NWS-La Crosse Forecast Discussion

						FXUS63 KARX 030823
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
323 AM CDT Thu Apr 3 2025

.KEY MESSAGES...

- Chances for light precipitation Friday night and Sunday night
  into Monday but accumulations in both cases will be minimal.
  Otherwise dry conditions expected.

- Seasonable temperatures expected through the weekend ahead of
  cold front Sunday. Much cooler temperatures expected Monday
  with highs in the 30s to low 40s.

&&

.DISCUSSION...
Issued at 318 AM CDT Thu Apr 3 2025

Light Rain Friday Night, Wintry Mix/Snow Possible Late Sunday
into Monday

As the upper low responsible for the recent winter and severe
weather across the area finally starts to depart to the northeast
through the day today, our area will be left in southwest flow
aloft. This is due to persistent deep troughing over the Western
CONUS that stays in place through the end of the week thanks to a
cutoff upper low across the desert Southwest. Much further north,
another upper low is currently making its way across Northern
Saskatchewan and Manitoba, working its way east. In conjunction with
that upper low across Canada, a long, trailing cold front is
extending into the Northern US Rockies with a weak surface low near
its tail end. As we move into Friday, this will phase with a weak
Colorado low and wave train across the Mid Mississippi Valley to
create an area of widespread precip chances late Friday into
Saturday morning across much of the Central CONUS. Moisture will be
a bit more limited with northward extent so precip chances will be
highest across southwestern Wisconsin and dropping off north of I-
90. QPF will be limited at best with most places seeing less than a
tenth of an inch of rain by Saturday morning. Temperatures should be
warm enough across the area that precipitation will stay all liquid
with a low chance that some snowflakes could mix in early Saturday
morning with overnight lows falling close to freezing.

Once this surface front moves through the area, the aforementioned
upper level troughs will begin to phase together over the weekend as
the southern trough finally rejoins the main upper level flow. As
they phase together and the Canadian upper low begins to rotate over
the Hudson Bay and northwestern Quebec, this will send a trough axis
through our area Monday into Tuesday. At the surface, a strong
Canadian high pressure system begins to drop out of the Canadian
Plains, pushing a cold front extending off of a weak surface low in
the Upper Great Lakes through our area midday Sunday into early
Monday. Long-range ensembles are hinting at some precipitation with
this frontal passage, mainly in the form of snow. The GFS is a bit
more aggressive with the banded snowfall as it has a stronger
mid-level frontogenesis band moving through the area. Roughly
half of GFS ensemble members show measurable snow at La Crosse
compared to roughly 1/3 of ECMWF ensemble members. This band
would be quick moving if it extends into our area so it would be
a quick shot of snow. Once this front passes, the surface high
behind it sets up overhead and keeps us dry through midweek.

Near Normal Temperatures through the Weekend, Colder Monday

Temperatures through the weekend should remain near normal in the
upper 40s to lower 50s. A subtle dip in temperatures will occur
Saturday and Sunday behind the weak cold front that moves through
late Friday but otherwise expect seasonable temperatures through
Sunday. The second cold front that moves through Sunday into Monday
will bring a much more noticeable temperature drop as we move into
Monday as the air behind this front will be coming from the Canadian
Plains. Temperatures Monday will struggle to get out of the 30s at
many locations with a few lower 40s scattered across the river
valleys. The good news is that this cold snap will be short lived as
surface winds shift back to the south by Tuesday with temperatures
warming back into the 50s and lower 60s by Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1010 PM CDT Wed Apr 2 2025

CIGS: MVFR cigs expected through the night and the better part of
the day Thursday. Short term models scatter it out Thu evening as
weak high pressure moves overhead...and favored through Thu night.
That said, a few models suggest some low level RH could linger, and
perhaps re-manifest as low stratus Thu night. Going to stay the
SKC/SCT for now and monitor.

WX/vsby: no impacts expected.

WINDS: west staying fairly breezy/gusty through Thu morning. Winds
will be diminishing by mid/late afternoon Thu as high pressure
starts to influence the region. Light north/northeast Thu night.

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...Rieck