Chaska, Minnesota Weather Forecast Discussion

977
FXUS63 KMPX 102317
AFDMPX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
617 PM CDT Wed Sep 10 2025
.KEY MESSAGES...
- Another round of fog expected overnight, though it should be
  less widespread and primarily confined to northeast MN and
  northwest WI.
- Temperatures will warm through the end of the week peaking in
  the mid to upper 80s on Saturday.
&&
.DISCUSSION...
Issued at 226 PM CDT Wed Sep 10 2025
Regional radar this afternoon shows that low level stratus has
quickly cleared, with diurnal cu taking its place. Most places
will stay dry through tonight, with only a low chance for
sprinkles closer to central WI. With winds remaining light in
addition to the clearing skies, our saturated airmass will
provide a favorable setup again for radiation fog overnight
into Thursday morning. It does not look to be as widespread, and
the highest confidence is primarily over northeast MN and
northwest WI. A Dense Fog Advisory may needed, though confidence
in the extent southwards is too low to issue at this time.
Our dry period should continue through at least Friday with
large scale ridging centered over the Plains. CAMs do hint at
the potential for a couple rounds of convection along the
ridge, though that should remain across NoDak and northern MN
either day. Highs in the 80s will be common this weekend, and it
may actually feel quite humid with dewpoints in the mid to
upper 60s.
It is looking more likely that a shortwave trough from the west
will start to break down our ridge by late this weekend. Though
there is no strong signal still, this will be our next window
to watch for active weather as southwesterly flow increases
aloft over the northern Plains. Highest PoPs come Sunday into
Monday as the associated surface low tracks northeast into
towards the Upper Midwest. That said, there is still quite a bit
of variability across long range guidance so chances are capped
at 30 to 40 percent. Near or slightly above normal temperatures
are expected to hold steady through the middle of next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 556 PM CDT Wed Sep 10 2025
Mostly clear skies to start the period with all locations at
VFR. However, the combination of light winds & clear skies will
support another round of fog overnight into Thursday morning.
The CAMs favor the 09-14Z Thursday morning period across east-
central Minnesota and western Wisconsin.  Greatest confidence
in dense fog looks to be at RNH and EAU where conditions could
fall to LIFR to even VLIFR. STC and MKT will be close as some
models support IFR condition, I`ve opted for a brief period of
IFR at those sites. Elsewhere, confidence is lower so I`ve
targeted MVFR or VFR with 6SM. BUFKIT soundings favor another
blanket of low stratus (similar to this morning`s) to accompany
the heaviest fog Thursday morning. This stratus may be slow to
break apart to result in VFR by the end of the period. Winds
turn light and variable under 5 knots tonight, then turn
southeast and increase to 5-10 knots Thursday morning.
KMSP...Have included BR in the TAF for Thursday morning but fog
potential looks less favorable than Wednesday morning. I`ve
opted to go with a short window of 5SM BR vs 6 SM.
/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...None.
WI...None.
&&
$$
DISCUSSION...BED
AVIATION...BPH

NWS MPX Office Area Forecast Discussion