Area Forecast Discussion
Issued by NWS La Crosse, WI

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251
FXUS63 KARX 280732
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
232 AM CDT Sun May 28 2017

.SHORT TERM...(Today and tonight)
Issued at 232 AM CDT Sun May 28 2017

Main impactful weather concerns are on shower chances this
morning then the potential for more showers and possibly an
isolated storm or two this afternoon.

We are currently watching a shortwave trough push through the
Upper Mississippi River Valley early this morning providing the
forcing for showers. The most concentrated area of showers will be
across portions of northeast Iowa through southwest into central
Wisconsin. The showers and storms will be fairly isolated today,
after mid morning anyway, with much of the area likely staying
dry along and south of Interstate 90. It will be on the breezy
side today with a tight pressure gradient and deep mixing across
the region. Plan on westerly winds of 14 to 18 mph with gusts to
around 30 mph in open areas. Any showers and storms will taper off
early this evening with the loss of daytime heating.

.LONG TERM...(Monday through Saturday)
Issued at 232 AM CDT Sun May 28 2017

Plan on a breezy, cool day across the region on Memorial Day with
scattered rain showers.  Cannot rule out an isolated thunderstorm or
two mainly east of the Mississippi River where MUCAPE values look to
range from 200 to possibly 500 J/kg.  Even cooler temperatures move
into the region on Tuesday when highs may struggle to reach 60,
especially north of Interstate 90. 850 mb temperatures cool to 0
to +3 C. Will continue with a model consensus blend for highs on
Tuesday but if trends continue we will have to lower those highs a
bit, but this will depend on how much cloud cover is in place
across the region. We finally see a break in rain chances from
Tuesday nigh through Wednesday night as surface high pressure
settles in from the west. Forecast models are coming into better
agreement bringing a shortwave through the region Thursday into
Thursday evening. This feature looks to bring showers and
thunderstorms to the area. In fact, the ECMWF is indicating
afternoon MUCAPE values could climb to around 1500 J/kg, but the
strongest shear is situated well to the north. In addition to
higher chances for rain showers, we have added a slight chance
for thunderstorms from late Thursday afternoon into Thursday
evening. Forecast models then start to diverge on the position of
a warm front across the Upper Midwest Friday through the weekend
which has a huge impact on the placement of showers and
thunderstorms. The ECMWF offers the most aggressive solution
bringing a potent trough and surface low through the area late
Friday through Saturday. Given the uncertainty from Friday and
beyond will maintain a model consensus blend for precipitation
chances and temperatures.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1008 PM CDT Sat May 27 2017

First batch of showers has exited to the east, with another round
expected to develop later tonight, impacting mainly LSE but also
potentially RST for a time. Regardless, conditions will remain
VFR, with clouds likely clearing for a time through the
morning/early afternoon hours as a cold front passes, before
some higher-based diurnal cumulus redevelops with colder air
arriving aloft. Gusty west to northwest winds will occur behind
the front as well into the afternoon, with gusts of 20-25 knots
expected, decreasing toward sunset.

&&

.HYDROLOGY...
Issued at 232 AM CDT Sun May 28 2017

Elevated river levels continue along the Mississippi River and flood
warnings are in effect for Wabasha, McGregor, and Guttenberg
where minor flooding is occurring. If you are planning any
recreational activities on the Mississippi River be alert for
these high water levels and watch out for debris in the water that
may pose a threat to watercraft.

&&

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

$$

SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
AVIATION...Lawrence
HYDROLOGY...Wetenkamp



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