Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 230420

Area Forecast Discussion
National Weather Service La Crosse WI
1120 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 06Z TAFS through 06Z Tuesday night)
Issued at 1120 PM CDT Mon May 22 2017

Cigs: looking at vfr cigs overnight-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 ifr/mvfr. However, some
of that is tied to an expanding stratus layer northwest of the
system`s sfc low/coupled with the upper level low. Not confident in
this scenario. Going to hold with MVFR/near MVFR cigs for both
KRST/KLSE from Tue afternoon through the period for now. Expect some
refinement in the forecast later in the day as trends become more

WX/vsby: a few lingering showers through about 08z or so, then the
threat for more showers returns by late morning/early afternoon -
especially for KRST (cold air advection/perky low level lapse rates
and the upper level low). Going -shra for KRST for now, with VCSH at
KLSE. Expect a decrease in coverage by 00z Wed.

Winds: mostly a north direction overnight - holding there through
Tue night.


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.




SHORT TERM...Wetenkamp
LONG TERM...Wetenkamp
HYDROLOGY...Wetenkamp is the U.S. government's official web portal to all federal, state and local government web resources and services.