Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 120710

Area Forecast Discussion
National Weather Service La Crosse WI
210 AM CDT Sat Aug 12 2017

.SHORT TERM...(Today through Tuesday)
Issued at 210 AM CDT Sat Aug 12 2017

Weekend shaping up to be quite a nice one as high pressure remains
the main weather influence for the region. Ample sunshine today, but
some high/mid level clouds expected to encroach from the west later
tonight, and could temper/filter some of that sunshine for Sunday.
If it stays mostly clear tonight, setup favors widespread valley

The GFS and NAM have been in good agreement with taking a shortwave
trough currently churning over MT east/southeast today, gradually
sliding it across the local area Sun afternoon/night. Not much
instability or wind shear to play with. A little low level moisture
transport to help fuel rain/storm chances. The deeper saturation
holds off until late Sunday/Monday - and the bulk of the
shower/storm chances could hold off until then.

.LONG TERM...(Wednesday through Friday)
Issued at 210 AM CDT Fri Aug 11 2017

Models remain in good agreement with a mid week system, taking an
upper level shortwave trough from the pac nw eastward, sliding it
across portions of the Upper Mississippi River Valley late Wed
through Thu (potentially into Friday). Previous runs of the GFS and
EC both suggested the shortwave would track across the U.S/Canadian
border, with the bulk of the upper level energy holding there. It`s
associated sfc front, coupled with low level moisture return and
some instability would have the most influence on rain chances
locally. Latest GFS run is farther south with the main piece of
upper level energy, resulting in greater qpf and higher threat for
showers/storms in the south. Both gradually shift the system into
the eastern great lakes. The previous EC run was slower, lingering
pcpn into Fri, but more on pace with the GFS now. However, the GFS
would bring another shortwave down across the region Friday. The EC
shows something similar, but weaker and faster. The GFS paints a
good shot for another round of showers/storms...the EC favors dry.
Feel good about the rain threat for late Wed into Thu, shakier with
the details for Friday. Don`t see much of a severe potential at this
time - some instability but weak wind shear.

Both the GFS and EC do hold the promise of high pressure for next


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 1009 PM CDT Fri Aug 11 2017

High pressure continues to build into the area will result in VFR
conditions the next 24 hours. Could still see a touch of fog in the
low lying areas and some river valleys through sunrise, though
stronger northerly winds just off the surface should keep any fog or
stratus out of the LSE terminal. Winds will remain from the north
under 10 knots.

Looking just ahead, the setup for some fog later Saturday night into
Sunday morning for LSE looks much better as high pressure drifts
overhead, but any fog would occur after the end of the current TAF




LONG TERM....Rieck
AVIATION...Lawrence is the U.S. government's official web portal to all federal, state and local government web resources and services.