Alert archive / South Dakota / Mesoscale Discussions in 2012
Mesoscale Discussion 917
The Storm Prediction Center issued this mesoscale discussion at May 26, 2012, 8:07 PM MDT for Cherry County, Keya Paha County, Nebraska; 11 counties in South Dakota. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- May 26, 2012, 8:07 PM MDT (02:07 UTC)
- Expired
- May 26, 2012, 9:00 PM MDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
Counties Cherry County, NE, Keya Paha County, NE, Bennett County, SD, Brule County, SD, Buffalo County, SD, Hughes County, SD, Jackson County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Todd County, SD, Tripp County, SD
The radar
The North Platte radar (KLNX), 135 km from the middle of the area, began a volume at 02:08 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
N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 2.1 hours before the alert went out and 226 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
- 624 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 3705 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 65 m²/s²
- 0-3 km storm-relative helicity
- 105 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
118 ACUS11 KWNS 270208 SWOMCD SPC MCD 270207 SDZ000-NEZ000-270300- MESOSCALE DISCUSSION 0917 NWS STORM PREDICTION CENTER NORMAN OK 0907 PM CDT SAT MAY 26 2012 AREAS AFFECTED...NRN NEB INTO SD CONCERNING...SEVERE THUNDERSTORM WATCH 302... VALID 270207Z - 270300Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 302 CONTINUES. SUMMARY...SEVERE THREAT IS BECOMING INCREASINGLY MARGINAL OVER THE REMAINING PARTS OF WW 302 IN NRN NEB. WW IS SCHEDULED TO EXPIRE AT 03Z. THE PRIMARY ZONE OF ADDITIONAL STORM DEVELOPMENT IS EXPECTED TO REMAIN IN SD WHERE SOME HAIL REMAINS POSSIBLE...BUT THREAT APPEARS TOO MARGINAL FOR ANOTHER WW ISSUANCE AT THIS TIME. DISCUSSION...ISENTROPIC ASCENT ASSOCIATED WITH THE STRENGTHENING SLY LLJ WILL CONTINUE TO PROMOTE THE DEVELOPMENT OF ELEVATED STORMS NORTH OF WARM FRONT FROM EXTREME NRN NEB INTO SD THIS EVENING WITH PRIMARY ZONE OF DEVELOPMENT EXPECTED IN SD. HOWEVER...STORMS ARE ELEVATED ABOVE A STABLE BOUNDARY LAYER AND LIKELY ROOTED BETWEEN 800-700 MB BASED ON BOTH 00Z OBSERVED AND POINT FORECAST SOUNDINGS. GIVEN THE STEEP LAPSE RATE ENVIRONMENT AND 1000-1500 J/KG MUCAPE...STORMS MAY REMAIN CAPABLE OF PRODUCING AT LEAST MARGINALLY SEVERE HAIL. HOWEVER...EFFECTIVE SHEAR IS MODEST AND STORMS WILL LIKELY PERSIST AS POORLY ORGANIZED MULTICELLS. ..DIAL.. 05/27/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FSD...ABR...LBF...UNR... LAT...LON 42729957 42360104 42340225 44400137 44409824 42729957
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 27, 1:58 PM MDT | Mesoscale Discussion | SPC | Adams, Antelope, Boone, Buffalo, Burt, Butler and 42 more | 62 min |
| May 27, 2:42 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Antelope, Boone, Buffalo, Burt, Butler and 39 more | 8 hr |
| May 27, 5:55 PM MDT | Mesoscale Discussion | SPC | Adams, Antelope, Boone, Buffalo, Burt, Butler and 30 more | 2 hr |
| May 26, 10:57 PM MDT | Mesoscale Discussion | SPC | Marshall | 93 min |
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.