Alert archive / North Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 2020

October 3, 201212 counties in Minnesota; 16 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Oct 3, 2012, 11:15 PM CDT for 12 counties in Minnesota; 16 counties in North Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Oct 3, 2012, 11:15 PM CDT (04:15 UTC)
Expired: Oct 4, 2012, 4:15 AM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 28 counties

Becker County, MN, Clay County, MN, Clearwater County, MN, Kittson County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Eddy County, ND, Foster County, ND, Grand Forks County, ND, Griggs County, ND, LaMoure County, ND, Nelson County, ND, Pembina County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Steele County, ND, Stutsman County, ND, Traill County, ND, Walsh County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 20 km from the middle of the area, began a volume at 04:17 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

Bismarck Municip, ND (KBIS), launched 00:00Z, 4.3 hours before the alert went out and 289 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: 487 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 229 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.

556 
ACUS11 KWNS 040415
SWOMCD
SPC MCD 040415 
MNZ000-NDZ000-040915-

MESOSCALE DISCUSSION 2020
NWS STORM PREDICTION CENTER NORMAN OK
1115 PM CDT WED OCT 03 2012

AREAS AFFECTED...ERN ND...NWRN MN

CONCERNING...HEAVY SNOW 

VALID 040415Z - 040915Z

SUMMARY...A BAND OF HEAVY SNOW -- WITH RATES TO 1 IN/HR -- IS
EXPECTED TO DEVELOP AND GRADUALLY SHIFT EWD OVERNIGHT
TONIGHT...LIKELY AFFECTING THE AREA FROM AROUND 07Z THROUGH SUNRISE
THURSDAY MORNING.

DISCUSSION...A LOW-LEVEL BAROCLINIC ZONE...WITH AN ACCOMPANYING SFC
FRONT LYING FROM THE ARROWHEAD OF MN SWWD TO A LOW ALONG THE MN/SD
BORDER...WILL BECOME INCREASINGLY FRONTOGENETIC AS A SHORTWAVE
TROUGH APPROACHES FROM THE WEST. THE FRONTOGENETIC CIRCULATION
COMBINED WITH STRENGTHENING ISENTROPIC ASCENT ALOFT ON THE COLD SIDE
OF THE SFC FRONT -- REF. VERTICALLY VEERING WIND PROFILE PER GRAND
FORKS VWP DATA -- WILL SUPPORT A BAND OF HEAVY PRECIP. COLUMNAR
COOLING RESULTING FROM /1/ ADIABATIC EFFECTS ASSOCIATED WITH ASCENT
ACCOMPANYING THE SHORTWAVE TROUGH...AND /2/ DIABATIC/NOCTURNAL
COOLING...WILL ALLOW SNOW TO BECOME THE DOMINANT PRECIP TYPE FROM
WEST TO EAST THROUGH THE NIGHT. NAM/RAPID REFRESH FORECAST SOUNDINGS
DEPICT AN ELEVATED/BELOW-700-MB ISOTHERMAL LAYER AROUND 100-150 MB
DEEP...SUGGESTING EFFICIENT SNOW AGGREGATION. HEAVY/WET SNOW IS
EXPECTED...AIDED BY MEAGER ELEVATED INSTABILITY PROVIDING SOME
CONVECTIVE ENHANCEMENT. NLY/NNWLY SFC WINDS OF 15-20 KT WITH HIGHER
GUSTS WILL ALSO SUPPORT BLOWING/DRIFTING SNOW.

..COHEN.. 10/04/2012

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

ATTN...WFO...FGF...BIS...

LAT...LON   48999627 48789509 47939504 46999545 46489591 46129665
            46009759 46149843 46799901 47459903 48109880 48769809
            48969747 48999627

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 4, 5:50 AM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Kittson, Lake of the Woods and 7 more	6 hr

Nearby

Mesoscale Discussions in North 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.