Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 270741

Area Forecast Discussion
National Weather Service La Crosse WI
241 AM CDT Tue Sep 27 2016

.SHORT TERM...(Today through Wednesday)
Issued at 241 AM CDT Tue Sep 27 2016

Main concern in the short term is rain chances with large upper
low spinning through the Great Lakes Region for the next few
days. Satellite imagery shows the low spinning over eastern
Lake Superior, and it will slowly drop south today. An extensive
shield of cloud cover is seen, and models all indicate overcast
conditions will prevail as the system advances southward. There is
enough instability and lift in this cold pool that widespread
light showers should occur. Bumped rain chances up as it appears
rain will occur, albeit amounts will be on the light side. With
the clouds and showers, temperatures will not go up too much.
Highs will only be in the 50s for most areas, except for over the
far southern counties where the sun will hang on longest.

.LONG TERM...(Wednesday Night through Monday)
Issued at 241 AM CDT Tue Sep 27 2016

Upper system finally shifts just far enough east by Wednesday
night that the main cloud shield and any rain threat will be out
of the area. This occurs as upper ridging tries to build in from
the west. But these two features will continue to battle all the
way into the weekend as the upper system closes off and settles
into the Ohio Valley to finish out the week. We may still see some
influence from this...with clouds perhaps spinning toward us from
the east or southeast. The big question comes in by the weekend as
the models try to figure out how to handle the closed system and
how it will react to the weakening ridge and deepening western
trough approaching from the west coast. ECMWF has for a couple of
runs now retrograded the low back west toward the area spreading a
chance for showers from east to west across WI/IL toward the
Mississippi River Valley by Saturday. For now we are favoring the
solutions that keep the rain and main impact from that just east
of the forecast area. But this bears watching. Either way,
attention will quickly shift to the advance of the western trough
moving in for the Monday/Tuesday timeframe next week. Temperatures
and instability will be on the increase, with a rainy period
again in the offing for the first half of next week.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1142 PM CDT Mon Sep 26 2016

The 27.00Z NAM continues to indicate the surface winds will remain
around 10 knots through the night which should limit any potential
for low level wind shear despite winds at 2000 feet remaining in
the 35 to 40 knot range. A short wave trough will rotate across
the Upper Midwest and Great Lakes Tuesday afternoon and evening.
This wave will push the clouds currently over northern Minnesota
and Wisconsin into the area during the afternoon. Some light
showers will likely be embedded in with these clouds. Will bring
in MVFR to VFR ceilings with a VCSH. Guidance suggests that the
ceilings will come down to MVFR at both airports late in the
afternoon with the showers and will include this trend.


Issued at 241 AM CDT Tue Sep 27 2016

Flood Warnings continue along the lower Kickapoo River, but the
river should drop below flood stage at Gays Mills and Steuben by
tonight. The Yellow River at Necedah will remain above flood stage
for another few days. Along the Mississippi River, water levels
are now falling at La Crosse, with the crest occurring now in the
Brownsville and Genoa areas. The crest is expected from Genoa down
through Guttenberg by Thursday, with minor flooding anticipated
through this region. With about a week of dry weather, hopefully
all rivers can get back down to a more reasonable level before the
rains hit again next week.




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