Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 1839

August 2, 200413 counties in Nebraska; 11 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 2, 2004, 4:23 PM CDT for 13 counties in Nebraska; 11 counties in South Dakota. It was in force for 37 min.

The area

The outline as issued.

The facts

Issued
Aug 2, 2004, 4:23 PM CDT (21:23 UTC)
Expired
Aug 2, 2004, 5:00 PM CDT
In force
37 min
Issued by
the Storm Prediction Center
All 24 counties

Antelope County, NE, Boyd County, NE, Brown County, NE, Cedar County, NE, Cherry County, NE, Dixon County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Wayne County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Gregory County, SD, Hutchinson County, SD, Mellette County, SD, Todd County, SD, Tripp County, SD, Turner County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 153 km from the middle of the area, began a volume at 21:24 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, 9.4 hours before the alert went out and 229 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 2004-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 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 2004-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
9 J/kg
Mixed-layer CIN
-668 J/kg
Mixed-layer LCL
3509 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
39 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.

191 
ACUS11 KWNS 022124
SWOMCD
SPC MCD 022123 
NEZ000-SDZ000-022200-

MESOSCALE DISCUSSION 1839
NWS STORM PREDICTION CENTER NORMAN OK
0423 PM CDT MON AUG 02 2004

AREAS AFFECTED...PORTIONS OF SRN SD AND NRN NEB

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 022123Z - 022200Z

WW MAY BE REQUIRED SOON FOR PORTIONS OF SRN SD AND NRN NEB.

VIS IMAGERY SHOWED A TOWERING CU OVER KEYA PAHA COUNTY NEB OR 15 NNE
ANW.  THIS CONVECTION IS DEVELOPING ALONG A STATIONARY BOUNDARY THAT
EXTENDED E-W ALONG THE NEB/SD BORDER...WITH THE AIR MASS ALONG AND
EAST OF THIS AREA HAS BECOME VERY TO EXTREMELY UNSTABLE /MLCAPE
VALUES RANGING FROM 2500-4000 J/KG/.  THE TOWERING CU SUGGESTS THE
CAP IS WEAKENING ALONG THIS BOUNDARY AS LARGE SCALE ASCENT SPREADS
EWD ACROSS THIS AREA AHEAD OF A SHORT WAVE TROUGH TOPPING THE RIDGE
OVER ERN WY ATTM.  AS THE SHORT WAVE CONTINUES TO MOVE EWD LATE THIS
AFTERNOON AND EVENING...ADDITIONAL STORMS WILL LIKELY DEVELOP ALONG
THE STATIONARY BOUNDARY.  THE DEGREE OF INSTABILITY AND STRONG DEEP
LAYER SHEAR WILL SUPPORT VERY LARGE HAIL AND ISOLATED TORNADOES.

..PETERS.. 08/02/2004

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

ATTN...WFO...FSD...OAX...ABR...LBF...UNR...

43660149 43700022 43619746 43249685 42339663 41909742
42010033 42320155

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 10:35 PM CDTSevere Thunderstorm WatchSPCAntelope, Boyd, Burt, Cedar, Cuming, Dakota and 9 more5 hr
Aug 2, 3:02 AM CDTMesoscale DiscussionSPCAntelope, Burt, Cedar, Cuming, Dakota, Dixon and 8 more58 min
Aug 2, 4:56 AM CDTMesoscale DiscussionSPCNemaha, Richardson94 min
Aug 2, 4:55 PM CDTSevere Thunderstorm WatchSPCAntelope, Blaine, Boone, Brown, Cedar, Colfax and 15 more5 hr
Aug 1, 7:22 PM CDTMesoscale DiscussionSPCBeadle, Brookings, Brown, Campbell, Clark, Codington and 17 more53 min
Aug 1, 7:45 PM CDTTornado WatchSPCBeadle, Brookings, Brown, Buffalo, Campbell, Clark and 26 more6 hr
Aug 1, 10:00 PM CDTMesoscale DiscussionSPCBeadle, Buffalo, Campbell, Edmunds, Faulk, Hand and 7 more60 min
Aug 1, 11:29 PM CDTMesoscale DiscussionSPCAurora, Beadle, Bon Homme, Brule, Buffalo, Charles Mix and 19 more61 min
Aug 2, 12:20 AM CDTSevere Thunderstorm WatchSPCLake, Lincoln, Minnehaha, Moody, Union4 hr
Aug 2, 3:12 PM CDTMesoscale DiscussionSPCBeadle, Brookings, Clark, Deuel, Hamlin, Jerauld and 7 more2 hr
Aug 2, 3:50 PM CDTSevere Thunderstorm WatchSPCBrookings, Davison, Hanson, Kingsbury, Lake, McCook and 4 more5 hr
Aug 2, 6:30 PM CDTSevere Thunderstorm WatchSPCAurora, Bennett, Bon Homme, Brule, Buffalo, Charles Mix and 17 more6 hr

Nearby

Mesoscale Discussions in Nebraska, 2004Mesoscale Discussions in South Dakota, 2004Every mesoscale discussion in 2004

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.