Alert archive / Wisconsin / Mesoscale Discussions in 2021

Mesoscale Discussion 1363

July 27, 2021Houston County, Minnesota; 10 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 27, 2021, 7:48 AM CDT for Houston County, Minnesota; 10 counties in Wisconsin. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jul 27, 2021, 7:48 AM CDT (12:48 UTC)
Expired: Jul 27, 2021, 9:45 AM CDT
In force: 117 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

Counties Houston County, MN, Adams County, WI, Crawford County, WI, Iowa County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Monroe County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 38 km from the middle of the area, began a volume at 12:51 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 0.8 hours before the alert went out and 226 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1421 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 378 m²/s²
0-3 km storm-relative helicity: 563 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

529 
ACUS11 KWNS 271248
SWOMCD
SPC MCD 271248 
WIZ000-IAZ000-MNZ000-271445-

Mesoscale Discussion 1363
NWS Storm Prediction Center Norman OK
0748 AM CDT Tue Jul 27 2021

Areas affected...Portions of far southeastern MN...far northeastern
IA...and southwestern WI

Concerning...Severe potential...Watch unlikely 

Valid 271248Z - 271445Z

Probability of Watch Issuance...5 percent

SUMMARY...A small cluster of storms may pose an isolated hail/wind
threat in the short term, but watch issuance is not expected at this
time.

DISCUSSION...Convection associated with a modest west-southwesterly
low-level jet has persisted over the past several hours across
western WI. This activity has largely remained elevated while posing
mainly an isolated threat for small hail. Recently these storms have
congealed into small cluster while moving south-southeastward.
Recent imagery from the KARX radar shows strong inbound velocities
(40-50+ kt) moving across west-central WI, and isolated
severe/damaging wind gusts appear possible in the short term as this
activity spreads into parts of southwestern WI. Marginally severe
hail may also occur with any embedded supercell. However,
instability rapidly decreases with southward extent across this
region. Current expectations are for these storms to weaken over the
next couple of hours as they encounter a less favorable
thermodynamic environment and as the low-level jet shifts eastward
across the Great Lakes.

..Gleason/Edwards.. 07/27/2021

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

ATTN...WFO...GRB...MKX...ARX...

LAT...LON   43629174 43979173 44279130 44429046 44368998 43848964
            43318960 42939013 43009107 43629174

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 26, 7:12 PM CDT	Mesoscale Discussion	SPC	Aitkin, Carlton, Cass, Crow Wing, Kanabec, Mille Lacs and 1 more	93 min
Jul 26, 7:40 PM CDT	Mesoscale Discussion	SPC	Becker, Big Stone, Clay, Douglas, Grant, Otter Tail and 6 more	95 min
Jul 26, 8:41 PM CDT	Mesoscale Discussion	SPC	Carlton, Pine	94 min
Jul 27, 4:00 AM CDT	Mesoscale Discussion	SPC	Anoka, Benton, Carver, Chisago, Dakota, Hennepin and 11 more	3 hr
Jul 26, 7:25 PM CDT	Severe Thunderstorm Watch	SPC	Ashland, Bayfield, Burnett, Douglas, Iron, Price and 2 more	3 hr
Jul 26, 11:50 PM CDT	Mesoscale Discussion	SPC	Bayfield, Brown, Calumet, Door, Douglas, Fond du Lac and 20 more	55 min

Nearby

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