Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 032102

Area Forecast Discussion
National Weather Service La Crosse WI
302 PM CST Sat Dec 3 2016

.SHORT TERM...(This evening through Sunday)
Issued at 255 PM CST Sat Dec 3 2016

At 2 PM, water vapor imagery shows a vigorous short wave trough
over eastern South Dakota and another short wave trough moving
into the Nebraska pan handle. The first short wave trough will
move northeast through Minnesota tonight. Meanwhile the second
short wave will move east across Iowa on Sunday. Weak to moderate
925 and 850 mb moisture transport will develop ahead of these
short waves after midnight tonight and Sunday morning. This will
result in the preciptable water values climbing into the 0.50 to
0.55 inch range. This in the 90th percentile for early December.
As a result, it is not too surprising that the models have
continue to increase the precipitation totals across the region.
The 03.12z models increased their QPF anywhere from 0.05 to 0.15
inches into the 0.15 to 0.40inch range. Like yesterday, the
soundings have anywhere from 50 to 100 mb of omega located in the
dendritic growth zone. As a result...the snow to liquid ratios
are running 10-13 to 1. This results in snow totals anywhere from
1 to 4 inches. Due to these snow totals and this being the first
measurable snow for most locations, opted to issue a Winter
Weather Advisory for tonight and Sunday for much of the area.

.LONG TERM...(Sunday night through Saturday)
Issued at 255 PM CST Sat Dec 3 2016

From Monday night into Tuesday, an arctic cold front will move
east through the area. Like the past 2 days, it continues to look
like one short wave will move northeast through western and
northern Minnesota and another one will move northeast from east
Texas into the eastern Great Lakes. The first wave may produce
some light snow or rain to areas along and north of Interstate 90.
Meanwhile the second wave will remain to far to our southeast to
bring any precipitation to the area.

On Thursday, an arctic cold front will move south through the
area. This will bring a reinforcing shot of arctic cold air and
maybe some flurries to the area.

For next weekend, the GFS bring a Colorado low through the
Chicago area. This would put us in a favorable snow region.
Meanwhile the ECMWF develops its low over east Texas and then
moves northeast into the eastern Great Lakes. This track would
keep our area dry. With such uncertainty, just kept the model
consensus which only has a chance of snow.

There are still some questions on whether there will be any snow
on the ground from Wednesday through Saturday. If there is a
snow cover, we would be likely looking at high temperatures in
the teens. If there is little or no snow, these high temperatures
would be in the 20s. This fits in well with the ECMWF ensembles
which continue to show a wide spread in their maximum temperatures.
Their lowest values are in the 10 to 15 degree range and their
highest values are in the 20s.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1100 AM CST Sat Dec 3 2016

Cigs: low clouds look to give us a break as the current mass shifts
to the north/northeast this afternoon...per latest satellite trends.
The low cigs quickly return later this evening as an upper level
disturbance approaches from the west. Expect ifr/mvfr cigs to then
hold through the better part of Sunday.

WX: a couple upper level shortwave troughs to bring snow to the
region tonight through Sunday afternoon. First shortwave will bring
light snow/flurries, with the second/stronger wave bringing the main
area of accumulating snows/impacts in for Sunday morning. Should get
a few hours of 1-2sm with these snows...and while the bulk of the
accumulations will be on grassy surfaces...expect some on pavement
as well. KLSE at risk for a bit more compared to KRST...generally 1-

Winds: light/variable wind becomes south/southeast this evening,
gradually increasing overnight as the sfc pressure gradient


WI...Winter Weather Advisory from midnight tonight to noon CST Sunday
     for WIZ032.

     Winter Weather Advisory from 3 AM to 3 PM CST Sunday for WIZ017-

MN...Winter Weather Advisory from midnight tonight to noon CST Sunday
     for MNZ088-095-096.

IA...Winter Weather Advisory from midnight tonight to noon CST Sunday
     for IAZ009-010-018-019-029.

     Winter Weather Advisory from 3 AM to 3 PM CST Sunday for IAZ011-



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