Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 240445
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1145 PM CDT Sun Apr 23 2017

.SHORT TERM...(Tonight through Thursday)
Issued at 215 PM CDT Sun Apr 23 2017

Cold front slated to push eastward from the Plains to across the
Upper Mississippi River Valley by 12z Tue, getting a shove by an
upper level shortwave trough swinging northeast from the northern-
central Plains. The low level jet/moisture transport noses into
northern MN by 18z Mon, pushing into and across an west-east running
warm front. The combo of this interaction with the upper level
trough should be a broad area of showers across northern parts of
the region, with perhaps a few showers farther south ahead of the
front. Little if any instability, so don`t see much of a thunder
threat at this time.

Should see a better shot for some rain locally as another shortwave
trough tracks through the central plains and into the cold front
later tue afternoon-night. 50 kt 850 mb jet pointing into southwest
WI by 00z Wed, but better upper level jet support is shifted into MN
as a 300 mb jet streak runs from IA into northwest WI. Models place
the higher rain threat mostly behind the cold front, from northwest
IA into northwest WI - more associated with the shortwave. Don`t see
much of a thunder threat with any of this activity either as
instability holds mostly south.

Yet one more piece of upper level energy is progged to move
northeast into the cold front Wed/Wed night. Trends in the
NAM/GFS/EC suggest enough transition east with the front that the
higher rain threat would be across IL into southeast WI. It should
be noted that it looks cold enough to support snow...especially
north of I-94 Wednesday night. Could be some minor accumulations on
grassy surfaces - but wouldn`t stick around very long.

Overall, its going to be a wet start to the week, but on the plus
side, the heavier rains could fall just outside the local area.
Amounts likely wouldn`t negatively impact the already high river
level.

.LONG TERM...(Friday through Sunday)
Issued at 215 PM CDT Sun Apr 23 2017

Another round of wet weather for the region looks likely next
weekend. 500 mb trough/closed low over the desert southwest is
progged to lift northeast to across parts of the Upper Mississippi
River Valley Sunday. Some differences in placement/timing between
the GFS and EC, but both agree on widespread rain accompanying the
system. Nice push of gulf moisture with the low and another 1-2
inches certainly possible. The rain would keep it rather cool with
highs in the low 50s - about 10 degrees below the late April
normals.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1145 PM CDT Sun Apr 23 2017

An area of low pressure will move out of western Nebraska tonight
and into central Minnesota by late Monday evening as a cold front
moves east. The gradient will tighten up ahead of these features
Monday for sustained south winds in the 15 to 20 knot range. Once
the low level inversion breaks Monday morning, good low level
mixing will push some stronger winds down to create gusts of 25 to
30 knots. The gusts should then dissipate around sunset as the low
level inversion redevelops and cuts off the mixing. Forecast
soundings from the 24.00Z NAM suggest the potential for low level
speed shear at KLSE Monday evening. However, confidence is not
high as the speeds are right on the edge of criteria so do not
plan to include it right now. By late afternoon into the evening,
ceilings will come down some, but remain VFR. There could also be
some sprinkles/light showers around, but with lots of mid level
dry air expected to be in place, don`t expect these to amount to
much and will stay with a dry forecast.

&&

.FIRE WEATHER...Monday
Issued at 215 PM CDT Sun Apr 23 2017

Near critical fire weather conditions expected for parts of
southwest into central Wisconsin Monday afternoon as minimum
humidities fall to near 30 percent and brisk south winds produce
gusts upwards of 30 mph (sustained 15 to 17 mph).

&&

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

$$

SHORT TERM...Rieck
LONG TERM....Rieck
AVIATION...04
FIRE WEATHER...Rieck



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