Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 166

February 28, 201212 counties in Minnesota; 12 counties in North Dakota; 26 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2012, 2:43 PM CST for 12 counties in Minnesota; 12 counties in North Dakota; 26 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Feb 28, 2012, 2:43 PM CST (20:43 UTC)
Expired: Feb 28, 2012, 7:15 PM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 50 counties

Becker County, MN, Clay County, MN, Crow Wing County, MN, Douglas County, MN, Grant County, MN, Morrison County, MN, Otter Tail County, MN, Stevens County, MN, Todd County, MN, Traverse County, MN, Wadena County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Dickey County, ND, Emmons County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Sioux County, ND, Stutsman County, ND, Brown County, SD, Campbell County, SD, Corson County, SD, Day County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Meade County, SD, Mellette County, SD, Perkins County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Aberdeen radar (KABR), 43 km from the middle of the area, began a volume at 20:44 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, 8.7 hours before the alert went out and 51 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 954 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 276 m²/s²
0-3 km storm-relative helicity: 401 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

666 
ACUS11 KWNS 282043
SWOMCD
SPC MCD 282043 
MNZ000-SDZ000-NDZ000-290115-

MESOSCALE DISCUSSION 0166
NWS STORM PREDICTION CENTER NORMAN OK
0243 PM CST TUE FEB 28 2012

AREAS AFFECTED...S-CNTRL/SERN ND...CNTRL/NRN SD...CNTRL/W-CNTRL MN

CONCERNING...HEAVY SNOW 

VALID 282043Z - 290115Z

HEAVY SNOW WITH RATES OF 1-2 IN/HR WILL DEVELOP AFTER 22Z AND SPREAD
NEWD ACROSS S-CNTRL/SERN ND...CNTRL/NRN SD...AND CNTRL/W-CNTRL MN
AND CONTINUE THROUGH THE EVENING. POCKETS OF NEAR-BLIZZARD
CONDITIONS WILL BE POSSIBLE.

SFC PRESSURE FALLS OF 2-4 MB PER 2 HRS FROM SWRN NEB NEWD INTO NRN
IA AND SRN MN ARE BEING DRIVEN BY STRENGTHENING DCVA IN ASSOCIATION
WITH A STRONG MID-LEVEL LOW/SHORTWAVE TROUGH APPROACHING FROM THE
ROCKIES AND WAA WITHIN THE WARM CONVEYOR BELT EAST OF THE TROUGH.
THESE PRESSURE FALLS WILL ALLOW FOR THE CONTINUED STRENGTHENING AND
NEWD MOTION OF A SFC LOW CURRENTLY OVER SWRN NEB. IN
RESPONSE...LOW-TO-MID LEVEL FRONTOGENESIS WILL INTENSIFY IN A ZONE
FROM CNTRL MN WWD INVOF AND SOUTH OF THE ND/SD BORDER. ASCENT IN
ASSOCIATION WITH THE FRONTOGENETIC CIRCULATION...DCVA...AND
WAA...WILL ALLOW ONE OR MORE BANDS OF HEAVY SNOW TO DEVELOP AND
SPREAD NEWD TO THE NW OF THE SFC LOW TRACK AND CONTINUE THROUGH THE
EVENING. SUFFICIENT ASCENT AND MODEST MID-LEVEL LAPSE RATES THROUGH
A NEARLY 50-MB DEEP DENDRITIC GROWTH ZONE WILL SUPPORT SNOWFALL
RATES OF 1-2 IN/HR...HIGHEST NEAR ANY EMBEDDED ELEVATED CONVECTIVE
ELEMENTS /WITH AN ISOLATED LIGHTNING STRIKE OR TWO ALSO POSSIBLE/.
FURTHERMORE...THE TIGHTENING SFC PRESSURE GRADIENT WILL ALLOW
SUSTAINED WINDS TO INCREASE TO 20-30 MPH OVER THE NWRN SEMICIRCLE OF
THE SFC LOW...WITH GUSTS OCCASIONALLY REACHING 35 MPH. THIS WILL
YIELD CONSIDERABLE BLOWING/DRIFTING SNOW ALONG WITH POCKETS OF
NEAR-BLIZZARD CONDITIONS.

..COHEN.. 02/28/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DLH...MPX...FGF...ABR...BIS...UNR...

LAT...LON   44789862 43699959 43430053 43440170 44000269 44580292
            45780258 46780018 47189777 46989540 46399336 45899389
            45509620 44789862

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 28, 6:18 AM CST	Mesoscale Discussion	SPC	Jackson, Nobles, Rock	5 hr
Feb 28, 11:43 AM CST	Mesoscale Discussion	SPC	Big Stone, Brown, Carver, Chippewa, Cottonwood, Jackson and 21 more	5 hr
Feb 28, 2:40 PM CST	Mesoscale Discussion	SPC	Anoka, Benton, Carver, Chisago, Dakota, Dodge and 18 more	4 hr

Nearby

Mesoscale Discussions in South Dakota, 2012 Mesoscale Discussions in Minnesota, 2012 Mesoscale Discussions in North Dakota, 2012 Every 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.