Alert archive / Iowa / Mesoscale Discussions in 2012
Mesoscale Discussion 550
The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2012, 1:56 PM CDT for 34 counties in Iowa; 24 counties in Minnesota. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Apr 15, 2012, 1:56 PM CDT (18:56 UTC)
- Expired
- Apr 15, 2012, 3:30 PM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
All 58 counties
Audubon County, IA, Boone County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Story County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Carver County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Redwood County, MN, Rice County, MN, Rock County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN
The radar
The Des Moines radar (KDMX), 164 km from the middle of the area, began a volume at 18:56 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 12:00Z, 6.9 hours before the alert went out and 187 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
- 502 m above ground
- 0-6 km bulk shear
- 79 kt
- 0-1 km storm-relative helicity
- 125 m²/s²
- 0-3 km storm-relative helicity
- 222 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
256
ACUS11 KWNS 151856
SWOMCD
SPC MCD 151856
MNZ000-IAZ000-152030-
MESOSCALE DISCUSSION 0550
NWS STORM PREDICTION CENTER NORMAN OK
0156 PM CDT SUN APR 15 2012
AREAS AFFECTED...CNTRL/N-CNTRL IA...SRN MN
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 151856Z - 152030Z
PORTIONS OF CNTRL/N-CNTRL IA AND SRN MN ARE BEING MONITORED FOR THE
POSSIBLE ISSUANCE OF A TORNADO WATCH THIS AFTERNOON.
SFC ANALYSIS INDICATES A COLD FRONT TRAILING SWD FROM A TRIPLE POINT
30 MILES SE OF SIOUX FALLS SD...WITH A WARM FRONT ARCING ENEWD FROM
THE TRIPLE POINT ACROSS SRN MN INTO W-CNTRL WI. INHIBITION WITHIN
THE WARM SECTOR CONTINUES TO ERODE...WITH THE MODIFIED
MINNEAPOLIS-ST PAUL 18Z RAOB ACCOUNTING FOR SFC OBS IN THE WARM
SECTOR INDICATING UPWARDS OF 1000 J/KG OF MLCAPE WITH NEAR-ZERO
CINH. A WELL-DEFINED AXIS OF CONFLUENCE ALIGNS WITH THE COLD
FRONT...WITH SUPPORTING LOW-LEVEL CONVERGENCE POTENTIALLY BECOMING
RESPONSIBLE FOR CONVECTIVE INITIATION BETWEEN 1930Z AND 21Z AS
DIABATIC HEATING CONTINUES TO THE EAST. ALREADY...VISIBLE SATELLITE
IMAGERY DEPICTS MODEST VERTICAL DEVELOPMENT WITHIN BANDS OF CUMULUS
NEAR THE COLD FRONT IN WRN IA. THIS COULD EVOLVE INTO DEEPER
CONVECTION WITHIN THE NEXT COUPLE OF HOURS. ONCE STORMS FORM...THEY
WILL HAVE THE POTENTIAL TO QUICKLY BECOME SVR GIVEN EFFECTIVE BULK
SHEAR MAGNITUDES OF 50-70 KT. LOW-LEVEL SHEAR WILL BE SUFFICIENT FOR
TORNADIC SUPERCELLS...PARTICULARLY NEAR THE WARM FRONT WHERE SFC
WINDS REMAIN RELATIVELY BACKED.
..COHEN.. 04/15/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...ARX...MPX...DMX...FSD...OAX...
LAT...LON 41949325 41609457 41809547 42429585 43729628 44479528
44979382 44839301 44209248 43519224 42959240 41949325SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 7:50 PM CDT | Mesoscale Discussion | SPC | Benton, Buchanan, Cedar, Delaware, Henry, Iowa and 13 more | 55 min |
| Apr 14, 7:51 PM CDT | Mesoscale Discussion | SPC | Cherokee, Ida, Lyon, Monona, O'Brien, Osceola and 3 more | 84 min |
| Apr 14, 8:41 PM CDT | Severe Thunderstorm Watch | SPC | Cedar, Clinton, Des Moines, Henry, Iowa, Jackson and 9 more | 4 hr |
| Apr 14, 9:54 PM CDT | Mesoscale Discussion | SPC | Cedar, Clinton, Jackson, Jones, Louisa, Muscatine and 1 more | 96 min |
| Apr 14, 10:09 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Harrison, Mills, Monona, Montgomery, Page and 3 more | 6 hr |
| Apr 14, 11:28 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more | 92 min |
| Apr 15, 3:25 AM CDT | Mesoscale Discussion | SPC | Adams, Audubon, Cass, Fremont, Harrison, Mills and 5 more | 95 min |
| Apr 15, 3:37 PM CDT | Tornado Watch | SPC | Cerro Gordo, Chickasaw, Clay, Dickinson, Emmet, Floyd and 8 more | 7 hr |
| Apr 15, 12:25 PM CDT | Mesoscale Discussion | SPC | Benton, Big Stone, Chippewa, Douglas, Kandiyohi, Lac qui Parle and 13 more | 65 min |
| Apr 15, 5:54 PM CDT | Mesoscale Discussion | SPC | Anoka, Carver, Chisago, Dakota, Hennepin, Ramsey and 3 more | 96 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.