Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 142029

Area Forecast Discussion
National Weather Service La Crosse WI
329 PM CDT Fri Jul 14 2017

.SHORT TERM...(This evening through Saturday)
Issued at 328 PM CDT Fri Jul 14 2017

At 3 PM, MVFR clouds remain trapped below a subsidence inversion.
As the surface ridge axis slides east tonight, expect skies to
gradually clear. However with this said, we will have to watch out
for the possibility that some of this low level moisture could
return to southwest and central Wisconsin as the winds become
southerly late tonight. The clouds may linger into Saturday

On Saturday afternoon and evening, the models continue to show
that a cold front will move southeast through the area. Still
plenty of questions on how much the dew points will recover and
whether the cap will erode enough for the development for storms.
Overall with weaker cap and better convergence, the best chances
for storms will be across western Wisconsin. However if the dew
points can get into the mid 70s or the temperatures can get into
the lower 90s west of the Mississippi River, scattered storms
could also form in that area too. Depending on the dew points, the
0-1 km mean layer CAPES will be in the 2 to 4K J/kg range. Like
yesterday, much of the shear remains in the 0-3 km range, so there
could be some organization with any storms that happen to
develop. Soundings suggest that the primary concern will be large
hail. Other threats will be damaging winds and heavy rain.

With 925 mb temperatures in the 24 to 27C range, the maximum
temperatures for Saturday looked too cool, so bumped them up a
couple of degrees.

.LONG TERM...(Saturday night through Friday)
Issued at 328 PM CDT Fri Jul 14 2017

From Monday night into Thursday, the models continue to show that
the upper level ridge will flatten and this will result in zonal
flow across the Upper Mississippi River. Like yesterday, there are
still plenty of questions on where the frontal boundary will be
located. This will affect both severe weather and flooding


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1240 PM CDT Fri Jul 14 2017

MVFR clouds are proving to be stubborn early this afternoon. Not
terribly surprising given a lack of mixing and a stronger
inversion aloft, and given trends, expect at least another few
hours of MVFR conditions before ceilings gradually try to lift and
then eventually dissipate into the evening as high pressure works
into the area. So...what could go wrong? If clouds are not able to
completely mix out by sunset, chances are high that lower stratus
will redevelop overnight, though we will simply have to watch
trends to see where they take us. Winds through sunrise will
remain light, gradually shifting back to the southwest at 8-15
knots by midday Saturday.




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