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afdarx

Area forecast discussion
National Weather Service La Crosse WI
508 PM CST Tue Dec 10 2019

Short term...(this evening through wednesday)
issued at 218 PM CST Tue Dec 10 2019

Abnormally cold air mass remains in place as upper trough axis
passes through. Some patchy stratus still being tracked in remaining
cold air advection area, but upstream subsidence and dry air should
make for a quiet, but cold night. Although winds are fairly light
and time of day not conducive for big wind chill impacts
typically, based on latest temperature trends, have slightly
expanded wind chill headlines one tier southward. Readings there
could be in the 20 to 30 below for numerous hours.

Brief period of low to mid level warm air advection that sets up
tonight to our southwest could bring a period of clouds and
associated light snow as it translates through the area in northwest
flow. Bulk of this should brush northeast Iowa into far southern
Wisconsin but minimal impact, if any, expected.

Although a chilly start to the day expected Wednesday morning,
moderation begins as height rise and troughs moves east. Should see
plenty of sunshine until upstream clouds start to filter in.

Long term...(wednesday night through tuesday)
issued at 218 PM CST Tue Dec 10 2019

The region is under upper level northwesterly flow, so the
precipitation chances over the forecast period are introduced by
passing short waves. So starting overnight Wednesday, a quick
clipper is expected to bring snowfall to the region. The highest
amounts of 2-3" are focused north of Interstate 94. Areas south
and along Interstate 90 could see around 1" of snow. Freezing rain
and drizzle are possible at the tail end of this system, but any
accumulations will be really light.

Warm air advection on Friday will bring the highs into the 30s across
the region. A weak surface low pressure system will bring a chance
for a wintry mix of precipitation Friday through Saturday. This
system is not well organized so the exact details of timing and
area impacted is not well agreed upon between the different
models.

After that system passes, high pressure builds into the region
giving way to mostly dry conditions through the rest of the
forecast period. The southern part of the region may see some
snow on Monday, but these are really low chances.

&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 508 PM CST Tue Dec 10 2019

VFR conditions expected at both sites through the taf period thanks
to an area of surface high pressure. Mostly clear skies overnight
with maybe a few passing high clouds associated with a quick hitting
system passing by south of both taf sites. Winds will generally be west-
southwest overnight into Wednesday morning, with speeds generally
less than 10 kts. Winds will turn more west-northwest during the day
on Wednesday before becoming east-southeast by late Wednesday
afternoon or evening ahead of the next approaching system. A few mid
to high clouds will be present on Wednesday with coverage increasing
toward the end of the taf period.

&&

Arx watches/warnings/advisories...
WI...Wind Chill Advisory from 9 PM this evening to noon CST Wednesday
for wiz017-029-032>034.

Minnesota...Wind Chill Advisory from 9 PM this evening to noon CST Wednesday
for mnz079.

Iowa...none.
&&

$$

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