961
FXUS63 KMPX 102337
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
637 PM CDT Thu Apr 10 2025

.KEY MESSAGES...

- Warming trend through the weekend, with highs in the 60s and 70s.

- Isolated rain showers this evening, additional rain chances late
Saturday into Sunday.

&&

.DISCUSSION...
Issued at 242 PM CDT Thu Apr 10 2025

2 PM surface analysis reveals surface low pressure located over
southeastern Minnesota. A trailing vort lobe located over northern
Minnesota is diving south and is responsible for renewed rain
shower development this afternoon and evening. We can already
see an increase in radar echoes across central Minnesota ahead
of this feature. Our latest forecast features broad 30-40 PoPs
across eastern MN and western WI ahead of the advancing
disturbance. Additional rainfall amounts should be minimal,
with perhaps a few hundredths of QPF possible. Confidence is
increasing in the development of fog late tonight through
daybreak Friday, so have included this addition in the latest
forecast grids. Any fog that develops should mix out relatively
quickly Friday morning, setting the stage for a very nice day!

Large scale subsidence across the Upper Midwest will yield a
mostly sunny and mild Friday, with highs in the upper 50s to
lower 60s. Expansive western ridge will translate east Friday
into Saturday. Height rises in advance of the ridge axis will
open the door for warm advection of an airmass rooted in the
central Plains. Surface winds will strengthen in response and
will support highs in the upper 60s to lower 70s both Saturday
and Sunday. The only knock against great outdoor weather
Saturday will be the magnitude of the southerly winds, which are
forecast to gust between 20-30 mph. The advance of a trough
over the Pacific Northwest will spawn a surface low across the
Plains Saturday. The surface low is forecast to track from
southwest to northeast across Minnesota towards Lake Superior
Sunday into Monday. This track places southern Minnesota/western
Wisconsin in the "warm sector" of the system, allowing for the
development of warm advection driven rain showers potentially as
early as Saturday night and continuing through the day on
Sunday. It does not appear to be an all day washout, which is
good news for those with outdoor plans (it will be another warm
day!). That being said, we cannot rule out isolated thunderstorms
across southern Minnesota, where guidance places a few hundred
J/kg of CAPE and steep lapse rates in excess of 7.5C/km. The
surface low pressure system is forecast to occlude over the
Great Lakes Monday, which will allow for wrap around precipitation
to linger across the Upper Midwest through the day. Temperatures
drop into the low 50s Monday with chance PoPs for scattered
showers throughout the day. Given that we`ll be located within
the cold air advection regime, there are some members of the
guidance suite that try to mix-in frozen precipitation. The best
chance for a transition in p-type appears to be north of I-94
in central MN/western WI, however amounts associated with such
occurrence appear to be inconsequential at this time.

The large scale storm system exits the region Tuesday, though
temperatures are forecast to remain in the 50s owing to little
change in the airmass/weak NW flow aloft. Extended guidance slides
the next shortwave trough aloft across the northern CONUS in the
Wednesday/Thursday timeframe. There is growing confidence in a wing
of warm advection preceding this feature, such that NBM`s highs have
climbed into the 60s for the middle of the week. PoPs increase to 20-
30 percent midweek ahead of the trailing frontal passage, which
seems reasonable at this distance.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 614 PM CDT Thu Apr 10 2025

The last lobe of upper forcing is sliding through the metro
right now, which will keep some showers going in the vicinity of
MSP/RNH for the first couple of hours of this period. Behind
this, high pressure and light winds move in, which leads to the
main uncertainties this period, how does the strato-cu field
evolves through the night, which will then determine where the
fog threat will be. Forecast soundings from the RAP/NAM/GFS all
show the 3k to 5k foot layer remaining close to saturation into
Friday afternoon, so there`s quite a bit uncertainty on how the
clouds will evolve with subsidence moving in as well. The site
the models show the most agreement on fog occurring at is STC,
so that`s where we hit the fog the hardest for now, but again,
how bad the fog ends up being will depend on what happens with
the strato-cu. For Friday, SCT to BKN VFR stratocu will remain
through most of the day, with light winds slowly trending to the
south in the afternoon.

KMSP...Fog threat for tonight is the radiational type, which
tends to be tough to achieve for MSP. However, if skies manage
to clear out, we could see some fog between 11z and 13z. The one
thing that does support the fog potential is dewpoints are in
the upper 30s, so if skies clear, we don`t have far to go to get
fog.

/OUTLOOK FOR KMSP/
SAT...VFR. Wind S 10-20G25kts.
SUN...Mainly VFR. Chc MVFR/-RA. Wind S 10-15kts becoming W.
MON...Chc MVFR cigs. Slight chc -RA. Wind NW 15-25G30-35kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...MPG