Area Forecast Discussion
Issued by NWS La Crosse, WI

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725
FXUS63 KARX 221658
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1158 AM CDT Sun Apr 22 2018

.SHORT TERM...(Today through Monday night)
Issued at 217 AM CDT Sun Apr 22 2018

Water vapor satellite this morning shows a closed upper level low
over Kansas that was moving slowly to the southeast. Clouds from
this system covered a good share of the area Saturday but now are
slowly retreating to the south with the upper level low. This low
is expected to sink into Arkansas today taking even more of
the clouds with it so that by afternoon much of the area will have
mostly sunny skies. Temperatures the last couple of days have
responded nicely to the late April sunshine and expect that to
continue again today with highs in the upper 50s where there is
still some snow on the ground to the middle 60s. Similar readings
expected for Monday under mostly sunny skies again.

.LONG TERM...(Tuesday through Saturday)
Issued at 217 AM CDT Sun Apr 22 2018

Starting to see better consensus from the models with the system
coming in for Tuesday. The short wave trough will move onto the
Pacific Northwest Coast today and form an upper level low Monday
when the wave moves out over the High Plains. As this system
starts to move southeast it will begin to run into the current
upper level low as it moves slowly to the northeast out of the
lower Mississippi River Valley into the Ohio River Valley. This
will cause the low to drop south through the Plains and miss the
area. At the same time, a northern stream short wave trough will
be moving across southern Canada that will eventually be the
kicker to the closed low moving northeast across the Ohio River
Valley. The differences that still exist in the models is how far
south this northern stream system will extend. The 22.00Z NAM,
ECMWF and GEM all keep this wave to the north of the area with the
southern extent about Lake Superior. The GFS has been consistently
showing this entire system coming across the area but recent runs
have been trending more toward the other model solutions. The
22.00Z run now also shows the system coming in off the Pacific to
miss the area to the southwest but is still farther south with the
northern stream system and tries to produce some light
precipitation across the area Tuesday afternoon and evening.

Plenty of model differences with the next system. All the models
show another northern stream short wave trough moving southeast
out of western Canada. After that, the ECMWF bring this through as
a positive tilt trough with the main short wave energy missing the
area to the north and south. The GFS winds this system up into a
closed low over the northern Great Lakes by Thursday night while
the GEM has a solution in between the other two. For now, will
just have a general 20 to 40 percent chance for this system
Thursday and Thursday night.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1158 AM CDT Sun Apr 22 2018

Solidly VFR conditions the next 24 hours as high pressure remains
in control, with just some passing cirrus at times, especially
through this evening. There is some very small risk for fog
development later tonight across southern Minnesota once again
over the deeper melting snow pack, though the chance for either
RST or LSE is VERY low at this time. Winds will remain light,
generally from an east to southeast direction under 10 knots right
through Monday evening.

&&

.HYDROLOGY...
Issued at 217 AM CDT Sun Apr 22 2018

Flood warnings are in effect for the Trempealeau River at Dodge
and the Kickapoo River at Viola, Readstown, and Gays Mills with
minor flooding expected this week. See the latest flood
statements for more information.

As the recent snow melts and runs off into area streams,
additional flooding will be possible, including parts of the
Mississippi River, with additional details in the latest
hydrologic statement.

&&

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

$$

SHORT TERM...04
LONG TERM...04
AVIATION...Lawrence
HYDROLOGY...04



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