Alert archive / Wisconsin / Special Weather Statements in 2021

Special Weather Statement, NWS Twin Cities, MN

August 11, 2021Polk County, Wisconsin

NWS Twin Cities, MN issued this special weather statement at Aug 11, 2021, 7:50 AM CDT for Polk County, Wisconsin. It was in force for 25 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 11, 2021, 7:50 AM CDT (12:50 UTC)
Expired
Aug 11, 2021, 8:15 AM CDT
In force
25 min
Issued by
NWS Twin Cities, MN
Hail
0.88 in
Wind
30

County Polk County, WI

The radar

The Minneapolis radar (KMPX), 116 km from the middle of the area, began a volume at 12:50 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 0.8 hours before the alert went out and 118 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 258 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 210 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
258 J/kg
Mixed-layer CIN
-298 J/kg
Mixed-layer LCL
1470 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
210 m²/s²
0-3 km storm-relative helicity
198 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

851 
WWUS83 KMPX 111250
SPSMPX

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
750 AM CDT Wed Aug 11 2021
 
MNZ053-WIZ014-111315-
Chisago MN-Polk WI-
750 AM CDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of southeastern Chisago
and Polk Counties through 815 AM CDT...

At 750 AM CDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Milltown, or 22 miles southeast of Pine City, moving
east at 60 mph.

HAZARD...Winds in excess of 30 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

This strong thunderstorm will be near...
  Frederic, Luck and Milltown around 800 AM CDT.

This includes U.S. Highway 8 in Minnesota between mile markers 8 and
22.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

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 4537 9216 4536 9295 4564 9278 4565 9253
      4573 9252 4572 9215
TIME...MOT...LOC 1250Z 262DEG 50KT 4557 9268 

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH

$$

ETA

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 11, 6:12 AM CDTSpecial Weather StatementMPXHennepin, Wright33 min
Aug 11, 6:45 AM CDTSevere Thunderstorm WarningMPXAnoka, Hennepin, Ramsey30 min
Aug 11, 8:16 AM CDTSpecial Weather StatementMPXBarron44 min

Nearby

Special Weather Statements in Wisconsin, 2021Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.