Flooding and Heavy Rain in Iowa, June 7 to 11, 2018

Area Forecast Discussion
National Weather Service La Crosse WI
1100 PM CDT Thu Jun 7 2018

.SHORT TERM...(This evening through Friday)
Issued at 236 PM CDT Thu Jun 7 2018

Primary forecast concerns through Friday center on precip chances.
Visible satellite indicated quite a bit of high convective debris
cloud cover across the area this afternoon along with some diurnal
cu development. However, high pressure to the north continues to
exerts its influence over the area with relatively dry easterly
flow, keeping the area mainly precip free this afternoon. Weak
radar returns across southern Minnesota into northern Iowa could
yield a few sprinkles, but otherwise quiet weather should continue
into the evening.

For tonight, will be watching a convectively-enhanced upper
shortwave trough slowly moving east out of the central plains. While
model guidance has struggled in this pattern, with mesoscale
details heavily influencing precip placement given the weak
background synoptic forcing, it appears that the wave coming out
of the plains will focus precip chances over the area later
tonight into Friday. Did slow down precip chances through the
evening given consensus among the high res models. At this time,
the highest chances look to be across southern parts of the area
where low-level moisture transport and deep layer moisture look
to be maximized ahead of the wave. Not expecting much in the way
of instability, but could see MUCAPEs up to 1000 J/kg into
northeast IA and southwest WI to support thunder. Behind the
wave, precip chances are expected to decrease during the morning.
Trended precip chances downward through the day on Friday as
confidence decreases. Convective evolution tonight and early
Friday will dictate subsequent evolution later tomorrow. Cloud
cover could keep highs down in the 70s on Friday.

.LONG TERM...(Friday night through Thursday)
Issued at 236 PM CDT Thu Jun 7 2018

Not much change in the overall pattern is expected through the
weekend. While upper ridging will build across the Upper Midwest,
weak shortwave troughs are expected to drop through the ridge.
The area will remain on the edge of the deeper moisture with
easterly flow around the dry surface high over eastern Canada. As
a result, the CAPE axis should remain generally south and west of
the area. Did maintain some lower end pops at times given the
potential for low predictability upper shortwaves to impact the
area. Temps will be near seasonal norms in the 70s to low 80s.

An upper trough migrating along the international border from the
northern Rockies into the northern plains early next week will drag
a cold front through the area Monday afternoon or Monday night with
a chance for showers and storms. High pressure will spread across
the region behind the front with drier weather for mid-week and
seasonable temps.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1100 PM CDT Thu Jun 7 2018

Cluster of showers and storms tied to a shortwave and weak
instability/moisture transport - although the pcpn continues to exit
the better CAPE pool to the south/west. The showers/isold storms
should continue to make slow progress east overnight, although meso
models suggest drier sfc/near sfc westward flow will slow eastward
progress into western wi, along with dissipating it.

More bits of upper level energy are slated to spin across the region
later Friday into Sat. Not a lot of consensus between the various
models and when/where/impacts...keeping forecast confidence low on
when/if to add more pcpn to the forecast. Will leave "dry" for now,
monitor and refine as conditions/confidence warrants.

Cigs: generally looking at vfr even with shra/ts - although some of
the stronger storms have dipped cigs into MVFR territory. Will hold
with predominantly VFR for now.

WX/vsby: periods of shra for KRST, and likely for KLSE, into mid
Friday morning. Could still see some thunder chances despite
instability holding south. Better chance for KRST. With confidence
low in how shra/ts will play out then later in the day, with keep
TAFs dry and adjust as needed.

Winds: holding from the east into Friday night.

&&

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

SHORT TERM...JM
LONG TERM...JM
AVIATION...Rieck

Hazardous Weather Outlook
National Weather Service La Crosse WI
1128 AM CDT Thu Jun 7 2018

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-081200-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
1128 AM CDT Thu Jun 7 2018

This Hazardous Weather Outlook is for parts of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...This Afternoon and Tonight

Isolated thunderstorms are possible tonight mainly southwest
of Interstate 94. Lightning will be the main threat.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Occasional thunderstorm chances continue through the weekend into
next week. The threat for any severe weather looks low at this
time.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

DAS/Shea

Special Weather Statement
National Weather Service La Crosse WI
917 PM CDT Thu Jun 7 2018

IAZ008-MNZ086-094-080400-
Mitchell-Dodge-Mower-
Including the cities of Osage, Dodge Center, and Austin
917 PM CDT Thu Jun 7 2018

...Storms Moving In...

A cluster of showers and thunderstorms will push into parts of
southeast Minnesota and northeast Iowa through 11 pm. Lightning
and heavy downpours can be expected with the storms. Hail up to
1/2 inch is also possible.

A few cities that will be impacted include Austin, Lansing and
Lyle in Minnesota and Otranto, Toeterville, and Carpenter in Iowa.

Seek shelter inside when storms approach.

Rieck