Alert archive / Nebraska / Mesoscale Discussions in 2003

Mesoscale Discussion 2134

August 9, 2003Sedgwick County, Colorado; 16 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2003, 1:52 PM MDT for Sedgwick County, Colorado; 16 counties in Nebraska. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Aug 9, 2003, 1:52 PM MDT (19:52 UTC)
Expired
Aug 9, 2003, 3:45 PM MDT
In force
113 min
Issued by
the Storm Prediction Center

Counties Sedgwick County, CO, Arthur County, NE, Box Butte County, NE, Cherry County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, Logan County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Sheridan County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 108 km from the middle of the area, began a volume at 19:56 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 7.9 hours before the alert went out and 154 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 2003-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 73 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 2003-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 square meters per square second.193958Sfc1 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
73 J/kg
Mixed-layer CIN
-344 J/kg
Mixed-layer LCL
1353 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
176 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.3

Open this sounding in Storm Lab

The text

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

947 
ACUS11 KWNS 091952
SWOMCD
SPC MCD 091952 
NEZ000-SDZ000-COZ000-092145-

MESOSCALE DISCUSSION 2134
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SAT AUG 09 2003

AREAS AFFECTED...WRN/CENTRAL NEB...EXTREME NERN CO

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 091952Z - 092145Z

THUNDERSTORMS ARE EXPECTED TO CONTINUE DEVELOPING OVER PARTS OF
WRN/N CNTRL NEB AND AREA IS BEING MONITORED FOR A WW.

ISOLATED HIGH-BASED THUNDERSTORMS ARE DEVELOPING ACROSS PARTS OF THE
NEB PANHANDLE NEAR SURFACE WIND SHIFT LINE EXTENDING FROM WRN CHERRY
COUNTY INTO SCOTTS BLUFF COUNTY.  VERY STEEP LAPSE RATES NEAR 8.5
C/KM COUPLED WITH SURFACE DEW POINTS IN THE LOW 60S SOUTHEAST OF THE
WIND SHIFT LINE ARE RESULTING IN MODERATE INSTABILITY WITH MLCAPE OF
1500-2500 J/KG.  VISIBLE IMAGERY SHOWS CU STREETS BECOMING APPARENT
ACROSS THE SERN PANHANDLE SUGGESTING THE CAP IS WEAKENING AND
ADDITIONAL THUNDERSTORMS MAY DEVELOP OVER THE NEXT 2 HOURS. 
ALTHOUGH WINDS ALOFT ARE RELATIVELY WEAK ATTM /RUC HOURLY ANALYSIS
INDICATES 10-15 KT AT 500 MB/...THE MID LEVEL FLOW IS FORECAST TO
INCREASE TO AROUND 20 KT LATER THIS AFTERNOON WITH AN INCREASE IN
DIRECTIONAL SHEAR WITH HEIGHT AS THE LOW LEVEL FLOW BACKS. 
POTENTIAL FOR SEVERE STORMS IS EXPECTED TO GRADUALLY INCREASE AND
AREA IS BEING MONITORED FOR POSSIBLE WW.

..WEISS.. 08/09/2003

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

ATTN...WFO...LBF...UNR...BOU...CYS...

43040278 43080118 42890014 42430005 41540044 40540160
40680288 41430364 42710318

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 2:35 PM MDTSevere Thunderstorm WatchSPCSedgwick5 hr
Aug 9, 4:15 PM MDTSevere Thunderstorm WatchSPCAntelope, Boone, Boyd, Cedar, Garfield, Greeley and 9 more6 hr

Nearby

Mesoscale Discussions in Nebraska, 2003Mesoscale Discussions in Colorado, 2003Every mesoscale discussion in 2003

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.