Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 040701

Area Forecast Discussion
National Weather Service La Crosse WI
201 AM CDT Sat Apr 4 2020

.SHORT TERM...(Today and tonight)
Issued at 201 AM CDT Sat Apr 4 2020

A large upper trough and associated cold front continue to lift
further north and east early this morning as surface high pressure
builds in from the Northern Plains. Low stratus remain present
areawide of 2 am, but as the surface high axis inches further
eastward, low clouds should begin to erode from west to east as
better subsidence comes into play. Once clouds scatter out, a dry
and mostly sunny Saturday is in store with high temperatures
warming into the 40s to 50s.

.LONG TERM...(Sunday through Friday)
Issued at 201 AM CDT Sat Apr 4 2020

Surface high pressure drifts east of the area on Sunday, providing
continued dry conditions. Warm air advection will ramp up early in
the week as broad upper ridging amplifies over the central CONUS.
Moisture transport will increase heading into Monday with PWATs
climbing to 0.8" or higher across much of the forecast area.
Meanwhile a weak shortwave traversing the ridge will cross the Upper
MS Valley late Sunday night into Monday, bringing the next chance of
showers and perhaps some storms south of I-90 as highs top out in
the 50s to lower 60s.

A stronger shortwave trough will dig into the Upper Midwest on
Tuesday with a corresponding surface low crossing from the Dakotas
into northern Wisconsin. As a warm front lifts northward through the
area during the day, temperatures will climb through the 60s to
lower 70s. Dewpoints are progged to rise through the 50s, perhaps
flirting with 60 in the south. The result will be favorable surface
based instability of 1000-1500 J/kg (per GFS) with low level capping
eroding by mid-late afternoon. Ample deep layer shear will also be
present, so will continue to monitor the potential for some strong
to severe storms in the afternoon and evening until a weak cold
front pushes through.

A stronger cold front will drop through the region on Wednesday,
providing another opportunity for showers and perhaps a few storms.
850mb temps then show a cooler pattern in store for the remainder of
the week as a pool of Canadian air spills into the region behind a
deep cyclone marching across eastern Canada.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1050 PM CDT Fri Apr 3 2020

The cold front has pushed well east of the region this evening
with the precipitation off the the east as well. An area of high
pressure was building in from the west and was pushing clearing
toward the region. The back edge of the clouds have been good
eastward progress and will work across both sites overnight. Until
the clouds do scatter out, the MVFR conditions will continue. VFR
conditions with little to no cloud cover is expected Saturday as
the high continues to build into the region.




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