Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 102005
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
205 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 18Z TAFS through 18Z Monday afternoon)
Issued at 1137 AM CST Sun Dec 10 2017

Area currently enshrouded in MVFR stratocumulus in broad cyclonic
flow. Bout of impactful weather expected tonight into Monday as a
low pressure system drops southeast out of Canada into the region.
Light snow expected to break out at KRST around 05z and KLSE by
07z. Expected MVFR cloud to continue through the period with the
exception of occasional IFR (mainly 06-08z time frame for KRST
and 08-10z at KLSE). Expect reductions in visibility in the snow
as well down to 1 SM in the snow during same time periods. Right
now, thinking total snow amounts will be around an inch.

&&

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

$$

SHORT TERM...Rogers
LONG TERM...Rogers
AVIATION...DAS



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