Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 040603

Area Forecast Discussion
National Weather Service La Crosse WI
1203 AM CST Sun Dec 4 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 06Z TAFS through 06Z Sunday night)
Issued at 1203 AM CST Sat Dec 3 2016

The light snow continues to advance slowly to the northeast ahead
of the approaching short wave trough. This snow will overspread
both airports by 06Z or not long after. Once the snow moves in,
conditions should quickly go down to IFR and stay there until the
snow ends. Expecting the snow to taper off by late morning in KRST
and early afternoon in KLSE. Once the snow ends, the visibility
will improve rapidly once the snow ends but ceilings will remain
IFR through the afternoon. Conditions expected to improve to VFR
Sunday evening as the ceilings come up in the wake of the
departing system.


WI...Winter Weather Advisory until noon CST Sunday for WIZ032.

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

MN...Winter Weather Advisory until noon CST Sunday for MNZ088-095-096.

IA...Winter Weather Advisory until noon CST Sunday for IAZ009-010-018-

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



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