430
FXUS63 KMPX 111106
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
606 AM CDT Thu Sep 11 2025

.KEY MESSAGES...

- Dense Fog Advisory for eastern MN/western WI through this morning.
  Fog is possible across central/southern MN, however should not be
  as dense.

- Temperatures will continue to warm through the weekend. Highs
  are forecast to climb into the upper 80s Saturday and Sunday.

&&

.DISCUSSION...
Issued at 225 AM CDT Thu Sep 11 2025

Our main focus in the short term is another round of dense fog that
has developed across eastern MN/western WI. Similar to Tuesday
night, we observed several sites dropping below a mile fairly
early on in the overnight shift. Given the trends, we went ahead
with a Dense Fog Advisory for counties along and east of a line
from Morrison to Goodhue counties, along with Rice, Steele, &
Freeborn. Of note, this headline does not include Hennepin and
Ramsey counties, where forecast guidance is bit lest aggressive
with the development of fog likely due to the urban heat
influence that will keep temperatures from falling to the dew
point. Forecast soundings were most aggressive across western
WI, where several hours of visibility at or below a half mile
is likely. Locations to the west of the headline across
central/southern MN may observe pockets of dense fog (especially
in the river valleys), however the depth of the fog layer is
quite shallow on the latest forecast soundings. Dense fog will
begin to lift in the first few hours after daybreak. Will likely
see the persistence of stratus through the morning across far
eastern MN/western WI where the morning fog is most prevalent.
This afternoon looks nice, with highs in the mid to upper 70s
under mostly sunny skies.

The big story starting tomorrow through the weekend will be the
return of much warmer September air. We can see signs of the
upcoming warming trend when looking at the upper-level pattern early
this morning. RAP 500mb analysis displays a ~590 dm ridge centered
over the southern Plains. The ridge axis is oriented to the north
across the northern Plains and is progged to shift east later today.
Resultant height rises will open the door for mid-level southwesterly
flow to advect 925mb temperatures between 28-30C over southern
MN to open the weekend. Not much change in the latest NBM run,
which continues to advertise areawide highs in the low 80s
Friday, the mid to upper 80s Saturday (low 90s possible along
I-90), and still in the mid to upper 80s, perhaps near 90 on
Sunday. Just a quick moment of reflection, it was only one week
ago when there was chatter on our social media channels
speculating whether or not MSP would hit 80 again this Fall
-- Fast forward and the pieces are in place for not only
multiple 80s, but it`s likely that MSP makes a run towards the
90 degree mark either Saturday or Sunday afternoon!

Most of the weekend will be dry, however there are a few periods to
watch for some showers or storms. The first precipitation
opportunity will arrive late tonight into early Friday, as the
low-level jet extends over western MN. Forecast soundings reveal
quite the mid-level warm nose associated with the aforementioned
warm advection, so it`s entirely possible that little or nothing
develops tonight. However, should storms develop they would be
elevated and are not expected to pose a severe weather threat.
20-30% PoPS from the NBM are reasonable and were not adjusted
for this forecast period. Though currently looking less likely,
the early Saturday morning period may eventually need low end
PoPs as the nose of the low-level jet remains positioned over
western MN. Once again, severe weather is not expected.

The best chance for showers and thunderstorms over the weekend will
be later Sunday into Monday. By Sunday, the ridge axis will
move east over Lake Superior in response to an advancing
shortwave trough from the west. While there is some variance in
the global guidance, the consensus solution depicts the trough
becoming negatively tilted over the Dakotas by Sunday afternoon,
resulting in a region of broad ascent to the east over our
forecast area. For now, timing differences across the guidance
make it a challenge to diagnose the potential for severe
weather, however I would not be surprised if we end up talking
about the potential for deeper convection since the approach of
the trough should enhance the vertical shear. NBM displays dew
points in the upper 60s Sunday afternoon, so it doesn`t appear
that moisture would be an issue. For now, NBM`s 30% PoPs for
scattered showers and thunderstorms during the second half of
Sunday will suffice. We`ll have more details as confidence
increases one way or another.

Large scale southwesterly flow will continue to advect warm air into
the Upper Midwest to open next week. For now, it looks like we`ll
trend on the mostly dry side Monday and Tuesday. However, the
forecast takes on a cooler and more active look from Wednesday
onward as several waves ride the westerly upper-flow. There are some
rather complex solutions displayed across the global suite, so
confidence in the evolution of the upper air pattern is very
low at this time. The uncertainty supports daily chance PoPs for
precipitation and a downward temperature trend for the middle
to end of next week. Again, this is subject to change as the
guidance is rather muddied.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 606 AM CDT Thu Sep 11 2025

Main aviation concern for the start of the 12z TAF period is IFR or
lower visibility due to dense fog. There are two main areas of
concern for fog. The first is across eastern MN/western WI, where
dense fog has been ongoing for several hours. LIFR visibility is a
common observation at several stations including RNH/EAU. The other
area of of focus is across western MN, where pockets of dense fog
have developed (most likely to impact RWF). Have included fog or a
visibility reduction in all terminals other than MSP, where only a
brief dip to MVFR is expected. Fog will lift by mid-morning, though
locations across western WI may be slow to clear due to lingering
MVFR stratus. Otherwise, all terminals trend VFR by midday with
southeasterly winds generally between 5-10 kts.

KMSP...Could still see visibility dip to 4 or 5SM early in the 12z
period, however we are not currently expecting a greater impact to
MSP from fog.

/OUTLOOK FOR KMSP/
FRI...VFR. Wind SE 10-15 kts.
SAT...VFR. Wind SE 5-10 kts.
SUN...VFR. Chc -TSRA/MVFR late. Wind S 10-15 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 11 AM CDT this morning for Anoka-
     Benton-Chisago-Dakota-Freeborn-Goodhue-Isanti-Kanabec-
     Mille Lacs-Morrison-Rice-Sherburne-Steele-Washington.
     Dense Fog Advisory until 10 AM CDT this morning for Brown-
     Martin-Redwood-Watonwan-Yellow Medicine.
WI...Dense Fog Advisory until 11 AM CDT this morning for Barron-
     Chippewa-Dunn-Eau Claire-Pepin-Pierce-Polk-Rusk-St. Croix.

&&

$$

DISCUSSION...Strus
AVIATION...Strus