Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 914

May 26, 201215 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 26, 2012, 5:44 PM MDT for 15 counties in Nebraska. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: May 26, 2012, 5:44 PM MDT (23:44 UTC)
Expired: May 26, 2012, 7:15 PM MDT
In force: 91 min
Issued by: the Storm Prediction Center

Counties Arthur County, NE, Blaine County, NE, Brown County, NE, Cherry County, NE, Garden County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Rock County, NE, Thomas County, NE, Valley County, NE

The radar

The North Platte radar (KLNX), 34 km from the middle of the area, began a volume at 23:45 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.7 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 298 J/kg
Mixed-layer CIN: -618 J/kg
Mixed-layer LCL: 581 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 387 m²/s²
0-3 km storm-relative helicity: 377 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.

246 
ACUS11 KWNS 262345
SWOMCD
SPC MCD 262344
NEZ000-270115-

MESOSCALE DISCUSSION 0914
NWS STORM PREDICTION CENTER NORMAN OK
0644 PM CDT SAT MAY 26 2012

AREAS AFFECTED...NRN NEB

CONCERNING...SEVERE THUNDERSTORM WATCH 302...

VALID 262344Z - 270115Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 302
CONTINUES.

SUMMARY...THE THREAT FOR PRIMARILY ISOLATED LARGE HAIL AND POSSIBLY
DAMAGING WIND GUSTS WILL PERSIST OVER NRN NEB THROUGH AT LEAST 02Z.
THREAT FOR ISOLATED LARGE HAIL MAY SHIFT NWD INTO SRN SD TOWARD MID
EVENING.

DISCUSSION...EARLY THIS EVENING A WARM FRONT STRETCHES ACROSS NRN
NEB. ISOLATED HIGH BASED STORMS THAT INITIATED IN THE DEEPLY MIXED
AIR SOUTH OF THIS FRONT ARE IN THE PROCESS OF CROSSING THE BOUNDARY
WHERE A COOLER AND MOIST SFC LAYER EXISTS...AND WHERE BACKED NEAR
SFC FLOW IS CONTRIBUTING TO 250-350 M2/S2 0-1 KM STORM RELATIVE
HELICITY. HOWEVER...EFFECTIVE LAYER HELICITY IS LIKELY MUCH LESS
SINCE STORMS MOVING INTO THE COOLER AIR NORTH OF THE FRONT ARE
PROBABLY ROOTED ABOVE A BOUNDARY LAYER THAT IS LIKELY CAPPED BY THE
EML. A SMALL WINDOW FOR A BRIEF TORNADO CANNOT BE COMPLETELY RULED
OUT AS STORMS INTERACT WITH FRONT. HOWEVER...A STABILIZING BOUNDARY
LAYER SUGGESTS THE POTENTIAL FOR SFC BASED STORMS IN COOL SECTOR IS
DECREASING WITH ONSET OF NOCTURNAL COOLING. THIS SUGGESTS THE MAIN
THREATS WILL CONTINUE TO BE ISOLATED LARGE HAIL AND DAMAGING WIND.
PRIMARY THUNDERSTORM DEVELOPMENT SHOULD PERSIST FROM NRN NEB AND
EVENTUALLY INTO SRN SD AS THE SLY LLJ STRENGTHENS AND ENHANCES
ISENTROPIC LIFT NORTH OF THE FRONT. WARM SECTOR DEVELOPMENT WILL
PROBABLY BEGIN TO WANE AS THE BOUNDARY LAYER COOLS AND STABILIZES.

..DIAL.. 05/26/2012

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

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

LAT...LON   41529857 41320098 41360240 42730202 42909852 41529857

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 25, 8:17 PM MDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Burt, Butler, Cass and 43 more	88 min
May 25, 11:46 PM MDT	Mesoscale Discussion	SPC	Burt, Dakota, Thurston	89 min
May 26, 12:58 AM MDT	Mesoscale Discussion	SPC	Boyd, Holt, Keya Paha, Knox, Rock	92 min
May 26, 2:48 PM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Boone, Buffalo, Burt, Butler and 50 more	87 min
May 26, 2:55 PM MDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Deuel, Garden and 7 more	2 hr
May 26, 3:48 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Blaine, Boyd, Brown, Cherry, Custer and 15 more	5 hr

Nearby

Mesoscale Discussions in Nebraska, 2012 Every 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.