Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 141743
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1243 PM CDT Mon May 14 2018

.SHORT TERM...(Today and tonight)
Issued at 333 AM CDT Mon May 14 2018

Main forecast concerns are on chances for showers and thunderstorms
today into tonight.

Showers and thunderstorms continue across portions of northeast Iowa
and extreme southwest Wisconsin early this morning on the nose of
850 mb transport.  The thunderstorms have been efficient rain
producers with radar estimates of 0.8 to 1.3 inches across southern
Clayton into southern Grant Counties. Thunderstorms will continue
across these area through around 4 AM. Will have to keep a close
watch on the potential for flash flooding if storms can repeat
over the same areas. The higher chances for this appear to be just
south and east of the forecast area as storms continue to
propagate southward this morning.

After the early morning thunderstorms end in the south we should see
a break this morning then a shortwave moves in this afternoon
generating more showers and thunderstorms. The bulk of the
activity should be closer to boundary situated over central Iowa
into northern Illinois. Further north we will likely see some
showers and perhaps a few rumbles of thunder from southeast
Minnesota northeast into north central Wisconsin where a weak band
of frontogenesis sets up around 700 MB. The main frontal boundary
will gradually be shunted south late tonight forcing any showers
and storms along it south of the forecast area.

.LONG TERM...(Tuesday through Sunday)
Issued at 333 AM CDT Mon May 14 2018

High pressure builds into the region on Tuesday providing dry and
warm conditions across the region.  A drier airmass building in and
deep mixing will allow Tuesday afternoon relative humidity values to
drop into lower 20s at several locations north of Interstate 90.
Winds will be on the light side so not anticipating fire weather
concerns at this time, but will have to watch Taylor County closely.
Dry and warmer conditions are expected across the region Wednesday
into Thursday then chances for showers and storms return this
weekend. There is increasing agreement between the forecast models
that showers and thunderstorms will impact the area Saturday into
Saturday evening as the main trough axis and cold front move through
the region. Then the main question will be when does this activity
exit the area.  The ECMWF would take it out of the area by Sunday
afternoon while the GFS keeps showers over the region through much
of Sunday.  There is the potential for some stronger storms on
Saturday and possibly some heavier rain but details are far from
certain. Monitor forecasts closely, especially if you have any
outdoor plans for next weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1243 PM CDT Mon May 14 2018

Expect MVFR ceilings to trend to VFR this afternoon. Scattered
showers/isolated thunderstorms will develop this afternoon into
the evening. Did not include any thunder at this time or
visibility/ceilings, but will need to monitor. Some showers could
linger tonight, although confidence is lower. Skies will gradually
clear Tuesday morning as drier air moves into the region. Winds
will remain light through the period.

&&

.HYDROLOGY...This Afternoon Into Tonight
Issued at 333 AM CDT Mon May 14 2018

Periods of heavier rains fell across southern Clayton and Grant
Counties early this morning. MRMS precipitation estimates 1 to
1.3 inches of rain over these areas. Will have to watch this area
closely this afternoon into tonight. If thunderstorms develop over
these same areas, flooding could become a concern.

&&

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

$$

SHORT TERM...Wetenkamp
LONG TERM....Wetenkamp
AVIATION...JM
HYDROLOGY....Wetenkamp



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