Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 120534
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1134 PM CST Thu Jan 11 2018

.SHORT TERM...(This evening through Friday)
Issued at 249 PM CST Thu Jan 11 2018

Early this afternoon, the cold front that brought the steep drop
in temps this morning has cleared the area to the east. Several
areas of precip were moving through the area, including a
deformation zone band lifting from north central Iowa
northeastward into northwest Wisconsin, and a secondary area
across eastern Iowa into southern Wisconsin in association with a
fairly strong upper level shortwave trough rotating
northeastward. Both of these areas of mainly snow will continue
to push northeast through late afternoon before quickly exiting.
While additional snow amounts will be light, will maintain the
Winter Weather Advisory through 6 pm with light snow ongoing in
some areas and areas of blowing/drifting snow in open areas.

As the upper trough axis swings through this evening and tonight,
skies will gradually clear from the west. Low-level cold
advection will continue through the night, with temps falling into
the single digits on either side of zero, coldest west of the
Mississippi. With a tight pressure gradient in place ahead of the
approaching surface high, winds will remain up overnight,
allowing wind chills to fall below zero. Have issued a wind chill
advisory for the open areas of southeast Minnesota and northeast
Iowa where the coldest wind chills (20 to 25 below zero) will be
found. Friday will be mostly sunny but cold with temps remaining
in the single digits and teens.

.LONG TERM...(Friday night through Thursday)
Issued at 249 PM CST Thu Jan 11 2018

Northwest flow aloft will continue through the weekend while at the
surface strong high pressure drops southeastward from the northern
plains. Cold air will remain in place with highs in the single
digits and teens while wind chills will drop to 10 to 30 below zero
early Saturday and Sunday mornings. An upper trough will amplify
across the western Great Lakes region Sunday night into early next
week. Forcing ahead of the upper trough and from a weak surface wave
will lead to a period of snow Sunday afternoon into Sunday night.
Deterministic and ensemble models remain consistent with about
0.10 to 0.20 inches of QPF, yielding an inch or two of fluffy
snow.

Reinforcing cold air will follow for Monday and Tuesday with highs
mainly in the single digits and wind chills during the nighttime and
morning hours falling to 15 to 30 below zero. Under cyclonic flow
low clouds and possibly some light snow/flurries will continue into
Monday/Tuesday. Consensus remains for dry weather for mid-week as
the surface ridge axis approaches, with indications for some
moderation in temps toward late next week with return southerly
flow.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1134 PM CST Thu Jan 11 2018

VFR conditions are expected through the TAF period. Arctic high
pressure builds into the TAF sites tonight providing cold
temperatures and mostly clear skies. Mid level clouds could move
into the TAF sites late Friday afternoon into Friday evening with
cloud bases around 10kft.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Wind Chill Advisory until 10 AM CST Friday for MNZ079-086-087-
     094-095.

IA...Wind Chill Advisory until 10 AM CST Friday for IAZ008-009-018-
     019.

&&

$$

SHORT TERM...JM
LONG TERM...JM
AVIATION...Wetenkamp



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