Rochester, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

347
FXUS63 KARX 252337
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
637 PM CDT Sat Jul 25 2026

.KEY MESSAGES...

- Dangerous Sunday and potentially Monday with daytime heat
  indices over 100 degrees expected across much of the forecast
  area for Sunday. An Extreme Heat Warning is in effect for
  Sunday for much of the area given the high heat indices.

- Storm chances return late tonight and again Sunday afternoon
  and evening. There is some potential for severe storms to
  occur with damaging winds and large as the primary hazards
  with any severe storm.

&&

.DISCUSSION...
Issued at 152 PM CDT Sat Jul 25 2026

Today-Monday: Hot and Humid with Storm Chances

After a break from the hot and humid conditions, they are returning
today and lingering through Monday. A ridge that has been sitting
off to our west has begun to build eastward towards the Upper
Midwest. This amplification of the ridge brings warmer and humid
conditions for the next few days. The 850mb temperatures increase
today and furthermore on Sunday with temperatures ranging from 24 to
26C based on the mean HREF 850mb temperatures. Despite the cloud
cover from this morning, temperatures will get into the mid to upper
80s for most locations with some areas getting into the low 90s. The
areas that see the warmest temperatures, basically our western tier
of counties and Wabasha and Olmsted counties are in a Heat Advisory
for today as heat indices should get near 100F and up to 105F. Most
other locations across the forecast area will see heat indices in
the upper 80s to upper 90s.

Focusing on Sunday, there is also a decent EFI signal where values
of 0.7 to 0.9 exist indicating that the forecasted temperatures are
on the warmer side of climatological normal. Dewpoints, aided by the
corn sweat, are expected to get into the mid and upper 70s for most
areas. Portions of northeast Iowa and southeast Minnesota could see
dewpoints in the low 80s. Combining both of these we get heat
indices in the 100 to 115F range! The areas that have the best
chances at seeing the 110F+ heat indices are more focused in
northeast Iowa and along the Mississippi River Valley. Poor
overnight recovery into Monday is possible as apparent temperatures
stay in the mid to upper 70s for most locations. Uncertainty remains
for how hot the area gets on Monday due to potential convection.
This all being said, there is an Extreme Heat Warning for most of
the CWA for Sunday with a Heat Advisory for Clark, Taylor, Juneau,
and Adams counties. As the ridge gradually shifts back south, a
front comes through the Upper Midwest. The timing of this front will
play a role in how hot we truly get on Monday. Current forecasted
heat indices are in the low 100s for areas south of I-90 and in the
mid to upper 90s to the north. If the front is slower to pass
through, then the higher temperatures and dewpoints will be around
longer, helping to reach heat headline criteria. Due to the
uncertainty for Monday regarding the timing of this front and the
potential convection or convective debris, have kept the Extreme
Heat Watch in place for northeast Iowa and far southwest Wisconsin.

As we turn our attention to the thunderstorm chances over the next
few days, they sure are difficult to forecast! Within this pattern,
the low-level shear is not impressive (mainly in the 10 to 25 kts
range for 0-1km shear), while the deep layer shear has some modest
values to it (around 40 to 60 kts of 0-6km shear). Instability wise,
there is plenty of it, 2500 to 4000 J/kg of MLCAPE. There is also
quite a few perturbations that pass through the Upper Midwest that
could be helpful for storm development. CAMs have come into good
agreement that an MCS is expected to form in South Dakota this
evening and make its way eastward along the theta-e gradient.
Earlier runs of some of the CAMs brought this MCS all the way to our
western half of the CWA, however only a couple CAMs remain that
continue to support that. By Sunday, as mentioned previously, a few
waves move through the area increasing convective potential, however
there is low confidence on exact locations of storms for the
afternoon and early evening. Instability and shear will be present
all day, depending on morning convective debris the destabilization
could be delayed. CAMs have shown scattered storm development across
the entire CWA with each model showing different locations. With
strong northwest flow, 40 to 50 kts in the midlevels, these storms
would race southwestward with a damaging wind or hail risk. The main
problem for Sunday is if the capping in place will be overcome by
the weak waves that move through. If this occurs then there could be
quite a few storms out there. Then the attention would turn to
outflow boundaries and what those could do as they interact with
storms. Confidence does increase for the later evening as a slightly
more defined wave pushes into Wisconsin. This would increase storm
chances for areas east of the Mississippi River. By Monday, a front
moves through the region, however there does not appear to be good
convergence along the front and combining this with the capping in
place, storms are not expected to fire for Monday afternoon and
evening.

Tuesday-Saturday: Warm Temperatures Continue with Storm Chances

The ridge shifts westward just enough and northwest flow remains in
place. Both of these will mean temperatures cool down slightly, into
the mid to upper 80s but it also means that the 70F dewpoints would
be less likely to occur. Heat indices will also stay in the 80s to
around 90F. With this flow pattern, ensemble guidance has low
precipitation chances through midweek with better chances as we head
towards the weekend. Another thing to note is that given the
northwest flow pattern, we will have to watch for any waves that
ride around the ridge as these would impact portions of the Upper
Midwest.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 637 PM CDT Sat Jul 25 2026

MVFR cigs are expected to scatter out slightly this evening across
the area resulting in sct low-VFR cigs into the overnight. With some
additional moisture moving into the region overnight, the recent
HREF has some respectable probabilities (20-50%) for MVFR cigs to
return for a brief period at KLSE early in the morning. Otherwise, a
decaying MCS may progress (20-40% chance) into portions of southeast
MN and northeast IA overnight which may bring some strong wind gusts
along with it. However, confidence that it will maintain its
strength into the local area remains too low to include in the TAF.
Additional storms will be possible during the afternoon hours on
Sunday across the region, however with hi-res models not painting a
clear picture for how this would evolve at this point, have opted to
hold off on any precipitation mention at this time.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Extreme Heat Warning from noon to 9 PM CDT Sunday for
     WIZ032>034-041-042-053>055-061.
     Extreme Heat Watch from Sunday evening through Monday evening
     for WIZ053>055-061.
     Heat Advisory from noon to 9 PM CDT Sunday for WIZ017-029-043-
     044.
MN...Heat Advisory until 8 PM CDT this evening for MNZ079-086-087-
     094.
     Extreme Heat Warning from noon to 9 PM CDT Sunday for MNZ079-
     086>088-094>096.
IA...Heat Advisory until 8 PM CDT this evening for IAZ008-018.
     Extreme Heat Warning from noon to 9 PM CDT Sunday for
     IAZ008>011-018-019-029-030.
     Extreme Heat Watch from Sunday evening through Monday evening
     for IAZ008>011-018-019-029-030.

&&

$$

DISCUSSION...Cecava
AVIATION...Naylor