Rochester, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

512
FXUS63 KARX 121848
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
148 PM CDT Tue Aug 12 2025

.KEY MESSAGES...

- A few showers and thunderstorms may (15-40%) occur this
  afternoon, primarily east of the Mississippi. Gusty winds may
  occur with any storms.

- Heat returns Friday and Saturday.

- Potential for thunderstorms Friday through Monday with a
  threat for heavy rain with any storms that develop through
  this period. Additionally, Friday and Saturday could see
  severe storms.

&&

.DISCUSSION...
Issued at 147 PM CDT Tue Aug 12 2025

Showers, storms possible today:

18z WV satellite shows a longwave upper trough sliding east over MN.
Surface obs indicate an associated cold front is starting to push
through our western CWA. Visible satellite shows an axis of cumulus
ahead of this front. While occasional attempts at vertical growth
have occurred, as of yet, no notable updrafts have sprouted near our
CWA.

Moving later into the afternoon, do expect at least a few showers
and thunderstorms to develop as the front encounters areas that have
had longer to destabilize via insolation. Limiting factor looks to
be potential for temperatures aloft, in particular within the 500-
600mb layer, to be too warm, an outcome seen across several runs of
the HRRR. Due to the mostly consistent signal in the HRRR, have kept
PoPs around 40% or less with this update. As for hazards aside from
lightning, can`t rule out a strong wind gust given 12.12z HREF mean
DCAPE is around 800-900 J/kg.

Heat Friday and Saturday:

Upper ridge builds over the central CONUS Friday into Saturday.
WHile this feature will very likely be centered to our south, 12.00z
NAEFS and ECENS 700mb temperatures in our area look to surpass the
97.5th percentile. As this occurs, southerly near surface flow will
advect plentiful moisture to the Upper Midwest - mean 12.00z
NAEFS/ECENS 850/925mb specific humidity values are above at least
the 90th percentile. This should lead to humid and very warm to hot
conditions with a potential return to triple digit heat index
values with Saturday the more probable day of the two.

Thunderstorms Friday through Monday:

Low level moist advection described above should also be reflected
in available moisture for rainfall with 12.00z NAEFS/ECENS PWAT
values above the 90th percentile. The end result looks to be
potential for showers and thunderstorms with robust rain rates as
various disturbances eject eastward on the poleward side of the
upper ridge. Of some concern is potential for round of convection
early in this period to leave lingering NW-SE oriented boundaries in
the region as moderate southwesterly 850mb moisture transport looks
to continue through at least Sunday night. Guidance seems to hint
that this could occur although, as expected, run to run consistency
and consistency between models on timing, placement, and exact
boundary orientation is extremely low.

In addition to the risk for heavy rain, Friday and Saturday may
bring severe thunderstorms. Given the large amount of potential
instability that will be present, potentially (20-70%) north of 3000
J/kg SBCAPE, much will depend on capping associated with the upper
ridge. 12.00z ECENS seems to favor the capped solution with joint
CAPE/CIN/Shear probabilities supportive for severe storms largely to
the north of our CWA while GEFS probabilities suggest areas along
and north of I-90 would be in play. Thus, in addition to the heavy
rain ingredients described above, will also need to monitor severe
storm potential over the coming days.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1241 PM CDT Tue Aug 12 2025

A cold front will move through the TAF sites through early this
afternoon. There might be a few showers and storms, so kept the
PROB30 going at KLSE through 12.21z. In addition, smoke will
produce MVFR visibilities at KRST through the next hour.

As far as fog potential tonight, it will be likely restricted to
the Wisconsin River and its tributaries.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...Ferguson
AVIATION...Boyne