Alert archive / Wisconsin / Mesoscale Discussions in 2012
Mesoscale Discussion 1601
The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2012, 12:09 PM CDT for Boone County, McHenry County, Illinois; 33 counties in Wisconsin. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2012, 12:09 PM CDT (17:09 UTC)
- Expired
- Jul 26, 2012, 2:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 35 counties
Boone County, IL, McHenry County, IL, Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Kewaunee County, WI, Langlade County, WI, Manitowoc County, WI, Marquette County, WI, Menominee County, WI, Milwaukee County, WI, Oconto County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Shawano County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI
The radar
The Green Bay radar (KGRB), 105 km from the middle of the area, began a volume at 17:11 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, 5.2 hours before the alert went out and 104 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
- 826 J/kg
- Mixed-layer CIN
- -26 J/kg
- Mixed-layer LCL
- 749 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- -2 m²/s²
- 0-3 km storm-relative helicity
- 1 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
885
ACUS11 KWNS 261710
SWOMCD
SPC MCD 261709
WIZ000-ILZ000-261915-
MESOSCALE DISCUSSION 1601
NWS STORM PREDICTION CENTER NORMAN OK
1209 PM CDT THU JUL 26 2012
AREAS AFFECTED...PORTIONS WI...EXTREME NRN IL...WRN LM.
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 261709Z - 261915Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...TSTMS FCST TO INCREASE IN COVERAGE AND INTENSIFY OVER WRN
PORTIONS DISCUSSION AREA AND MOVE ESEWD TO SEWD...WITH POTENTIAL FOR
LARGE HAIL AND OCNL DAMAGING GUSTS.
DISCUSSION...16Z SFC MESOANALYSIS SHOWS OCCLUSION TRIPLE POINT OVER
N-CENTRAL/NWRN WI W RHI...WITH DIFFUSE COLD FRONT SSWWD ACROSS
EXTREME SERN MN. WARM FRONT WAS DRAWN FROM TRIPLE POINT SEWD ACROSS
CENTRAL LM THEN EWD AND QUASISTATIONARY OVER CENTRAL LOWER MI. WARM
FRONT SHOULD DRIFT NEWD WHILE COLD FRONT PROCEEDS SEWD 15-20 KT.
VIS IMAGERY SHOWS WELL-DEFINED WRN LOW-CLOUD EDGE NEAR OR JUST AHEAD
OF SFC COLD FRONT...WITH THICKEST CU/TCU AND A FEW SMALL CB OVER SFC
MOIST AXIS. THAT CORRESPONDS TO AREA OF HIGHEST BUOYANCY AND
WEAKEST CAPPING...MLCAPE RANGING FROM NEARLY 2000 J/KG OVER SWRN WI
TO AROUND 500 J/KG ALONG WARM FRONT. CONVERGENCE SHOULD REMAIN WEAK
ALONG/AHEAD OF COLD FRONT...INDICATING
1. GREATEST POTENTIAL FOR ADDITIONAL DEVELOPMENT TO ITS E NEAR MOIST
AXIS AND
2. THREAT EVOLUTION SHOULD BE GRADUAL...NOT EXPLOSIVE IN NATURE.
AIR MASS SHOULD CONTINUE TO DESTABILIZE IN WARM SECTOR...WITH
DIABATIC HEATING AND UPPER 60S TO LOW 70S F SFC DEW POINTS BOOSTING
MLCAPE ANOTHER 500-1000 J/KG ABOVE PRESENT VALUES THROUGH MID-AFTN.
STRONGEST DEEP-LAYER SHEAR WILL BE OVER SRN WI...PERHAPS SHIFTING
SWD TOWARD IL BORDER WITH TIME...IN STEP WITH MID-UPPER LEVEL JET
AXIS. EFFECTIVE SHEAR MAGNITUDES 40-50 KT SUPPORT POTENTIAL FOR A
FEW SUPERCELLS...ENHANCING HAIL/WIND RISK ON STORM SCALE.
..EDWARDS/HART.. 07/26/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GRB...LOT...MKX...DVN...ARX...
LAT...LON 42779054 44398957 45488953 45288846 44528730 42058789
42779054SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 8:40 PM CDT | Mesoscale Discussion | SPC | Carroll, Henry, Jo Daviess, Mercer, Rock Island, Stephenson and 1 more | 65 min |
| Jul 25, 8:57 PM CDT | Severe Thunderstorm Watch | SPC | Carroll, Jo Daviess, Lee, Ogle, Rock Island, Stephenson and 2 more | 6 hr |
| Jul 25, 11:34 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Henry, Jo Daviess and 7 more | 86 min |
| Jul 26, 1:40 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Cook, DeKalb, DuPage, Grundy and 15 more | 65 min |
| Jul 26, 1:25 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Clay, Clinton, Cumberland, Edwards and 27 more | 65 min |
| Jul 26, 1:46 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Clark, Clay, Clinton, Crawford, Cumberland and 28 more | 10 hr |
| Jul 26, 3:55 PM CDT | Mesoscale Discussion | SPC | Alexander, Clay, Clinton, Crawford, Edwards, Franklin and 24 more | 35 min |
| Jul 26, 6:29 PM CDT | Mesoscale Discussion | SPC | Alexander, Gallatin, Hamilton, Hardin, Johnson, Massac and 5 more | 61 min |
| Jul 25, 7:20 PM CDT | Mesoscale Discussion | SPC | La Crosse | 85 min |
| Jul 25, 8:28 PM CDT | Mesoscale Discussion | SPC | Brown, Calumet, Kewaunee, Manitowoc, Sheboygan | 92 min |
| Jul 25, 11:09 PM CDT | Mesoscale Discussion | SPC | Ozaukee, Sheboygan | 96 min |
Nearby
Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Illinois, 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.