Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 2158

December 15, 2012Big Stone County, Lyon County, Yellow Medicine County, Minnesota; 6 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Dec 15, 2012, 4:26 AM CST for Big Stone County, Lyon County, Yellow Medicine County, Minnesota; 6 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Dec 15, 2012, 4:26 AM CST (10:26 UTC)
Expired: Dec 15, 2012, 9:00 AM CST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Big Stone County, MN, Lyon County, MN, Yellow Medicine County, MN, Clark County, SD, Day County, SD, Grant County, SD, Hand County, SD, Roberts County, SD, Spink County, SD

The radar

The Aberdeen radar (KABR), 103 km from the middle of the area, began a volume at 10:26 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 00:00Z, 10.4 hours before the alert went out and 93 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: 1300 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 104 m²/s²
0-3 km storm-relative helicity: 102 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.

011 
ACUS11 KWNS 151027
SWOMCD
SPC MCD 151026
MNZ000-SDZ000-151500-

MESOSCALE DISCUSSION 2158
NWS STORM PREDICTION CENTER NORMAN OK
0426 AM CST SAT DEC 15 2012

AREAS AFFECTED...PARTS OF EAST CENTRAL AND NERN SD INTO A SMALL
PORTION OF SWRN-WEST CENTRAL MN

CONCERNING...FREEZING RAIN

VALID 151026Z - 151500Z

SUMMARY...FREEZING RAIN RATES OF 0.05 INCH PER 3-HOURS CAN BE
EXPECTED IN A 30-40 MILE WIDE CORRIDOR ORIENTED SW-NE IN NERN SD
/FROM HAND COUNTY TO ROBERTS COUNTY/ AND ADJACENT WRN TRAVERSE/BIG
STONE COUNTIES MN.  MEANWHILE...A SMALLER SPATIAL COVERAGE FREEZING
RAIN THREAT EXISTS IN A 25 MILE WIDE CORRIDOR ORIENTED NW-SE FROM
ERN GRANT COUNTY SD TO MML IN SWRN MN...WHERE RATES COULD EXCEED
0.1-0.2 INCH PER 3-HOURS THROUGH 15Z.

DISCUSSION...TRENDS IN OVERNIGHT/EARLY MORNING SURFACE OBSERVATIONS
INDICATED TEMPERATURES REMAINING BELOW 32 F...GENERALLY W-N OF A
LINE FROM 9V9 /CHAMBERLAIN SD/ TO HON TO ATY.  ALTHOUGH MOST SURFACE
TEMPERATURES IN CENTRAL AND SRN MN WERE ABOVE 32 F...A SMALL
CORRIDOR EXTENDING FROM MML TO WRN PARTS OF YELLOW MEDICINE/LAC QUI
PARLE COUNTIES MN TO THE MN/SD BORDER AT GRANT COUNTY SD HAD
TEMPERATURES REMAINING IN THE MID-UPPER 20S.  REGIONAL RADAR IMAGERY
SUGGESTED A NW-SE DEFORMATION ZONE WAS DEVELOPING IN THE
AFOREMENTIONED SW-NE ORIENTED CORRIDOR IN NERN SD.  GIVEN THIS
REGION IS EXPECTED TO REMAIN ON THE NWRN EXTENT OF LOW LEVEL
MOISTURE INFLOW AS THE SURFACE LOW TRACKS NEWD INTO WEST CENTRAL IA
BETWEEN 15-18Z...PRECIPITATION RATES SHOULD TEND TO BE LESS THAN
LOCATIONS FARTHER EAST IN MN.

MEANWHILE...REGIONAL RADAR/SURFACE OBSERVATIONS INDICATED HIGHER
REFLECTIVITY AND RAINFALL RATES...RESPECTIVELY OCCURRING IN NWRN IA
/0.1 TO 0.3 INCH PER HR IN THE 09-10Z OBSERVATIONS/.  A BAND OF
CONVECTIVE SHOWERS EXTENDING FROM FAR NWRN IA INTO SWRN MN WILL
CONTINUE TO SHIFT NWWD REACHING LYON COUNTY BY 12Z AND THE REST OF
THE SWRN-WEST CENTRAL MN SUB-FREEZING SURFACE TEMPERATURES BETWEEN
12-15Z.  ALTHOUGH TEMPERATURES MAY WARM A FEW DEGREES IN THIS
REGION...MODELS SUGGEST FREEZING RAIN SHOULD BE THE PREDOMINANT
PRECIPITATION-TYPE THROUGH 15Z...WITH RATES EXCEEDING 0.1 INCH IN
1-3 HOURS.

..PETERS.. 12/15/2012

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

ATTN...WFO...MPX...FSD...ABR...

LAT...LON   45839683 45899655 45509643 44999619 44579562 44339579
            44649625 45089685 45009733 44389842 44219893 44419935
            44809919 45479792 45889730 45839683

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 15, 9:24 AM CST	Mesoscale Discussion	SPC	Hubbard, Itasca	4 hr

Nearby

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