161
FXUS63 KMPX 172340
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
640 PM CDT Sun May 17 2026

.KEY MESSAGES...

- Severe thunderstorms likely this evening, with the highest
  risk across southern Minnesota (level 3 out of 5).

- Initial storms will have potential for large to very large
  hail (2-3") and tornadoes.

- Individual storms will quickly form into a line as they
  progress through MN and WI. Significant severe wind (70-80+
  mph) will become the primary hazard with brief QLCS tornadoes
  possible across south-central MN.

- Another round of thunderstorms is likely Monday night. Severe
  thunderstorms are possible across southeast Minnesota &
  western Wisconsin.

&&

.DISCUSSION...
Issued at 124 PM CDT Sun May 17 2026


Today is setting up to have potential to be a higher end day for
portions of the Enhanced Risk area. Latest visible satellite
imagery shorting plenty of clearing with the low-level cloud
deck through much of MN, but especially across the southern
portion of the state. A bubbling cu field is beginning to
develop ahead of ongoing convection tied to the surface low near
the NE/SD state line. Surface winds are largely out of the
SE/ESE for MN and western WI, and dewpoints have been steadily
increasing through the day so far. The best environment is
across southern MN where dewpoints have climbed into the 60s
already and plenty of clearing is allowing for efficient
daytime heating, priming the environment for intense convection
later today.

Based on satellite and hi-res model data, we expect timing to be
maybe slightly earlier than forecast this morning, but generally
along the same timeframe. Supercells and storm clusters will
develop across Nebraska and South Dakota during the afternoon
(around 3-5pm) and progress slightly northeastward into
southwest MN and northern IA (around 6-7pm). At this point,
storms will be tied to the triple point and situated in a
favorable environment for large to very large hail (2-3" in
diameter) and damaging wind gusts (60+ mph). Storms will quickly
develop into a line along the cold front and turn into a
significant wind (70-80+ mph), QLCS setup with line-embedded
tornadoes possible within that Enhanced Risk area (stretching
from Redwood Falls, MN over to Owatonna, MN and south). Forecast
soundings show increasing low-level shear and humped hodographs
in the region ahead of the line, which is also reflected in
models like the RRFS and HRRR producing a zone of STP values of
5+ across southern MN. Typically QLCS tornadoes are weaker than
supercell tornadoes, so we really want to highlight that there
is higher- end potential with today`s environment compared to
your average QLCS setup. Any tornadoes that develop will likely
still be brief, like any typical QLCS setup, though the strength
of the tornadoes may be capped at an EF2 level rather than EF1.
This is all in general-speak, but the point is that the higher-
end environment warrants being prepared for slightly stronger
tornadoes than you typically get with linear setups (around
here at least). The main time window for this to move through is
between 7-10pm. The faster the line develops, the quicker it
will move east.

To the north of the main line, we should still see a surge of
low-level moisture as the low tracks northeast. The overall
environment just is not as impressive north of the Enhanced Risk
region, due to the limited northern progression of the warm
front today. It will be high shear/low CAPE setup for much of
our forecast area today, but especially for areas north of the
Redwood Falls to Owatonna line. A Slight Risk (level 2/5)
remains in place to cover this threat for scattered severe storm
potential. The primary hazards will be damaging wind (60+ mph)
and large hail (1"+ in diameter). Any high end potential will be
limited, including the tornado risk. Storms will move through
the western MN to St Cloud, MN region around 6-8pm, the Twin
Cities metro and eastern MN around 9-11pm, and eventually
progress through western WI around 11pm-1am. The severe threat
will begin to decrease as the line progresses into WI given that
there will likely be scattered storms ahead the cold front,
limiting the environment.

The severe threat for Monday continues to decrease, and although
there is still a Slight Risk (level 2/5) extending from south-
central MN into west-central WI, we expect that region to shift
even further southeast after we realize our round of storms this
evening. We will struggle to build in any real instability and
deep layer shear will become more limited as well. In reality,
tomorrow will likely feel like a typical rainy Spring day with
cool showers and storms through much of the second half of the
day. Isolated chances for severe weather will exist, mainly for
areas along I-35 and east during the evening.

A much drier, and seasonably cool pattern will set up for the
rest of the week. Temperatures on Tuesday will be about 10-15
degrees below average, and we could once again have concern for
patchy frost overnight (lows in the mid-low 30s) into Wednesday
for areas in west- central MN near Stevens, Douglas, and Todd
counties. It won`t be until Friday that we see our next notable
chance for rain as a shortwave develops over the Northern
Plains. It looks to be a slow- progressing pattern that would
provide us with additional chances for showers and storms
throughout the rest of Memorial Day weekend, though confidence
is low at this time.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 628 PM CDT Sun May 17 2026

Main concern is line of storms over southwest MN. MKT is the
only field with much of a severe potential with this line,
though several hours of TSRA are expected at MSP and WI
terminals. Besides the line of storms, we`ve seen storms develop
ahead of hit within the LLJ and associated WAA that will result
in the several hours of TS threat we have. Behind the line, we
will dry out, with MVFR/IFR cigs slowly building east across
southern MN. Did delay the arrival of MVFR cigs some, but by
sunrise Monday, we should see widespread MVFR/IFR cigs over the
area that will stay in place this period. By the end of this
period, we should see showers developing by the late afternoon
as the next wave approaches from the southwest.

KMSP...Scattered shra/tsra currently down by MKT will be in the
MSP VCNTY between 1z and 2z. This is out ahead of what will be
the northern end of the severe line of storms to our south that
will move through roughly between 4z and 6z. By the end of the
period, the next round of showers will be rapidly developing,
with another round of shra/tsra expected to develop between 0z
and 2z (Monday evening) that will last into Monday night.
Doesn`t look like we have a big severe risk with this activity,
just heavy rain and lightning.

/OUTLOOK FOR KMSP/
TUE...MVFR cigs becoming VFR. Wind NW 10-15G25kts.
WED...VFR. Wind lgt and vrb.
THU...VFR. Wind SE 10G20kts.

&&

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

&&

$$

DISCUSSION...BED
AVIATION...MPG