Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 260445

Area Forecast Discussion
National Weather Service La Crosse WI
1145 PM CDT Thu Apr 25 2019

.SHORT TERM...(Tonight through Friday Night)
Issued at 315 PM CDT Thu Apr 25 2019

Latest water vapor satellite imagery shows vigorous shortwave trough
over the Upper Midwest/Upper Great Lakes Region. Latest mosaic radar
indicates frontogenetic light rain band extending from northeast
Wisconsin to central Iowa in association with the shortwave trough.

Tonight into Friday...Surface low/shortwave trough deepens over the
Great Lakes region late tonight into Friday. This will tighten the
pressure gradient on the northwest periphery of the surface low and
produce breezy conditions across the forecast area. Winds are
expected to gust up to 25 miles per hour. However...the 25.12z
GFS/NAM bufkit soundings...suggest parts of the area could mix aloft
higher and potentially produce wind gust to 30 miles per hour in the
afternoon. Have increased wind gust to around 30 miles per
hour...especially in open areas.

Temperatures Friday will be the 25.12z deterministic
models indicate 925mb temperatures of plus 7 to plus 8 degrees
celsius. High temperatures are expected to be in the middle 50s to
lower 60s.

.LONG TERM...(Friday night through Wednesday)
Issued at 315 PM CDT Thu Apr 25 2019

All eyes on very dynamic storm system impacting the area Saturday.
Models seem to be coming into better agreement on timing and track
of surface/mid-level low and axis of heavy precipitation band across
our area. Very strong frontogenetic forcing evident in the 700-500mb
layer is expected to cool column and support heavier snow rates with
surface temperatures hovering in the mid/upper 30s for highs. Expect
very terrain-dependent snowfall, with heavier snow over bluff
tops/higher terrain areas. Right now, there is the potential for 4
to 8 inches of wet/heavy snow for areas mainly south of I-94.

System exits the area rapidly Saturday evening with high pressure
building in overnight through Sunday for a brief respite. Look for
rather cold overnight lows Saturday night in the 20s, followed by
unseasonably cool highs Sunday in the upper 40s to the lower 50s.

Weather continues to look active for next week with a rain-making
system coming through every other day. Temperatures will remain
slightly below normal with highs in the 50/lower 60s and lows in the


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1144 PM CDT Thu Apr 25 2019

Northwest winds are picking up behind a slow-moving cold front
sliding southeast through the area. LSE may see a brief period of
low level wind shear as the front moves through, while surface
winds remain stronger at RST. Gusty northwest winds will become
more of an issue heading into late Friday morning as the pressure
gradient strengthens overhead. Gusts to around 25 knots will be
commonplace through late afternoon, when surface high pressure
will begin to settle overhead. Otherwise VFR conditions through
the TAF period.


.HYDROLOGY...(Saturday into Next Week)
Issued at 315 PM CDT Thu Apr 25 2019

Rain and snowmelt from Saturday system looks to produce 1/2 to 1
inch of liquid equivalent. With antecedent moist ground conditions,
expect runoff and river rises, especially along and south of I-90.




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