019
FXUS63 KMPX 131911
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
211 PM CDT Wed Aug 13 2025

.KEY MESSAGES...

- Active weather returns late tonight and continues through the
  weekend. Multiple rounds of heavy rain and thunderstorms are likely.

- Primary threat associated with weekend storms will be
  localized flooding. Rainfall totals in excess of 3" are
  possible.

&&

.DISCUSSION...
Issued at 211 PM CDT Wed Aug 13 2025

THIS AFTERNOON - EARLY FRIDAY...

Beautiful afternoon underway across south central MN/western WI,
with mostly sunny skies and temperatures warming through the 70s.
It`s possible that folks may sense a hint of lingering wildfire
smoke outside which is tied to a narrow band of smoke that has
settled south across central MN. That being said, the latest
from MPCA shows air quality in the yellow category and no AQA`s
in effect. Our attention turns from the present tranquil weather
to the return of an active pattern. In fact, regional radar
display shows us the start of a change, with showers and
thunderstorms ongoing to the west across SD. This activity has
sustained on the nose of the low-level jet and expectations are
that it should begin to decay as it turns southeast towards the
SD/MN border. Admittedly, the short term guidance has struggled
to resolve this convection so will follow gradient trends and
include slight chance PoPs into the evening across western MN.

Evolution of deepening surface low across central Canada will be the
primary driver of our weather over the next few days. An initial
shortwave displaced from the parent low is progged to slide across
the Dakotas through tonight. The expectation has been for this wave
to kick off deeper convection across southern SD, which will
translate east overnight. A 40+ knot low-level jet is forecast to
develop across eastern SD/western MN ahead of the advancing wave. The
LLJ will be the primary forcing mechanism for convection, however
instability will be rather limited across our forecast area. While
still messy, CAM signal is in better agreement with scattered
showers and storms moving into/developing across western MN late
tonight and moving into central MN through tomorrow morning. No
significant changes were made to the going 30-40% PoPs. Could see a
few airmass showers/storms through tomorrow afternoon/evening,
though severe weather chances are low.

By tomorrow afternoon, a mature surface cyclone is forecast to be
located over northern Manitoba, with a cold front extending south
into central ND. This front will be the focus for deeper
convection across eastern ND and northwest MN tomorrow night.
SPC has a Slight Risk in place across this portion of the Upper
Midwest, where severe weather parameters are the most impressive
ahead of the front. Locally, we may have isolated to scattered
showers/storms within the low-level jet axis/wing of warm
advection tomorrow night, however the threat of more widespread
deeper convection is trending to be less likely.

FRIDAY - EARLY NEXT WEEK...

The aforementioned cold front will sag south through Friday and
the latest guidance has trended on the drier side during the
daytime hours. The front will stall somewhere near the MN/IA
border and will become the focus for a pattern change that aims
to bring multiple rounds of showers and thunderstorms into the
Upper Midwest through early next week. Aloft, a potent ~594dm
ridge is forecast to develop over the eastern Great Plains/extend
into the Ohio Valley. Several weak disturbances will "ride the
ridge" from the southwest and intersect the stalled out
boundary. Favorable moisture transport will advect PWATs in
excess of 2" locally, which will set the stage for heavy rain in
any convection that develops. It`s somewhat of a challenge to
narrow down precip windows at this point, though cloud bearing
wind/low-level jet relationship supports slow storm motions and
potential back-building/training of storms (especially the
second half of the weekend). Nailing down precise rainfall
expectations for any one location is also a low confidence part
of the forecast given the convective nature of the setup.
However, cannot deny the consistent signals from the global
ensembles that depict high probabilities of greater than 2" of
QPF through the weekend across central MN/western WI along the
I-94 corridor. Still a question of whether each round of
convection is going to track over the same general area or
"stair-step" southward each time period. Of course, the first
scenario is much more concerning when it comes to a localized
flood threat -- and it is the one that is advertised by some of
the most recent 12z guidance.

At this point, it`s fair to say that much of central/southern
MN and western WI will observe 1-2" of QPF through the weekend,
with localized amounts of 3"+ appearing likely. Slow storm
motions and training over any one area could see amounts climb
above 4", though will need to wait for real time trends and
short term hi-res guidance over the weekend to address most
likely axis of such an occurrence. The pattern will continue
into Monday, prior to the passage of a more potent shortwave
across the northern CONUS heading into Tuesday. This will bring
an end to the daily/nightly 30-50% storm chances and drop
temperatures slightly heading into the middle of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1241 PM CDT Wed Aug 13 2025

VFR conditions expected throughout this duration. Upper level
smoke will move across the region this afternoon but not
expected to drop visibility out of VFR range. Mid-level ceilings
will develop overnight through Thursday afternoon, with possibly
a few rain showers over western into central MN in the few hours
either side of sunrise. Chances too low at this time to include
precip mention in southern and eastern MN but will see how
models and radar trends evolve. NW winds under 10kts will go
light/variable overnight then pick up from the SE mostly under
10 kts tomorrow, with western MN becoming a bit more
breezy/gusty.

KMSP...Minimal issues expected with this TAF. There is a small
non-zero chance of having a few showers near and after sunrise
Thursday morning but too low to include at this point. No
visibility or ceiling restrictions expected.

/OUTLOOK FOR KMSP/
FRI...Mainly VFR. Chc MVFR/-TSRA late. Wind S 10-15 kts.
SAT...Mainly VFR. Chc MVFR/-TSRA early. Wind variable 5 kts,
becoming E 10 kts late.
SUN...Mainly VFR. Chc MVFR/-TSRA. Wind E 10-15 kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...JPC