Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 102348
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
548 PM CST Sun Dec 10 2017

.SHORT TERM...(This evening through Monday)
Issued at 205 PM CST Sun Dec 10 2017

10.20Z analysis shows a strong short-wave across northern Alberta.
This wave will race southeastward through tonight and across the
forecast area by Monday morning. Expect a band of warm advective
snow to impact portions of southeast MN into southwest and central
WI through Monday morning where a quick 1-2 inches will accumulate.
A few spots across Taylor/Clark Counties could see as much as 3
inches. Behind the snow band, drying aloft could result in a loss
of cloud ice and some light freezing drizzle or a wintry mix. Snow
and/or a wintry mix is likely to result in slick spots on area
roads and impact the Monday morning commute.

Ice aloft will return by late Monday morning and into the afternoon
with a southward moving deformation precipitation band, but with
surface temperatures rising to near or slightly above freezing,
periods of a wintry mix could continue before all precipitation
moves out Monday night. Additional snow accumulation will be
minimal Monday afternoon, although winds will increase and shift
to the north behind a secondary surface cold front.

.LONG TERM...(Monday night through Sunday)
Issued at 205 PM CST Sun Dec 10 2017

Monday night through Tuesday will be dry as surface high pressure
builds across the region. That said, Tuesday will be cold in the
wake of Monday`s wave. 925 hPa temperatures drop to between -10
and -15 Celsius, resulting in afternoon highs only in the mid
teens to lower 20s. With light northwest wind, wind chills through
the day will likely drop into the single digits above zero.

Wednesday through Friday, northwest flow aloft continues, but
models differ on the timing, strength and placement of short-
waves. Looks like the best chance for some additional light snow
will be Wednesday/Wednesday night and then again late Friday.
Temperatures through the period will generally be near or slightly
below normal with daily highs in the 20s to low 30s.

Eastern CONUS trough finally pushes east next weekend, allowing
for a more zonal flow across the forecast area. Both GFS/ECMWF
show a strong wave ejecting eastward from the Pacific on Saturday,
but the ECMWF is about 12 hours faster. Right now, best
precipitation chances with this system appear to be north of the
forecast area, but something to watch through the week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 548 PM CST Sun Dec 10 2017

IFR to LIFR conditions are expected in snow at both TAF sites
tonight. The main band of snow is expected to move through KRST in
the 6-8Z timeframe and through KLSE in the 8-10Z timeframe. Very
light snow or possibly drizzle is then expected through late
morning. Then another band of snow could move through from north
to south, producing brief IFR conditions. Northwest winds will
then increase to 13 to 15 kts with gusts to around 27 kts late
Monday afternoon and these winds will last well into Monday
evening. A few gusts to around 35 kts are possible at KRST.

&&

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

$$

SHORT TERM...Rogers
LONG TERM...Rogers
AVIATION...Wetenkamp



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