870
FXUS63 KARX 072312
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
612 PM CDT Tue Oct 7 2025

.KEY MESSAGES...

- Frost/Freeze Potential Tonight and Wednesday Night

- Scattered showers and few storms possible Thursday Night

- Additional showers and storms will be possible early next
  week.

&&

.DISCUSSION...
Issued at 130 PM CDT Tue Oct 7 2025

> OVERVIEW: "steady as she goes" in the GEFS and EPS when it comes
to the rest of the week. A surface high builds across the region
tonight while the upper level ridge axis eases in Thu. However, both
ensemble suites continue to drop a shortwave trough across the
ridge, cutting across it and spinning over portions of the upper
mississippi river valley. There have been disagreements with
placement/strength of the shortwave - and those continue. But timing
of late Thu night/Fri remains. The upper level ridge then set to
work back east from the plains to across the western great lakes by
Sunday.

Moving into the following work week disagreements become more
pronounced between the GEFS and EPS, namely in how quickly they move
the ridge east, and thus how quickly they drive a trough in from the
west. This is evidenced well in the WPC clusters with fairly robust
differences in phase of the upper levels. Predictability (and
confidence) low in this time frame as a result.


> TEMPERATURES: frost/freeze across the north tonight. Gradual
warming into the weekend.

Clear skies, light winds and some low level cold air advection
setting the stage for a rather cool/cold night tonight - and the
likelihood for areas of frost and/or a freeze. NBM probs for 32
degrees or colder sit at 50 to 80% from the I-94 corridor northward.
With bog and other low lying, cold drainage areas in central WI,
some upper 20s for lows can`t be ruled out.

Per coordination with surrounding offices, expanding the Frost Adv
westward along the I-90 corridor to cover areas where frosty temps
are more likely to occur for 3+ hours. Note - where counties border
the Mississippi River, valley locations are unlike to experience
frost.

A gradual climb in temps moving through the upcoming weekend. 75% of
the GEFS and EPS are persistent in pushing highs into the upper
60s/mid 70s - with Sunday still the warmest of the bunch.


> RAIN CHANCES: return overnight Thu/Fri. Minimal amounts where
realized.

Upper level shortwave still set to spin across portions of the
region overnight Thu/Fri. Sfc cold front precedes it, but pressure
gradient is middling at best and frontogenetic forcing could be
fairly weak. Deeper QG convergences holds with the the shortwave.
That said, where that feature moves is still not clear, with
variances in the models almost daily - so investing too much in the
current details probably not the wisest move. In addition, degree of
saturation will impact pcpn potential (coverage and amounts). Latest
GrandEnsemble gives a 10 to 20% chance to exceed more than 1/10" - a
slight uptick over yesterday. GEFS/EPS QPF is mostly associated with
the front, keeping most of the light rain chances to the overnight
Thu/early morning hours Friday. GrandEnsemble holding pops in the 20-
30% range, likely due to light nature of the QPF and differences in
the models. Chances will likely increase, although with still
minimal amounts, as we move through the week.

Later Sunday and for the start of the new week looks to harbor a
higher rain threat - both in coverage and amounts. However,
aforementioned differences in the GEFS and EPS make timing/location
difficult. Will hold with the model blend.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1219 PM CDT Tue Oct 7 2025

VFR conditions expected through the 08.00Z TAF period as high
pressure gradually rotates light winds clockwise over the
period.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory from 3 AM to 9 AM CDT Wednesday for WIZ032-033-
     041>044-053-055.
     Freeze Warning from 3 AM to 9 AM CDT Wednesday for WIZ017-029-
     034.
MN...Frost Advisory from 3 AM to 9 AM CDT Wednesday for MNZ079-
     086>088.
IA...None.

&&

$$

DISCUSSION...Rieck
AVIATION...JAR