Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 2136

December 8, 201216 counties in Minnesota; Ransom County, Richland County, Sargent County, North Dakota; 5 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Dec 8, 2012, 5:58 PM CST for 16 counties in Minnesota; Ransom County, Richland County, Sargent County, North Dakota; 5 counties in South Dakota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Dec 8, 2012, 5:58 PM CST (23:58 UTC)
Expired: Dec 8, 2012, 10:00 PM CST
In force: 4 hr
Issued by: the Storm Prediction Center

All 24 counties

Big Stone County, MN, Chippewa County, MN, Cottonwood County, MN, Grant County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Pipestone County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Stevens County, MN, Swift County, MN, Traverse County, MN, Yellow Medicine County, MN, Ransom County, ND, Richland County, ND, Sargent County, ND, Day County, SD, Deuel County, SD, Grant County, SD, Marshall County, SD, Roberts County, SD

The radar

The Aberdeen radar (KABR), 158 km from the middle of the area, began a volume at 00:04 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, 12.0 hours before the alert went out and 159 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: 779 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 210 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.

659 
ACUS11 KWNS 082358
SWOMCD
SPC MCD 082358 
MNZ000-SDZ000-NDZ000-090400-

MESOSCALE DISCUSSION 2136
NWS STORM PREDICTION CENTER NORMAN OK
0558 PM CST SAT DEC 08 2012

AREAS AFFECTED...SWRN MN...FAR NERN SD...FAR SERN ND

CONCERNING...HEAVY SNOW 

VALID 082358Z - 090400Z

SUMMARY...A BAND OF MODERATE TO HEAVY SNOWFALL IS EXPECTED TO MOVE
NEWD INTO SWRN MN...FAR NERN SD...AND FAR SERN ND DURING THE NEXT
HOUR OR TWO. THIS BAND IS EXPECTED TO PERSIST FOR THE NEXT SEVERAL
HOURS WITH SNOWFALL RATES APPROACHING 1 INCH/HOUR AT TIMES.

DISCUSSION...SURFACE ANALYSIS REVEALS A LOW CENTERED OVER S-CNTRL
SD. RADAR IMAGERY DEPICTS A BAND OF MODERATE TO HEAVY SNOW TO THE
NEWD OF THE SURFACE LOW...EXTENDING FROM PQN NWWD TO ABR. SURFACE
PRESSURE FALLS SUGGEST THE SURFACE LOW WILL CONTINUE EWD WITH AN
ASSOCIATED EWD/NEWD SHIFT OF THE SNOW BAND. ESTIMATED MOTION OF THIS
BAND IS GENERALLY NEWD AT 30 KT. THIS MOVEMENT IS SLOWER THAN
PREVIOUSLY OBSERVED...LIKELY DUE TO THE SLOWER EWD PROGRESSION OF
THE SURFACE LOW. 

FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD BE
ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-LEVEL
FRONTOGENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO PERSIST INTO
SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL RATES ARE
GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT BRIEF/ISOLATED
RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.

..MOSIER.. 12/08/2012

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

ATTN...WFO...MPX...FGF...FSD...ABR...BIS...

LAT...LON   45199734 45709812 46439829 46679787 46629718 46209606
            45799558 44989488 44519463 44099482 43869534 43869608
            44049638 45199734

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 8, 9:24 AM CST	Mesoscale Discussion	SPC	Billings, Dunn, Golden Valley, Hettinger, McKenzie, Mercer and 2 more	4 hr
Dec 8, 1:43 PM CST	Mesoscale Discussion	SPC	McIntosh	4 hr

Nearby

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