Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 291141

Area Forecast Discussion
National Weather Service La Crosse WI
641 AM CDT FRI JUL 29 2016

.SHORT TERM...(Today through Sunday)
Issued at 231 AM CDT Fri Jul 29 2016

Water vapor satellite early this morning showed a short wave
trough over the Nebraska/Iowa border, another over central South
Dakota with a third over Montana. All these waves are expected to
move rather slowly to the southeast today taking a track across
Iowa into Illinois. While these waves will not produce much
forcing for the local area as they move by to the south, they will
help to hold a surface trough essentially stationary across the
southern sections of the forecast area. Weak moisture convergence
in the low levels will be focused on this surface trough and with
some vertical motion along the trough from the passing waves, this
should be enough to generate some scattered showers and possibly a
rumble or two of thunder during the afternoon across the southeast
sections of the forecast area. These showers should taper off this
evening with a dry overnight expected as the short wave troughs
move east of the region. However, by Saturday, another short wave
trough will be moving in from the northwest that could generate
some more showers as the surface trough will still be in the area.
Once the Saturday short wave trough moves by the area, upper level
heights will start to build which should lead to a dry Sunday.

.LONG TERM...(Sunday night through Thursday)
Issued at 231 AM CDT Fri Jul 29 2016

The weak upper level ridging that builds in over the area Sunday
will quickly get flattened starting Sunday night. An upper level
low should be in place over central Manitoba by this time with a
short wave trough coming through the flow underneath the low which
will flatten the ridge. This will lead to a chance for some
showers and storms from late Sunday nigh into Monday night. The
upper level ridge tries to rebuild over the area starting Tuesday
but does so just enough that additional short wave troughs topping
the ridge will be pretty close to the area. This will keep the
chance of showers and storms in the forecast for most of next week
with some higher chances Wednesday night into Thursday as a cold
front moves into the area.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 641 AM CDT Fri Jul 29 2016

Trough of low pressure will continue to generate vfr clouds and
isolated shra today across the area. Did not include vcsh for now
due to lower confidence of shra being close to KLSE/KRST airports.
Clouds are expected to scatter out this evening as the trough
exits east and high pressure builds in. Included some fog/stratus
mention at KRST/KLSE after 10z due to clearing skies/moist lower
boundary layer/light surface winds.


.ARX Watches/Warnings/Advisories...


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