Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 182341

Area Forecast Discussion
National Weather Service La Crosse WI
541 PM CST Sat Nov 18 2017

.SHORT TERM...(This evening through Sunday)
Issued at 242 PM CST Sat Nov 18 2017

Skies have cleared through the day with strong subsidence behind the
upper trough exiting to the southeast. Despite low-level cold
advection and brisk northwest winds, the increasingly sunny skies
have helped bump temps up into the upper 30s to low 40s. With high
pressure spreading across the area tonight and Sunday, quiet
weather is expected. A bit more cloud cover will persist into
tonight over north-central WI as an upper shortwave drops
southeastward. With mostly clear skies across much of the rest of
the area tonight, temps should drop into the teens to low 20s,
recovering back into the 30s in most spots on Sunday.

.LONG TERM...(Sunday night through Saturday)
Issued at 242 PM CST Sat Nov 18 2017

All in all, it`s shaping up to be a fairly quiet weather week for
holiday travelers across the Upper Midwest, although with a few back
and forth temp swings and low-end precip chances.

Monday still looks mild, with 925 mb temps rising into the 6-8C
range and south to southwest winds. Highs should reach into the 40s,
with low 50s in some river valley locations.

A strong upper shortwave trough diving towards the Great Lakes will
drive a cold front through Monday night, with a surge of low-level
cold advection in its wake into Tuesday morning. It`s not out of the
question that a few snow showers could occur as the front drops
through, but otherwise expect a much cooler Tuesday with highs in
the 20s and 30s along with gusty northwest winds. Cool temps will
continue into Wednesday under high pressure. Both the 18.12Z
GFS/ECMWF swing an upper shortwave/cold front through late Wed/Wed
night. The ECMWF actually generates some light precip aided by
strong mid-level warm advection, but at this time, confidence is
low in any precip occurring.

Thanksgiving Day is looking dry and seasonable as high pressure
spreads southeast from the northern plains. Confidence is a
little lower for temps late this week, with the ECMWF now showing
cooler 850 mb temps spreading back across the area Thanksgiving
Day behind the cold front thanks to a stronger, slightly more
amplified upper shortwave trough passing to the north. The ECMWF
is then slower bringing warmer back northward as the low-level
flow turns southerly on Friday. Temps should rebound on Friday,
but just how much is the question. Stuck close to consensus given
the model spread, with highs in the 40s. By Saturday, another low
pressure system/cold front is expected to pass across the region,
but confidence is low in the details.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 541 PM CST Sat Nov 18 2017

A narrow band of VFR clouds with a broken ceiling is working
across the area early this evening. These should be east of KRST
and will just go with a scattered deck while KLSE will see these
broken VFR clouds through about the middle of the evening. After
that, look for clear skies through the overnight with just some
high level clouds moving in Sunday. The gusty northwest winds will
persist through the evening before the gradient begins to relax
and the speeds aloft diminish to allow the gusts to stop. The
winds will swing around to the southwest Sunday once the low level
ridge axis moves past the area.




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