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000
FXUS63 KARX 190406
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1106 PM CDT Thu Apr 18 2024

.KEY MESSAGES...

- Frost/Freeze Headlines are in effect tonight/Friday morning.
  Highest probabilities (60-90%) for subfreezing temperatures
  remain west of the Mississippi River.

- Blustery to end the week, with a cooler and drier weekend
  ahead. Will be monitoring the potential for additional
  frost/freeze headlines.

- System moving in early next week brings the return of shower
  chances to the area.

&&

.DISCUSSION...
Issued at 249 PM CDT Thu Apr 18 2024

Tonight - Weekend:

Current radar mosaic this afternoon shows rain showers continuing to
move across the area, with lightning plots showing much of the
lightning activity remaining with the storms further south. Hi-res
guidance suggests showers will begin to push out of the area,
exiting west to east through the afternoon and early evening. A dry,
but much cooler night follows with lows dropping into the upper 20s
to mid 30s across the area. With favorable conditions expected,
frost/freeze headlines have been issued for tonight/Friday morning
for the most susceptible counties. With the highest probabilities
(60-90%) for subfreezing temperatures remaining west of the
Mississippi River, a freeze warning was issued for those locations.
A frost headline remains for those counties along the river with
valleys likely remaining a tad bit warmer.

An upper level low is forecast to track eastward across Canada
through the day on Friday, with a few weak waves dropping down
through the region. CAM solutions do try to develop some light
echoes across northern portions of the forecast area Friday
afternoon-evening. Model forecast soundings do suggested steepening
lapse rates through the day with some instability, and while not
much, there appears to be a tad bit more saturation as you go
towards more northern locations. With this, cannot rule out some
isolated showers and flurries, so will maintain some low
precipitation chances across our north for now. However, the more
widespread concern through the day on Friday will revolve around the
return of gusty west winds with a tightening pressure gradient and
deeper mixing expected. There are still some differences between
model guidance on how deeply we mix, bringing lower confidence on
reaching into any wind criteria. Right now, the forecast keeps wind
gusts in the 30s mph range, though the typical wind prone areas
could see a few higher gusts.

In addition, cooler conditions are expected to spread across the
region as surface high pressure settles across the central U.S. High
temperatures hang in the 40s and 50s Friday and Saturday, with a
slight bump into the 50s for most on Sunday. The main concern will
revolve around a couple more cool nights/mornings Saturday and
Sunday, with NBM probabilities (~80-100%) showing confidence in
freezing temperatures for many areas (outside of valleys and some
portions of far SW WI where probs are a bit lower). Will continue to
monitor as additional frost/freeze headlines may be needed through
the weekend.

Next Week:

Model guidance suggests an upper level shortwave trough
driving down through the region late Monday into Tuesday. Both the
GEFS and EC ensemble solutions highlight this time period for a
return of showers to the forecast area. Behind this system upper
level ridging builds eastward across the central CONUS bringing
drier conditions for mid-week. Temperatures look to trend back
towards more seasonable late in the period, though it is noted
that ensemble spread does also increase quite a bit.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1105 PM CDT Thu Apr 18 2024

As diurnal heating occurs on Friday, the winds will become
gusty (25 to 30 knots) and there will be scattered VFR clouds.
While the clouds will be dissipating on Friday evening, a
scattered mid deck of clouds will move in as a shortwave moves
to our north.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory until 8 AM CDT Friday for WIZ032-033-041-
     053>055-061.
MN...Freeze Warning until 8 AM CDT Friday for MNZ086-087-094-095.
     Frost Advisory until 8 AM CDT Friday for MNZ079-088-096.
IA...Freeze Warning until 8 AM CDT Friday for IAZ008>010-018-019-
     029.
     Frost Advisory until 8 AM CDT Friday for IAZ011-030.

&&

$$

DISCUSSION...EMS
AVIATION...Boyne