Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 1949

August 11, 201114 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 11, 2011, 9:22 PM CDT for 14 counties in Nebraska. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Aug 11, 2011, 9:22 PM CDT (02:22 UTC)
Expired
Aug 11, 2011, 10:15 PM CDT
In force
53 min
Issued by
the Storm Prediction Center

Counties Blaine County, NE, Boyd County, NE, Brown County, NE, Cherry County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keya Paha County, NE, Loup County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 70 km from the middle of the area, began a volume at 02:26 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 00:00Z, 2.4 hours before the alert went out and 144 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, N. Platte/Lee Bi, NE at 00:00Z on 2011-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2513 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, N. Platte/Lee Bi, NE at 00:00Z on 2011-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
2513 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
1288 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
281 m²/s²
Significant tornado parameter
1.9
Supercell composite
19.6

Open this sounding in Storm Lab

The text

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

930 
ACUS11 KWNS 120222
SWOMCD
SPC MCD 120222 
SDZ000-NEZ000-120315-

MESOSCALE DISCUSSION 1949
NWS STORM PREDICTION CENTER NORMAN OK
0922 PM CDT THU AUG 11 2011

AREAS AFFECTED...NE

CONCERNING...TORNADO WATCH 767...

VALID 120222Z - 120315Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 767 CONTINUES.

INTENSE SUPERCELLS HAVE PRODUCED SEVERAL TORNADO REPORTS ON THE TAIL
END OF THE SEVERE QLCS MOVING INTO NRN NEB THIS EVENING. NORTH
PLATTE VWP INFORMATION UPDATED WITH ESTIMATED STORM MOTION VECTOR OF
315 AT 34KT RESULTS IN 0-1KM SRH NEARING 700 M2/S2 ALONG AND AHEAD
OF THE THREE OR FOUR TAIL-END SUPERCELLS. THESE STORMS CONTINUE
SPREADING INTO A ZONE WHERE ABUNDANT INSTABILITY IS INDICATED BY
LATEST OBJECTIVE ANALYSIS DATA. THUS...WOULD EXPECT A HIGH
PROBABILITY OF ALL SEVERE WEATHER TYPES...DAMAGING WINDS... LARGE
HAIL...AND TORNADOES...TO CONTINUE...PRIMARILY ACROSS CENTRAL AND
ERN AREAS OF TORNADO WATCH 767 OVER THE NEXT 1-2 HOURS.

..CARBIN.. 08/12/2011

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

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

LAT...LON   42940275 42989834 41719834 41720203 41970202 41990267
            42940275

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 11, 7:19 PM CDTSevere Thunderstorm WatchSPCAntelope, Boone, Burt, Cedar, Colfax, Cuming and 9 more5 hr
Aug 11, 9:42 PM CDTMesoscale DiscussionSPCAntelope, Boone, Burt, Cedar, Colfax, Cuming and 12 more63 min
Aug 11, 10:16 PM CDTSevere Thunderstorm WatchSPCAdams, Buffalo, Clay, Dawson, Fillmore, Gosper and 12 more6 hr
Aug 12, 1:45 AM CDTMesoscale DiscussionSPCAdams, Blaine, Buffalo, Cherry, Clay, Custer and 27 more2 hr

Nearby

Mesoscale Discussions in Nebraska, 2011Every mesoscale discussion in 2011

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.