Alert archive / Iowa / Mesoscale Discussions in 2012
Mesoscale Discussion 1886
The Storm Prediction Center issued this mesoscale discussion at Sep 4, 2012, 9:51 PM CDT for 18 counties in Iowa; 7 counties in Minnesota. It was in force for 54 min.
The area
The outline as issued.
The facts
- Issued
- Sep 4, 2012, 9:51 PM CDT (02:51 UTC)
- Expired
- Sep 4, 2012, 10:45 PM CDT
- In force
- 54 min
- Issued by
- the Storm Prediction Center
All 25 counties
Buena Vista County, IA, Calhoun County, IA, Cerro Gordo County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Franklin County, IA, Hamilton County, IA, Hancock County, IA, Humboldt County, IA, Kossuth County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Cottonwood County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Watonwan County, MN
The radar
The Des Moines radar (KDMX), 170 km from the middle of the area, began a volume at 02:52 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
Minneapolis, MN (KMPX), launched 00:00Z, 2.9 hours before the alert went out and 205 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3109 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 4 m²/s²
- 0-3 km storm-relative helicity
- 63 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
845
ACUS11 KWNS 050252
SWOMCD
SPC MCD 050251
IAZ000-MNZ000-050345-
MESOSCALE DISCUSSION 1886
NWS STORM PREDICTION CENTER NORMAN OK
0951 PM CDT TUE SEP 04 2012
AREAS AFFECTED...NRN IA THROUGH SRN MN
CONCERNING...SEVERE THUNDERSTORM WATCH 615...
VALID 050251Z - 050345Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 615
CONTINUES.
SUMMARY...STORMS EXPECTED TO CONTINUE THROUGH NRN IA AND SRN MN WITH
A THREAT FOR ISOLATED DAMAGING WIND NEXT FEW HOURS. STORMS WILL
APPROACH THE ERN BOUNDARY OF WW 615 BY 330Z...AND IF INTENSITIES ARE
MAINTAINED A NEW WW WILL PROBABLY BE REQUIRED.
DISCUSSION...STORMS HAVE EVOLVED INTO A LINE THAT IS MOVING EWD AT
30-35 KT. THE ACTIVITY IS EMBEDDED WITH 40 KT EFFECTIVE SHEAR AND
ORGANIZED STORM STRUCTURES CONTINUE TO BE OBSERVED. THERE IS SOME
CONCERN THAT THE STABILIZING SFC LAYER MAY CONTRIBUTE TO A SLOW
DECREASE IN OVERALL STORM INTENSITIES. HOWEVER...SELY BOUNDARY LAYER
WINDS AND SLY LLJ WILL MAINTAIN INFLOW FROM UNSTABLE WARM
SECTOR...AND STORMS WILL LIKELY CONTINUE TO FORWARD PROPAGATE ALONG
INSTABILITY GRADIENT NEXT FEW HOURS. PRIMARY THREAT IS EXPECTED TO
BE ISOLATED DAMAGING WIND...BUT HAIL ALSO REMAINS POSSIBLE.
..DIAL.. 09/05/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MPX...DMX...FSD...
LAT...LON 42349542 43259537 44009541 44129377 43559320 42349328
42349542SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 4, 7:27 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Dickinson, Lyon, O'Brien and 3 more | 63 min |
| Sep 4, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 5 more | 6 hr |
| Sep 4, 8:30 PM CDT | Mesoscale Discussion | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Chickasaw and 8 more | 60 min |
| Sep 4, 8:51 PM CDT | Severe Thunderstorm Watch | SPC | Buchanan, Clinton, Delaware, Dubuque, Jackson, Jones | 5 hr |
| Sep 4, 10:19 PM CDT | Severe Thunderstorm Watch | SPC | Black Hawk, Bremer, Butler, Calhoun, Cerro Gordo, Emmet and 14 more | 5 hr |
| Sep 4, 11:16 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more | 4 hr |
| Sep 5, 1:14 AM CDT | Mesoscale Discussion | SPC | Allamakee, Audubon, Benton, Black Hawk, Boone, Bremer and 54 more | 91 min |
| Sep 5, 3:43 AM CDT | Mesoscale Discussion | SPC | Benton, Cedar, Clinton, Des Moines, Dubuque, Henry and 14 more | 92 min |
Nearby
Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Minnesota, 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.