Plymouth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

185
FXUS63 KMPX 201156
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
656 AM CDT Sun Jul 20 2025

.KEY MESSAGES...

- Dry and relatively comfortable weather continues today.

- More active weather expected starting Tuesday and lasting through
late week with multiple chances for showers/thunderstorms.

- Warm and humid conditions return Tuesday, including heat index
values rising to the low-mid 90s, persisting through the week.

&&

.DISCUSSION...
Issued at 332 AM CDT Sun Jul 20 2025

Surface analysis early this morning depicts high pressure
centered over central Canada sagging south into MN/WI, helping
keep plentiful convection ongoing over IA, owing to a stalled
frontal boundary and limited inhibition, to the south and not
reaching northward into the WFO MPX coverage area. Meanwhile,
multiple low pressure centers dot the western CONUS with a few
weak boundaries, but nothing that has impetus to shift east for
today. A stronger wave of low pressure is evident over western
Canada, which will play a part in more active weather later this
week.

For today, the modified Canadian-origin high pressure dominating
the weather for today will keep comfortable conditions in
place with highs 75-80 degrees for today with dewpoints mainly
from the upper 50s to mid 60s. The high pressure area will slide
off to the east tonight through tomorrow, allowing for modest
warm air and moisture advection into the region for Monday.
Highs will not change all that much, nearly a copy of today
except for a few degrees warmer in far western MN. This part of
the state may also see a few isolated showers/t-storms well in
advance of the aforementioned cold front still situated over
western Canada by Monday evening.

The multitude of weak lows in the western CONUS will develop
into a primary low over eastern MT by late Monday. The larger
feature will be the approaching cold front which will drop
southeast across the region Tuesday through Tuesday night. A
much stronger push of warm and moist air into the region will
allow temperatures and humidity levels to surge starting Tuesday
with highs in the 80-90 degree range. However, dewpoints will
climb to the low-mid 70s, which will not only push heat index
values for much of the WFO MPX coverage area into the low-mid
90s, but also promote a highly unstable environment for
showers/thunderstorms starting Tuesday afternoon but
particularly for Tuesday night. Strong nocturnal jetting within
this unstable environment may promote both strong thunderstorm
development and periods of heavy rain. Both aspects still have
plenty of uncertainty to be resolved over the next 36-48 hours
but the overriding theme here is that a more active period of
weather will commence starting Tuesday. The cold front will have
a much slower progression Tuesday night and Wednesday, keeping
rainfall going for Wednesday into Thursday, but have little in
the way of stopping the heat/humidity. Wednesday highs will run
from the lower 80s in western MN to the lower 90s in western WI,
again with heat index values reaching the mid 90s for much of
southern-eastern MN into western WI with dewpoints into the mid
70s.

A small break from the relatively excessive heat comes Thursday
behind the cold front, and this will also bring a reduction in
precip chances for the area with more stable air settling in.
Precip chances will remain rather low for the end of the week
into the weekend, owing to modest upper level ridging moving
into the central CONUS. However, this dome of high pressure will
promote the return of heat and humidity for the end of the week
into the weekend. Highs will climb back to the mid 80s to
around 90, and again with heat index values into the low-mid 90s
for much of the coverage area.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 642 AM CDT Sun Jul 20 2025

VFR conditions expected throughout this duration with high
pressure under control. Only exception may be for far western
MN, specifically AXN, for a few showers prior to sunrise Monday
morning which may drop conditions into MVFR range. Otherwise,
FEW-SCT high clouds will prevail through this morning, followed
by mid-level fair wx diurnal cumulus clouds this afternoon.
Winds will be easterly throughout with speeds around 10kts.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
TUE...Mainly VFR. Chc MVFR/SHRA/TSRA. Wind S 10-15 kts.
WED...Mainly VFR. Chc MVFR/SHRA/TSRA. Wind SW 5-10 kts.
THU...Mainly VFR. Chc MVFR/SHRA/TSRA. Wind NW 5-10 kts.

&&

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

&&

$$

DISCUSSION...JPC
AVIATION...JPC