Area Forecast Discussion
Issued by NWS La Crosse, WI

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125
FXUS63 KARX 071128
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
528 AM CST Wed Dec 7 2016

.SHORT TERM...(Today through Thursday)
Issued at 340 AM CST Wed Dec 7 2016

The southern edge of the stratus associated with the upper low
over southern Ontario continues to remain near our area this
morning. NAM model soundings struggle to erode the low-level
moist layer, and even if any clearing of the lower clouds occurs,
mid-level cloud cover is spreading northeastward into NE IA and
SW WI, so once again expect most areas to remain on the cloudy
side with some flurries possible under lower cloud cover today.
Gusty westerly winds will keep wind chills in the single digits
above and below zero for much of the day with little improvement
through Thursday.

Low clouds will spread back southward over the entire tonight as the
upper flow becomes a bit more cyclonic with an upper shortwave
trough swinging southward on the western edge of the departing upper
low. Light snow/flurries will be possible within this regime. With
high snow ratios / around 20 to 1 /, much of the saturated layer
within the favored dendritic growth zone and relatively steep
low-level lapse rates, some very light fluffy accumulations up to
perhaps 1/2 inch to 1 inch may be possible especially north of
I-94.

.LONG TERM...(Thursday Night through Tuesday)
Issued at 340 AM CST Wed Dec 7 2016

The main concern for the extended period will be Saturday into
Saturday Night with the potential for accumulating snowfall. Some
differences persist with the timing and placement of the system
with the GFS somewhat slower and deeper with the upper shortwave
that ejects from the Rockies and also higher with precip amounts
resulting from the stronger forcing. Confidence continues to
increase that some snow will occur across the area most likely in
the Saturday afternoon/evening timeframe, but questions remain as
to the placement and amounts.

Beyond this system, quieter weather will return late in the weekend
into early next week. The 07.00Z GFS/ECMWF do show a stronger
cold push sometime near the end of the period, so confidence is
high that temps will remain below average for the foreseeable
future.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 528 AM CST Wed Dec 7 2016

KRST/KLSE remain stuck under the MVFR clouds wrapping around the sfc-
mid level low north of lk Superior. With the lower level flow slowly
transitioning from W-SW to more W-NW and NW thru the next 24 hrs, it
appears these lower clouds will continue to plague the TAF sites
thru today and tonight into Thu morning. May be a few breaks/brief
scattering of the clouds this morning, but with the colder air
aloft, cyclonic flow and steep low level lapse rates, a BKN/OVC MVFR
deck is looking to be the rule. The cold cyclonic flow and lower
level cloud moisture will continue to wring out some flurries today
but vsby restrictions are not expected. Winds will remain brisk/
gusty from the W to NW at 13-18kt g22-28kt today/tonight, with the
stronger winds at the higher elevation/open country sites like KRST.

&&

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

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION.....RRS



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