Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 727

May 6, 201223 counties in Iowa; 9 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 2:12 AM CDT for 23 counties in Iowa; 9 counties in Minnesota. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
May 6, 2012, 2:12 AM CDT (07:12 UTC)
Expired
May 6, 2012, 3:15 AM CDT
In force
63 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 32 counties

Buena Vista County, IA, Butler County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Sioux County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Mower County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN

The radar

The Des Moines radar (KDMX), 170 km from the middle of the area, began a volume at 07:16 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

Minneapolis, MN (KMPX), launched 00:00Z, 7.2 hours before the alert went out and 186 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.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2012-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2012-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -28 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
850 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
-28 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

023 
ACUS11 KWNS 060713
SWOMCD
SPC MCD 060712
IAZ000-MNZ000-060815-

MESOSCALE DISCUSSION 0727
NWS STORM PREDICTION CENTER NORMAN OK
0212 AM CDT SUN MAY 06 2012

AREAS AFFECTED...NRN IA...SRN MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 060712Z - 060815Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...STORMS WILL PERSIST OVER NRN IA AND SRN MN WITH MARGINALLY
SEVERE HAIL OR WIND LIKELY. THE NEED FOR A WATCH IS BEING
CONSIDERED.

DISCUSSION...THE CNTRL MN COMPLEX HAS LAID DOWN AN OUTFLOW BOUNDARY
OVER SERN MN...TRAILING SWWD INTO WRN IA AND ERN NEB WHERE ANOTHER
BOUNDARY WAS INTERSECTING THIS ONE...RESULTING IN VIGOROUS
CONVECTION ACROSS NWRN IA. WITH AMPLE THETA-E AHEAD OF THESE
STORMS...DEEP LAYER SHEAR WILL REMAIN FAVORABLE FOR SOME SEVERE WIND
AND HAIL.

..JEWELL.. 05/06/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ARX...MPX...DMX...FSD...

LAT...LON   42599292 42339595 42499615 43009621 43379632 43779544
            44109422 44189373 43989282 43459245 43149245 43009250
            42599292

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 5, 10:03 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more7 hr
May 5, 11:31 PM CDTMesoscale DiscussionSPCLyon89 min
May 6, 4:55 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Fremont, Guthrie and 8 more2 hr
May 6, 7:17 AM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Clarke, Dallas, Davis and 16 more6 hr
May 6, 8:40 AM CDTMesoscale DiscussionSPCCedar, Clinton, Des Moines, Henry, Iowa, Jefferson and 9 more65 min
May 6, 9:29 AM CDTSevere Thunderstorm WatchSPCBenton, Cedar, Clinton, Des Moines, Henry, Iowa and 12 more4 hr
May 6, 1:42 PM CDTSevere Thunderstorm WatchSPCDes Moines, Henry, Lee, Louisa, Van Buren7 hr
May 6, 3:56 PM CDTMesoscale DiscussionSPCLee64 min
May 5, 8:18 PM CDTSevere Thunderstorm WatchSPCBig Stone, Chippewa, Lac qui Parle, Pope, Stevens, Swift and 2 more4 hr
May 5, 9:51 PM CDTMesoscale DiscussionSPCAnoka, Benton, Big Stone, Blue Earth, Brown, Carver and 29 more84 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.