Alert archive / Nebraska / Mesoscale Discussions in 2005

Mesoscale Discussion 993

May 24, 200539 counties in Nebraska; 10 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 24, 2005, 6:13 PM CDT for 39 counties in Nebraska; 10 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 24, 2005, 6:13 PM CDT (23:13 UTC)
Expired: May 24, 2005, 8:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 49 counties

Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Buffalo County, NE, Cedar County, NE, Chase County, NE, Custer County, NE, Dawson County, NE, Dundy County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Garfield County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Harlan County, NE, Hayes County, NE, Hitchcock County, NE, Holt County, NE, Howard County, NE, Kearney County, NE, Keya Paha County, NE, Knox County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, Madison County, NE, Nance County, NE, Phelps County, NE, Pierce County, NE, Red Willow County, NE, Rock County, NE, Sherman County, NE, Thomas County, NE, Valley County, NE, Wheeler County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Gregory County, SD, Hutchinson County, SD, Lincoln County, SD, Tripp County, SD, Turner County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 128 km from the middle of the area, began a volume at 23:12 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, 11.2 hours before the alert went out and 118 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: 249 J/kg
Mixed-layer CIN: -381 J/kg
Mixed-layer LCL: 1549 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: -40 m²/s²
0-3 km storm-relative helicity: -57 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.

000 
ACUS11 KWNS 242313
SWOMCD
SPC MCD 242313 
IAZ000-SDZ000-NEZ000-KSZ000-250115-

MESOSCALE DISCUSSION 0993
NWS STORM PREDICTION CENTER NORMAN OK
0613 PM CDT TUE MAY 24 2005

AREAS AFFECTED...PORTIONS SERN SD...N-CENTRAL/NERN
NEB...CENTRAL/SWRN NEB

CONCERNING...SEVERE THUNDERSTORM WATCH 324...

VALID 242313Z - 250115Z

SFC MESOANALYSIS INDICATES COLD FRONT FROM CHARLES MIX COUNTY SD
SWWD ACROSS ANW AREA THEN BECOMING DIFFUSE SWWD INTO LARGE TSTM
COMPLEX OVER NERN CO.  FRONT SHOULD CONTINUE DRIFTING EWD. 
POTENTIAL FOR TSTM DEVELOPMENT APPEARS TO BE DECREASING ALONG FRONT.
 VIS IMAGERY SHOWS LOW LEVEL BILLOWS OVER AREA...INDICATING BOUNDARY
LAYER AIR MASS REMAINS STABLY STRATIFIED.  ALSO...ANVIL CANOPY FROM
LARGE NERN CO TSTM COMPLEX WILL SPREAD OVER AREA AND SIGNIFICANTLY
INHIBIT FURTHER HEATING ALONG FRONT.  SOME CLEARANCE OF WW MAY BE
NEEDED INVOF FRONT IN NEXT COUPLE HOURS IF THESE TRENDS DO NOT
REVERSE.

PRIMARY CONVECTIVE FOCUS IS EXPECTED TO REMAIN CONVERGENCE LINE --
ANALYZED AT 2230Z FROM UNION COUNTY SD SWWD TO NEAR HDE.  SEVERE
POTENTIAL SHOULD DIMINISH WITH ANY ACTIVITY MOVING MORE THAN 20-30
NM EWD FROM THIS LINE INTO RELATIVELY LOW-THETAE BOUNDARY LAYER. 
MOIST AXIS -- CHARACTERIZED BY LOW 60S F DEW POINTS --ABOUT HALFWAY
BETWEEN CONVECTIVE/CONVERGENCE BOUNDARY AND FRONT.  MOST FAVORABLE
LOW LEVEL INFLOW AND MOISTURE APPEARS TO BE WITH ACTIVITY IN SERN
PORTION WW -- INVOF HDE.  15-20 KT SELYS ARE EVIDENT IN NEARBY UEX
VWP DATA IN THIS AREA...ALONG WITH 1000-1500 J/KG MLCAPES DERIVED
FROM RUC SOUNDINGS.

..EDWARDS.. 05/24/2005

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

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

40009886 39980205 43519989 43539649

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 24, 1:03 PM CDT	Mesoscale Discussion	SPC	Chase, Dundy, Perkins	117 min
May 24, 3:07 PM CDT	Mesoscale Discussion	SPC	Antelope, Blaine, Boone, Boyd, Cedar, Chase and 20 more	53 min
May 24, 3:35 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Blaine, Boone, Boyd, Brown, Buffalo and 33 more	7 hr

Nearby

Mesoscale Discussions in Nebraska, 2005 Mesoscale Discussions in South Dakota, 2005 Every mesoscale discussion in 2005

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.