Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 202034

Area Forecast Discussion
National Weather Service La Crosse WI
334 PM CDT Fri Apr 20 2018

.SHORT TERM...(This evening through Saturday)
Issued at 334 PM CDT Fri Apr 20 2018

At 3 PM, a 1033 mb high was centered over south central Minnesota.
Under mostly to partly sunny skies, temperatures warmed into the
mid and upper 40s over the deep snow pack from southeast Minnesota
southeast into northeast Iowa. Elsewhere, temperatures were in the

The 20.12z models are in good agreement that a short wave trough
will move southeast through southwest Minnesota and western and
southern Iowa. A weak 700 to 500 mb frontogenetic band moves into
southeast Minnesota and northeast Iowa overnight and early
Saturday. Beneath this band, the air is rather dry, so there are
questions on whether any of this precipitation will even reach the
surface, so kept precipitation chances at 20 percent or less. If
precipitation happens to reach the ground, it would be a brief
wintry mix.

.LONG TERM...(Saturday night through Friday)
Issued at 334 PM CDT Fri Apr 20 2018

From Saturday night into Monday night, the temperatures will
continue to slowly rise each day. The high temperatures will range
from the mid 50s to lower 60s on Sunday, and in the lower and mid
60s Monday.

With deep mixing on Sunday, some dry air will mix toward the
surface on Sunday afternoon. However, this will be likely limited
due to light winds aloft. Due to this, only lowered the dew points
by 3 to 5F.

From Tuesday into Wednesday, the models continue to struggle on
the strength and timing of a short wave trough. The GFS continues
to be the strongest with this system and it produces rain from
Tuesday afternoon through Wednesday. There may be even a brief mix
wintry mix on Tuesday night. The Canadian keeps more of an open
wave and as a result it is much faster at moving a cold front
through the region. Due to this, its rain is confined from Tuesday
afternoon through Wednesday morning. Meanwhile, the ECMWF does not
phase the northern and southern stream systems. This results in
the precipitation splitting around our area and we mainly remain
dry. In addition, it is not as cold as the other models in the
wake of this system.

From Thursday afternoon into Thursday evening, another short wave
trough will move quickly southeast through the region. The thermal
profile suggests that this precipitation will be all rain. While
there is better consensus with this system, there are still
differences on the amount of cold air which will be in the wake of
this front.

For late in the week, another short wave trough will move
southeast through the region. Like the Tuesday system, there are
some timing issues with this system. The Canadian produces rain as
early as Friday afternoon. Meanwhile, the GFS and ECMWF are
slightly later with their passage.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1207 PM CDT Fri Apr 20 2018

VFR conditions expected this afternoon through Saturday afternoon.

Increasing VFR cloud cover expected tonight into Saturday as an
upper low moves into the Central Plains. Broken-overcast cloud
bases will generally be at or above 9kft, with scattered-broken
cloud bases as low as 4-5kt at times late tonight into Saturday
morning. Otherwise, look for light and variable winds 5kt or less
tonight, becoming light south/southeasterly 5kt or less through
Saturday afternoon.


Issued at 334 PM CDT Fri Apr 20 2018

A flood warning remains in effect for the Trempealeau River at
Dodge with minor flooding is expected over the weekend. See the
latest flood statement for more information.

As the recent snow melts and runs off into area streams,
additional flooding will be possible, especially along the
Kickapoo River with additional details in the latest hydrologic

A lot of the snow is expected to melt over the upcoming days with
daytime highs in the 50s on Saturday, mid 50s to lower 60s
Sunday, and in the lower and mid 60s Monday. Most of the area
should drop back below freezing at night to slow the melt at
night. This will slow some of the rise due to snow melt.




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