Alert archive / Wisconsin / Mesoscale Discussions in 2012
Mesoscale Discussion 1206
The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2012, 12:40 PM EDT for Delta County, Menominee County, Michigan; 33 counties in Wisconsin. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 18, 2012, 12:40 PM EDT (16:40 UTC)
- Expired
- Jun 18, 2012, 2:45 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 35 counties
Delta County, MI, Menominee County, MI, Adams County, WI, Brown County, WI, Buffalo County, WI, Calumet County, WI, Clark County, WI, Door County, WI, Eau Claire County, WI, Florence County, WI, Fond du Lac County, WI, Forest County, WI, Green Lake County, WI, Jackson County, WI, Juneau County, WI, Kewaunee County, WI, La Crosse County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Marinette County, WI, Marquette County, WI, Menominee County, WI, Monroe County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Shawano County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI
The radar
The Green Bay radar (KGRB), 89 km from the middle of the area, began a volume at 16:43 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.
The nearest sounding before it
Green Bay/Straub, WI (KGRB), launched 12:00Z, 4.7 hours before the alert went out and 90 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.
- Mixed-layer CAPE
- 67 J/kg
- Mixed-layer CIN
- -387 J/kg
- Mixed-layer LCL
- 1455 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 382 m²/s²
- 0-3 km storm-relative helicity
- 524 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.7
The text
As transmitted, in the capitals the NWS used until 2016.
871
ACUS11 KWNS 181641
SWOMCD
SPC MCD 181640
MIZ000-WIZ000-MNZ000-181845-
MESOSCALE DISCUSSION 1206
NWS STORM PREDICTION CENTER NORMAN OK
1140 AM CDT MON JUN 18 2012
AREAS AFFECTED...CNTRL/NERN WI...ERN UPPER MI
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 181640Z - 181845Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...SEVERE POTENTIAL WILL INCREASE WITH BOTH A CLUSTER OF
TSTMS ALONG THE WI/MI BORDER AND ADDITIONAL TSTMS LIKELY FORMING
ALONG A SW/NE-ORIENTED PRE-FRONTAL CONFLUENCE BAND. DEEP-LAYER SHEAR
WILL BE HIGHLY FAVORABLE FOR INITIAL SUPERCELLS AND EVENTUAL UPSCALE
GROWTH INTO AN MCS WITH BOWING SEGMENTS.
DISCUSSION...CU HAS INCREASED ALONG A PRE-FRONTAL CONFLUENCE BAND
SEEN IN VISIBLE SATELLITE IMAGERY FROM AROUND 30 S MSP TO 45 NE EAU
IN THE WAKE OF PROBABLE ELEVATED CONVECTION ALONG THE WI/MI BORDER.
AIR MASS IS STRONGLY DESTABILIZING IN BETWEEN THESE TWO FEATURES
WITH MLCAPE NEARING 2000 J/KG AND WEAKENING MLCIN. GIVEN THE DEGREE
OF INSTABILITY IN WI...IT APPEARS LIKELY THAT AT LEAST ISOLATED
TSTMS SHOULD FORM ALONG THE CONFLUENCE BAND BY 18-19Z. WITH 50-60 KT
EFFECTIVE SHEAR AND DEEP-LAYER FLOW LARGELY PARALLELING THE
INITIATING BOUNDARY...INITIAL SUPERCELLS SHOULD QUICKLY GROW UPSCALE
WITH EMBEDDED BOWING STRUCTURES. ALTHOUGH LOW-LEVEL FLOW IS LARGELY
VEERED IN THE WARM SECTOR...AN ISOLATED TORNADO OR TWO IS POSSIBLE
IN NERN WI WHERE FLOW SHOULD REMAIN MORE BACKED. OTHERWISE...SEVERE
WIND/HAIL WILL BE THE PRIMARY RISKS.
..GRAMS/HART.. 06/18/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MQT...GRB...MKX...DLH...ARX...MPX...
LAT...LON 44869150 45448996 45928836 46028746 46048668 45668641
44848712 44238751 43738809 43528948 43609085 43809139
44349194 44869150SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 18, 10:33 AM EDT | Mesoscale Discussion | SPC | Branch, Calhoun, Eaton, Genesee, Hillsdale, Ingham and 13 more | 2 hr |
| Jun 18, 1:24 PM EDT | Severe Thunderstorm Watch | SPC | Delta, Dickinson, Iron, Menominee, Schoolcraft | 8 hr |
| Jun 18, 1:38 PM EDT | Mesoscale Discussion | SPC | Monroe | 67 min |
| Jun 18, 4:50 PM EDT | Mesoscale Discussion | SPC | Antrim, Benzie, Charlevoix, Cheboygan, Crawford, Emmet and 12 more | 85 min |
| Jun 18, 5:46 PM EDT | Severe Thunderstorm Watch | SPC | Alcona, Alpena, Antrim, Arenac, Benzie, Charlevoix and 25 more | 6 hr |
| Jun 17, 8:27 PM EDT | Mesoscale Discussion | SPC | Pierce, Polk, Saint Croix | 93 min |
| Jun 17, 8:57 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Barron, Buffalo, Burnett, Chippewa, Clark and 21 more | 8 hr |
| Jun 17, 11:55 PM EDT | Mesoscale Discussion | SPC | Buffalo, La Crosse, Pierce, Trempealeau | 95 min |
| Jun 18, 2:28 AM EDT | Mesoscale Discussion | SPC | Adams, Buffalo, Chippewa, Clark, Columbia, Dunn and 22 more | 62 min |
| Jun 18, 3:49 PM EDT | Mesoscale Discussion | SPC | Brown, Calumet, Kewaunee, Marinette, Menominee, Oconto and 5 more | 86 min |
| Jun 18, 7:00 PM EDT | Mesoscale Discussion | SPC | Brown, Calumet, Door, Green Lake, Kewaunee, Manitowoc and 7 more | 60 min |
Nearby
Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Michigan, 2012Every mesoscale discussion in 2012
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.