Alert archive / South Dakota / Mesoscale Discussions in 2005
Mesoscale Discussion 2178
The Storm Prediction Center issued this mesoscale discussion at Sep 12, 2005, 4:25 PM MDT for Dawes County, Nebraska; 12 counties in South Dakota; Crook County, Wyoming. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 12, 2005, 4:25 PM MDT (22:25 UTC)
- Expired
- Sep 12, 2005, 6:30 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Dawes County, NE, Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Ziebach County, SD, Crook County, WY
The nearest sounding before it
Rapid City, SD (KUNR), launched 12:00Z, 10.4 hours before the alert went out and 4 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
- 1809 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 102 m²/s²
- 0-3 km storm-relative helicity
- 297 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 122226 SWOMCD SPC MCD 122225 NEZ000-SDZ000-MTZ000-WYZ000-130030- MESOSCALE DISCUSSION 2178 NWS STORM PREDICTION CENTER NORMAN OK 0525 PM CDT MON SEP 12 2005 AREAS AFFECTED...FAR NERN WY...WRN SD...AND FAR NWRN NEB CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 122225Z - 130030Z LINE OF THUNDERSTORMS PRODUCING SEVERE WIND GUSTS SHOULD GRADUALLY LESSEN IN INTENSITY DURING THE EVENING HOURS. ALTHOUGH THREAT SHOULD DECREASE...ISOLATED AREAS OF DAMAGING WINDS REMAIN POSSIBLE ACROSS WRN SD AND FAR NWRN NEB THROUGH 01Z. WW IS NOT PRESENTLY ANTICIPATED FOR THIS AREA. FAST MOVING CONVECTIVE LINE...WITH MOTION 240/40-45KT...WILL TRACK FROM NERN WY ACROSS WRN SD AND FAR NWRN NEB DURING THE NEXT 2-3 HOURS. CONVECTION IS BEING SUPPORTED BY A VIGOROUS UPPER TROUGH AND ASSOCIATED DIFFERENTIAL PVA MOVING ENEWD ACROSS CENTRAL WY. DESPITE THIS...CONVECTION IS PROCESSING BEST INSTABILITY AT THE PRESENT TIME...WHERE SURFACE TEMPERATURES WARMED INTO THE LOW TO MID 70S DURING THE PAST FEW HOURS. ACROSS WRN SD/NWRN NEB...COOLER BOUNDARY LAYER AND DEWPOINTS ONLY IN THE LOW 40S SHOULD RESULT IN AN OVERALL WEAKENING TREND OF ONGOING ACTIVITY. GREATEST SEVERE THREAT WILL BE LOCALIZED DAMAGING WINDS GIVEN CONVECTIVE MODE AND SPEED OF MOVEMENT. AS CONVECTION WEAKENS OVERALL...POTENTIAL FOR DOWNWARD MOMENTUM TRANSFER SHOULD LESSEN SUGGESTING THREAT OF SEVERE WINDS WILL GRADUALLY BECOME MORE ISOLATED DURING THE NEXT 2-3 HOURS. ..BANACOS.. 09/12/2005 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LBF...UNR...CYS...BYZ... 42730394 43760446 44720469 45280420 45450355 45570286 45560227 45290164 44630136 43890125 43210125 42830170 42720221 42630304
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 12, 2:40 PM MDT | Tornado Watch | SPC | Boyd | 4 hr |
| Sep 12, 4:31 PM MDT | Mesoscale Discussion | SPC | Adams, Antelope, Boone, Buffalo, Clay, Franklin and 18 more | 59 min |
| Sep 12, 4:55 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Antelope, Boone, Boyd, Buffalo, Clay and 18 more | 4 hr |
| Sep 12, 5:47 PM MDT | Mesoscale Discussion | SPC | Boyd | 88 min |
| Sep 12, 1:27 PM MDT | Mesoscale Discussion | SPC | Aurora, Beadle, Brookings, Brule, Buffalo, Clark and 28 more | 2 hr |
Nearby
Mesoscale Discussions in South Dakota, 2005Mesoscale Discussions in Nebraska, 2005Mesoscale Discussions in Wyoming, 2005Every 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.