Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 543

April 15, 201211 counties in Iowa; 28 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2012, 3:25 AM CDT for 11 counties in Iowa; 28 counties in Nebraska. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2012, 3:25 AM CDT (08:25 UTC)
Expired
Apr 15, 2012, 5:00 AM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 39 counties

Adams County, IA, Audubon County, IA, Cass County, IA, Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Gage County, NE, Hamilton County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Thayer County, NE, Washington County, NE, Webster County, NE, York County, NE

The radar

The Omaha radar (KOAX), 8 km from the middle of the area, began a volume at 08:28 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, 8.4 hours before the alert went out and 7 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 2012-04-15Temperature 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, Omaha, NE at 00:00Z on 2012-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 276 square meters per square second.1939587897Sfc1 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
871 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
276 m²/s²
0-3 km storm-relative helicity
483 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

185 
ACUS11 KWNS 150825
SWOMCD
SPC MCD 150825 
IAZ000-MOZ000-NEZ000-151000-

MESOSCALE DISCUSSION 0543
NWS STORM PREDICTION CENTER NORMAN OK
0325 AM CDT SUN APR 15 2012

AREAS AFFECTED...SRN IA AND NRN MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 150825Z - 151000Z

A MARGINAL TORNADO THREAT COULD EXIST ACROSS SRN IA AND NRN MO OVER
THE NEXT 2 TO 3 HOURS. ALTHOUGH THE THREAT IS CONDITIONAL...WW
ISSUANCE CAN NOT BE RULED OUT ACROSS THE REGION EARLY THIS MORNING.

A BOWING LINE-SEGMENT IS CURRENTLY ONGOING AT THE STATE-LINE
INTERSECTION OF MO...NEB AND KS VERY NEAR TO THE ANALYZED POSITION
OF A 60 TO 75 KT LOW-LEVEL JET. THIS JET IS HELPING TO CREATE STRONG
LOW-LEVEL SHEAR PROFILES WITH REGIONAL WSR-88 VWPS SHOWING 0-1 KM
SHEAR OF 600 M2/S2. IN SPITE OF VERY WEAK INSTABILITY...THIS COULD
COMPENSATE ENOUGH FOR THE DEVELOPMENT OF ROTATING STORMS. ALTHOUGH
THE POTENTIAL FOR MORE THAN ONE BRIEF TORNADO REMAINS SOMEWHAT
LOW...THE STORMS EXITING TORNADO WATCH 175 WILL BE MONITORED CLOSELY
FOR SIGNS OF INCREASING ROTATION MAINLY DUE TO THE LOW-LEVEL JET
PROXIMITY.

..BROYLES.. 04/15/2012

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

ATTN...WFO...DMX...EAX...OAX...GID...

LAT...LON   42159628 41819460 41069442 40079617 40109913 41439774
            42159628

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 14, 7:50 PM CDTMesoscale DiscussionSPCBenton, Buchanan, Cedar, Delaware, Henry, Iowa and 13 more55 min
Apr 14, 7:51 PM CDTMesoscale DiscussionSPCCherokee, Ida, Lyon, Monona, O'Brien, Osceola and 3 more84 min
Apr 14, 8:41 PM CDTSevere Thunderstorm WatchSPCCedar, Clinton, Des Moines, Henry, Iowa, Jackson and 9 more4 hr
Apr 14, 9:54 PM CDTMesoscale DiscussionSPCCedar, Clinton, Jackson, Jones, Louisa, Muscatine and 1 more96 min
Apr 14, 10:09 PM CDTSevere Thunderstorm WatchSPCFremont, Harrison, Mills, Monona, Montgomery, Page and 3 more6 hr
Apr 14, 11:28 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more92 min
Apr 15, 1:56 PM CDTMesoscale DiscussionSPCAudubon, Boone, Buena Vista, Butler, Calhoun, Carroll and 28 more94 min
Apr 15, 3:37 PM CDTTornado WatchSPCCerro Gordo, Chickasaw, Clay, Dickinson, Emmet, Floyd and 8 more7 hr
Apr 15, 1:18 PM CDTMesoscale DiscussionSPCAntelope, Cedar, Garfield, Greeley, Knox, Pierce and 3 more87 min

Nearby

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