Alert archive / South Dakota / Mesoscale Discussions in 2004

Mesoscale Discussion 945

May 27, 20045 counties in Montana; 12 counties in North Dakota; 24 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 27, 2004, 2:18 PM MDT for 5 counties in Montana; 12 counties in North Dakota; 24 counties in South Dakota. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: May 27, 2004, 2:18 PM MDT (20:18 UTC)
Expired: May 27, 2004, 4:15 PM MDT
In force: 117 min
Issued by: the Storm Prediction Center

All 41 counties

Daniels County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Grant County, ND, Hettinger County, ND, McKenzie County, ND, Sioux County, ND, Slope County, ND, Stark County, ND, Williams County, ND, Brule County, SD, Buffalo County, SD, Butte County, SD, Corson County, SD, Dewey County, SD, Gregory County, SD, Haakon County, SD, Harding County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Ziebach County, SD

The radar

The Rapid City radar (KUDX), 163 km from the middle of the area, began a volume at 20:19 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

Rapid City, SD (KUNR), launched 12:00Z, 8.3 hours before the alert went out and 170 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1876 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 54 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.

988 
ACUS11 KWNS 272018
SWOMCD
SPC MCD 272018 
SDZ000-NDZ000-MTZ000-272215-

MESOSCALE DISCUSSION 0945
NWS STORM PREDICTION CENTER NORMAN OK
0318 PM CDT THU MAY 27 2004

AREAS AFFECTED...FAR NERN MT AND THE CENTRAL/WRN DAKOTAS

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 272018Z - 272215Z

SCATTERED THUNDERSTORM ACTIVITY WILL PERSIST INTO THIS EVENING
BEFORE WEAKENING ACROSS THE NRN HIGH PLAINS REGION. THREAT OF
ISOLATED LARGE HAIL AND STRONG DOWNDRAFTS WILL EXIST DURING THE NEXT
SEVERAL HOURS.

SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG A STATIONARY SURFACE
FRONT THAT EXTENDS FROM SERN SD NWWD INTO THE NERN CORNER OF MT. IN
DEEPLY MIXED AIR WEST OF THE BOUNDARY...AIR MASS HAS BECOME
MARGINALLY UNSTABLE WITH TEMPERATURES IN THE 70S AND DEWPOINTS IN
THE 40S. RUC SOUNDINGS INDICATE 850-500MB LAPSE RATES BETWEEN
7.5-8.0 C/KM AND 500MB TEMPERATURE AROUND -18C ACROSS THE WRN
DAKOTAS AND FAR ERN MT...WHICH IS CONTRIBUTING TO MLCAPE OF 500-1000
J/KG. LOW WBZ HEIGHTS IN THIS ENVIRONMENT SUGGEST THE POSSIBILITY OF
LARGE HAIL WITH STRONGER CORES AS CELLS SPREAD ESEWD AT 25-30 KT. IN
ADDITION...SURFACE DEWPOINT DEPRESSIONS OF 30-35F SUGGEST LOCALIZED
DAMAGING WINDS ARE POSSIBLE WITH EVAPORATIVE COOLING POTENTIAL IN
CONVECTIVE DOWNDRAFTS.

ACTIVITY IS LARGELY DRIVEN BY DIURNAL HEATING AND STEEP LOW TO MID
LEVEL LAPSE RATES. THEREFORE...STORMS SHOULD RAPIDLY DIMINISH IN
INTENSITY DURING THE MID-LATE EVENING HOURS.

..BANACOS.. 05/27/2004

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

ATTN...WFO...FSD...ABR...BIS...UNR...BYZ...GGW...

46860458 49010591 48900399 45169980 43219857 43080057
43300280 43930317

Nearby

Mesoscale Discussions in South Dakota, 2004 Mesoscale Discussions in North Dakota, 2004 Mesoscale Discussions in Montana, 2004 Every 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.