Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 222332
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
630 PM CDT Mon May 22 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM CDT Mon May 22 2017

Main impactful weather concerns are on thunderstorms this evening
with the potential for some small to perhaps isolated large hail and
gusty winds.

Currently watching a shortwave moving through South Dakota, headed
for the local area. Surface based CAPE values are expected to top
out in the 700 to 1000 J/kg range late this afternoon. Showers
and thunderstorms should initiate around 4 pm over portions of
south central Minnesota into north central Iowa. These storms will
then track east into southeast Minnesota and northeast Iowa by
late this afternoon into this evening. 0-6 km bulk shear values
are expected to range from 25 to 35 kts. So storms may become
organized briefly with the potential to produce large hail and
gusty winds. Freezing levels are also fairly low (right around
7kft), so hail production should be fairly efficient in any
stronger updrafts. We may see some hail up to the size of quarters
or possibly a little larger. Showers and thunderstorms will then
work east across the area through the evening hours. The main
areas impacted by these showers and storms will be locations south
of the Interstate 94 corridor across southeast Minnesota,
northeast Iowa, and southwest Wisconsin.

Low pressure then spins over the region on Tuesday with continued
chances for showers and perhaps a few thunderstorms.

.LONG TERM...(Tuesday night through Monday)
Issued at 255 PM CDT Mon May 22 2017

The low will exit the area late on Wednesday but lingering cyclonic
flow aloft may bring isolated to scattered showers to the region.
The low finally exits the area late Wednesday into Thursday with dry
weather expected. High temperatures will trend upward slightly
Thursday into Friday as another trough approaches from the west. The
trough then pushes a weak front through the region on Friday and we
may see some showers and possibly a few thunderstorms with this
feature. Small chances for showers and possibly thunderstorms
continue through the weekend into early next week as a long wave
trough moves across the Upper Mississippi River Valley. So, if you
have outdoor plans for this Memorial Day weekend keep a close eye
on the weather. The pattern favors slightly cooler temperatures
and chances for rain showers and a few thunderstorms.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 630 PM CDT Mon May 22 2017

Cigs: looking at vfr cigs tonight-Tue morning as upper level
trough/low drops south/southeast through the region. Models
suggesting that the clouds will continue to lower Tue
afternoon/evening - with the potential for mvfr. Trend looks
reasonable and will add some late afternoon mvfr for KRST.

WX/vsby: scattered shra/ts sliding across the area this evening,
exiting east overnight. Thunder threat mainly through about 04z.
Showers could spark again for Tue afternoon under cold air
advection/perky low level lapse rates and the upper level low. Will
add vcsh for both sites.

Winds: winds mostly light/variable for the first part of tonight,
settling into a more north direction overnight - holding there
through Tue night.

&&

.HYDROLOGY...
Issued at 255 PM CDT Mon May 22 2017

Minor flooding is expected along portions of the Mississippi
River this week. Minor flooding continues on the Yellow River at
Necedah and the Trempealeau River at Dodge. Monitor river levels
closely if you have interests along these rivers.

&&

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

$$

SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
AVIATION...Rieck
HYDROLOGY...Wetenkamp


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