Alert archive / Minnesota / Mesoscale Discussions in 2012
Mesoscale Discussion 646
The Storm Prediction Center issued this mesoscale discussion at May 1, 2012, 2:30 PM CDT for 4 states. It was in force for 60 min.
The area
The outline as issued.
The facts
- Issued
- May 1, 2012, 2:30 PM CDT (19:30 UTC)
- Expired
- May 1, 2012, 3:30 PM CDT
- In force
- 60 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 78 counties
Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Big Stone County, MN, Blue Earth County, MN, Brown County, MN, Chippewa County, MN, Cottonwood County, MN, Douglas County, MN, Grant County, MN, Jackson County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Pipestone County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Rock County, MN, Sibley County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Traverse County, MN, Watonwan County, MN, Yellow Medicine County, MN, Antelope County, NE, Boyd County, NE, Cedar County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Holt County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Stanton County, NE, Thurston County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Brookings County, SD, Charles Mix County, SD, Clay County, SD, Codington County, SD, Davison County, SD, Deuel County, SD, Douglas County, SD, Grant County, SD, Hamlin County, SD, Hanson County, SD, Hutchinson County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Roberts County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Sioux Falls radar (KFSD), 64 km from the middle of the area, began a volume at 19:34 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, 7.5 hours before the alert went out and 173 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
- 364 J/kg
- Mixed-layer CIN
- -252 J/kg
- Mixed-layer LCL
- 607 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 217 m²/s²
- 0-3 km storm-relative helicity
- 233 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
281
ACUS11 KWNS 011930
SWOMCD
SPC MCD 011930
MNZ000-IAZ000-NEZ000-SDZ000-012030-
MESOSCALE DISCUSSION 0646
NWS STORM PREDICTION CENTER NORMAN OK
0230 PM CDT TUE MAY 01 2012
AREAS AFFECTED...FAR ERN SD...SW MN...NW IA...NE NEB
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 011930Z - 012030Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED DURING THE
NEXT FEW HOURS WITH THE POSSIBILITY OF A FEW SEVERE STORMS CAPABLE
OF PRODUCING HAIL AND STRONG WINDS. PART OR ALL OF THIS AREA WILL
LIKELY NEED A WW BY 21Z.
DISCUSSION...19Z SURFACE ANALYSIS DEPICTS AN AREA OF LOW PRESSURE
OVER N-CNTRL SD WITH A WARM FRONT EXTENDING FROM MBG EWD TO ETH AND
THEN SEWD TO AXA AND A COLD FRONT EXTENDING SWWD TO OGA.
TEMPERATURES HAVE CLIMBED INTO THE MID TO UPPER 70S SOUTH OF THIS
FRONT WITH DEWPOINT VALUES IN THE UPPER 50S TO LOW 60S. AS A
RESULT...AN AXIS OF INSTABILITY EXISTS ACROSS THE DISCUSSION AREA
WITH THE HIGHEST MLCAPE VALUES /AROUND 1000 J/KG/ IN AND AROUND FSD.
CONTINUED HEATING SHOULD ALLOW FOR INCREASED DESTABILIZATION SOUTH
OF THE WARM FRONT WITH CONVECTIVE INITIATION BECOMING MORE LIKELY.
SHEAR PROFILES INDICATE STORM ORGANIZATION IS PROBABLE WITH PRIMARY
THREATS OF SEVERE HAIL AND STRONG WIND GUSTS. FARTHER E /ACROSS
MN/...BACKED LOW-LEVEL FLOW INDICATES AN ENHANCED TORNADO
THREAT...ESPECIALLY ALONG AND JUST AHEAD OF THE ADVANCING WARM
FRONT. HOWEVER...THIS AREA WILL LIKELY REMAIN CAPPED UNTIL AFTER THE
WARM FRONT MOVES THROUGH. AS SUCH...VEERING WINDS ALONG AND BEHIND
THE FRONT SHOULD KEEP THE TORNADO THREAT ISOLATED.
..MOSIER/BUNTING/MEAD.. 05/01/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MPX...DMX...FGF...FSD...OAX...ABR...LBF...
LAT...LON 45839676 46029623 46039553 45699452 44779386 44109366
43299452 42479558 41869650 41549736 42249957 42819911
43529836 44169767 44619739 45549706 45839676SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 1, 2:59 PM CDT | Tornado Watch | SPC | Clay, Dickinson, Lyon, O'Brien, Osceola, Sioux | 6 hr |
| May 1, 4:58 PM CDT | Severe Thunderstorm Watch | SPC | Buena Vista, Cherokee, Ida, Monona, Plymouth, Woodbury | 4 hr |
| May 1, 6:11 PM CDT | Mesoscale Discussion | SPC | Clay, Dickinson, Emmet, Kossuth, Lyon, O'Brien and 3 more | 94 min |
| May 1, 6:10 PM CDT | Tornado Watch | SPC | Anoka, Blue Earth, Brown, Carver, Chisago, Dakota and 16 more | 6 hr |
| May 1, 6:57 PM CDT | Mesoscale Discussion | SPC | Kittson, Lake of the Woods, Marshall, Pennington, Polk, Roseau | 2 hr |
Nearby
Mesoscale Discussions in Minnesota, 2012Mesoscale 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.