Garfield, Minnesota Weather Forecast Discussion

613
FXUS63 KMPX 171923
AFDMPX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
223 PM CDT Wed Sep 17 2025
.KEY MESSAGES...
- Chances for thunderstorms increase this afternoon, which will
begin a period of unsettled weather expected to last through  the
weekend.
- Slow moving storms and high atmospheric moisture content will
  likely lead to areas of heavy rain totals each of the next few
  days.
&&
.DISCUSSION...
Issued at 223 PM CDT Wed Sep 17 2025
Water vapor imagery this afternoon shows broad troughing that
extends from interior PacNorthwest down to the 4-Corners region then
up to the Great Lakes. Featured within this troughing pattern, h700
low pressure rotates near the SD/NE border. Closer to home, a
stationary boundary currently resides from Lake Superior down across
southwestern MN. Cloudier skies exist across much of MN, thus have
decided to lower MaxT values this afternoon a couple of degrees
using a blend of NBM and HiRes guidance. The previously mentioned
surface boundary will continue to serve as the primary source of
convection for the rest of today. Latest RAP guidance indicates that
increased moisture will advect from the south throughout the course
of this afternoon and evening. Moderate mixed-layer instability
ranges between 1000 to 1500 J/kg and PWATs exceed 1.5 inches, which
should maintain the risk of scattered showers and thunderstorms. The
wind field continues to appear weak, thus storms will be slow moving
or meander on outflow boundaries. Given this slow storm motion
setup, it is possible that areas that do observe heavier periods of
rainfall could see localized ponding/flooding. As of the 12z HREF
QPF LPMM, a narrow corridor extends near Granite Falls over to the
Twin Cities that could see localized rainfall amounts between 2 to
2.5 inches.
As we transition into the latter half of this week into early next
week, high pressure building in over south-central Canada will serve
as a Rex Block to our current troughing pattern, meaning our PoPs
will continue to remain elevated through Friday into much of this
weekend. It is likely that daily PoPs will continue to increase as
we get closer to the weekend. Precip activity looks to simmer down
early next week once ridging over the central CONUS develops. As for
temperatures, values will return to the 70s with lows in the
mid 50s lower 60s. &&
.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1252 PM CDT Wed Sep 17 2025
An area of low pressure will remain to the west of the MPX
terminals through this period. This will keep us in a continuous
feed of southerly winds into the area, with a moist and unstable
airmass remaining in place. This is a low confidence forecast
with respect to precip potential, with our current forecast
having 12+ continuous hours of 30% or higher PoPs at all of our
terminals. The first more enhanced chance for showers will come
this afternoon/evening along the weak boundary that is laid out
from roughly Granite Falls, to the Twin Cities, and up to
Ladysmith in WI. After that, much of the short term guidance
shows the wave and slug of moisture bringing the showers
currently over Iowa coming up across MN tonight into Friday
morning. Given the uncertainty, was pretty restrictive on when
to mention any precip chances until we have better confidence on
narrower (less than 4 hours long) windows of when precip may
happen. Also of lower confidence is the cig forecast for tonight
into Monday morning. RAP forecast sounding certainly have the
low level moisture profiles to support low clouds, but how
prolific and widespread the stratus would be is uncertain,
though chances for MVFR/IFR cigs increases the closer you get to
the surface low (so highest in western MN and lowest in western
WI).
KMSP...our current grids have at least 30% chances for rain from
23z this afternoon through the rest of the period, so they
support 25 consecutive hours for a prob30. Not wanting to have
never ending precip mention, tried to focus on the first chance
along this boundary this evening. Based on the RAP, pushed the
prob30 group back a bit, though the incoming bank of mid-level
moisture (clouds) an the building cu-field along the boundary in
the north metro do hint at precip chances possibly beginning
early than what we have.
/OUTLOOK FOR KMSP/
FRI...MVFR. -SHRA likely, chc -TSRA. Wind SE 5-10 kts.
SAT...Chc MVFR/-TSRA. Wind S 5-10 kts.
SUN...Chc MVFR/-TSRA. Wind S 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Borghoff
AVIATION...MPG

NWS MPX Office Area Forecast Discussion