Flash Flooding and Flooding in Minnesota, June 28 to 29, 2020

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
700 PM CDT Sun Jun 28 2020

.SHORT TERM...(This evening through Monday night)
Issued at 401 PM CDT Sun Jun 28 2020

MCV moving into the Mankato area will be the focus for
thunderstorms this afternoon that will track up into the Twin
Cities and eventually the Twin Ports region. We're starting to get
hints of deep moist convection initiating, though to this point,
this feature has been fairly stable. However, with over 5000 j/kg
of MUCAPE up into western IA, persistent southerly flow will
continue to push more unstable air northward, so agree with the
HRRR and HopWRFs that we will eventually a cluster of storms
develop that moves north through the Twin Cities later this
afternoon. Again, with the better instability and shear off to the
southwest, these storms look to remain sub-severe.

After this MCV moves through, attention turns to threat for where
storms develop along the warm front. This next round of storms
will tap into the extreme instability down across IA, but there
continues to be little continuity in the models with where this
batch of rain ends up. For example, the HRRR between 12z and 18z
look fairly similar, the only difference is the 12z HRRR had the
evening/overnight storms from south central MN up into the Twin
Cities, while the 18z shifted it all north, with the heavy rain
from the Twin Cities/east central MN into northwest WI. At this
point, still favor a more southern solution like what the 12z
HREF and 15z HopWRF mean have, with the warm front ending up from
about Marshall to the MN/WI/IA border, with the greatest heavy
rain and severe risk through the night centered closer to that
region. Both the 12z and 18z HRRR show the potential for training
of storms along where the warm front sets up, with some areas
receiving 3+ inches of QPF. Fortunately, antecedent soil
conditions are dry, so really think to have much of a flash flood
threat, we're going to need to see heavy rain in the urban core of
the Twin Cities metro. Everywhere else, soils are dry enough to
handle some good rains.

For the severe threat, that again looks better closer to the MN/IA
border, where instability will be greater and shear is increased
by the jet streak currently apparent on satellite imagery over KS
moving up over IA this evening. For the severe threat to
materialize, we probably need the souther solution to work out
(12z HRRR). If we see a more northern solution as we are seeing
with the 18z HRRR and the 18z HopWRF members just rolling in,
we'll likely have a lower severe threat as these areas will be
displaced from the stronger instability and shear.

This activity tonight will likely generate an MCV, that will then
serve as the focus for thunderstorm development Monday afternoon.
There was certainly a trend from the GFS/NAM for the MPX area to
be hot and capped on Monday, but like the idea of the 18z HRRR.
Because of where it develops convection tonight, the HRRR
generates an MCV near the Twin Cities, that by Monday afternoon is
up by Duluth, with storms initiating there then tracking
southeast into western WI. This should be how things play out,
it's just a matter of where that MCV ends up and given uncertainty
with where that will be, have kept PoPs mainly in the 30s north
of I-94. As you get southwest of I-94, you will be encountering
stronger and stronger capping, so have a dry day for Monday by the
time you get to south central, southwest, and west central MN.

With the lower cloud cover and drier conditions expected, this
will translate to hot conditions southwest of I-94, with
afternoon heat indices forecast to be in the mid 90s to lower
100s. Haven't issued any heat headlines yet until we get a better
handle on how clouds and convection will trend Monday afternoon,
but a heat advisory is looking pretty likely for at least the Twin
Cities metro on Monday.

.LONG TERM...(Tuesday through Sunday)
Issued at 401 PM CDT Sun Jun 28 2020

For the long term, Tuesday is looking hot and dry, with the best
forcing for precip out in the Dakotas. Wednesday/Wednesday night
still looks to feature the passage of a weak cold front, but both
the GFS/ECMWF trended drier with it. This makes sense as the main
upper wave forcing this front will be going from the Dakotas into
northern Saskatchewan. So forcing and shear will be weak across
the MPX area with the front, with the severe threat really driven
by the presence of strong instability along the front.

Behind the front we see building heights and a drying trend
for Thursday through Saturday. Stuck with NBM PoPs for Thursday,
though those look overdone. Really it doesn't look like we have
much of precip threat until Sunday, when a weak cold front looks
to drop down from the north. For temperatures, it still looks hot,
with the potential for us to pile on quite a few 90+ degree highs
through the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 700 PM CDT Sun Jun 28 2020

MCV moving through now bringing an initial round of storms. Still
some uncertainty with where the next round develops. The HRRR has
been bouncing around with where storms develop through the rest of
the night, but it has been bouncing additional storm development
around east central MN and western WI. Kept the similar theme
going with previous TAFs, but there's still plenty of potential
for things to work out differently. Looks like MVFR cigs are going
to be confined closer to the MCV circulation in central MN, so
kept MVFR mention confined to AXN/STC, with models trending away
from MVFR or lower cigs elsewhere. For Monday, the trend
continues to be for drier conditions, with best TS potential in
WI, but confidence in TS occurring is not high enough to include
in the TAFs.

KMSP...MCV related precip will be off the field by 1z. After that,
it's wait and see if we get another round. That next round looks
to get going near or shortly after 6z, possibly persisting out to
12z Monday. CIG trends have been to back away from MVFR potential,
so kept MSP VFR outside of TSRA, with a SCT cloud group at the
MVFR to handle that threat.

/OUTLOOK FOR KMSP/
Tue...Mainly VFR. Slight Chc TSRA/MVFR. Wind SE 15G25 kts.
Wed...Mainly VFR. Chc TSRA/MVFR. Wind SE 5-10 kts.
Thu...Mainly VFR. Chc TSRA/MVFR. Wind lgt and vrb.

&&

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

SHORT TERM...MPG
LONG TERM...MPG
AVIATION...MPG

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
849 AM CDT Sun Jun 28 2020

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
291400-
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-
849 AM CDT Sun Jun 28 2020

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

.DAY ONE...Today and Tonight.

Scattered severe thunderstorms will be possible late this
afternoon into the evening from south central into east central
Minnesota, including the Twin Cities metro area, and adjoining
portions of western Wisconsin. Very large hail and damaging winds
will be the main threats, with an isolated tornado possible as
well.

Locally heavy rainfall is also likely with thunderstorms that
develop tonight. A flash flood threat exists wherever multiple
rounds of thunderstorms are able to redevelop over the same area.
The greatest risk for flash flooding exists from south central
into east central Minnesota and far western Wisconsin.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Daily chances for thunderstorms exist Monday through Thursday. Monday
and Wednesday have best chances for thunderstorms, with severe
thunderstorms possible again on Wednesday.

Excessive heat will be possible next week across western and
southern Minnesota, as afternoon heat indices approach or exceed
100 F.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed this afternoon into
tonight.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
516 PM CDT Sun Jun 28 2020

MNZ077-085-282300-
Steele-Rice-
516 PM CDT Sun Jun 28 2020

...A LINE OF STORMS WILL AFFECT NORTHERN STEELE AND RICE COUNTIES...

At 515 PM CDT, radar indicated strong thunderstorms were located
along a line extending from 6 miles north of Warsaw to near Medford.
Movement was northeast at 15 mph.

Winds in excess of 40 mph, half inch hail, and funnel clouds are
possible with these storms.

Locations impacted include...
Owatonna, Faribault, Northfield, Dundas, Medford, Morristown, Warsaw,
Bridgewater, Clinton Falls, Merton, Moland and Deerfield.

This includes the following highways...
 Interstate 35 between mile markers 41 and 71.
 U.S. Highway 14 between mile markers 170 and 173.

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

LAT...LON 4403 9330 4417 9341 4419 9341 4420 9344
      4431 9353 4454 9333 4449 9327 4447 9328
      4447 9325 4428 9304 4418 9305
TIME...MOT...LOC 2215Z 213DEG 15KT 4434 9344 4414 9321

LS

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
518 PM CDT Sun Jun 28 2020

MNZ085-282245-
Steele-
518 PM CDT Sun Jun 28 2020

...A STRONG THUNDERSTORM WILL AFFECT EASTERN STEELE COUNTY...

At 517 PM CDT, a strong thunderstorm was located near Owatonna,
moving north at 45 mph.

Wind gusts up to 50 mph and half inch hail are possible with this
storm.

Atmospheric conditions are favorable for the development of funnel
clouds.

Locations impacted include...
Owatonna, Blooming Prairie, Merton, Moland, Steele Center and Bixby.

This includes the following highways...
 Interstate 35 between mile markers 33 and 42.
 U.S. Highway 14 between mile markers 172 and 182.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4389 9323 4404 9331 4420 9314 4419 9305
      4399 9304 4385 9305
TIME...MOT...LOC 2217Z 182DEG 40KT 4401 9316

BPH

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
534 PM CDT Sun Jun 28 2020

MNZ059-060-066>070-076-077-282315-
Le Sueur-Dakota-Rice-Hennepin-McLeod-Carver-Sibley-Wright-Scott-
534 PM CDT Sun Jun 28 2020

...A LINE OF STORMS WILL AFFECT SOUTHEASTERN WRIGHT...HENNEPIN...
NORTHWESTERN DAKOTA...NORTHEASTERN LE SUEUR...NORTHEASTERN SIBLEY...
SCOTT...NORTHEASTERN MCLEOD...NORTHWESTERN RICE AND CARVER
COUNTIES...

At 533 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Glencoe to near Carver to near New
Prague. Movement was north at 40 mph.

Wind gusts up to 50 mph and pea size hail are possible with these
storms.

Locations impacted include...
Minneapolis, Buffalo, Bloomington, Brooklyn Park, Plymouth, Eagan,
Maple Grove, Eden Prairie, Burnsville, Lakeville, Minnetonka and
Apple Valley.

This includes the following highways...
 Interstate 35 between mile markers 78 and 80.
 U.S. Highway 12 between mile markers 125 and 140.
 U.S. Highway 212 between mile markers 125 and 126.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Tornado Watch remains in effect until 1000 PM CDT for south
central, central and east central Minnesota.

LAT...LON 4523 9405 4517 9346 4477 9313 4431 9353
      4461 9373 4471 9408
TIME...MOT...LOC 2233Z 198DEG 37KT 4479 9409 4473 9366 4452 9349

BPH

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
551 PM CDT Sun Jun 28 2020

MNZ070-077-078-282330-
Dakota-Rice-Goodhue-
551 PM CDT Sun Jun 28 2020

...A LINE OF STORMS WILL AFFECT DAKOTA...GOODHUE AND EASTERN RICE
COUNTIES...

At 550 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Elko New Market to Stanton to near
Nerstrand. Movement was northeast at 30 mph.

Wind gusts up to 50 mph are possible with these storms.

Atmospheric conditions are favorable for the development of funnel
clouds.

Locations impacted include...
Northfield, Red Wing, Eagan, Lakeville, Apple Valley, Cottage Grove,
Inver Grove Heights, Hastings, Rosemount, Farmington, Cannon Falls
and Kenyon.

This includes the following highways...
 Interstate 35 between mile markers 71 and 74.
 U.S. Highway 61 between mile markers 96 and 104.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Tornado Watch remains in effect until 1000 PM CDT for south
central, southeastern and east central Minnesota.

LAT...LON 4420 9307 4439 9317 4453 9334 4455 9328
      4460 9328 4483 9308 4481 9301 4477 9301
      4477 9295 4478 9293 4472 9273 4465 9265
      4439 9251 4419 9297
TIME...MOT...LOC 2250Z 232DEG 28KT 4460 9325 4448 9305 4433 9299

BPH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
603 PM CDT SUN JUN 28 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0455 PM     TSTM WND DMG     4 E LEMOND              43.97N 93.29W
06/28/2020                   STEELE             MN   PUBLIC

            4-6 INCH TREE BRANCHES DOWN. TIME ESTIMATED
            BY RADAR.

&&

TDH

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
635 PM CDT Sun Jun 28 2020

MNZ070-077-078-290000-
Dakota-Rice-Goodhue-
635 PM CDT Sun Jun 28 2020

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN DAKOTA...WEST
CENTRAL GOODHUE AND EAST CENTRAL RICE COUNTIES...

At 635 PM CDT, a strong thunderstorm was located near Nerstrand, or 9
miles southeast of Northfield, moving northeast at 30 mph.

Winds in excess of 40 mph are possible with this storm.

Atmospheric conditions are favorable for the development of funnel
clouds.

Locations impacted include...
Cannon Falls, Kenyon, Stanton, Nerstrand, Vasa, Hampton, Vermillion,
Miesville, New Trier, Wastedo, Hader and Lake Byllesby.

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

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Tornado Watch remains in effect until 1000 PM CDT for south
central, southeastern and east central Minnesota.

LAT...LON 4424 9306 4433 9322 4447 9310 4469 9298
      4445 9261
TIME...MOT...LOC 2335Z 231DEG 26KT 4438 9301

BPH