Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 061925

Area Forecast Discussion
National Weather Service La Crosse WI
125 PM CST Wed Dec 6 2017

.SHORT TERM...(Tonight through Thursday Night)
Issued at 125 PM CST Wed Dec 6 2017

Region remains firmly entrenched in cold/cyclonic flow with closed
low centered over James Bay Canada. GOES-East water vapor
imagery/RAP analysis this afternoon showing an embedded trough
within this northwest flow aloft rotating southeast into northern
MN/WI. Visible satellite showing copious stratocumulus and scattered
flurry/snow shower activity tied to this trough. So, expect
increasing clouds and snow shower activity rest of this afternoon
into this evening as this trough rotates through. Only expecting a
trace to perhaps up to 1/2 inch of snowfall under the more vigorous
snow showers. Main forcing from this trough pushes southeast of the
area around midnight but lingering cyclonic flow will likely
continue flurry activity through the overnight hours. Otherwise,
plan on chilly overnight lows in the 10 to 20 degree range.

Thursday looks mostly sunny as a weak ridge of high pressure passes
through the region. Still unseasonably cold though with expected
highs only in the upper teens to middle 20s.

We will see an increase in clouds again Thursday night from
northwest to southeast Thursday night as yet another embedded
northwest flow mid-level trough rotates into the region. A few
flurries will likely be seen as well mainly across north central WI.
Overnight lows again be in the 10 to 20 degree range.

.LONG TERM...(Friday through Wednesday)
Issued at 125 PM CST Wed Dec 6 2017

Focus turns to Friday night as a more vigorous mid-level trough
rotates southeast through the the area. Will likely see some light
snow accumulations with this feature, mainly east of the Mississippi
River. Right now, thinking 1/4 to 1.5 inches is possible. Also,
could see some localized blowing around of this fresh snow as fairly
strong surface cyclogenesis and tightening pressure gradient produce
gusty northwest winds by early Saturday morning.

Look for clearing skies Saturday as high pressure build in from the
Northern Plains. Still no upward swing anticipated in temperatures
though with highs only in the upper teens to middle 20s.

Region remains locked in northwest flow aloft into mid-next week
which will lead to colder than normal temperatures with intermittent
light snow chances as weak embedded troughs rotate through.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1149 AM CST Wed Dec 6 2017

Clear skies will come to an end during the early afternoon hours as
an MVFR cloud deck in the 1500 to 2500 ft agl range continues to
slowly approach from the north. Some light snow is also falling out
of this deck, with some MVFR visibilities being observed.
Gusty northwest winds will also be seen through much of the TAF
period, with gusts near 25 kts possible through the evening and
overnight hours. Given these winds, it is possible that some brief
IFR visibilities could be observed, but with the snowfall expected
to be rather light, confidence is not high enough to include any
mention. Snow is expected to come to an end by 3Z, with ceilings
rising to VFR levels. Could see a few flurries through the overnight
hours, but no visibility restrictions are expected should this
occur. Clouds will then begin to exit the area from west to east
early Thursday morning, with wind speeds slightly decreasing
throughout the day.




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