Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 150444

Area Forecast Discussion
National Weather Service La Crosse WI
1144 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 06Z TAFS through 06Z Saturday night)
Issued at 1144 PM CDT Fri Jul 14 2017

Skies have cleared under high pressure and are expected to remain
cloud-free through the night. One caveat will be the potential
development of some patchy fog near sunrise Saturday morning,
especially within river valleys. For now, will keep KLSE fog free
as model guidance suggests near surface winds will increase just
enough to preclude restrictions to visibility.

Some cumulus development is expected through Saturday, mainly in
the 3000 to 5000 ft agl layer. A cold front will then drop south
across TAF airfields in the early evening. This could result in
some scattered showers/thunderstorms, especially at KLSE, but not
enough confidence in timing/coverage to include storm mention at
this time.

Light and variable wind overnight will increase slightly from the
south-southwest after sunrise and then eventually shift to the
northwest after cold frontal passage late in the period.




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