Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 885

May 23, 201229 counties in Iowa; 37 counties in Nebraska; Lincoln County, Union County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 23, 2012, 8:56 PM CDT for 29 counties in Iowa; 37 counties in Nebraska; Lincoln County, Union County, South Dakota. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
May 23, 2012, 8:56 PM CDT (01:56 UTC)
Expired
May 23, 2012, 10:30 PM CDT
In force
94 min
Issued by
the Storm Prediction Center
All 68 counties

Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Fremont County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Woodbury County, IA, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Hamilton County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thayer County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, York County, NE, Lincoln County, SD, Union County, SD

The radar

The Omaha radar (KOAX), 121 km from the middle of the area, began a volume at 01:59 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 00:00Z, 1.9 hours before the alert went out and 121 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 2012-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1035 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 2012-05-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 195 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
1035 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
2387 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
195 m²/s²
0-3 km storm-relative helicity
291 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.7

Open this sounding in Storm Lab

The text

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

181 
ACUS11 KWNS 240156
SWOMCD
SPC MCD 240156 
MNZ000-IAZ000-MOZ000-NEZ000-SDZ000-240330-

MESOSCALE DISCUSSION 0885
NWS STORM PREDICTION CENTER NORMAN OK
0856 PM CDT WED MAY 23 2012

AREAS AFFECTED...ERN NEB/WRN IA/FAR SERN SD

CONCERNING...SEVERE THUNDERSTORM WATCH 293...

VALID 240156Z - 240330Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 293
CONTINUES.

SUMMARY...ISOLATED SEVERE THREAT CONTINUES.

DISCUSSION...LATEST RADAR LOOP SHOWS THE BROKEN BAND OF
STRONG/ISOLATED SEVERE STORMS MOVING ACROSS SERN NEB/WRN IA
ATTM...JUST AHEAD OF THE ADVANCING COLD FRONT.  MEANWHILE...ELEVATED
STORMS CONTINUE TO INCREASE JUST W OF THE WATCH ACROSS NERN NEB...TO
THE COOL SIDE OF THE SURFACE FRONT AS A SLY LOW-LEVEL JET INCREASES
/NOW 55 KT PER VWP/PROFILER DATA/.  THE BOUNDARY LAYER CONTINUES TO
COOL AHEAD OF THE CONVECTION...WITH SURFACE TEMPERATURES NOW 5-6
DEGREES F COOLER OVER THE PAST TWO HOURS.  WITH FURTHER
COOLING...WIND THREAT WILL CONTINUE TO SLOWLY DIMINISH. 
MEANWHILE...POTENTIAL FOR ISOLATED/MARGINALLY SEVERE HAIL -- BOTH
WITH THE PRE-FRONTAL BAND OF STORMS AND WITH CONVECTION INCREASING
IN THE COOLER AIRMASS BEHIND THE FRONT -- WILL CONTINUE.

..GOSS.. 05/24/2012

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

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

LAT...LON   43579421 43179400 41489477 40009594 40169890 43469660
            43579421

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 24, 6:33 AM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buchanan, Chickasaw, Clayton and 8 more57 min
May 24, 1:34 PM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Butler, Cerro Gordo, Chickasaw and 10 more116 min
May 24, 3:06 PM CDTMesoscale DiscussionSPCAllamakee, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 38 more114 min
May 24, 3:30 PM CDTSevere Thunderstorm WatchSPCAllamakee, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 39 more4 hr
May 24, 5:42 PM CDTMesoscale DiscussionSPCAllamakee, Appanoose, Benton, Black Hawk, Buchanan, Cedar and 24 more2 hr
May 23, 10:29 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Butler, Cedar and 38 more91 min
May 23, 10:47 PM CDTSevere Thunderstorm WatchSPCAdams, Antelope, Boone, Buffalo, Burt, Butler and 37 more6 hr

Nearby

Mesoscale Discussions in Nebraska, 2012Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in South Dakota, 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.