Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 190445

Area Forecast Discussion
National Weather Service La Crosse WI
1145 PM CDT Wed Apr 18 2018

Issued at 1126 PM CDT Wed Apr 18 2018

Last of the snow has moved out of the forecast area, so cancelled
the remaining Winter Storm Warning across northeast IA and
southwest WI. Continue to exercise caution if traveling overnight
as roads may be slick.

In addition, added some patchy fog to the cranberry bogs of west-
central WI overnight as both Black River Falls and Sparta have
reported reduced visibility. As skies clear from north to south
overnight, will need to watch for possible expansion of fog across
the area due to relatively light winds and ample low-level

UPDATE Issued at 954 PM CDT Wed Apr 18 2018

Snow has ended across a large portion of the forecast area,
allowing for the cancellation of the Winter Weather Advisory and
most of the Winter Storm Warning. Lingering light snow across far
southwest WI and adjacent portions of northeast Iowa could result
in additional accumulations up to an inch through midnight.

Please be aware that any untreated roads and wet surfaces may
become slick overnight as temperatures fall below freezing.
Continue to exercise caution if traveling tonight.


.SHORT TERM...(This evening through Thursday)
Issued at 228 PM CDT Wed Apr 18 2018

Through the remainder of this afternoon, the frontogenetic
band will remain along the Minnesota and Iowa border east across
southern Wisconsin. This band will gradually weaken during the
early to mid evening. As this occurs, the snow will taper off to
flurries and end. Additional snow amounts will range from 2 to 5
inches this afternoon and from a trace to 1 inch between 7 PM and
10 PM this evening. This will raise the storm snowfall total into
the 6 to 12 inch range in the aforementioned band. There may be a
few higher totals along the Minnesota and Iowa border in Mower
and Fillmore counties in southeast Minnesota and Mitchell and
Howard counties in northeast Iowa.

Due to the heavy snow south along and south of Interstate 90,
lowered the maximum temperatures by 5 to 7F.

.LONG TERM...(Thursday night through Wednesday)
Issued at 228 PM CDT Wed Apr 18 2018

From Thursday night through Monday, high pressure will provide
some much needed dry weather for the region. Snow cover will
initially limit some of the warming on Friday and Saturday, but
by the end of the weekend much of it should be melted and high
temperatures will become more seasonable (lower and mid 60s).

From Monday night into Wednesday, the models move a Canadian cold
front southeast through the region. The timing of this frontal
passage is highly uncertain due to differences in the models. The
GFS moves this front through from Monday night into Tuesday. The
ECMWF moves it through from Tuesday into Wednesday morning.
Meanwhile, the Canadian has an upper level low moving through the
region, so it keeps the precipitation over the area through the
mid week period. This precipitation will be mainly rain. However,
the may be enough cold air in the wake of this front for a brief
period of snow.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1145 PM CDT Wed Apr 18 2018

With all snow now south of TAF airfields, expect VFR conditions at
both KRST/KLSE through the period. The one caveat will be possible
fog tonight. Clearing skies, relatively light wind, and high low-
level moisture may result in some reductions in visibility.
Confidence is not high, however, due to lower upstream surface dew
points moving into the area. Will monitor observations and amend
as necessary. Winds through the period will be light from the
northwest, becoming light and variable Thursday evening.




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