NWS Forecast Discussion
315
FXUS63 KMPX 151957
AFDMPX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
257 PM CDT Fri May 15 2026
.KEY MESSAGES...
- Today will be the last day of critical fire weather
conditions, possibly of the Spring. We will have very low RHs
again on Saturday, but without the wind, with a considerably
more moist airmass expected Sunday through next week.
- Scattered thunderstorms are expected across southern
Minnesota and western Wisconsin this evening. The strongest
storms could contain large hail.
- Multiple rounds of storms expected Sunday through Monday.
Severe storms look likely Sunday evening and again Monday
afternoon and evening.
- Quieter weather expected the rest of next week, with below
normal temperatures Tuesday and Wednesday.
&&
.DISCUSSION...
Issued at 257 PM CDT Fri May 15 2026
We`ll start with today. There`s a sub-990mb surface low currently in
northwest Ontario. The pressure gradient associated with it extends
south into northern MN, but down here in central/southern MN, we`re
in a bubble high between that Ontario low and lee-side low near the
OK Panhandle. This bubble high is giving us a weak pressure gradient
and considerably lower winds than what they`re seeing in northern MN
today. The other impact of this pressure pattern is the cold front
moving across MN is starting to put on the brakes, which sets the
stage for our first convective potential of the next several days.
It`s not exactly cold behind the front, but dewpoints have crashed
into the 30s behind the front, with 40s and some low 50 dewpoints
ahead of it. As we move out into the 6pm to 9pm timeframe, the HREF
shows this cold front stalling out, with moisture even surging a bit
back northwest in this time range. We will see dewpoints creep back
up into the mid/upper 50s south and southeast of Mankato. Aloft, the
MN/IA border region will find itself within the right entrance
region of an upper jet across northern MN into Lake Superior. The
combination of the surface front and upper divergence in the jet
entrance region will provide the forcing for convection this
evening. Current expectations is we`ll see storms develop down
around Faribault county between 5pm and 7pm, with storms developing
northeast along the front from there. We`ll have enough shear and
instability to support rotating updrafts, with a hail and wind risk
existing with any storms that develop. Where the SPC bumped their
Slight risk in the Day 1 outlook up toward Albert Lea and Rochester
looks good for where the highest severe risk will be locally. Though
t The bigger severe risk for today will be down in central IA where
instability will be significantly higher.
The best day of the weekend will definitely be Saturday. The front
from today will sag south down into Nebraska and Iowa. We`ll again see
deep mixing and a crashing of dewpoints, with afternoon humidities
down in the teens again looking likely for Saturday, but this time
around, we`ll be missing the winds for the fire weather threat. By
Saturday evening, storms will have developed along the boundary to
our south as it begins heading north as a warm front. Most guidance
shows this convection creating and MCV in Nebraska that will track
northeast across MN Sunday morning. The net result is we should see
a large area of showers and storms lifting northeast through the
night, with a wet Sunday morning expected as the MCV pushes across
the area. As this happens, the main upper trough to the west will
help strengthen a surface trough/front across Nebraska into
southeast SD. At the northern edge of this surface trough, muCAPE
values are expected to build to at least 2000-3000 j/kg, which will
provide the fuel for aggressive convective initiation late Sunday
afternoon in southeast SD. This convection should grow upscale
pretty quick, with a forward propagating MCS expected to race across
southern MN Sunday evening/overnight. RRFS reflectivity forecasts
show bowing line segments developing Sunday evening, so we`ll have
to watch how things evolve, but we are certainly seeing potential
for a damaging wind/QLCS tornado threat with this MCS potential
Sunday evening.
For Monday, how Sunday nights activity evolves will be key to what
our severe risk looks like for Monday. But on Monday, the synoptic
setup looks similar to Sunday, it`s just the surface front will be
father east. So where Sunday sees storms develop in southeast SD,
Monday afternoon, storms will develop east of the front once again,
though this time likely in the vicinity of south central to east
central MN. Given that we look to be where storms initiate, all
modes of severe weather will be on the table, it`s just a question
of exactly where the surface boundary is by the afternoon. Of course
there is some good with having these multiple rounds of
thunderstorms and that is we will finally see some much need
rainfall. Between Sunday and Monday, much of our area should see 1
to 2 inches of rain, with pockets of 2-3 inches possible. This rain
will help put a stop to the flash drought we`ve seen here in the
last 3 weeks or so. In addition, this rain combined with the greenup
being complete should finally bring an end to the Spring fire season
here in the MPX area.
Behind this system, we`ll get northwest flow and cooler air. Highs
Tuesday and Wednesday will likely struggle to hit 60, with lows
Wednesday and Thursday morning falling into the 30s and 40s (with
some frost being possible in central MN Wednesday morning). By
Thursday, our surface winds will turn back out of the south, which
will allow for highs to get back up to near normal by the end of the
week. There`s also some potential for a few showers to develop
Thursday and Friday within this broad warm advective pattern, though
the threat of any heavy rain or severe weather looks pretty low at
this point.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1215 PM CDT Fri May 15 2026
Westerly winds will become breezy this afternoon as mixing
increases. Peak gusts are forecast to top out between 20-25kts.
VFR conditions will persist this afternoon, with the chance for
a few Cu to develop between 8-10k feet. A few thunderstorms are
possible across far southern MN/western WI this evening, so have
maintained the PROB30 at EAU for -TSRA between 00-04z. Hi-res
model guidance shows storms developing near or just to the
southeast of MKT, so we may need to add in a PROB30/TEMPO later
despite low confidence at issuance time. Quiet aviation weather
overnight continues into Saturday, with light northwesterly
flow.
KMSP...No additional concerns. Storms this evening are forecast
to develop and track well to the southeast of the terminal.
/OUTLOOK FOR KMSP/
SUN...-SHRA/-TSRA likely, IFR/MVFR. Wind ESE 10-15G30kts.
MON...-SHRA/-TSRA likely, IFR/MVFR. Wind SW to E 10-15G20kts.
TUE...VFR. Wind WNW 10-15G30kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Red Flag Warning until 9 PM CDT this evening for Benton-
Chippewa-Chisago-Douglas-Isanti-Kanabec-Kandiyohi-Lac Qui
Parle-McLeod-Meeker-Mille Lacs-Morrison-Pope-Redwood-
Renville-Sherburne-Stearns-Stevens-Swift-Todd-Wright-
Yellow Medicine.
WI...Red Flag Warning until 9 PM CDT this evening for Barron-Polk-
Rusk.
&&
$$
DISCUSSION...MPG
AVIATION...Strus
NWS MPX Office Area Forecast Discussion