Alert archive / Iowa / Mesoscale Discussions in 2012
Mesoscale Discussion 700
The Storm Prediction Center issued this mesoscale discussion at May 4, 2012, 5:31 PM CDT for 72 counties in Iowa; 7 counties in Minnesota; 60 counties in Nebraska. It was in force for 29 min.
The area
The outline as issued.
The facts
- Issued
- May 4, 2012, 5:31 PM CDT (22:31 UTC)
- Expired
- May 4, 2012, 6:00 PM CDT
- In force
- 29 min
- Issued by
- the Storm Prediction Center
All 139 counties
Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cedar County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Clayton County, IA, Clinton County, IA, Crawford County, IA, Dallas County, IA, Delaware County, IA, Dubuque County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Henry County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Kossuth County, IA, Linn County, IA, Louisa County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mitchell County, IA, Monona County, IA, Monroe County, IA, Muscatine County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Sac County, IA, Scott County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Faribault County, MN, Freeborn County, MN, Martin County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Adams County, NE, Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Cherry County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dawson County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Garfield County, NE, Gosper County, NE, Grant County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Hooker County, NE, Howard County, NE, Kearney County, NE, Keya Paha County, NE, Knox County, NE, Lancaster County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, Madison County, NE, McPherson County, NE, Merrick County, NE, Nance County, NE, Phelps County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thomas County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE
The radar
The Omaha radar (KOAX), 91 km from the middle of the area, began a volume at 22:33 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
Omaha, NE (KOAX), launched 12:00Z, 10.5 hours before the alert went out and 91 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
- 2705 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 584 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 10 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
527
ACUS11 KWNS 042231
SWOMCD
SPC MCD 042231
IAZ000-ILZ000-WIZ000-MNZ000-NEZ000-SDZ000-042300-
MESOSCALE DISCUSSION 0700
NWS STORM PREDICTION CENTER NORMAN OK
0531 PM CDT FRI MAY 04 2012
AREAS AFFECTED...IA...SRN MN WWD THROUGH ERN AND CENTRAL NEB
CONCERNING...SEVERE THUNDERSTORM WATCH 239...
VALID 042231Z - 042300Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 239
CONTINUES.
SUMMARY...A NEW SVR TSTM WATCH WILL BE COORDINATED FOR PARTS OF
CENTRAL AND ERN IA AS A DEVELOPING BOW ECHO OVER NRN IA TRACKS SEWD
THROUGH THE EVENING PRODUCING A THREAT FOR DAMAGING WINDS.
FARTHER W OVER NEB...TSTMS WILL CONTINUE TO DEVELOP ALONG A TRAILING
OUTFLOW BOUNDARY AS IT MOVES SWD. THUS...A NEW WW WILL BE NEEDED
OVER PARTS OF ERN AND CENTRAL NEB AS WELL.
DISCUSSION...AT 2220Z...REGIONAL RADAR IMAGERY SHOWED A DEVELOPING
FORWARD PROPAGATING MCS OVER NORTH CENTRAL IA...WITH THE NRN EXTENT
LOCATED OVER SRN MN. LATE AFTERNOON SURFACE AND OBJECTIVE ANALYSES
SHOWED A BOUNDARY AND CONCURRENT INSTABILITY GRADIENT EXTENDING FROM
THE DEVELOPING BOW INTO EAST CENTRAL IA AND WRN/CENTRAL IL. CURRENT
THINKING AND MODEL DATA SUGGEST THIS BOW WILL TRACK SEWD ALONG THE
AFOREMENTIONED GRADIENT...WHILE THE DEVELOPING COLD POOL AIDS IN THE
FORWARD PROPAGATION AS WELL.
FARTHER W OVER NEB...A MODERATELY-STRONGLY UNSTABLE AIR MASS AND
EFFECTIVE BULK SHEAR OF 40-50 KT SUGGESTS ADDITIONAL STORMS
DEVELOPING IN THIS ENVIRONMENT WILL POSE THREAT FOR LARGE HAIL AND
DAMAGING WINDS. A NEW WW WILL BE NEEDED OVER ERN AND CENTRAL NEB AS
THE OUTFLOW BOUNDARY MOVES SWD INTO THE FAVORABLE THERMODYNAMIC AND
KINEMATIC ENVIRONMENT.
..PETERS.. 05/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX...GID...LBF...
UNR...
LAT...LON 43010210 43039958 43019862 42889718 42399667 42929527
44159495 44179311 43579299 43119130 41949022 41239090
40699185 41349449 41619592 40539617 40339724 40309918
40510007 41140122 42100208 43010210SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 7:09 PM CDT | Tornado Watch | SPC | Adair, Adams, Appanoose, Cass, Cedar, Clarke and 23 more | 6 hr |
| May 3, 11:18 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Cass, Cedar, Clarke and 23 more | 27 min |
| May 4, 12:53 AM CDT | Severe Thunderstorm Watch | SPC | Des Moines, Henry, Jefferson, Lee, Van Buren | 4 hr |
| May 4, 2:16 AM CDT | Mesoscale Discussion | SPC | Appanoose, Davis, Decatur, Des Moines, Henry, Jefferson and 9 more | 119 min |
| May 4, 1:50 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Dickinson, Emmet, Ida and 7 more | 25 min |
| May 4, 2:00 PM CDT | Severe Thunderstorm Watch | SPC | Buena Vista, Calhoun, Carroll, Cerro Gordo, Cherokee, Clay and 23 more | 9 hr |
| May 4, 3:52 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cerro Gordo, Cherokee, Clay, Dickinson, Emmet and 17 more | 53 min |
| May 4, 5:52 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more | 5 hr |
| May 4, 6:01 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Black Hawk, Boone, Bremer, Buchanan, Butler and 22 more | 3 hr |
| May 4, 6:49 AM CDT | Mesoscale Discussion | SPC | Antelope, Boyd, Cedar, Dixon, Holt, Keya Paha and 5 more | 116 min |
Nearby
Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Nebraska, 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.