Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 111252

Area Forecast Discussion
National Weather Service La Crosse WI
652 AM CST Thu Jan 11 2018

Issued at 647 AM CST Thu Jan 11 2018

Updated the winter weather advisory to expand this to the east.
Flash freezing has occurred behind the cold front over portions of
southeast Minnesota and northeast Iowa with roads quickly becoming
ice covered and very slippery. The band of rain along and ahead of
the front is likely putting down more moisture than can be dried
off and expect the flash freezing to occur farther east as well
with a rapid deterioration in road conditions expected. For now,
will leave Adams and Juneau Counties out of the advisory but these
counties may have to be added later.


.SHORT TERM...(Today and tonight)
Issued at 317 AM CST Thu Jan 11 2018

For today arctic cold front will move quickly east through the
area. This front will produce a wintry mix of precipitation or all
snow. Snow totals will be up to 1 inch.

In the wake of this front, there will 2 areas of additional
frontogenesis. This will produce additional precipitation across
the area from late morning into the afternoon.

The first area will be a 900 to 700 mb band of frontogenesis
(associated with a short wave moving currently located over
Missouri) which will move northeast across the eastern portions
of northeast Iowa and southwest and central Wisconsin. Soundings
suggest that the precipitation will be mainly in the form of snow.
However, there may be a brief period of freezing drizzle at the
onset of this precipitation. Snow totals in these areas will be up
to an inch.

The second area of 800 to 500 mb frontogenesis (associated with
the mid level trough moving out of the Dakotas) will bring another
round of accumulating snow to southeast Minnesota and along and
north of Interstate 90. Additional snowfall totals will be in the
1 to 4 inch range.

The heaviest snow (2 to 5 inches) will be fall across southeast
Minnesota, north-central Iowa, and in west-central and north-
central Wisconsin. With a shift slightly east with this snow band
and disjointed forcing aloft, changed the winter storm warning
counties to a winter weather advisory. Other than that no changes
were made to the headlines this morning. We will also be issuing a
Special Weather Statement for the remainder of the area to cover
the rapid freeze up of water on road ways which may cause them to
become slippery.

For tonight, temperatures will cool into the single digits below
zero across northeast Iowa, southeast Minnesota, and north of
Interstate 90 in western Wisconsin and into the single digits
above zero in southwest and central Wisconsin. With a northwest
wind in the 10 to 20 mph range, wind chills will likely fall into
the 15 to 30 below range across much of the area. If this trend
continues, a Wind Chill Advisory will likely be needed for late
tonight and Friday morning.

.LONG TERM...(Friday through Wednesday)
Issued at 317 AM CST Thu Jan 11 2018

On Friday night, another arctic cold front will move quickly
southeast through the area. With much of the lift and moisture
remaining to our west and south, not anticipating any snow with
this frontal passage.

While the winds will be less than 10 mph on both Friday and
Saturday nights, wind chills will likely fall into the minus 15 to
30 range.

On Sunday afternoon and night, the models continue to show that a
short wave will move quickly southeast through the region. Due to
this, the snow chances were increased.  Like yesterday it looks
like the precipitation totals will be around 5 hundredths of an
inch. With snow to liquid ratios of 20-25 to 1, snow totals at
this time look to be in the 1 to 2 inch range.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 542 AM CST Thu Jan 11 2018

A cold front extended from far northwest Wisconsin into central
Iowa this morning. This front will move quickly east across the
region this morning switching the winds around to the
west/northwest with gusts of 20 to 30 knots expected from mid
morning through much of the night. Several bands of precipitation
will occur today as the front and several short wave troughs move
across the region. With the front already through KRST, these band
of precipitation should be all snow. At KLSE, light rain or
drizzle is expected early this morning before changing over to
snow by mid morning. The snow is then expected to end by late
afternoon. IFR conditions are expected until the snow ends and
then improving to MVFR. Ceilings will continue to lift during the
evening with VFR conditions for both airports expected to develop.


WI...Winter Weather Advisory until 6 PM CST this evening for WIZ017-

     Winter Weather Advisory until 6 PM CST this evening for WIZ041-

MN...Winter Weather Advisory until 6 PM CST this evening for MNZ079-

     Winter Weather Advisory until 6 PM CST this evening for MNZ096.

IA...Winter Weather Advisory until 6 PM CST this evening for IAZ008-

     Winter Weather Advisory until 6 PM CST this evening for IAZ010-



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