749
FXUS63 KMPX 190755
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
255 AM CDT Tue Aug 19 2025

.KEY MESSAGES...

- Dense fog will linger through mid to late morning. A few weak
showers and drizzle are possible this afternoon and evening.

- Dry and quiet weather continues this week, with a chance for
  showers Friday. Quiet weather continues with cooler
  temperatures this weekend.

&&

.DISCUSSION...
Issued at 255 AM CDT Tue Aug 19 2025

In stark contrast to the last few nights, there is relatively quiet
weather across the MPX CWA with the primary concern being areas of
dense fog that have developed due to elevated dew points from all
the rain we have received over the last few days. The fog is
thickest in southern Minnesota with low level clouds in western WI
resulting in patchier fog and the remnants of what were a few
showers moving across western Minnesota also resulting in slightly
higher visibility. There is a Dense Fog Advisory active across
southern Minnesota through 9am, however it may need to be expanded
as the dew point depression across most of the area is only a few
degrees at most and the morning inversion will only strengthen until
we get a couple of hours past sunrise. Forecast soundings from the
RAP/HRRR show the fog potential lingering through at least 9am
before rising temperatures will help dissipate the fog, as dew
points begin to slowly drop for the rest of the day. Northwest flow
over the lingering higher dew points could result in a few showers
during the afternoon and evening, however the vast majority of the
region will be dry today with dry conditions expected to continue
for the rest of the week.

Surface high pressure and subsidence will ride the edge of an upper
level ridge, bringing mostly clear skies and pleasant weather to the
region through most of the week with our only chance for showers
after today arriving on Friday via a cold front stretching
southwards from a surface low over Hudson Bay. This surface low is
being forced ahead of an upper level occlusion and longwave trough
which should stay far enough north to keep the majority of the
forcing away from the area. This coupled with a lack of moisture due
to the lower dew points and limited access to a good moisture source
will result in isolated to scattered showers but limited potential
beyond this. The main thing that could potentially throw a wrench
into things is the rate of evapotranspiration due to the maturity of
vegetation at this point in August, however the lack of significant
heat should also quell this risk somewhat. As the upper level trough
shifts eastwards, broad northerly flow will stack across the area at
all levels of the troposphere, resulting in falling temperatures and
highs in the low 70s by next weekend. There is even a chance that a
significant portion of the area struggles to see a high of 70 on
Sunday, which seems like a rarity for the first weekend of the State
Fair (it hasn`t happened in August for the State Fair since
2018).

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1052 PM CDT Mon Aug 18 2025

Only site to have precipitation concerns is AXN with the
decaying cluster of SHRA/TSRA from NW MN. Have maintained a
couple hours of precipitation at initialization but not
expecting much from this area of precip.

Otherwise, conditions are looking rather good for fog
development overnight with plenty of surface moisture trapped
under the nightly inversion along with winds going calm. Have
indicated prevailing MVFR with TEMPO drops to IFR but conditions
worse than IFR along with a longer duration are each very
possible near and through sunrise. Conditions will return to VFR
by late morning and remain as such through Tuesday evening.

KMSP...MSP will not be immune from the ground fog development
overnight, with MVFR conditions likely by around 09z and a good
shot at some duration of IFR-or-worse conditions through the
morning push. Conditions will improve to VFR thereafter.

/OUTLOOK FOR KMSP/
WED...VFR. Wind E 5kts.
THU...VFR. Wind S 5-10kts.
FRI...VFR. Chance -SHRA/-TSRA. Wind NW 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 9 AM CDT this morning for Blue Earth-
     Faribault-Freeborn-Goodhue-Le Sueur-Martin-Rice-Steele-
     Waseca-Watonwan.
WI...None.

&&

$$

DISCUSSION...TDH
AVIATION...JPC