Alert archive / South Dakota / Mesoscale Discussions in 2012
Mesoscale Discussion 2134
The Storm Prediction Center issued this mesoscale discussion at Dec 8, 2012, 1:43 PM CST for McIntosh County, North Dakota; 21 counties in South Dakota. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 8, 2012, 1:43 PM CST (19:43 UTC)
- Expired
- Dec 8, 2012, 5:45 PM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
All 22 counties
McIntosh County, ND, Aurora County, SD, Beadle County, SD, Brown County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Douglas County, SD, Edmunds County, SD, Faulk County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Jerauld County, SD, Kingsbury County, SD, McPherson County, SD, Miner County, SD, Sanborn County, SD, Spink County, SD, Walworth County, SD
The radar
The Aberdeen radar (KABR), 59 km from the middle of the area, began a volume at 19:42 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, 7.7 hours before the alert went out and 29 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 779 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 70 m²/s²
- 0-3 km storm-relative helicity
- 210 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
269
ACUS11 KWNS 081943
SWOMCD
SPC MCD 081943
SDZ000-NDZ000-082345-
MESOSCALE DISCUSSION 2134
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CST SAT DEC 08 2012
AREAS AFFECTED...N CNTRL/ERN SD...S CNTRL/ERN ND
CONCERNING...HEAVY SNOW
VALID 081943Z - 082345Z
SUMMARY...A TRANSITORY BAND OF HEAVY SNOW WILL PRODUCE LOCALIZED
INCH AN HOUR RATES. CURRENT TRACKING SHOWS THE BAND MOVING 40 MPH
ENEWD...WHICH MAY LIMIT OVERALL DURATIONS OF HEAVY SNOW AS THE BAND
QUICKLY REACHES ERN SD/SERN ND BY 22Z. ADDITIONAL SNOW IS LIKELY
OVERNIGHT.
DISCUSSION...FORMERLY DRY LOW LEVELS ARE BEGINNING TO
SATURATE...IMPLIED VIA INCREASING SURFACE DEW POINT VALUES. RECENT
OBSERVATIONS SHOW A 1-2 DEGREE INCREASE PER HOUR SINCE 16Z. IN THE
INITIAL STAGES OF THE BAND DEVELOPMENT...ONLY VIRGA WAS PRESENT.
HOWEVER...THE 19Z MBG OBSERVATION IS NOW REPORTING HEAVY SNOW AS THE
BAND MOVES OVERHEAD...LENDING FURTHER CREDENCE THAT LOW LEVELS ARE
SATURATED ENOUGH TO SUPPORT INCREASING RATES. A WARM ADVECTION
REGIME NOTED ON AREA VAD WIND PROFILE DATA AS WELL AS A SUBTLE LEAD
UPPER DISTURBANCE SHOULD ENHANCE VERTICAL MOTION ENOUGH TO ALLOW THE
BAND TO CONTINUE TO DEVELOP ENEWD WITH TIME. MODEL FORECASTS ALSO
SUGGEST ADDITIONAL DEVELOPMENT MAY INITIATE ACROSS WRN SD/NEB LATER
THIS AFTERNOON AS A COLD FRONT SURGES EWD INTO THE PLAINS.
..DISPIGNA.. 12/08/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FSD...ABR...BIS...
LAT...LON 46020069 46219920 45889809 45499713 44999690 44459710
43539752 43329818 43569886 44449887 45139990 45660060
46020069SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 8, 9:24 AM CST | Mesoscale Discussion | SPC | Billings, Dunn, Golden Valley, Hettinger, McKenzie, Mercer and 2 more | 4 hr |
| Dec 8, 5:58 PM CST | Mesoscale Discussion | SPC | Ransom, Richland, Sargent | 4 hr |
Nearby
Mesoscale Discussions in South Dakota, 2012Mesoscale Discussions in North Dakota, 2012Every mesoscale discussion in 2012
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.