Alert archive / Wisconsin / Mesoscale Discussions in 2017

Mesoscale Discussion 261

March 6, 2017Pine County, Minnesota; 17 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Mar 6, 2017, 7:00 PM CST for Pine County, Minnesota; 17 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 6, 2017, 7:00 PM CST (01:00 UTC)
Expired: Mar 6, 2017, 9:00 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Pine County, MN, Adams County, WI, Barron County, WI, Burnett County, WI, Chippewa County, WI, Clark County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Monroe County, WI, Rusk County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Washburn County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 126 km from the middle of the area, began a volume at 00:59 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 65Mar 6, 7:40 PM CST

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 1.0 hours before the alert went out and 176 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: 923 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 993 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 432 m²/s²
0-3 km storm-relative helicity: 528 m²/s²
Significant tornado parameter: 2.2
Supercell composite: 10.3

Open this sounding in Storm Lab

The text

As transmitted.

631 
ACUS11 KWNS 070101
SWOMCD
SPC MCD 070100 
WIZ000-MNZ000-070300-

Mesoscale Discussion 0261
NWS Storm Prediction Center Norman OK
0700 PM CST Mon Mar 06 2017

Areas affected...Western Wisconsin

Concerning...Severe potential...Watch possible 

Valid 070100Z - 070300Z

Probability of Watch Issuance...40 percent

SUMMARY...A broken line of strong to severe storms will move into
the region beginning between 0100-0130Z.  An isolated wind damage
threat will exist with this activity.

DISCUSSION...A broken band of strong to severe storms persists over
far eastern Minnesota currently.  A general weakening trend has been
observed especially on the northern end of this band of storms
(about 70 NNE MSP).  50s to low 60s F surface temperatures exist
immediately downstream of this activity in southeastern Minnesota
and far western Wisconsin, which was contributing to 500-1000 J/kg
MUCAPE and a marginal severe wind threat continuing in the
short-term, although nocturnal boundary layer cooling should result
in continued weakening of instability with eastward extent.

At this time, the eastward extent of the severe threat is in
question.  Convective trends will be monitored for the possibility
of a small severe thunderstorm watch issuance.

..Cook/Guyer.. 03/07/2017

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

ATTN...WFO...GRB...MKX...DLH...ARX...MPX...

LAT...LON   45499204 45709211 45719239 45829283 46019307 46239296
            46389256 46359198 46219151 45929098 45419024 44878991
            44178970 43838968 43618982 43499035 43459077 43509094
            43659129 43759140 43909148 45499204

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 6, 6:11 PM CST	Mesoscale Discussion	SPC	Anoka, Benton, Carver, Chisago, Dakota, Dodge and 22 more	2 hr
Mar 6, 7:42 PM CST	Severe Thunderstorm Watch	SPC	Adams, Columbia, Crawford, Dane, Grant, Green and 11 more	5 hr
Mar 6, 10:15 PM CST	Mesoscale Discussion	SPC	Dane, Dodge, Jefferson, Rock, Walworth	60 min
Mar 6, 10:35 PM CST	Severe Thunderstorm Watch	SPC	Dodge, Fond du Lac, Green Lake, Jefferson, Kenosha, Milwaukee and 7 more	4 hr

Nearby

Mesoscale Discussions in Wisconsin, 2017 Mesoscale Discussions in Minnesota, 2017 Every mesoscale discussion in 2017

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.