Alert archive / Wisconsin / Mesoscale Discussions in 2017

Mesoscale Discussion 992

June 12, 2017Delta County, Menominee County, Michigan; 9 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2017, 12:59 AM EDT for Delta County, Menominee County, Michigan; 9 counties in Wisconsin. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Jun 12, 2017, 12:59 AM EDT (04:59 UTC)
Expired
Jun 12, 2017, 2:30 AM EDT
In force
91 min
Issued by
the Storm Prediction Center

Counties Delta County, MI, Menominee County, MI, Door County, WI, Florence County, WI, Forest County, WI, Langlade County, WI, Marathon County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI, Shawano County, WI

The radar

The Green Bay radar (KGRB), 83 km from the middle of the area, began a volume at 05:01 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, 5.0 hours before the alert went out and 85 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 2017-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 428 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 2017-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 288 square meters per square second.19395878Sfc1 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
428 J/kg
Mixed-layer CIN
-274 J/kg
Mixed-layer LCL
1257 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
288 m²/s²
0-3 km storm-relative helicity
452 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.0

Open this sounding in Storm Lab

The text

As transmitted.

566 
ACUS11 KWNS 120459
SWOMCD
SPC MCD 120459 
MIZ000-WIZ000-120630-

Mesoscale Discussion 0992
NWS Storm Prediction Center Norman OK
1159 PM CDT Sun Jun 11 2017

Areas affected...North-central and northeast WI into southern Upper
MI

Concerning...Severe Thunderstorm Watch 315...

Valid 120459Z - 120630Z

The severe weather threat for Severe Thunderstorm Watch 315
continues.

SUMMARY...Hail cannot be ruled out with any of the remaining
stronger storms across the north-central and northeast WI into
south-central Upper MI portions of WW 315.  However, recent trends
in radar imagery suggest the overall severe-weather threat should
diminish overnight and this watch could be canceled prior to the 08Z
expiration.

DISCUSSION...Radar imagery and surface observations showed an
outflow boundary, attendant to storms that are now moving eastward
through far northern Lake Michigan, extended southwest through
southern Door County to northern Waupaca County to southern Marathon
County.  A veered/southwesterly 40-45 kt low-level jet extending
into north-central and northeast WI overnight will maintain a
warm-air advection regime to support additional thunderstorms, given
the presence of moderate elevated instability.  Given most of the
storms are elevated north of the convective outflow boundary and
surface-based inhibition has strengthened through the evening, the
damaging-wind threat is greatly reduced, while hail could still
occur with any remaining stronger updrafts.  However, this latter
potential is also diminishing as indicated by recent weakening
trends in MRMS MESH data.

..Peters.. 06/12/2017

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

ATTN...WFO...MQT...GRB...ARX...

LAT...LON   44649048 45588928 45938840 45878734 45798663 45338671
            44658740 44608831 44649048

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 11, 9:01 PM EDTSevere Thunderstorm WatchSPCDelta, Dickinson, Menominee6 hr
Jun 11, 10:39 PM EDTMesoscale DiscussionSPCDelta, Dickinson, Menominee2 hr
Jun 12, 6:48 PM EDTMesoscale DiscussionSPCClare, Lake, Manistee, Mason, Missaukee, Osceola and 2 more2 hr
Jun 12, 12:28 PM EDTMesoscale DiscussionSPCCrawford, La Crosse, Vernon92 min
Jun 12, 12:47 PM EDTSevere Thunderstorm WatchSPCAdams, Buffalo, Crawford, Grant, Jackson, Juneau and 5 more7 hr
Jun 12, 3:22 PM EDTMesoscale DiscussionSPCBuffalo, Crawford, Jackson, La Crosse, Monroe, Trempealeau and 1 more113 min
Jun 12, 5:37 PM EDTSevere Thunderstorm WatchSPCBrown, Calumet, Columbia, Dane, Dodge, Door and 29 more5 hr
Jun 12, 7:38 PM EDTMesoscale DiscussionSPCBrown, Calumet, Columbia, Dane, Dodge, Fond du Lac and 24 more2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2017Mesoscale Discussions in Michigan, 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.