211
FXUS63 KARX 231116
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
516 AM CST Sun Nov 23 2025

.KEY MESSAGES...

- Last mostly clear day today with above normal temperatures in
  the 50s accompanied by rain chances starting Monday.

- Quick cooling midweek switches persistent rain chances to snow
  Wednesday with strong winds possible.

&&

.DISCUSSION...
Issued at 305 AM CST Sun Nov 23 2025

Mostly Clear, Above Normal Temperatures Today:

While upper level water vapor imagery exhibits increasing moisture
running the upper level ridge over the Rocky Mountain West
early this morning, low level dry air (10th percentile at MPX
23.00Z RAOB - SPC Climatology) will provide another mostly
clear day for the Upper Mississippi River Valley. Additional
warming with return flow in the wake of the low level ridge
axis, over the Northern Plains early this morning according to
surface and VWP observations, through the afternoon into the
evening likely will usher even warmer temperatures than
Saturday, 10+ degrees above 30-year normals (near 40).

Initial Precipitation Chances Monday:

Precipitation chances increase early Monday morning as northeastern
lobe of increased low level moisture becomes wedged in an area of
confluence across the forecast area, between the upper level low on
satellite imagery over the Desert Southwest progressing through
the Mississippi River Valley and a subsequent shortwave trough
along an enhanced upper level jet streak on GOES west derived
winds upstream of the ridge axis off the coast of the Pacific
Northwest. Increasing ensemble agreement for a stronger, more
southern solution to this subsequent shortwave increases local
confidence in a lack of /widespread/ precipitation later on
Monday. The resultant southern shunt in moisture transport
originating from a more zonal advection to the closed low
becoming an open wave is evident over recent cluster and
individual ensemble runs (EPS/GEFS).

Higher ensemble agreement in location of the initial low level
convergence zone collocated with an increased moisture lobe
gains confidence for a 0.1"+ band of rainfall Monday and Monday
Night. While highest confidence (50-70%) in the EPS (23.00Z)
differs from GEFS (40-60%) a bit, current location along and
northeast of the Mississippi River Valley will eventually be
determined by strength, phasing, and location of the incoming
wave, varying potential scenarios by shifting highest amounts
meridionally. Regardless, clusters and individual ensembles
paint high confidence for measurable precipitation Monday
through Wednesday night with a short break possible Tuesday
between forcing mechanisms; initially the southern currently
closed upper level low and eventually a subsequent upper level
low phasing and deepening over the Great Lakes through Wednesday
night. While Cluster Analyses aren`t in touch with most recent
runs due to the time lag, both the EPS and GEFS lengthened
probabilities for measurable precipitation into early Thursday
morning. Given temperature profiles suggesting snowfall as
precipitation type by this time, will be subsequent specific to
keep an eye on.

Rainfall Amounts Through Wednesday Night:

Depending on confluence behavior of synoptic forcings affecting
location of initial higher amounts as well as duration and location
of subsequent higher rainfall, current cluster and individual
ensemble confidence for highest rainfall amounts of 0.5" graze our
northern peripheral counties in central Wisconsin (30-50%). While
overall agreement differs on southern extent of highest confidence,
this is an improvement compared to previous runs.

Precipitation Type & Additional Impacts:

Rapid deepening of the surface low advecting across the Great
Lakes through midweek ushers in anomalous cold air across the
Upper Midwest. The wrap around cold air will eventually switch
precipitation type to snow Tuesday night through Wednesday.
Given the quickly changing airmass, current ensemble and cluster
soundings suggest limited window for frozen precipitation types
but further interrogation and agreement would be needed for
upper level ice availability. Gradient in confidence for 1"+ of
snowfall starts as far south as the IA/MN border, increasing
points north, grazing 70%+ probabilities along locally
northern- most counties in central Wisconsin.

The tightened surface pressure gradient and strong low level cold
air advection, a 15C swing from 5-7C above normal at 850mb to 10C
below normal in ensemble guidance, raises concerns regarding
strong winds through Wednesday. The EPS solution, which seems
to have a high bias for winds, increased probabilities for 34+
knot wind gusts from 20- 60% to 60-90% initially early Wednesday
morning through the evening hours. Grain of salt given previous
experiences and 10-40% probabilities for the same in the GEFS.
Although GEPS probabilities for 20 knot sustained winds
underwent the same increase over its last run as well.

Regardless, will be quite shocking as apparent temperatures in
the mid 40s on Tuesday drop into the teens to single digits and
potentially even below zero depending on exact wind gust
strength through Wednesday morning.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 520 AM CST Sun Nov 23 2025

VFR expected through much of the 23.12Z TAF period. Light west
winds overnight turn anti-clockwise through today, becoming southwest
this afternoon and south this evening.

Increasing low level moisture overnight raises aviation impact
concerns for the early morning hours; the later forecast hours
of the 23.12Z TAF period. While high resolution model soundings
suggest low level saturation nearing the surface, increased
winds will likely abate decreasing surface visibilities. Given
lower confidence on exact height of lowering ceilings, longer
forecast hour, and precipitation chances increasing confidence
in subsequent impacts after the 23.12Z TAF period terminus, have
not included impacts in either TAF (KLSE & KRST) site at this
time and will need to be further addressed in coming forecasts.

&&

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

&&

$$

DISCUSSION...JAR
AVIATION...JAR