109
FXUS63 KMPX 122326
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
626 PM CDT Sat Sep 12 2026

.KEY MESSAGES...

- Widespread rain arrives Monday, but forecast rain amounts
  continue to trend lower.

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

&&

.DISCUSSION...
Issued at 225 PM CDT Sat Sep 12 2026

To simply put it, it finally feels like fall this afternoon. Winds
still remain on the breezy side, especially across western Minnesota
where gusts between 20-25 mph are being reported. These winds are
remnant from a post-mid-level wave which is now located over
southern Ontario. Winds will decrease this evening once this wave
distances itself away from the northern plains. Skies for the rest
of this afternoon should remain clear although some clouds will
build from the west this evening. Afternoon highs expected to reach
the mid-60s to lower 70s and lows overnight falling to lower 50s and
some upper 40s north and east of I-94.

On Sunday, an upper-level trough will move east across Alberta into
Ontario. The apex of this trough is forecast to sink as far south as
southern Minnesota. Forcing is expected to be rather weak however
its possible that a few scattered rain showers develop mainly south
of the MN River Valley. However, brought slight chance PoP values up
into portions of southern MN for any rouge precip that wants
develop. By Sunday afternoon, a 1020mb sfc high builds in over the
western Great Lakes region allowing for skies to clear with
afternoon with highs near 70 degrees.

Our eyes remain fixed on Monday`s forecast. There is still
favorable disagreement between model membership for total QPF.
For example, the EPS still holds as the wetter solution. If this
system develops in favor of EPS trends, an inch of rain could
fall as far north as the Twin Cities metro and closer to 1.5
inches across southern and southeastern Minnesota. On the other
side of the coin, the GEFS remains incredibly pessimistic. Much
of the northern half of Minnesota including the Twin Cities
metro could see closer to 0.25" while southeastern MN would see
near 0.75". For now, decided to remain with NBM QPF amounts
which would provide 1-1.5 inches from a line south of Ladysmith,
WI down to Fairmont, MN. Areas northwest of this line would see
between 0.5-1.0" of rainfall.

To make sense of the model disagreement, a break down of both the
EPS and GEFS can help paint the picture. Aloft, both models have a
negatively tilted trough that digs in over southern Saskatchewan
allowing for favorable forcing to be in place over the northern
plains. However, the EPS features a tighter pressure gradient
compared to the GEFS. In the lower-to-mid levels, both models
favor strong warm moisture advection which clearly supports the
increased rainfall chances. At the surface, beneath the
negatively tilted trough aloft, the GEFS depicts 998mb surface
low while the EPS shares the same feature but stronger at
992mb. Now if we factor in the GEPS (Canadian Ensemble), this
favors closer to the result of what the GEFS is suggesting.
Another element to be aware of is the low-end severe weather
potential mainly along the I-90 corridor. the upper-level wave
producing this system could make for a narrow window of wind-
shear of about 30kts. The thermodynamic profiles are not
impressive but with Low LCLs and combined shear, we cannot turn
our head away from a small tornado threat Monday evening. In the
end, the QPF forecast remains highly uncertain. Any shift in
track could greatly decrease/increase QPF amounts for a given
area. Of course, those who manage to see greater thunderstorm
activity will have a shot at observing locally higher amounts.

Beyond Monday, much of the remaining forecast period is under zonal
flow. Forecast highs will remain the the upper 60s to lower 70s. A
couple of additional rain chances will arrive late Wednesday and
then again on Friday.

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 624 PM CDT Sat Sep 12 2026

A relatively quiet TAF period is expected with VFR for all sites
and a small chance for a few isolated showers from roughly
08-13z. These showers would favor the southern sites,
specifically RWF/MKT, with a much lower chance for the rest,
although confidence was too low for all sites to include for now.
Winds will become VRB03kt after 06z with BKN to OVC 080-100
level cigs developing through 14-15z, before scattering out and
becoming SKC by period`s end.


KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
MON...-SHRA/MVFR likely, chc IFR. Wind SE 10-15G30kts.
TUE...VFR. Wind NW 5-15kts.
WED...VFR. Chc MVFR/-SHRA PM. Wind E 5-10kts.

&&

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

&&

$$

DISCUSSION...Dunleavy
AVIATION...TDH