Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
238 AM CDT Mon Jun 11 2018

.SHORT TERM...(Today and tonight)
Issued at 237 AM CDT Mon Jun 11 2018

Showers and thunderstorms are expected to develop and move across
the region today and tonight. The main threat with these storms is
heavy rain. WPC has a slight risk of excessive rain across most of
Minnesota. A secondary threat today is large hail, but overall the
severe threat is lower than the hydro threat. SPC has a marginal
risk for severe weather across the southern half of the forecast
area, and slight risk down along I-90.

Early morning IR satellite imagery showed another batch of MCSs
across the Midwest. One was located in the eastern Dakotas, while
another one was located across Iowa. There is a upper level trough
over the high plains, with weak ridging over the Mississippi River
Valley. As a result, the shear profile is considerably less across
the southeast compared to the northwest. As the surface there is a
trough of low pressure in eastern South Dakota, and this trough will
slowly migrate eastward today and tonight.

As it does so, low level convergence will lead to thunderstorm
development. These storms should be elevated based on the forecast
soundings. The soundings do show a stout elevated mixed layer, and
this will set the stage for around 1500 to 2000 J/kg of MUCAPE,
which should lead to updrafts strong enough for some large hail. The
deep layer shear is marginal, and the hodograph shows a confused
wind profile in the mid levels of the storm. This should lead to a
multicellular storm mode, so anticipate more of a pulse-severe
threat than an organized storm mode.

Precipitable water is on the order of 1.75 to 2 inches, so those
storms that don't produce hail will likely produce very heavy rain.
HiRes models show a few 2 to 4 inch bullseyes across the region, so
isolated rainfall amounts of this magnitude seems reasonable. This
could lead to flooding along some smaller rivers and creeks that
are already running high.

.LONG TERM...(Tuesday through Sunday)
Issued at 237 AM CDT Mon Jun 11 2018

With the slowing of the frontal boundary precipitation now looks
to linger across west-central WI into Tuesday morning. Much drier
air moves in behind the front with sunny skies, dewpoints in the
low 50s, & highs around 80 leading to a couple of fantastic early
summer days Tuesday & Wednesday.

As high pressure at the surface slides off to the east warm
advection on the back side will help generate our next chance of
thunderstorms Wednesday night into Thursday morning, with the best
chances for precipitation across southern Minnesota.

An upper-level trough approaches the northern plains Friday which
looks to set the stage for an active couple of days over the
weekend. Large scale southerly flow will allow our highs to
approach 90 degrees Friday through Sunday & with the Gulf wide
open we'll see much more humid air return as dewpoints approach 70
degrees. Models are inconsistent with the timing & location of
the best thunderstorm chances but for now it looks like we'll have
decent chances across the area Friday through Sunday. With PW
values on the order of 1.5"-2" over the weekend, we'll have to
monitor the threat for heavy rain & potential flooding.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1057 PM CDT Sun Jun 10 2018

A strip of MVFR cigs continues from west central MN to southeast
MN and should remain there for the night. Eventually these cigs
will expand and lower to IFR across western MN late tonight.
Showers and thunderstorms will develop along the MN river around
that time, but will weaken to a few showers as they head into a
more stable airmass east of STC-MKT Monday morning. Additional
development expected as instability builds Monday afternoon ahead
of a cold front.

KMSP...VFR through much of the period, but some MVFR cigs are
possible as showers and thunderstorms expand in coverage later
Monday. It may be dry through early Monday afternoon, but TSRA
chances increase during the mid afternoon.

/OUTLOOK FOR KMSP/
Tue...MVFR early then VFR. Wind NW at 10-15 kts.
Wed...Mainly VFR. Wind W 10 kts.
Thu...VFR with MVFR/-TSRA possible early. Wind SE at 10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

SHORT TERM...JRB
LONG TERM...ETA
AVIATION...BORGHOFF

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
333 AM CDT Mon Jun 11 2018

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
120845-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Sherburne-Isanti-Chisago-Lac Qui Parle-Swift-Chippewa-
Kandiyohi-Meeker-Wright-Hennepin-Anoka-Ramsey-Washington-
Yellow Medicine-Renville-McLeod-Sibley-Carver-Scott-Dakota-
Redwood-Brown-Nicollet-Le Sueur-Rice-Goodhue-Watonwan-Blue Earth-
Waseca-Steele-Martin-Faribault-Freeborn-Polk-Barron-Rusk-
St. Croix-Pierce-Dunn-Pepin-Eau Claire-
333 AM CDT Mon Jun 11 2018

This Hazardous Weather Outlook is for portions of central and
southern Minnesota...and west central Wisconsin.

.DAY ONE...Today and Tonight
Thunderstorms are expected across western and far-southern MN
this morning, a few may become locally severe with large hail the
primary hazard. Additional thunderstorm development is expected
this afternoon & evening into central/eastern Minnesota & west-
central Wisconsin. Storms this afternoon will be capable of
producing large hail & damaging winds, but most of the severe
threat is expected to be contained to along the MN/IA border.
Heavy rain leading to localized flooding is the more likely hazard
area-wide, especially along the Minnesota River valley where
streams & rivers are already high from prior rainfall.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The next chance for thunderstorms comes Wednesday night.
Thunderstorms with a threat for heavy rain & flooding are
possible over the weekend.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed Monday afternoon &
evening, especially across far-southern Minnesota.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
438 AM CDT MON JUN 11 2018

MNZ091-111015-
Martin-
438 AM CDT MON JUN 11 2018

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL MARTIN COUNTY...

At 437 AM CDT, a strong thunderstorm was located near Alpha, or 8
miles east of Jackson In Jackson County, moving north at 5 mph.

Nickel size hail & localized flooding are possible with this storm.

This storm will remain over mainly rural areas of west central Martin
County.

This includes Interstate 90 between mile markers 82 and 86.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4375 9485 4374 9474 4360 9474 4360 9485
TIME...MOT...LOC 0937Z 182DEG 6KT 4367 9482

ETA