Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 221629
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1129 AM CDT Fri Mar 22 2024

.KEY MESSAGES...

- Snow continues through the morning hours and exiting to the
  east by noon. Heaviest snow in northeast Iowa and southern
  Wisconsin. Friday morning commute will be impacted with snow
  covered, slippery roads. Winter Weather Advisories continue
  for the area.

- Potential continues for another impactful storm to end the
  weekend into early next week. This storm will bring snow, then
  rain to the region. Winds will also be a bit stronger for
  Sunday.

&&

.UPDATE...This Morning
Issued at 1127 AM CDT Fri Mar 22 2024

With the accumulating snow band exiting the area, followed NWS
Milwaukee and Green Bay and cancelled the Winter Weather
Advisory early for northeast Iowa and southwest Wisconsin.

&&

.DISCUSSION...
Issued at 317 AM CDT Fri Mar 22 2024

This Morning: widespread light snow persisting across the local area
early this morning, but making steady progress east. West-east
northward hanging band laying up from southern MN into central WI
showing some weakening but still dropping 1-2 mile snows. However,
the low level jet has kicked off convection across northern IA into
southern WI and latest RAP/HRRR focuses most of the frontogenetic
lift in this area...with some trends suggesting the band could shift
a bit more south (perhaps just south of the local area). Expectation
is that the band will continue to enhance over the next few hours
(1" per hour snowfall rates) and be the main snow accumulator after
12z. There have been a few reports of sleet, even brief freezing
rain from time to time in northeast IA/southwest WI, but soundings
suggest just snow in the enhancing band. Additional accums from 2 to
5" still expected across these areas.

Will continue to monitor the evolution of the this southerly snow
band, and if it continues to trend a bit more south, may be able to
cancel parts of the advisory early.

Saturday through early next week:

An active weather pattern will continue through early next week as
another round of snow, rain, and wintry mix will be possible across
the area. A low will move off the Rockies and into the Plains on
Sunday. As this low moves northeastward towards the Upper Midwest,
the current forecasted trajectory is for the center of the low to
pass through northern Iowa and eastern Minnesota by Monday night.
Ahead of this low will be warm air advection as shown by surface
winds being southeasterly and southerly 850hPa winds indicating
veering winds with height. There will also be a low level jet that
ranges from 40kts to 60kts across the area. This warm air advection
and low level jet will work in conjunction with strengthening
moisture advection. As these ingredients come together, along with
good frontogenesis, snow is expected to develop late Saturday
afternoon and persist through Sunday. Current ensemble guidance
suggests a good agreement on where there is a 50% to 70% chance
of at least 3 inches of snow in the western and northwestern
portions of the forecast area. In addition to this snow, strong
winds are also forecasted on Sunday. The current forecast has a
warm front that shifts northward and transitions the snow to
rain with the possibility (10% to 20%) of thunderstorms on
Monday. Rain would continue through Monday until northwest flow
returns on Tuesday and some light snow showers would be
possible.

This forecast has plenty of uncertainty with where the storm track
goes. When comparing the recent runs of the GFS and ECMWF, the ECMWF
has the track further west and thus has less snow than the GFS which
has the track going over our forecast area which would lean towards
more snow over the area. The track is key to how much snow we would
get. Another item to note is when the snow transitions to rain. This
is also based on the storm track. Confidence in this forecast is
that our area will receive some form of accumulating snow and
then changeover to rain. Current QPF totals based on the storm`s
current track is between .2" and 1" with the highest totals in
the western and northwestern portions of the forecast area.
Based on current expected storm total snow forecast, would
potentially need a winter storm watch for portions of the
forecast area. Stay tuned for further updates regarding this
storm.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 541 AM CDT Fri Mar 22 2024

CIGS: IFR cigs will gradually improve today as the responsible
winter storm exits east. Should bump to MVFR by mid afternoon and
likely scatter out by mid evening.

WX/vsby: the bulk of the accumulating snows look to be south/east of
the TAF sites by 12z. However, the RAP and HRRR hint that a light
snow band could develop around I-90 by 15-16z and linger a few
hours. However, the forcing is weak and likely only produce light
snow/flurries with minimal impacts to vsby.

WINDS: northerly with an uptick and some gusts (mostly under 10 kts)
for the afternoon. Lightens up tonight with generally light easterly
for Sat.

&&

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

&&

$$

UPDATE...Boyne
DISCUSSION...Cecava/Rieck
AVIATION...Rieck


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