Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
601 AM CDT Sat Jul 20 2019

.UPDATE...
Issued at 553 AM CDT Sat Jul 20 2019

Updated for the 12Z aviation discussion below.

&&

.SHORT TERM...(Today through Sunday)
Issued at 413 AM CDT Sat Jul 20 2019

The main forecast concern in the short term period is the showers
and thunderstorms forecast to move through the Minnesota and western
Wisconsin today.

As of early this morning, a surface low was noted across eastern
Colorado with thr frontal boundary we've been dealing with for days
in place across northern Iowa. North of the front across southern
MN and western WI, dew points have fallen into the mid to upper 60s
and temperatures have cooled into the upper 60s to lower 70s.
Meanwhile, an MCS was progressing eastward across South Dakota, and
will eventually move across our local area today with additional
thunderstorm development out ahead of the MCS north of the front.

The strongest instability has shifted south of with the front
itself, but up to 3,000 J/kg of MUCAPE will be in place across
southern MN which could lead to strong elevated storms with
isolated large hail. The main issue will be heavy rainfall and
lightning. The strongest forcing, including 600-700mb Fgen will
shift nearly due east across southern MN and western WI today.
There have been some differences in the model guidance on exactly
how far north or south the main slug of precipitation will go. The
HRRR is one of the more northern solutions while the global
models tend to point to far southern MN along the Iowa border.
Leaned toward the northern solution as CAMs have been consistently
showing this from run to run. From mid morning through mid
afternoon, expect showers and thunderstorms to work east across
southern MN and western WI, with a narrow 1-2" swath of rainfall
(and possibly locally higher amounts)expected.

Skies will clear from west to east this evening as reinforcing dry
northerly flow pushes in with pressure rises from the north. Sunday
will start out clear and dry, but a quick moving shortwave trough
will approach from the west by afternoon, introducing some chances
of precipitation to the forecast.

.LONG TERM...(Sunday night through Friday)
Issued at 413 AM CDT Sat Jul 20 2019

A pattern change is on the horizon in the long term, as the large
scale flow transitions to ridging over the Intermountain west and
troughing over the eastern CONUS. Overall this will mean dry and
mild weather for the forecast area, with the exception of possibly
the entry into and out of the pattern.

Sunday will be one of those days, in which we should see overall
dry weather, but a few stray showers can't be ruled out given
fleeting northwest flow aloft. After that, we see several days
with mostly sunny skies and high temps moderating from the 70s to
low/mid 80s.

On Friday the western ridge flattens, which looks to bring back
northwest flow to the region. Both GFS and ECMWF models bring a
weak front across the area as a shortwave trough pivots over
northwest Ontario. Therefore the Friday night - Saturday time
frame would be the next decent opportunity for organized shower
and thunderstorm activity.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 553 AM CDT Sat Jul 20 2019

Thunderstorms developing along and north of the west to east
oriented frontal boundary will be the main concer. Expect the
storms to lift north toward the metro, then translate eastward
with time through the day. MVFR cigs will be mostly be limited to
thunderstorms, mainly due to VIS issues. Storms should be on the
way out by this afternoon, with rapidly improving conditions after
that.

KMSP...A prolonged period of thunderstorms from 14Z through 19Z
is possible. Severe weather chance is low this far north.

/OUTLOOK FOR KMSP/
Sun...VFR. Wind N 5 kts.
Mon...VFR. Wind NW 5 kts.
Tue...VFR. Wind W 5kts.

&&

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

UPDATE...SPD
SHORT TERM...SPD
LONG TERM...LS
AVIATION...SPD

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
430 AM CDT Sat Jul 20 2019

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
210930-
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-
430 AM CDT Sat Jul 20 2019

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

.DAY ONE...Today and Tonight

Showers and thunderstorms are likely today. A few strong to
severe storms are possible, primarily across southern Minnesota.
Locally heavy rainfall is expected with these storms as well,
which may lead to flash flooding.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
625 AM CDT Sat Jul 20 2019

MNZ067-075-076-201215-
Le Sueur-Sibley-Nicollet-
625 AM CDT Sat Jul 20 2019

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN LE SUEUR...
SOUTHEASTERN SIBLEY AND NORTHEASTERN NICOLLET COUNTIES...

At 625 AM CDT, a strong thunderstorm was located 7 miles northwest of
St. Peter, or 16 miles north of Mankato, moving east at 20 mph.

Nickel size hail is possible with this storm.

Locations impacted include...
St. Peter, Le Sueur, Henderson, Ottawa, Rush River and Norseland.

This includes U.S. Highway 169 between mile markers 68 and 80.

LAT...LON 4432 9418 4444 9425 4458 9392 4436 9380
TIME...MOT...LOC 1125Z 249DEG 16KT 4439 9409

SPD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
655 AM CDT SAT JUL 20 2019

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

0630 AM     HAIL             ST. PETER               44.33N 93.96W
07/20/2019  M0.75 INCH       NICOLLET           MN   PUBLIC

            DIME TO PENNY SIZED HAIL. PICTURE VIA
            TWITTER.

&&

TDH

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
655 AM CDT Sat Jul 20 2019

MNZ076-083-084-201230-
Le Sueur-Waseca-Blue Earth-
655 AM CDT Sat Jul 20 2019

...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN LE SUEUR...NORTHEASTERN
BLUE EARTH AND NORTHWESTERN WASECA COUNTIES...

At 655 AM CDT, a strong thunderstorm was located over Eagle Lake, or
near Mankato, moving north at 25 mph.

Nickel size hail is possible with this storm.

This storm will be near...
  Madison Lake around 700 AM CDT.
  Cleveland around 715 AM CDT.

Other locations impacted by this storm include Lake Jefferson,
Mankato Airport, Smiths Mill and Greenland.

This includes the following highways...
 U.S. Highway 14 between mile markers 131 and 147.
 U.S. Highway 169 near mile marker 54.

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

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.

LAT...LON 4410 9404 4435 9393 4431 9359 4419 9365
      4411 9371 4404 9378
TIME...MOT...LOC 1155Z 201DEG 23KT 4419 9386

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
703 AM CDT Sat Jul 20 2019

MNZ085-201230-
Steele-
703 AM CDT Sat Jul 20 2019

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

At 703 AM CDT, a strong thunderstorm was located over Medford, or
near Owatonna, moving east at 45 mph.

Locations impacted include...
Owatonna, Medford, Clinton Falls, Merton, Moland, Deerfield and
Owatonna Airport.

This includes the following highways...
 Interstate 35 between mile markers 39 and 49.
 U.S. Highway 14 between mile markers 166 and 182.

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

LAT...LON 4404 9340 4420 9340 4419 9305 4403 9305
      4404 9323
TIME...MOT...LOC 1203Z 247DEG 39KT 4414 9321

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
721 AM CDT Sat Jul 20 2019

MNZ075-083-201245-
Blue Earth-Nicollet-
721 AM CDT Sat Jul 20 2019

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL BLUE EARTH AND
SOUTHEASTERN NICOLLET COUNTIES...

At 721 AM CDT, a strong thunderstorm was located over Lake Crystal,
or 13 miles west of Mankato, moving east at 20 mph.

Locations impacted include...
Mankato, North Mankato, Lake Crystal, Eagle Lake, St. Clair, Good
Thunder, Vernon Center, Garden City, Judson and Skyline.

This includes the following highways...
 U.S. Highway 14 between mile markers 126 and 139.
 U.S. Highway 169 between mile markers 35 and 56.

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

LAT...LON 4397 9429 4420 9429 4421 9385 4396 9383
TIME...MOT...LOC 1221Z 247DEG 16KT 4410 9424

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
732 AM CDT Sat Jul 20 2019

MNZ067-075-076-201330-
Le Sueur-Sibley-Nicollet-
732 AM CDT Sat Jul 20 2019

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN LE SUEUR...
SOUTHEASTERN SIBLEY AND NORTHEASTERN NICOLLET COUNTIES...

At 732 AM CDT, a strong thunderstorm was located near St. Peter, or
16 miles north of Mankato, moving northeast at 25 mph.

Locations impacted include...
St. Peter, Le Sueur, Henderson, Oshawa, Ottawa, Rush River, St Henry
and Norseland.

This includes U.S. Highway 169 between mile markers 66 and 80.

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

LAT...LON 4428 9415 4438 9423 4456 9395 4436 9374
TIME...MOT...LOC 1232Z 236DEG 24KT 4440 9403

SPD