Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 1421

July 6, 201216 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 6, 2012, 4:53 PM MDT for 16 counties in Nebraska. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Jul 6, 2012, 4:53 PM MDT (22:53 UTC)
Expired: Jul 6, 2012, 6:00 PM MDT
In force: 67 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Arthur County, NE, Blaine County, NE, Brown County, NE, Custer County, NE, Grant County, NE, Hayes County, NE, Holt County, NE, Hooker County, NE, Keith County, NE, Knox County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Rock County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 56 km from the middle of the area, began a volume at 22:56 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, 10.9 hours before the alert went out and 98 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2668 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 111 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.

879 
ACUS11 KWNS 062253
SWOMCD
SPC MCD 062253 
NEZ000-SDZ000-070000-

MESOSCALE DISCUSSION 1421
NWS STORM PREDICTION CENTER NORMAN OK
0553 PM CDT FRI JUL 06 2012

AREAS AFFECTED...N-CNTRL AND NERN NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 062253Z - 070000Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED DMGG WIND GUSTS AND HAIL MAY ACCOMPANY DEVELOPING
TSTMS OVER PARTS OF N-CNTRL AND NERN NEB. LIMITED COVERAGE SHOULD
PRECLUDE THE NEED FOR A WW.

DISCUSSION...VISIBLE SATELLITE LOOP SHOWS A TOWERING CU FIELD ALONG
A SLOW-MOVING COLD FRONT BISECTING NEB FROM SW TO NE. STRONG DAYTIME
HEATING HAS ALLOWED TEMPERATURES TO CLIMB TO NEAR 100 F ALONG/S OF
THE COLD FRONT. MIDLEVEL TEMPERATURE PROFILES ARE QUITE WARM...AND
ARE LIMITING AVAILABLE INSTABILITY /E.G. MLCAPE VALUES NEAR 1000
J/KG/ IN THE PRE-FRONTAL AIR MASS WHERE STRONG MIXING HAS OCCURRED.
GREATER INSTABILITY EXISTS N OF THE WIND SHIFT/COLD FRONT WHERE
BOUNDARY LAYER MOISTURE IS RICHER...AND RELATIVELY WARM TEMPERATURES
SHOULD STILL SUPPORT THE DEVELOPMENT OF ISOLATED SFC-BASED TSTMS.
THUS...A THREAT FOR ISOLATED STRONG-SVR DOWNBURST WINDS AND HAIL
COULD ACCOMPANY THESE STORMS...BUT THE THREAT SHOULD BEGIN TO WANE
AFTER SUNSET WITH THE LOSS OF HEATING.

..ROGERS/CORFIDI.. 07/06/2012

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

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

LAT...LON   42759769 42269834 41699935 40989989 40560043 40500112
            41090180 41770202 42190175 42690031 42879856 42759769

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 5, 8:52 PM MDT	Mesoscale Discussion	SPC	Sioux	53 min

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.