Alert archive / Minnesota / Mesoscale Discussions in 2021

Mesoscale Discussion 1611

August 26, 20219 counties in Minnesota; Pierce County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 26, 2021, 1:53 PM CDT for 9 counties in Minnesota; Pierce County, Wisconsin. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Aug 26, 2021, 1:53 PM CDT (18:53 UTC)
Expired
Aug 26, 2021, 3:30 PM CDT
In force
97 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Carver County, MN, Dakota County, MN, Goodhue County, MN, Hennepin County, MN, Le Sueur County, MN, Ramsey County, MN, Rice County, MN, Scott County, MN, Washington County, MN, Pierce County, WI

The radar

The Minneapolis radar (KMPX), 25 km from the middle of the area, began a volume at 18:54 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, 6.9 hours before the alert went out and 27 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 2021-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1566 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
146 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

546 
ACUS11 KWNS 261854
SWOMCD
SPC MCD 261853 
MNZ000-WIZ000-262030-

Mesoscale Discussion 1611
NWS Storm Prediction Center Norman OK
0153 PM CDT Thu Aug 26 2021

Areas affected...Southeast MN

Concerning...Severe potential...Watch unlikely 

Valid 261853Z - 262030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated damaging wind gusts remain possible with the
small thunderstorm cluster moving into southeast Minnesota. New
watch issuance is unlikely in the short term.

DISCUSSION...While the earlier well-organized MCS across MN has
mostly decayed, convection remains relatively vigorous
west/southwest of the Twin Cities area in southeast MN. The surface
reflection of this system is not as strong as noted earlier, though
rather substantial pressure rises are still being noted in the
immediate wake of the line. Limited buoyancy on the 18Z MPX suggests
that substantial reintensification of this cluster is unlikely, but
the relative dryness noted below 900mb may allow for some stronger
gusts to mix to the surface, despite the notable low-level
stability. Since the threat is expected to remain relatively limited
in areal coverage and magnitude, short-term watch issuance is
unlikely.

..Dean/Dial.. 08/26/2021

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

ATTN...WFO...ARX...MPX...

LAT...LON   45089400 45129336 45109282 44909249 44609237 44269243
            44289337 44299376 44349403 44599410 45089400

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 26, 8:36 AM CDTMesoscale DiscussionSPCBig Stone, Lac qui Parle84 min
Aug 26, 9:05 AM CDTSevere Thunderstorm WatchSPCBig Stone, Chippewa, Kandiyohi, Lac qui Parle, Lincoln, Lyon and 11 more4 hr
Aug 26, 10:43 AM CDTMesoscale DiscussionSPCLac qui Parle, Lincoln, Lyon, Murray, Pipestone, Redwood and 1 more92 min
Aug 26, 1:12 PM CDTMesoscale DiscussionSPCFillmore, Houston, Winona93 min

Nearby

Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Wisconsin, 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.