Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 070515

Area Forecast Discussion
National Weather Service La Crosse WI
1115 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 06Z TAFS through 06Z Thursday night)
Issued at 1115 PM CST Wed Dec 6 2017

As of 05z, the trailing edge of the MVFR cloud deck and areas of
MVFR vsbys in -SN were about to exit south of both the KRST/KLSE taf
sites. Once these clouds/-SN exit, good VFR expected this taf period
with BKN 8K-15K ft clouds for the overnight hours, then sct 14K-20K
ft clouds for most of the day on Thu. Moisture already starts to
return Thu evening, but clouds in the 00-06z period looking to be
mid level in the 7K-10K ft range.

Trend has been for less gustiness of the NW winds this evening and
trend is now for a bit less wind this taf period. NW winds 10-15kt
expected thru about 18z, with the winds decreasing and shifting to
the southwest for Thu evening.




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