend starts to see much less clustering in the global
ensembles and therefore less confidence in the rain forecast.
Membership shows continued rain chances, but widely scattered
from member to member. So if you have Labor Day Weekend plans
keep an eye on the weather forecast as we get closer and start
to get a better idea of when thunderstorms could occur.

Next week... This uncertain pattern remains into early next
week. NBM therefore keeps low PoPs spread across every day. As
this gets into days 1 to 3 details will come into alignment.
What is more certain is that there does look to be some cooling.
Still much above normal temperatures, but instead of 10+ above
normal it looks closer to 5 above normal. Normals right now are
in the upper 70s and will soon fall into the mid 70s.

&&

.AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 645 AM CDT Tue Sep 1 2026

Patchy MVFR/IFR/LIFR fog is affecting a few TAF sites across the
region, but conditions will improve as the sun rises and mixes
up the boundary layer.

For the rest of today, expect VFR conditions with just a few
high clouds and light westerly winds.

Overnight, thunderstorms will move in from the Dakotas and
should impact KRWF and KMKT. If storms develop a bit further
north, they could also impact KMSP, KRNH, and KEAU. They should
remain south of KAXN and KSTC.

KMSP...VFR conditions expected through at least 06Z tonight, but
then thunderstorms could impact KMSP. Right now the most likely
scenario is for storms to stay just to the south of KMSP, but
there is certainly enough confidence to have at least a Prob30
in the TAF.

These storms will exit the region by Wednesday morning, and
expect mainly VFR conditions for Wednesday.

/OUTLOOK FOR KMSP/
WED NIGHT /THU...VFR. Small chance TSRA. Wind SE 5-10 kts.
FRI...VFR. Small chance TSRA. Wind S 5-10 kts.
SAT...VFR. Wind SE 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...Dense Fog Advisory until 9 AM CDT this morning for Barron-Rusk.

&&

$$

DISCUSSION...NDC
AVIATION...JRB