369
FXUS63 KMPX 170815
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
Issued by National Weather Service La Crosse WI
315 AM CDT Tue Jun 17 2025

.KEY MESSAGES...

- Some shower / thunder chances across southern MN later today
  /30-45%/. Rainfall rates should be less than previous days.

- Periodic rain chances occur through the week with the area
  remaining in an active pattern. Again, many dry hours are
  still expected except Wednesday possibly further east/south of
  MSP.

- Increasing confidence in the area heating up this weekend with
  some heat indices over 95F Saturday and Sunday, then a cool
  off early next week.

&&

.DISCUSSION...
Issued at 314 AM CDT Tue Jun 17 2025

Shower and Storm Chances Southern MN Later Today

A much quieter day is expected across Minnesota & Wisconsin as
the frontal boundaries responsible for yesterdays multiple
rounds of thunderstorms move south and east of the area. Well
have a bit of patchy fog to deal with through early morning,
primarily in saturated low-lying areas that saw the heaviest
rainfall yesterday. After the fog dissipates, we should see some
Sun today with cooler temperatures in the upper 70s area-wide,
although still on the muggy-end with dewpoints remaining in the
60s.

Isolated to scattered showers/storms are expected later this
afternoon across far southern Minnesota, but anything heavy and
any potential for strong to severe thunderstorms should stay
just south of the border across Iowa.

Periodic Shower and Storm Chances Through Late Week

Southern MN and parts of northwest Wisconsin could be on the
northwest edge of a rain area with a stronger system moving
through southern Wisconsin. This has been well forecast for days
as a stronger tropospheric trough moves through the region. It
is really just a matter of the track and nuance of how far
northwest the rain shield tracks...for now have 40-50%
probabilities for precipitation from sc MN into nw WI,
decreasing northwestward.

On Thursday, some loose agreement exists on a northwest flow
shortwave trough moving through northern MN/northwest WI in the
afternoon per deterministic runs from 17.00Z. MLCAPE values
look to be around 1000 J/Kg with hodographs and wind shear
looking to support organized storms. Will continue to monitor
this time frame but severe storms could occur Thursday
afternoon. This is supported with CAPE/Shear joint probabilities
with least capping in the 16.12Z Grand Ensemble which targets
areas near I-94 and north. SPC has added a Marginal risk on
their Thu outlook with the latest issuance to begin the trend.

Ridge bulling begins in earnest on Friday with low-level
moisture increasing with warm advection / isentropic lift across
much of MN. Thunderstorm chances look favorable right now
Thursday night, evolving northeast Friday into Saturday on a
good 850mb moisture transport convergence signal across much of
the model guidance. Strong capping looks to build in from the
southwest in the convective system wake. Will have to see, this
could present a large hail threat from the elevated storms.

Heat Building in For the Weekend

Confidence continues to grow and the signals remain consistent
that large scale ridging will finally dominate the forecast
area. 16.12 Grand Ensemble values for heat index show a 60+%
probability of 95F+ Saturday mainly southwest of I-94,
increasing areawide with 70-80% probabilities for Sunday. This
could necessitate a Heat Advisory for the Twin Cities metro,
especially Sunday. It appears Monday will bring relief in the
form of a cool front moving through.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1246 AM CDT Tue Jun 17 2025

VFR is expected through the period for much of the area. Further
north, from KEAU-KAXN, some probabilities exist for MVFR
ceilings. In that area, this set of TAFs improves the forecast
from IFR, although some low probabilities still exist for this
to occur (10-20%).

KMSP...VFR is forecast through the period. Currently monitoring
MVFR cloud progressing through northern MN per satellite imagery
and it does continue to dissipate as it heads southward. Have
included a SCT020 and will continue to monitor if a ceiling
would make it to the airfield (10-20% probability).

/OUTLOOK FOR KMSP/
Some showers are possible on Wednesday on the northern edge of a
rainy system moving through Wisconsin. At this time, VFR is
still expected. Winds look to remain below 15 kts through
Friday.

&&

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

&&

$$

DISCUSSION...EA/Baumgardt
AVIATION...Baumgardt