Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 522

April 14, 201225 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2012, 11:27 AM CDT for 25 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 14, 2012, 11:27 AM CDT (16:27 UTC)
Expired
Apr 14, 2012, 1:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 25 counties

Adams County, NE, Buffalo County, NE, Clay County, NE, Fillmore County, NE, Franklin County, NE, Furnas County, NE, Gage County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Jefferson County, NE, Kearney County, NE, Merrick County, NE, Nuckolls County, NE, Phelps County, NE, Polk County, NE, Saline County, NE, Seward County, NE, Sherman County, NE, Thayer County, NE, Webster County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 60 km from the middle of the area, began a volume at 16:27 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 12:00Z, 4.5 hours before the alert went out and 150 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 12:00Z on 2012-04-14Temperature 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 12:00Z on 2012-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
1847 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

395 
ACUS11 KWNS 141627
SWOMCD
SPC MCD 141627 
NEZ000-141830-

MESOSCALE DISCUSSION 0522
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CDT SAT APR 14 2012

AREAS AFFECTED...SCNTRL THROUGH SERN NEB

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 141627Z - 141830Z

INITIAL THREAT FOR LARGE HAIL EXPECTED TO GRADUALLY TRANSITION TO A
TORNADO THREAT THIS AFTERNOON. A PDS TORNADO WATCH WILL BE NEEDED BY
EARLY AFTERNOON AS CONDITIONS BECOME INCREASINGLY FAVORABLE FOR
SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL AND TORNADOES...A
FEW OF WHICH COULD BE STRONG.

LATE THIS MORNING STORMS CONTINUE DEVELOPING WITHIN BROAD ZONE OF
WARM ADVECTION FROM NCNTRL THROUGH SERN NEB. WIDESPREAD LOW CLOUDS
ARE SLOWING BOUNDARY LAYER DESTABILIZATION AND STORMS REMAIN
ELEVATED ABOVE A SFC STABLE LAYER WITH AN INITIAL PRIMARY THREAT FOR
LARGE HAIL. LATEST OBJECTIVE ANALYSIS ALREADY SHOWS MODERATE MUCAPE
OVER CNTRL AND SRN NEB. WARM FRONT NEAR THE KS/NEB BORDER WILL LIFT
NWD...AND AS SFC DEWPOINTS INCREASE AND LOW CLOUDS BEGIN TO MIX OUT
FROM THE SW...AN AXIS OF 1500-2000 J/KG MLCAPE SHOULD EVOLVE IN THIS
REGION...PROMOTING DEVELOPMENT OF SURFACE BASED UPDRAFTS. SOME OF
THE STORMS CURRENTLY MOVING THROUGH NCNTRL KS WILL LIKELY BEGIN TO
SHIFT INTO SCNTRL NEB BY EARLY AFTERNOON. OTHER STORMS MAY DEVELOP
FARTHER WEST ALONG THE DRYLINE/TRIPLE POINT LATER THIS AFTERNOON.
THE 50-60 KT LLJ WILL STRENGTHEN AND SHIFT NWD THROUGH KS AND INTO
SRN NEB LATER TODAY WITHIN EXIT REGION OF APPROACHING UPPER JET
CONTRIBUTING TO VERY LARGE HODOGRAPHS. THE VERTICAL SHEAR PROFILES
AND THERMODYNAMIC ENVIRONMENT WILL SUPPORT SUPERCELLS CAPABLE OF
LONG TRACK TORNADOES AND VERY LARGE HAIL.

..DIAL.. 04/14/2012

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

ATTN...WFO...OAX...GID...LBF...

LAT...LON   40969692 40349634 40039723 40049995 41049978 41629860
            40969692

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 14, 10:43 AM CDTTornado Watch PDSSPCHitchcock, Red Willow7 hr
Apr 14, 12:00 PM CDTTornado Watch PDSSPCAdams, Antelope, Boone, Buffalo, Burt, Butler and 46 more7 hr
Apr 14, 1:41 PM CDTMesoscale DiscussionSPCArthur, Custer, Dawson, Frontier, Garden, Grant and 9 more2 hr
Apr 14, 2:15 PM CDTMesoscale DiscussionSPCAdams, Burt, Butler, Cass, Clay, Colfax and 22 more90 min
Apr 14, 2:33 PM CDTTornado WatchSPCBlaine, Custer, Frontier, Garfield, Hayes, Holt and 7 more8 hr
Apr 14, 4:47 PM CDTMesoscale DiscussionSPCCass, Douglas, Gage, Johnson, Lancaster, Nemaha and 5 more58 min
Apr 14, 5:24 PM CDTTornado Watch PDSSPCHitchcock, Red Willow9 hr
Apr 14, 6:27 PM CDTTornado Watch PDSSPCAdams, Buffalo, Cass, Clay, Dawson, Fillmore and 30 more9 hr
Apr 14, 6:57 PM CDTMesoscale DiscussionSPCAdams, Buffalo, Butler, Cass, Clay, Douglas and 26 more63 min

Nearby

Mesoscale Discussions in Nebraska, 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.