Alert archive / Wisconsin / Mesoscale Discussions in 2017

Mesoscale Discussion 1321

July 15, 20179 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 15, 2017, 11:25 PM CDT for 9 counties in Wisconsin. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 15, 2017, 11:25 PM CDT (04:25 UTC)
Expired
Jul 16, 2017, 1:00 AM CDT
In force
95 min
Issued by
the Storm Prediction Center

Counties Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 59 km from the middle of the area, began a volume at 04:29 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 00:00Z, 4.4 hours before the alert went out and 186 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, Green Bay/Straub, WI at 00:00Z on 2017-07-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1456 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, Green Bay/Straub, WI at 00:00Z on 2017-07-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 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
1456 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
1169 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
0.6
Supercell composite
6.5

Open this sounding in Storm Lab

The text

As transmitted.

613 
ACUS11 KWNS 160425
SWOMCD
SPC MCD 160425 
WIZ000-160600-

Mesoscale Discussion 1321
NWS Storm Prediction Center Norman OK
1125 PM CDT Sat Jul 15 2017

Areas affected...southern Wisconsin

Concerning...Severe Thunderstorm Watch 416...

Valid 160425Z - 160600Z

The severe weather threat for Severe Thunderstorm Watch 416
continues.

SUMMARY...Threat for a couple of strong to severe wind gusts will
persist through 05Z or 06Z, followed by a diminishing trend.

DISCUSSION...Broken line of multicell storms continues south through
southern WI at around 20 kt. Potential for a few strong wind gusts
will remain during the next hour or so as storms move through
corridor of moderate instability. However, storms will encounter a
significant increase in convective inhibition as they approach the
IL border, resulting in a weakening trend by 06Z.

..Dial.. 07/16/2017

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

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

LAT...LON   43498961 43348813 42968783 42558817 42558934 42639067
            43269079 43498961

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 15, 7:54 PM CDTMesoscale DiscussionSPCAdams, Calumet, Columbia, Crawford, Dane, Dodge and 15 more96 min

Nearby

Mesoscale Discussions in Wisconsin, 2017Every 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.