Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 142338
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
538 PM CST Sun Jan 14 2018

.SHORT TERM...(This afternoon through Monday)
Issued at 237 PM CST Sun Jan 14 2018

Watching a pesky band of light warm advective snow/flurries lifting
northeastward this afternoon across the forecast area. For the most
part, this will result in a trace to possibly a light dusting.
Higher impact snow is still upstream across central and northern MN,
but will move into the area late this afternoon and evening as a
strong clipper system closes off and drops south across MN.

Cold temperatures this evening through tomorrow result in a deep
dendritic growth zone (at times reaching 10 kft). With models
showing roughly 5-6 microbars per second of lift within the DGZ,
expect dendrites and higher snow ratios. Just how high is still a
bit of a question, but most guidance is near 20:1. At the same
time, QPF from GEFS/SREF plumes are clustered around 0.20 to 0.25
inches of liquid. This should result in snow amounts through
Monday in the 2 to 6 inch range. Higher amounts (3-6 inches) are
expected east of the Mississippi River as an inverted surface
trough pivots across western/central Wisconsin on Monday, resulting
in periods of additional light snow. Will add Buffalo and
Trempealeau Counties to the current Winter Weather Advisory based
on snow amounts.

Also watching winds and the potential for blowing/drifting snow. A
cold front moves into the forecast area after midnight, resulting
in increasing northwest wind. With roughly 25 to 30 kts in the
boundary layer, could see surface gusts around 30 mph for areas
west of the Mississippi River, especially on Monday. With less
expected snowfall for these areas, will include patchy blowing and
drifting snow, but will need to monitor the situation for expanded
coverage and possible Winter Weather Advisory headlines.

The above mentioned winds and cold air temperatures will result
in bitter cold wind chills tonight through Monday for areas west
of the Mississippi River. A Wind Chill Advisory will continue with
wind chills in the 20 to 35 below range. After collaboration with
neighboring offices, also added the counties between the Mississippi
River and the current Wind Chill Advisory.

.LONG TERM...(Monday night through Sunday)
Issued at 237 PM CST Sun Jan 14 2018

Light snow will finally diminish and move east Monday night,
although continued northwest breezes and air temperatures dropping
into the single digits below zero will result in bitter cold wind
chills for areas west of the Mississippi River through Tuesday
morning.

Tuesday through Friday look quiet as surface high pressure
dominates the regional weather pattern. Increasing ridging aloft
will allow temperatures in the single digits and teens above zero
on Tuesday to rise into the lower to mid 30s by Friday.

Next weekend, flow aloft shifts to the southwest allowing for a
larger system to lift northeastward somewhere across the Upper
Midwest. Run to run consistency has been poor, so details are far
from certain, but something to watch closely over the coming week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 538 PM CST Sun Jan 14 2018

IFR to LIFR conditions are occurring in snow this evening at both
TAF sites. Conditions slightly improve to IFR mainly after
midnight as the steadier snow shift east. Strong northwest winds
will develop late tonight into Monday morning creating areas of
blowing and drifting snow, especially at KRST. Periods of snow are
possible throughout the day at KLSE with the potential for IFR
conditions at times. Total snow accumulations of around 2 inches
are expected at KRST with 3 to 4 inches expected at KLSE.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until midnight CST Monday night for
     WIZ017-029-032>034-041>044-053>055-061.

MN...Wind Chill Advisory from 3 AM Monday to noon CST Tuesday for
     MNZ079-086>088-094>096.

IA...Wind Chill Advisory from 3 AM Monday to noon CST Tuesday for
     IAZ008>011-018-019-029-030.

&&

$$

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


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