Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 933

May 27, 201211 counties in Iowa; 5 counties in Minnesota; 17 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 27, 2012, 9:51 PM CDT for 11 counties in Iowa; 5 counties in Minnesota; 17 counties in Nebraska. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
May 27, 2012, 9:51 PM CDT (02:51 UTC)
Expired
May 27, 2012, 11:15 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 33 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Ida County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Woodbury County, IA, Blue Earth County, MN, Jackson County, MN, Martin County, MN, Nicollet County, MN, Watonwan County, MN, Burt County, NE, Butler County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dodge County, NE, Fillmore County, NE, Hamilton County, NE, Polk County, NE, Saline County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, York County, NE

The radar

The Omaha radar (KOAX), 92 km from the middle of the area, began a volume at 02:51 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

Omaha, NE (KOAX), launched 00:00Z, 2.9 hours before the alert went out and 92 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, Omaha, NE at 00:00Z on 2012-05-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 849 joules per kilogram.LCLLFCEL10008507005003002001001 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, Omaha, NE at 00:00Z on 2012-05-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
849 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
2094 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

934 
ACUS11 KWNS 280251
SWOMCD
SPC MCD 280251 
MNZ000-IAZ000-NEZ000-SDZ000-280415-

MESOSCALE DISCUSSION 0933
NWS STORM PREDICTION CENTER NORMAN OK
0951 PM CDT SUN MAY 27 2012

AREAS AFFECTED...ERN NEB THROUGH NWRN IA AND SCNTRL MN

CONCERNING...SEVERE THUNDERSTORM WATCH 304...

VALID 280251Z - 280415Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 304
CONTINUES.

SUMMARY...THREAT FOR DAMAGING WIND AND HAIL WILL PERSIST ANOTHER
COUPLE HOURS FROM ERN NEB...NWRN IA INTO SCNTRL MN. STORMS HAVE
GENERALLY BECOME LESS ORGANIZED...AND SEVERE THREAT IS EXPECTED TO
GRADUALLY WANE AFTER MIDNIGHT.

DISCUSSION...A LINE OF STORMS WITH A FEW EMBEDDED BOWING SEGMENTS
AND SUPERCELL STRUCTURES PERSIST FROM ERN NEB INTO SCNTRL MN. LOCAL
RADAR DATA SHOW OUTFLOW BOUNDARIES SURGING AHEAD OF PRECIPITATION
CORES IN ERN NEB...SUGGESTING CONVECTIVE INHIBITION IS BEGINNING TO
NEGATIVELY INFLUENCE STORM INTENSITIES. OVERALL TENDENCY HAS BEEN
FOR ACTIVITY TO BECOME LESS ORGANIZED...BUT STRONGER STORMS WILL
REMAIN CAPABLE OF ISOLATED DAMAGING WIND AND HAIL AS THEY PROPAGATE
THROUGH THE REMAINING NARROW INSTABILITY AXIS NEXT COUPLE HOURS.

..DIAL.. 05/28/2012

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

ATTN...WFO...MPX...DMX...FSD...OAX...GID...

LAT...LON   40219880 41299772 42699670 43749511 44579410 43909397
            40539692 40219880

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 28, 12:00 PM CDTMesoscale DiscussionSPCClayton, Dubuque60 min
May 28, 12:54 PM CDTSevere Thunderstorm WatchSPCClayton7 hr
May 28, 4:59 PM CDTMesoscale DiscussionSPCDes Moines, Lee, Scott91 min
May 27, 7:47 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Carlton, Carver, Chippewa and 33 more88 min
May 27, 10:11 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Blue Earth, Brown, Carlton and 45 more94 min
May 28, 1:48 PM CDTMesoscale DiscussionSPCAnoka, Benton, Carlton, Carver, Chisago, Dakota and 17 more57 min
May 28, 2:07 PM CDTSevere Thunderstorm WatchSPCAnoka, Benton, Carlton, Carver, Chisago, Dakota and 14 more6 hr
May 28, 3:58 PM CDTMesoscale DiscussionSPCAnoka, Benton, Carlton, Carver, Chisago, Dakota and 16 more92 min

Nearby

Mesoscale Discussions in Nebraska, 2012Mesoscale 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.