Alert archive / South Dakota / Mesoscale Discussions in 2013

Mesoscale Discussion 13

January 11, 20135 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jan 11, 2013, 11:08 AM MST for 5 counties in South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jan 11, 2013, 11:08 AM MST (18:08 UTC)
Expired
Jan 11, 2013, 5:15 PM MST
In force
6 hr
Issued by
the Storm Prediction Center

Counties Custer County, SD, Fall River County, SD, Haakon County, SD, Oglala Lakota County, SD, Pennington County, SD

The radar

The Rapid City radar (KUDX), 41 km from the middle of the area, began a volume at 18:10 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

Rapid City, SD (KUNR), launched 12:00Z, 6.1 hours before the alert went out and 39 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-pSkew-T log-p diagram, Rapid City, SD at 12:00Z on 2013-01-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Rapid City, SD at 12:00Z on 2013-01-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 64 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
734 m above ground
0-6 km bulk shear
80 kt
0-1 km storm-relative helicity
64 m²/s²
0-3 km storm-relative helicity
126 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.

939 
ACUS11 KWNS 111808
SWOMCD
SPC MCD 111808 
SDZ000-120015-

MESOSCALE DISCUSSION 0013
NWS STORM PREDICTION CENTER NORMAN OK
1208 PM CST FRI JAN 11 2013

AREAS AFFECTED...SWRN SD

CONCERNING...HEAVY SNOW 

VALID 111808Z - 120015Z

SUMMARY...SNOWFALL RATES AROUND 1 INCH PER HOUR ARE EXPECTED TO
DEVELOP THIS AFTERNOON.

DISCUSSION...WATER VAPOR IMAGERY LATE THIS MORNING SHOWS A VIGOROUS
SHORTWAVE TROUGH MOVING ACROSS THE CNTRL ROCKIES AND AN ATTENDANT
LOBE OF MID LEVEL ASCENT IS FORECAST TO SPREAD NEWD ACROSS ADJACENT
AREAS OF WY/NEB/SD THIS AFTERNOON.  THIS WILL CONTRIBUTE TO AN
INCREASE IN UPWARD VERTICAL MOTION AND SUPPORT A CONCURRENT
INTENSIFICATION OF SNOWFALL RATES AROUND 1 INCH PER HOUR BEGINNING
SHORTLY OR WITHIN THE NEXT 1-2 HRS.  WHEN SNOWFALL RATES ARE
GREATEST...OCCURRING PRIMARILY BEFORE 12/00Z...VISIBILITIES WILL BE
SUBSTANTIALLY REDUCED /AOB 0.5 MI/.  FURTHERMORE...AS THE CYCLONE
DEVELOPS NEWD FROM THE NERN CO TO THE ERN DAKOTAS BY THIS
EVENING...WINDS ARE EXPECTED TO INCREASE THROUGH THE AFTERNOON
--OWING TO AN INCREASED PRESSURE GRADIENT-- AND FACILITATE REDUCED
NEAR-GROUND VISIBILITIES AND EXTENSIVE BLOWING/DRIFTING OF SNOW.

..SMITH.. 01/11/2013

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

ATTN...WFO...ABR...UNR...

LAT...LON   43060395 43890358 44840161 44740111 43980114 43060264
            43060395

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 11, 4:54 PM MSTMesoscale DiscussionSPCCampbell, McPherson6 hr

Nearby

Mesoscale Discussions in South Dakota, 2013Every mesoscale discussion in 2013

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.