Alert archive / South Dakota / Mesoscale Discussions in 2012
Mesoscale Discussion 1872
The Storm Prediction Center issued this mesoscale discussion at Sep 3, 2012, 3:24 PM CDT for 8 counties in Nebraska; 15 counties in South Dakota. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Sep 3, 2012, 3:24 PM CDT (20:24 UTC)
- Expired
- Sep 3, 2012, 5:00 PM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 23 counties
Blaine County, NE, Boyd County, NE, Brown County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Loup County, NE, Rock County, NE, Aurora County, SD, Bon Homme County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hughes County, SD, Hutchinson County, SD, Hyde County, SD, Jerauld County, SD, Lyman County, SD, Tripp County, SD
The radar
The North Platte radar (KLNX), 190 km from the middle of the area, began a volume at 20:25 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
Aberdeen, SD (KABR), launched 12:00Z, 8.4 hours before the alert went out and 191 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
- 54 J/kg
- Mixed-layer CIN
- -313 J/kg
- Mixed-layer LCL
- 2120 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 21 m²/s²
- 0-3 km storm-relative helicity
- 43 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted, in the capitals the NWS used until 2016.
458
ACUS11 KWNS 032025
SWOMCD
SPC MCD 032024
SDZ000-NEZ000-032200-
MESOSCALE DISCUSSION 1872
NWS STORM PREDICTION CENTER NORMAN OK
0324 PM CDT MON SEP 03 2012
AREAS AFFECTED...CNTRL SD INTO NEB
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 032024Z - 032200Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...STORMS WILL FORM OVER THE NEXT FEW HOURS WITH SEVERE WIND
AND HAIL POSSIBLE.
DISCUSSION...SURFACE ANALYSIS SHOWS LOW PRESSURE NEAR PIR WITH A
COLD FRONT APPROACHING FROM THE NW. AN EXTENSIVE FIELD OF TCU WAS
FORMING SWD FROM THE ACROSS S CNTRL SD AND INTO NEB WHERE LAPSE RATE
PROFILES HAVE BECOME VERY STEEP. WHILE RELATIVELY DRY AIR STILL
EXIST OVER SERN SD AND WRN MN...SELY WINDS WERE HELPING TO MAINTAIN
DEWPOINTS IN THE 50S F JUST SE OF THE LOW...WITH LOWER 60S F FARTHER
SEWD ACROSS NEB WHERE CLOUDS HAVE HAMPERED MIXING.
AMPLE MID TO UPPER LEVEL SHEAR EXISTS TO HELP ORGANIZE STORMS WITH
BOTH WIND AND HAIL LIKELY. WITH THE AFOREMENTIONED DRY AIR ACROSS
ERN SD...THE EWD PROGRESSION OF ANY SEVERE THREAT IS LIKELY TO BE
LIMITED.
..JEWELL/CORFIDI.. 09/03/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FSD...OAX...ABR...LBF...UNR...
LAT...LON 43559755 42919754 42329814 41949886 41729972 41910036
43340041 44160039 44620010 44679956 44259844 43559755SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 3, 4:03 PM CDT | Severe Thunderstorm Watch | SPC | Antelope, Blaine, Boone, Boyd, Brown, Cedar and 12 more | 6 hr |
Nearby
Mesoscale Discussions in South Dakota, 2012Mesoscale Discussions in Nebraska, 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.