Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 1367

July 2, 20126 counties in Colorado; 10 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 2, 2012, 5:56 PM MDT for 6 counties in Colorado; 10 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 2, 2012, 5:56 PM MDT (23:56 UTC)
Expired
Jul 2, 2012, 8:00 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Adams County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Arthur County, NE, Cherry County, NE, Cheyenne County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, McPherson County, NE, Morrill County, NE

The radar

The North Platte radar (KLNX), 161 km from the middle of the area, began a volume at 23:55 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, 11.9 hours before the alert went out and 155 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 12:00Z on 2012-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 692 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 12:00Z on 2012-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 square meters per square second.1939Sfc1 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
692 J/kg
Mixed-layer CIN
-426 J/kg
Mixed-layer LCL
1902 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
-9 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.

617 
ACUS11 KWNS 022357
SWOMCD
SPC MCD 022356
NEZ000-COZ000-030200-

MESOSCALE DISCUSSION 1367
NWS STORM PREDICTION CENTER NORMAN OK
0656 PM CDT MON JUL 02 2012

AREAS AFFECTED...NERN CO...WRN NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 022356Z - 030200Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED THREAT FOR STRONG TO PERHAPS MARGINALLY SVR
STORMS WILL OCCUR THROUGH EARLY EVENING...AND WW ISSUANCE IS NOT
NEEDED.

DISCUSSION...LOW-LEVEL ASCENT ATTENDANT TO A STATIONARY FRONT
EXTENDING FROM 60 W VALENTINE NEB TO A 1004-MB DENVER CYCLONE HAS
AIDED THE DEVELOPMENT OF ISOLATED TO SCATTERED CONVECTION ACROSS
NERN CO INTO ADJACENT PARTS OF SWRN NEB...WITH MORE ISOLATED
CONVECTION DEVELOPING IN CHERRY COUNTY NEB. STRONG BOUNDARY-LAYER
HEATING OWING TO SFC TEMPS IN THE MIDDLE 90S TO AROUND 100 DEGREES
-- OUTSIDE OF ONGOING CONVECTION AND ASSOCIATED COLD POOLS/THETA-E
DEFICITS -- IS SUPPORTING 250-500 J/KG OF MLCAPE PER MODIFIED 12Z
DENVER RAOB. DESPITE SFC DEWPOINTS IN THE 40S TO LOWER 50S
CONTRIBUTING TO ONLY MARGINAL BUOYANCY...SFC TEMPERATURE-DEWPOINT
SPREADS AROUND 50F AND DCAPE VALUES IN EXCESS OF 1300 J/KG MAY
PROMOTE MICROBURSTS WITH STRONG TO PERHAPS MARGINALLY SVR WIND
GUSTS.

WITH THE REGION LYING TO THE SOUTH OF A BELT OF ENHANCED MID-LEVEL
WSWLYS/RELATIVELY STRONGER DEEP SHEAR...STORMS WILL LARGELY EXHIBIT
PULSE TO OCCASIONALLY MULTICELLULAR CHARACTERISTICS. GIVEN THE WEAK
VERTICAL SHEAR AND LARGE SFC TEMPERATURE-DEWPOINT SPREADS...STORMS
WILL LIKELY BECOME QUICKLY UNDERCUT BY OUTFLOW FOLLOWING INITIAL
STORM DEVELOPMENT. GIVEN THE BRIEF/DISORGANIZED NATURE OF ANY SVR
THREAT...A WW IS NOT NEEDED.

..COHEN/HART.. 07/02/2012

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

ATTN...WFO...LBF...GLD...BOU...CYS...

LAT...LON   41670327 42680200 42950149 42880102 42490065 41660107
            40710206 40040283 39440390 39960482 41670327

Nearby

Mesoscale Discussions in Nebraska, 2012Mesoscale Discussions in Colorado, 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.