Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 170445

Area Forecast Discussion
National Weather Service La Crosse WI
1145 PM CDT Wed May 16 2018

.SHORT TERM...(Tonight and Thursday)
Issued at 242 PM CDT Wed May 16 2018

Beautifully quiet weather again today - much needed dry time.
West-East surface ridge in place across Iowa into Michigan with
warming, west winds across northern Wisconsin. Only some diurnal
cumulus around that should dissipate for another quiet and clear
night. These drying trends should limit fog in valleys tonight but
light wind will make for another cool down in favored Wisconsin

There is a frontal boundary slipping across northern Minnesota into
Lake Superior region that will push into northeast Wisconsin by
tomorrow. In addition to a few more clouds, will see some cooler
temperatures, especially in parts of northern and central Wisconsin.
Will also have to watch amount of mixing and drying. This has pushed
dew points (relative humidities) down in sand/bog country today, and
could see lower than expected conditions on Thursday again.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 242 PM CDT Wed May 16 2018

Main focus for later forecast periods is rain chances as they
increase this weekend. Trends have been a bit slower. Overall risk
of severe weather appears minimal at this time, with higher CAPE
values likely remaining west/south of the area

Will be watching evolution of mean trough in the western states as
broad upper ridge gradually weakens over our area going into the
weekend. As short wave energy ejects from trough, expect showers and
thunderstorms to be most active west of the area initially, riding
northward along moisture axis. Modeled precipitable water shows
drier air over Wisconsin into Saturday which supports of idea of
more delayed rain chances, especially 16/12z NAM. This may allow
temperatures to be higher than earlier thought, especially in
central Wisconsin.

Will have to watch for weak short wave energy coming up from the
southeast too as some models suggest /NAM/ moisture could be
advecting in. For right now will focus on main synoptic threat with
rain chances coming in from the west by Saturday night and passing
through Sunday as main short wave crosses areas. This will keep
things cooler for Sunday as well.

Another ridge builds in for early next week it appears so should
return back to a dry regime for a couple days with mild temperatures.
Some hints of another wave passing by Tuesday night into Wednesday
but lots of unpredictability that far out.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1145 PM CDT Wed May 16 2018

VFR conditions set to stick around the next 24 hours. Still
watching a back-door "cold" front working southwest through
central Wisconsin at this late hour, with that feature expected to
slide westward across the area toward or after sunrise, sending
winds easterly at 8-10 knots through the coming daylight hours.
Will likely see some passing cirrus clouds at LSE into the
afternoon with a touch of cumulus around RST, though don`t believe
we`ll see enough moisture to spark off any showers out that way.




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