Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 241721

Area Forecast Discussion
National Weather Service La Crosse WI
1221 PM CDT Wed Apr 24 2019

.SHORT TERM...(Today through Thursday)
Issued at 300 AM CDT Wed Apr 24 2019

Forecast highlights include above average temps continuing with
light rain chances later tonight into Thursday.

Another very pleasant late April day is in store for today. A broad
upper low over the central plains will meander towards the Mid-
Mississippi Valley later today with little in the way of sensible
weather impacts locally. Southwesterly boundary layer flow will
increase ahead of a cold front approaching from the Dakotas and
Minnesota. With 925 mb temps climbing a few degrees from
yesterday and mixing above 850 mb, trended a bit warmer on temps,
with low to mid 70s likely for much of the area. These setups
have tended to end up warmer than forecast recently. With wind
gusts up to 20 mph this afternoon and RH dipping to locally below
25 percent, elevated fire concerns are possible.

Much of tonight looks dry as the boundary begins to sink across
the area, but a few showers are possible. There are signals for a
better chance for showers into the day on Thursday, especially
near and south of I-90 based on the 00Z guidance, as a shortwave
trough passes. If this model trend persists, may need to bump up
rain chances more over parts of the area. With models a bit slower
with the shortwave passage, clouds/showers may hold temps down on
Thursday, but with a mild airmass behind the boundary, temps
should remain seasonable to above average.

.LONG TERM...(Thursday night through Tuesday)
Issued at 300 AM CDT Wed Apr 24 2019

A cooler, but still seasonable day with highs in the upper 50s and
60s is expected for Friday behind a secondary cold front. Northwest
winds will be breezy with mixing above 800 mb. This will likely lead
to another afternoon of low RH, possibly even dropping into the
teens over parts of the area. As a result, Friday may be a day to
watch for fire weather.

At least the first half of the weekend continues to look unsettled.
A Pacific trough will approach on Saturday with an associated
surface cyclone tracking along the established mid-level baroclinic
zone. Despite some spread in the low track, 00Z models favor the
low passing near or to the south, with a chilly, rainy day for
much of the area and highs no better than the 40s. Any
north/southward shifts would certainly impact temps, though.
Depending on time of day/thermal profiles and precip rates, could
see some snow mixed in as well in some areas. The system will be
progressive, though, exiting by Saturday night. The system looks
quite dynamic and with models yet to come to agreement on exact
track and thermal profiles, some uncertainty in amounts/types

Forecast confidence really drops off going into next week with
significant model spread, but deterministic/ensemble solutions
indicate an active baroclinic zone hanging nearby with west to
southwest flow aloft for the better part of next week. That would
lead to a continued active, wetter pattern.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1221 PM CDT Wed Apr 24 2019

Will be watching a cold front move through the area overnight into
Thursday. Isolated to scattered showers are expected but cloud bases
and visibilities are expected to remain VFR. Look for south winds
swinging to the northwest with the frontal passage overnight into
Thursday morning.




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