Area Forecast Discussion
Issued by NWS La Crosse, WI

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900
FXUS63 KARX 190438
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1038 PM CST Wed Jan 18 2017

.SHORT TERM...(This evening through Friday)
Issued at 303 PM CST Wed Jan 18 2017

Main forecast concerns in the short term on on dense fog potential
tonight into Thursday morning. Focus then quickly turns to a chance
for a wintry mix which could produce slippery travel conditions
for some Thursday night into Friday.

An active weather pattern sets up across the region the the next
several days as a broad trough sets up across the western conus.
First off tonight, relatively warm and moist air flowing over the
snowpack across the area could lead to the development of dense fog
in areas and to go along with this, some low clouds/stratus. The
first trough then lifts into the region Thursday night into
Friday pushing a warm front through the area. Precipitation will
develop along and ahead of the approaching front and will most
likely start out as a wintry mix before transitioning over to all
rain. Locations north of interstate 90 look to remain cold enough
Thursday night into Friday morning that we may have some freezing
rain and perhaps some sleet concerns. The big concern is how
quickly will surface temperatures warm above freezing. By early
afternoon, most locations should be above freezing with rain the
main precipitation type. The freezing rain may produce travel
problems, especially north of Interstate 90, and on any untreated
secondary roads, before temperatures warm above freezing.

.LONG TERM...(Friday night through Wednesday)
Issued at 303 PM CST Wed Jan 18 2017

We then lose forcing for precipitation for the bulk of Friday night
ahead of the next through moving in from the south. Given the nearly
saturated lower levels, from surface through around 5 kft, the
most likley precipitation outcome will be drizzle or very light
rain. Steadier rain should then set in during the day on Saturday
and continue into Saturday evening. Surface temperatures will be
warm enough that any precipitation that falls should be in the
form of rain. Chances for light rain continue into Sunday then we
look to cool enough Sunday night into Monday for possibly
rain/snow mix. We are seeing mixed signals for a potential system
late Tuesday into Wednesday. What looks like a potential impactful
weather system in the GFS is now pretty much absent in the ECWMF.
A lot of uncertainty out there on days 6-7 so will continue to
keep an eye on future model runs.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1038 PM CST Wed Jan 18 2017

Mild/moist airmass over melting snow pack was producing areas of
IFR/local LIFR stratus and fog across the area late this evening.
Looking for this stratus/fog to expand overnight and continue
through Thursday night. A trough of low pressure will also bring
some light rain into ares along and east of the Mississippi by
early evening.

&&

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

$$

SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
AVIATION...DAS



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