Alert archive / Wisconsin / Mesoscale Discussions in 2021

Mesoscale Discussion 1629

August 28, 20215 counties in Minnesota; 11 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2021, 1:13 PM CDT for 5 counties in Minnesota; 11 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 28, 2021, 1:13 PM CDT (18:13 UTC)
Expired
Aug 28, 2021, 3:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Tornado watch 468

Counties Anoka County, MN, Chisago County, MN, Isanti County, MN, Kanabec County, MN, Pine County, MN, Ashland County, WI, Barron County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Iron County, WI, Polk County, WI, Price County, WI, Rusk County, WI, Sawyer County, WI, Washburn County, WI

The radar

The Duluth radar (KDLH), 100 km from the middle of the area, began a volume at 18:12 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, 6.2 hours before the alert went out and 179 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 2021-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1550 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2021-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 square meters per square second.193958Sfc1 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
1550 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
676 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
193 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

As transmitted.

290 
ACUS11 KWNS 281813
SWOMCD
SPC MCD 281813 
WIZ000-MIZ000-MNZ000-282015-

Mesoscale Discussion 1629
NWS Storm Prediction Center Norman OK
0113 PM CDT Sat Aug 28 2021

Areas affected...east-central Minnesota into northern Wisconsin

Concerning...Tornado Watch 468...

Valid 281813Z - 282015Z

The severe weather threat for Tornado Watch 468 continues.

SUMMARY...Severe storms are expected to persist out of Minnesota and
across northern Wisconsin, with primarily damaging gust potential.

DISCUSSION...A compact but long-lived MCS is now crossing the MS
River, with extensive outflow boundary trailing southwestward. The
strongest part of this MCS is traveling along a diffuse boundary.
South of this boundary, temperatures continue to slowly rise to near
80 F despite substantial cloud cover. Breaks in the clouds do exist
however, from near the Twin Cities into western WI.

Objective analysis indicates MLCAPE of 1500-2000 J/kg ahead of the
MCS, which should support a continues damaging wind threat. The 18Z
MPX sounding shows the effects of cooler, stabilizing outflow air
from convection over IA, and this will likely limit southward growth
potential with the ongoing MCS. Embedded areas of rotation cannot be
ruled out within the arcing line of convection, though effective SRH
ahead of the MCS is currently only averaging around 100 m2/s2.

..Jewell.. 08/28/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON   46289283 46729165 46989074 46759032 46249000 45698997
            45369041 45199157 45189320 45259367 45639341 45869329
            46039332 46289283

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 27, 9:57 PM CDTMesoscale DiscussionSPCFillmore, Houston93 min
Aug 28, 2:17 AM CDTMesoscale DiscussionSPCBig Stone, Stevens, Swift, Traverse2 hr
Aug 28, 2:32 AM CDTSevere Thunderstorm WatchSPCBig Stone, Traverse5 hr
Aug 28, 5:42 AM CDTMesoscale DiscussionSPCBenton, Big Stone, Chippewa, Douglas, Grant, Kandiyohi and 11 more2 hr
Aug 28, 7:08 AM CDTSevere Thunderstorm WatchSPCBig Stone, Chippewa, Douglas, Grant, Kandiyohi, Lac qui Parle and 13 more5 hr
Aug 28, 9:39 AM CDTMesoscale DiscussionSPCAnoka, Benton, Chisago, Douglas, Grant, Isanti and 12 more2 hr
Aug 28, 10:34 AM CDTTornado WatchSPCAitkin, Anoka, Benton, Carlton, Carver, Chisago and 14 more4 hr
Aug 28, 2:43 PM CDTMesoscale DiscussionSPCMurray, Nobles, Pipestone, Rock3 hr
Aug 28, 3:44 PM CDTTornado WatchSPCCottonwood, Jackson, Lincoln, Lyon, Murray, Nobles and 2 more5 hr
Aug 28, 3:57 PM CDTSevere Thunderstorm WatchSPCCottonwood, Jackson, Murray, Nobles, Rock7 hr
Aug 28, 5:27 PM CDTMesoscale DiscussionSPCBlue Earth, Brown, Carver, Cottonwood, Dakota, Dodge and 22 more63 min
Aug 28, 5:59 PM CDTSevere Thunderstorm WatchSPCBlue Earth, Brown, Carver, Faribault, Freeborn, Le Sueur and 11 more6 hr
Aug 28, 6:09 PM CDTMesoscale DiscussionSPCBlue Earth, Brown, Cottonwood, Nicollet, Watonwan66 min
Aug 27, 7:59 PM CDTMesoscale DiscussionSPCCrawford, Grant, Iowa, Lafayette2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Minnesota, 2021Every mesoscale discussion 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.