Hillman, Minnesota Weather Forecast Discussion

931
FXUS63 KMPX 171102
AFDMPX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
602 AM 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 342 AM CDT Wed Sep 17 2025
Conditions are tranquil across the Upper Midwest early this
morning, aside from some patchy fog across central MN and
western WI. Widespread showers and thunderstorms are ongoing to
the south across west central IA and northeast and central NE.
The portion of the activity across eastern NE and western IA is
not moving much and is anchored north of an outflow boundary.
Heavy rain totals as depicted by MRMS have exceeded 3 to 5
inches in some areas since last evening. Models have not
handled this convection well and still don`t, especially in IA.
Synoptically, a trough and upper low over the central and
northern Plains will lift north today. Meanwhile, a pool of
deeper moisture characterized by pwats exceeding 1.5 inches will
overspread the region. Lapse rates will remain weak, but
forecast soundings depict moist low levels and an uncapped,
moderately unstable atmosphere. A stationary front draped from
western Lake Superior to southwestern MN may start slowly
advancing south as a cold front this afternoon as surface high
pressure builds southeast across south central Canada. Although
wind fields will remain weak, there will be at least some modest
convergence along the front during peak heating this afternoon.
Isolated to scattered thunderstorms will develop this morning
across southern MN, but the greatest concentration in coverage
should occur this afternoon and evening along the front across
central MN where better forcing is expected. Models seem to
handle this overall scenario well, but may not be handling the
degree of convective coverage as well. Wind profiles will remain
very weak and cells will remain nearly stationary or meander
around with convective outflows. The moist profile, moderate
CAPE, lack of dry air layers in the profile, and slow storm
motions will lead to high rain rates - possibly approaching 2
inches per hour. HREF ensemble max QPF highlights a corridor
from near Madison or Granite Falls eastward to the Twin Cities
metro as the primary threat area for convection and suggests a
few inches of rain in localized areas are possible through
tonight.
Low pressure will remain nearly stationary across the northern
Plains through the week, before making better progress to the
north this weekend as the trough opens up to the flow across
Canada. Additional rounds of showers and thunderstorms are
expected as we remain on the moisture-laden eastern side of the
system. The setup each day through Friday will feature modest to
moderate instability, a deeply moist profile, and slow storm
motions. Localized heavy rainfall totals will continue to pose a
threat for flooding.
&&
.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 552 AM CDT Wed Sep 17 2025
A few storms have popped early this morning, confirming that
models are handling things poorly. However, this activity is
sparse enough that it has been left out of the TAF. Have made
some adjustments to the previous forecast, mainly the addition
of some prevailing VFR -SHRA with TEMPO/PROB30 to cover the
MVFR that will be associated with the -TSRA this afternoon and
evening. Additional -TSRA chances arrive after 04z, but have
once again opted to cover this with PROB30s for now.
KMSP...A thunderstorm developed to the northwest of the terminal
with other small, very isolated cells trying to get going
further away. Did not mention these in the first few hours of
the TAF period since they are so isolated. This afternoon and
evening, maintained the PROB30, but did add in VFR prevailing
showers from 04z through the end of the period.
/OUTLOOK FOR KMSP/
THU-FRI...Chc MVFR/-TSRA. Wind SE 5-10kts.
SAT...Chc MVFR/-TSRA. Wind S 5-10kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Borghoff
AVIATION...Dye

NWS MPX Office Area Forecast Discussion