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Area forecast discussion
National Weather Service La Crosse WI
239 am CDT Wed Oct 23 2019

Short term...(today and tonight)
issued at 239 am CDT Wed Oct 23 2019

Despite the low pressure system that has impacted the area the last
few days having moved well into Canada, plenty of associated cloud
cover continued to wrap around and into the forecast area (along and
north of I-94) early this morning. A few obs sites even reported
some drizzle during the late evening hours, but this has since
exited the area.

Those clouds should continue to slowly push off to the northeast
this morning, though more will be moving in as some shortwave energy
and surface low move in from the west. In addition, models show
decent frontogenesis in the 900 to 700 mb layer and produce some
light precipitation, mainly along and south of Interstate 90.
Guidance has trended toward a later arrival time of the precip
(moving in late morning), so expecting mainly rain (around 0.10" to
0.20"). However, a few snowflakes could mix in with any of the
lingering precip this evening in southwest Wisconsin as temperatures
cool into the 30s. It should also be noted that forcing is fairly
strong, so if precip is a bit heavier, the resultant cooling could
lead to a bit more snow mixing in than expected. All that said, not
expecting any snow accumulation or impacts.

Long term...(thursday through tuesday)
issued at 239 am CDT Wed Oct 23 2019

High pressure builds in for Thursday and leads to dry weather
through Saturday, though with upper level troughing through Friday
it will remain cool. Expect highs in the 40s and lows in the 20s to
lower half of the 30s, with Thursday night looking the coldest
(widespread lows in the 20s). Decent southerly flow returns for
Saturday as surface high pressure moves off to the east, which
should lead to warmer/closer to normal temperatures, with highs in
the 50s.

Confidence in the forecast from Saturday night on remains somewhat
low, with decent spread in model solutions. The one thing there's
agreement on is that a cold front will slide through at some point
on Sunday, and that it should be a mostly dry passage. The main
feature of disagreement is the track of a fairly potent low pressure
system that spins up over the Southern Plains on Saturday. The GFS
along with many gefs members keep the system and all associated
precip well south and east of the forecast area, with the low
tracking south of the Ohio River. In contrast, the European model (ecmwf) has
consistently brought the low toward Chicago, clipping at least
southeastern portions of the forecast area with some light precip
Saturday night into Sunday. However, the 23.00z run trended a bit
farther southeast and dry for the forecast area. Tend to side with
the drier solutions as that seems to be the general consensus, but
keeping small precip chances in parts of northeast Iowa and
southwest Wisconsin for now to Honor some of the gefs members and
past European model (ecmwf) runs.

Behind the front on Sunday, cooler weather will be on tap for the
beginning of the work week, with highs in the upper 30s to mid 40s.
The next chance for precipitation arrives Monday night/Tuesday, but
solutions differ on whether that will be along a stalled surface
boundary and/or associated with some shortwave energy moving through
out of the Dakotas.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1056 PM CDT Tue Oct 22 2019

Blanket of clouds has been slow to retreat this evening, but will
start to see more of a progression to the northeast overnight with
continued VFR conditions. Westerly winds are also still a tad
gusty, but they are expected to slowly diminish after 06z. Clouds
will increase again after daybreak as a clipper system
approaches. This system will bring a period of light rain, mainly
in the afternoon to early evening hours. Have slowed down the
rain's arrival a bit in these tafs. With this system will come
more MVFR ceilings heading into the mid to late afternoon hours,
which will likely stick around through the remainder of the taf
period. Light winds will turn northwest as this system pushes
through the region.


Arx watches/warnings/advisories...


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