Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
700 PM CDT Fri Aug 14 2020

.SHORT TERM...(This evening through tonight) Issued at 300 PM CDT
Fri Aug 14 2020

The key messages are the risk for severe storms this afternoon
across western Minnesota, transitioning eastward during the
evening hours. The main threat for tornadoes is across western
Minnesota, where there is a tornado watch in effect. The risk
transitions to more of a wind threat this evening as storms are
expected to form a line as they move east. There is also a risk of
large hail.

Complex severe weather scenario this afternoon, with a surface low
across the Minnesota/SD/ND border and a warm front draped out
eastward ahead of it. A cold front extended to the southwest, and
this will be the main focus for surface-based convection. The warm
sector in between had residual influences from the cold pool of
the morning convection, and was characterized by southeast winds,
and low T/Td depressions. This led to fairly high storm relative
helicity values and lower cloud bases. Combine that with the
building instability, and this set the stage for the potential of
tornadic thunderstorms as indicated by the Sig/Effective Sig Tor
parameters of 3 to 6. A tornado watch is in effect until 8PM this
evening for parts of west central Minnesota.

This watch may transition to a Severe Thunderstorm watch as storms
become more widespread, develop a cold pool, and transition into a
line of storms. We'll have to see how the convection evolved over
the next few hours before making this decision.

In summary, the parameter space is favorable for organize severe
weather, including tornadoes. The one element that gives some
pause is the idea that the HiRes CAMS show low Updraft Helicity
values, and the area of instability becomes more narrow and lower
with time this evening. In other words, the potential is there,
but this is certainly not a guarantee for widespread severe
weather.

.LONG TERM...(Saturday through Friday) Issued at 300 PM CDT Fri
Aug 14 2020

There are few if any weather concerns in the extended forecast.
High pressure will build across the region in the wake if this
cold front. That will lead to clear skies with cooler temperatures
and lower humidity values. There is a small chance for some
showers across Lake Superior Saturday night, but those should be
northeast of the forecast area.

A shortwave trough in northwest flow will slide across the Upper
Midwest, but this too should pass through dry. In fact, the
region remains dry through Monday. On Tuesday another shortwave
trough will move across the region, and this could produce a
chance for showers or thunderstorms. Overall expect a fairly dry
forecast into next week, which lines up with the WPC QPF forecast
in the extended forecast.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 700 PM CDT Fri Aug 14 2020

Did delay TEMPO groups for thunder an hour or two to account for
slightly slower than forecast timing with storms. Also added some
MVFR cigs for the first few hours in central MN where some post
frontal strato-cu has developed. Only change needed to TAFs for
Saturday was to back the winds to a bit more of a southwesterly
direction in the afternoon for MN terminals.

KMSP...Worst conditions with the line of storms looks to stay
north of MSP. Line looks to come in around 2z, with heavy rain
only lasting about 30 minutes. Rest of the TAF period looks much
calmer.

/OUTLOOK FOR KMSP/
Sun...VFR. Wind NW 10 kts.
Mon...VFR. Wind NW 10 kts.
Tue...VFR. Wind W 5 kts.

&&

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

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

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
1254 PM CDT Fri Aug 14 2020

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
151800-
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-
1254 PM CDT Fri Aug 14 2020

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

.DAY ONE...This Afternoon and Tonight.

A line of thunderstorms is expected to develop this afternoon in
western Minnesota, moving into eastern Minnesota and western
Wisconsin during the evening. Numerous severe thunderstorms are
possible with this activity. Damaging winds and very large hail
are the primary hazards, but a few tornadoes are also possible.
The severe weather threat will be greatest west of the Interstate
35 corridor in Minnesota before storms weaken in Wisconsin.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will be needed this afternoon and this
evening.

jrb

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
844 PM CDT FRI AUG 14 2020

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

0550 PM     FUNNEL CLOUD     3 W GAYLORD             44.56N 94.28W
08/14/2020                   SIBLEY             MN   AMATEUR RADIO

            REPORTED TO BE HALFWAY DOWN.

0539 PM     TORNADO          4 SW SPICER             45.20N 95.00W
08/14/2020                   KANDIYOHI          MN   LAW ENFORCEMENT

            REPORTED NEAR THE JUNCTION OF HIGHWAYS 71
            AND 23 NORTH OF WILLMAR.

0500 PM     TORNADO          7 S MOTLEY              46.24N 94.66W
08/14/2020                   TODD               MN   LAW ENFORCEMENT

            TREES DOWN. DEPUTY SAW FUNNEL CLOUD.

0525 PM     TSTM WND DMG     1 S SILVER LAKE         44.89N 94.20W
08/14/2020                   MCLEOD             MN   STORM CHASER

            LARGE BRANCHES DOWN BLOCKING ROAD ON COUNTY
            ROAD 2. TIME ESTIMATED BASED ON RADAR.

0500 PM     TSTM WND DMG     7 ENE BROWERVILLE       46.12N 94.73W
08/14/2020                   TODD               MN   LAW ENFORCEMENT

            TREES DOWN.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
847 PM CDT FRI AUG 14 2020

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

0800 PM     LIGHTNING        2 NW MINNEAPOLIS        45.00N 93.30W
08/14/2020                   HENNEPIN           MN   PUBLIC

            LIGHTNING STRUCK A TRANSFORMER AND STARTED A
            TREE FIRE.

&&

MED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
909 PM CDT FRI AUG 14 2020

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

0800 PM     TSTM WND DMG     1 E ROBBINSDALE         45.03N 93.31W
08/14/2020                   HENNEPIN           MN   TRAINED SPOTTER

            NUMEROUS 8 TO 10 INCH BRANCHES DOWN OVER
            SEVERAL BLOCKS JUST WEST OF 41ST AND PENN
            AVENUE IN NORTH MINNEAPOLIS.

&&

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
917 PM CDT Fri Aug 14 2020

MNZ078-150300-
Goodhue-
917 PM CDT Fri Aug 14 2020

...A STRONG THUNDERSTORM WILL AFFECT GOODHUE COUNTY...

At 916 PM CDT, a strong thunderstorm was located 7 miles west of
Goodhue, or 14 miles southwest of Red Wing, moving east at 45 mph.

Wind gusts up to 50 mph and dime size hail are possible with this
storm.

Locations impacted include...
Red Wing, Cannon Falls, Pine Island, Zumbrota, Kenyon, Goodhue,
Stanton, Wanamingo, Frontenac, Vasa, Bellechester and Miesville.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in the Twin Cities.

LAT...LON 4420 9305 4451 9304 4451 9292 4454 9291
      4454 9280 4463 9279 4463 9273 4453 9267
      4454 9232 4450 9230 4446 9225 4445 9243
      4437 9243 4436 9255 4420 9256
TIME...MOT...LOC 0216Z 266DEG 39KT 4442 9278

CTG

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
934 PM CDT Fri Aug 14 2020

WIZ024>028-150330-
Chippewa-Pierce-Dunn-Eau Claire-Pepin-
934 PM CDT Fri Aug 14 2020

...A STRONG THUNDERSTORM WILL AFFECT PEPIN...EASTERN PIERCE...
SOUTHERN DUNN...SOUTHWESTERN CHIPPEWA AND WESTERN EAU CLAIRE
COUNTIES...

At 934 PM CDT, a strong thunderstorm was located over Elmwood, or 11
miles southwest of Menomonie, moving east at 45 mph.

Wind gusts up to 50 mph and dime size hail are possible with this
storm.

Locations impacted include...
Eau Claire, Menomonie, Altoona, Lake Hallie, Durand, Elk Mound,
Pepin, Elmwood, Eau Galle, Plum City, Bay City and Stockholm.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in the Twin Cities.

LAT...LON 4460 9200 4456 9204 4441 9209 4445 9223
      4450 9230 4454 9231 4454 9214 4457 9214
      4455 9237 4457 9246 4486 9220 4486 9214
      4493 9213 4490 9142 4460 9142
TIME...MOT...LOC 0234Z 266DEG 38KT 4481 9211

CTG

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
936 PM CDT Fri Aug 14 2020

WIZ015-016-027-150330-
Chippewa-Barron-Rusk-
936 PM CDT Fri Aug 14 2020

...A STRONG THUNDERSTORM WILL AFFECT RUSK...NORTHERN CHIPPEWA AND
BARRON COUNTIES...

At 936 PM CDT, a strong thunderstorm was located over Chetek, or 10
miles south of Rice Lake, moving east at 45 mph.

Wind gusts up to 50 mph and dime size hail are possible with this
storm.

Locations impacted include...
Rice Lake, Ladysmith, Barron, Chetek, Cameron, Bruce, Almena, Prairie
Farm, Dallas, Weyerhaeuser, Sheldon and Sumner.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in the Twin Cities.

LAT...LON 4521 9203 4544 9209 4564 9150 4564 9112
      4522 9092
TIME...MOT...LOC 0236Z 248DEG 40KT 4535 9165

CTG