Area Forecast Discussion
Issued by NWS La Crosse, WI

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678
FXUS63 KARX 291131
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
631 AM CDT Mon May 29 2017

.SHORT TERM...(Today and tonight)
Issued at 331 AM CDT Mon May 29 2017

The latest water vapor imagery shows a short wave trough moving
east southeast through southeast South Dakota. The 29.00z models
are in good agreement that this system will move through the area
this afternoon and evening. In addition with cold air aloft and
diurnal heating, the 0-1 km mixed layer CAPES will climb up to
250 J/kg. This will result in the development of scattered showers
and isolated thunderstorms. The combination of steep 950 to
800 mb lapse rates and very dry sub cloud layer will result in
occasional wind gusts up to 30 mph at times.

.LONG TERM...(Tuesday through Sunday)
Issued at 331 AM CDT Mon May 29 2017

On Tuesday and Tuesday evening, a series of short wave troughs
will move southeast through the region. With 0-1 km mixed layer
CAPES up to 250 J/kg, expect scattered showers and isolated
thunderstorms to be seen across the Upper Mississippi River
Valley. In addition, steep 950-800 mb lapse rates will produce
wind gusts of 20 to 30 mph.

On Wednesday and Wednesday night, a 950 to 850 mb ridge will build
across the region. This will provide a brief period of dry
weather.

From Thursday into Friday night, the GFS, GEM, and ECMWF are in
agreement that a warm front will be located across the region.
Moderate 850 mb moisture transport into the region will result in
the development of showers and storms. While the instability will
be increasing across the region, the deep shear remains displaced
further to the northeast, so the severe weather threat looks
minimal. With warm cloud layer depths increasing to around
3500 J/kg from Friday into Friday night, we will have to watch
for the potential of heavy rain.

Beyond this time period, much uncertainty exists on the location
of warm front. The 29.00z ECMWF and GEM have a Canadian high
pressure area building across the region. Meanwhile the GFS has a
short wave trough moving through the region; thus, it keeps a
threat of showers and storms continuing into the weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 631 AM CDT Mon May 29 2017

VFR to possibly MVFR conditions expected at the TAF sites today.
Plan increasing clouds today as an upper level trough settles over the
region. Scattered showers and possibly isolated thunderstorms are
expected late this morning into this afternoon. Plan on BKN to
OVC cloud cover today with cloud bases in the 3 to 4 kft range
this morning increasing to mainly VFR by mid to late afternoon
with bases in the 4 to 5 kft range. It will be breezy today with
westerly winds of 13 to 16 kts with gusts to around 25 kts at
times. Clouds will decrease tonight with the loss of daytime
heating with VFR conditions expected.

&&

.HYDROLOGY...
Issued at 331 AM CDT Mon May 29 2017

A Flood Warning continues along the Mississippi River at both McGregor
and Guttenberg Dam 10. Meanwhile elevated river levels continue
along the Mississippi River north of McGregor.  If you are
planning any recreational activities on the Mississippi River be
alert for these high water levels and watch out for debris in the
water that may pose a threat to watercraft.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Wetenkamp
HYDROLOGY...Boyne



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