Alert archive / South Dakota / Mesoscale Discussions in 2003

Mesoscale Discussion 2201

August 20, 200311 counties in North Dakota; 29 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2003, 5:04 PM CDT for 11 counties in North Dakota; 29 counties in South Dakota. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Aug 20, 2003, 5:04 PM CDT (22:04 UTC)
Expired: Aug 20, 2003, 7:00 PM CDT
In force: 116 min
Issued by: the Storm Prediction Center

All 40 counties

Barnes County, ND, Cass County, ND, Dickey County, ND, Foster County, ND, Griggs County, ND, LaMoure County, ND, McIntosh County, ND, Ransom County, ND, Sargent County, ND, Steele County, ND, Stutsman County, ND, Aurora County, SD, Beadle County, SD, Brookings County, SD, Brown County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Deuel County, SD, Douglas County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Marshall County, SD, McCook County, SD, McPherson County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD

The radar

The Aberdeen radar (KABR), 22 km from the middle of the area, began a volume at 22:04 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

Aberdeen, SD (KABR), launched 12:00Z, 10.1 hours before the alert went out and 43 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: 3 J/kg
Mixed-layer CIN: -318 J/kg
Mixed-layer LCL: 1269 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -24 m²/s²
0-3 km storm-relative helicity: -27 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 202205
SWOMCD
SPC MCD 202204 
MNZ000-SDZ000-NDZ000-210000-

MESOSCALE DISCUSSION 2201
NWS STORM PREDICTION CENTER NORMAN OK
0504 PM CDT WED AUG 20 2003

AREAS AFFECTED...ERN ND / ERN SD

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 202204Z - 210000Z

CONVECTIVE TRENDS ARE BEING MONITORED AND IF TSTMS CAN BEGIN
DEVELOPING SWD INTO SD A WW MAY BE REQUIRED.

21Z MESOANALYSIS SHOWED SURFACE COLD FRONT EXTENDING FROM W OF DVL
SWD INTO N-CNTRL SD /W OF ABR/ AND THEN SWWD TO E OF PIR. REGIONAL
RADAR MOSAIC INDICATES TSTMS TRYING TO BECOME ESTABLISHED AHEAD OF
THIS FRONT FROM TOWNER COUNTY ND SWD INTO MCPHERSON/EDMUNDS COUNTIES
IN N-CNTRL SD. STRONG DIABATIC HEATING AHEAD OF THIS BOUNDARY
COUPLED WITH STEEP LOW/MID-LEVEL LAPSE RATES IS RESULTING IN A
MODERATELY UNSTABLE AIRMASS WITH MLCAPES OF 1000-1500 J/KG. WHILE
THE WARM SECTOR ACROSS ERN ND IS RELATIVELY NARROW AS A RESULT OF
RAIN-COOLED AIRMASS FROM THE RED RIVER EWD INTO NRN MN...A GREATER
ZONAL EXTENT OF UNSTABLE AIR EXISTS ACROSS ERN SD INTO SWRN MN.

AS FORCING FOR ASCENT AHEAD OF SHORTWAVE TROUGH /CURRENTLY OVER
WRN/CNTRL ND PER WATER VAPOR IMAGERY/ CONTINUES TO OVERSPREAD THE
WARM SECTOR...TSTMS MAY TRY TO BUILD SWD ALONG THE FRONT INTO PARTS
OF ERN SD. IF THIS OCCURS...RUC FORECAST SOUNDINGS SUGGEST THAT
DAMAGING WINDS WILL BE QUITE POSSIBLE WITH THE STRONGEST STORMS IN
ADDITION TO ISOLATED LARGE HAIL. IF IT APPEARS THAT THIS SCENARIO IS
BECOMING MORE LIKELY A WW MAY BE REQUIRED ACROSS ERN SD INTO SWRN
MN.

..MEAD.. 08/20/2003

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

ATTN...WFO...FGF...FSD...ABR...BIS...

44199919 46039949 47559927 48089761 45639673 43519661
43049835

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 1:42 PM CDT	Mesoscale Discussion	SPC	Benson, Burleigh, Eddy, Emmons, Foster, Kidder and 10 more	93 min
Aug 19, 7:10 PM CDT	Severe Thunderstorm Watch	SPC	Aurora, Bon Homme, Brule, Charles Mix, Davison, Douglas and 6 more	5 hr

Nearby

Mesoscale Discussions in South Dakota, 2003 Mesoscale Discussions in North Dakota, 2003 Every 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.