015
FXUS63 KMPX 131916
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
216 PM CDT Sun Sep 13 2026

.KEY MESSAGES...

- Widespread rain arrives Monday with additional chances later
  in the week.

- A cooler pattern has arrived with highs in the 60s to low 70s
  through next week.

&&

.DISCUSSION...
Issued at 215 PM CDT Sun Sep 13 2026

Now that the clouds are clearing, we`ve get a spectacular fall
weather day with high pressure that came out of the Canadian Rockies
moving overhead. However, all one needs to do is look at the h5 low
over the northwest CONUS to see what will bring this pleasant
weather to an end on Monday.

Tonight, We`ll be under the influence of the surface high. Cloud
cover will move into western MN, but skies will remain clear in
western WI, which will setup a decent gradient in lows tonight, with
clouds keeping temperatures up in the 50s in western MN, but the
clear skies and light winds allowing for some places out around
Mora, Rice Lake, and Ladysmith to drop into the upper 30s. Given
current forecast lows with isolated upper 30s, there`s no need for
any frost headlines in the MPX area at this time.

For Monday, the h5 low currently out around Idaho will deepen while
moving to along the NoDak/Canada border. A lead shortwave ahead of
this low will take on a negative tilt, with h85 winds responding
accordingly, getting up over 50 kts as the LLJ moves across the
Upper MS Valley. PWATs will increase to around 1.8", which is
pushing near the top of climatology for this point in September.
With that kind of moisture and the strong LLJ already noted, IVT
values are near climatology max as well. This will support some
efficient rain producers, but that lack of instability will really
limit the heavy rain threat on Monday. The main uncertainty for
tomorrow deals with where the heaviest rain falls, most of the
guidance shows a large band of 1-1.5" inches of rain falling with
this LLJ forced rainfall, but placement of that band ranges from
west central through central MN and south central MN through western
WI. With the uncertainty in placement of the heaviest rain, we stuck
with the NBM for now, which favors the northern solution. What we
did change from the NBM were the highs Monday. We took a good 5-10
degrees off of NBM highs for Monday, with cloud cover and rain
holding highs back in the 60s for most of the MPX area.

Going into Monday night, the LLJ and plume of high PWATS will
continue shifting east, largely moving east of the MPX area. Even
though the surface cold front will be lagging to the west of the
deeper moisture plume, the fact that the LLJ and plume of high PWAT
air moves east of the MPX area means that the next round of heavy
rain and storms that develops Monday evening through Monday night
will be largely east of the MPX area, falling along and east of a
line from roughly Omaha Nebraska to Wausau, WI.

Next week, this front will run into an unseasonably strong blocking
high over the southeast CONUS. This will cause the front to stall
out from lower MO River Valley to between the Great Lakes and Ohio
Valley. We`ll see multiple wave ripple across this front through the
week. The first one comes Tuesday night through Wednesday night.
This looks to largely impact northeast KS to southern Lake Michigan,
though the northern fringe of this rain shield does look to get up
into at least southern MN, which drives the PoPs Wednesday afternoon
through Wednesday night that are highest across south central and
southeast MN. The next wave arrives for Friday into Saturday and
this one looks to take a more northerly track, bringing better
precipitation chances to the MPX area. We`re again seeing models
pumping out another 1+" rain event with this system, so there`s
potential for some beneficial rains to both begin and end the work
week.

Next weekend, confidence in the forecast, at least for precipitation
chances, drops off. The intense southern ridge will finally start to
break down as a slow moving long wave trough moves across the north
central CONUS. The NBM PoPs are under 20%, but the Canadian and
ECMWF are starting to come around on the idea of a stronger wave
embedded within this trough driving another chance of rain across
the region Sunday/Sunday night, so it`s likely that we`ll start
seeing PoPs increase for the end of next weekend as the NBM starts
picking up on this newer development in the models.

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 102 PM CDT Sun Sep 13 2026

Skies will continue to clear this afternoon
with NW winds between 5-10kts and occasional gusts near 18kts. After
sunset, winds become light and variable until after midnight.
Winds then shift southeasterly and become gusty between 25-30kt
gusts. A wave will track across all sites tomorrow bringing
prevailing light to moderate rainfall. As of now, earliest
arrival for rain would be at RWF between 12-14z. Precip coverage
will become widespread with all MN sites filling in by mid to
late morning. Have included tempo groups for timing of when
moderate rainfall rates are anticipated and will overlap into
next period. Kept WI sites dry this period as timing for any
precip to occur is after 18 at those locations. Once the wave
passes, cigs will fall a combination of low-VFR to MVFR heights.


KMSP...Only concern is the arrival of precip late morning on Monday
as well as gusty SE`ly winds. Have introduced prevailing light rain
to start as early as 17z with moderate rainfall falling between 18-
22z. Light rain will linger beyond the moderate rain rate window
into next TAF period. Cigs fall to MVFR heights by tomorrow evening.
Winds will be out of the NW for the remainder of today and becoming
light and variable overnight. Winds shift SE`ly tomorrow morning
with speeds increasing to 25-30kts as early as 16z.

/OUTLOOK FOR KMSP/
TUE...VFR. Wind NW 10-15kts.
WED...VFR. Chc MVFR/-SHRA PM. Wind E 5-10kts.
THU...VFR. Chc MVFR/-SHRA AM. Wind E 5-10kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...Dunleavy