Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 191110
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
610 AM CDT Tue Mar 19 2024

.KEY MESSAGES...

- Elevated Fire Weather Conditions through Wednesday; still
  quite dry east of the Mississippi River Thursday.

- Accumulating snow continues to look likely from Thursday night
  into Friday (70-100%). This could result in travel impacts for
  Friday morning.

- From this weekend into early next week, still a lot of
  uncertainty related to storm track, temperatures,
  precipitation types, and amounts, but could be an impactful
  storm.

&&

.DISCUSSION...
Issued at 305 AM CDT Tue Mar 19 2024

Today - Thursday:

Clouds will fill into the area through the morning and the coverage
will decrease by the afternoon resulting in mostly clear skies
through Wednesday afternoon. Southwest flow aloft will allow for
broad WAA to be in the area for Tuesday allowing temperatures to be
the warmest of the forecast period with values ranging from the mid
40s up towards north central Wisconsin, to the low to mid 50s across
much of the forecast area. Winds on Tuesday will be quite gusty with
gusts being between 25mph and 35mph.  A cold front will then move
through the area on Tuesday allowing for northwest flow aloft
to be in place. This will bring CAA and continued dry conditions
to the area.

Thursday night into Friday:

Guidance continues to support a clipper system coming down from
Canada and bringing with it the chance of seeing accumulating snow.
This system still has a lot of uncertainty with it in regards
to how fast the clipper moves through and where the main band of
snow sets up. There are other details to monitor such as the
snow ratio and PWAT values which could in turn lower or raise
the forecasted snow amounts. Now there is good agreement with
what the NAM is beginning to show with a heavier band of snow
moving through some portion of the forecast area with other
models, however, when comparing this to the EC and GFS, the
heaviest snowfall area is further north compared to these two.
Current guidance does have PWAT values between 0.4" and 0.6"
which indicates that there will be a decent bit of moisture as
this clipper moves through, which could help increases the snow
amounts. QPF values could decrease if the clipper moves through
the area quicker. With all the aforementioned scenarios, current
forecasted snow amounts in the 25th and 75th percentiles range
from 3" to 7" across much of the forecast area. Overall there is
good agreement on a clipper impacting the region Thursday night
into Friday and producing accumulating snow. Where the heaviest
snow band sets up and how much snow we get is still uncertain.

Saturday through early next week:

After this clipper moves out, shortwave ridging returns for Saturday
into Sunday before the next potential storm arrives. Guidance
continues to show a low moving off the Rockies and into the region
on Sunday and bringing back another chance of accumulating snow.
Just like the Thursday night storm, there is still quite a bit of
uncertainty with this storm. Similar to the Thursday storm, there is
some broad WAA ahead of the arrival of the storm. This could
indicate that precipitation could start out as rain before changing
to snow, as northwest flow would eventually be in place. When
looking at the ensembles, there is about a 50/50 split in a
drier/wetter solution than the ensemble mean. We will continue to
monitor to both storms as they get closer. Stay tuned for further
updates as new guidance comes into the frame in the coming days.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 610 AM CDT Tue Mar 19 2024

VFR conditions will prevail at both the RST/LSE taf sites through
the taf period. A surface cold front is expected to move across
the region this morning. Pressure gradient tightens in the wake
of the surface front and increase wind speeds to 15 to 20 knots
with gusts of 25 to 30 knots. The wind directions will shift
from the west to northwest by 15z across the region.

&&

.FIRE WEATHER...
Issued at 305 AM CDT Tue Mar 19 2024

Elevated Fire Weather Conditions through Wednesday and through
Thursday east of the Mississippi River

Gusty northwest winds 25mph to 35mph Tuesday with high temperatures
5F to 8F above normal and 30-40% relative humidities. Drier for
Wednesday and still breezy with winds 15mph to 25mph and cooler
temperatures, but lower relative humidity values between 15% and
25%. The dry conditions continue through Thursday east of the
Mississippi Valley with relative humidities as low as 15 to 25%.

Drought areas with dry grasses will be susceptible to the spread of
fires due to the winds each day.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...DTJ
FIRE WEATHER...Cecava


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