Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 151155
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
555 AM CST Wed Nov 15 2017

.SHORT TERM...(Today and tonight)
Issued at 314 AM CST Wed Nov 15 2017

Main forecast concerns in the short term are on dense fog
potential early over north central Wisconsin. Focus then turns to
falling temperatures through the day and potential for a few rain
or snow showers over north central Wisconsin this afternoon and
gusty northwest winds.

A cold front continues to march east across the area this morning
and as of 3 AM was positioned near the Interstate 35 corridor.
Light rain/drizzle continues at times early this morning over the
area along with patchy to areas of fog. A weak surface low was
moving into west central Wisconsin and is expected to slide over
north central Wisconsin early this morning. A brief period of
dense fog is possible as this low moves through. Otherwise, look
for the light rain/drizzle to end as the front pushes through.
Cold air advection will then be in place for late this morning
through the afternoon hours. So, high temperatures for today will
be early this morning then look for temperatures to fall through
the day. Most areas should be in the low to mid 30s by late this
afternoon. A compact shortwave will move over northern Wisconsin
late this afternoon and may trigger a few rain or snow showers
north of Interstate 94. Also, as the pressure gradient tightens
today plan on gusty northwest winds. We could see some wind gusts
to around 35 mph in open areas.

.LONG TERM...(Thursday through Tuesday)
Issued at 314 AM CST Wed Nov 15 2017

Main forecast concerns in the long-term are on chances for light
snow or freezing drizzle Thursday night into Friday. A switch over
to light snow is possible Friday night into early Saturday
morning as colder air works into the region.

Another cold front then approaches the region Thursday night as a
broad upper trough moves across the northern plains. Low stratus
and possibly fog will overspread the region ahead of the front
Thursday night into Friday. Precipitation will also overspread
the region during this timeframe but then the question is what
will the precipitation type be? Looking at forecast soundings, it
appears most of the precipitation should be in the form of drizzle
or freezing drizzle. There is currently a wintry mix of
sleet/freezing rain/snow in the forecast for Friday morning over
central into northern Wisconsin. If the saturation doesn`t deepen
this likely won`t happen. So through coordination  As mentioned
the main precipitation types would be drizzle and freezing drizzle
where surface temperatures are cold enough. Lingering drizzle
should switch over to a period of light snow Saturday morning
before ending as colder air wraps into the region with low
pressure deepening over Lake Huron. At this time any snow
accumulation looks minor. We then look to enter a potential dry
and cool period from Sunday all the way into the middle of next
week with cool northwesterly flow aloft and surface high pressure
attempting to dominate.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 555 AM CST Wed Nov 15 2017

15.1130Z surface analysis shows a cold from near KEAU to KCCY,
moving eastward around 15-20 kts. KRST is already in the post
frontal air mass, which has scoured out fog/drizzle from overnight
and allowed winds to shift to the northwest. Expect frontal
passage at KLSE between 15.13Z and 15.14Z, after which visibility
will improve and drizzle will end.

Ceilings the rest of the day are tricky with some brief clearing
moving in from southwest MN, but another mass of MVFR clouds
across the eastern Dakotas and northwest MN are expected to drop
rapidly southward across TAF airfields. Tried to build in a brief
improvement of ceilings at KRST from mid-late morning, but think
KLSE will remain socked in with at least MVFR cloud bases through
most if not the entire period. Once MVFR ceilings move over KRST,
they will also remain for most of the period.

Northwest winds today will be quite strong, gusting at both TAF
airfields between 24 and 30 kts. Only later tonight should winds
begin to dissipate somewhat.

&&

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

$$

SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
AVIATION...Rogers



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