Alert archive / South Dakota / Mesoscale Discussions in 2016
Mesoscale Discussion 155
The Storm Prediction Center issued this mesoscale discussion at Feb 29, 2016, 1:06 PM CST for Keya Paha County, Nebraska; 9 counties in South Dakota. It was in force for 24 min.
The area
The outline as issued.
The facts
- Issued
- Feb 29, 2016, 1:06 PM CST (19:06 UTC)
- Expired
- Feb 29, 2016, 1:30 PM CST
- In force
- 24 min
- Issued by
- the Storm Prediction Center
Counties Keya Paha County, NE, Gregory County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Pennington County, SD, Todd County, SD, Tripp County, SD
The radar
The Rapid City radar (KUDX), 140 km from the middle of the area, began a volume at 19:10 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 (KRAP), launched 12:00Z, 7.1 hours before the alert went out and 142 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2339 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- -91 m²/s²
- 0-3 km storm-relative helicity
- -62 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
338
ACUS11 KWNS 291907
SWOMCD
SPC MCD 291906
SDZ000-NEZ000-291930-
MESOSCALE DISCUSSION 0155
NWS STORM PREDICTION CENTER NORMAN OK
0106 PM CST MON FEB 29 2016
AREAS AFFECTED...PORTIONS OF SOUTHERN SOUTH DAKOTA
CONCERNING...HEAVY SNOW
VALID 291906Z - 291930Z
SUMMARY...LOCALIZED REGION OF HEAVY SNOWFALL WITH RATES UP TO 1"/HR
WILL CONTINUE TO MOVE/DEVELOP EAST ACROSS SOUTHERN SOUTH DAKOTA
---INCLUDING THE I-90 CORRIDOR --- THROUGH MID- TO LATE-AFTERNOON
BEFORE WEAKENING IN THE PRESENCE OF INCREASINGLY DRIER LOW-LEVEL
HUMIDITY.
DISCUSSION...NARROW BANDS OF HEAVY SNOW HAVE DEVELOPED WITHIN A
SHIELD OF PRECIPITATION OVER WESTERN SOUTH DAKOTA AHEAD OF AN
AMPLIFYING SHORT-WAVE TROUGH AND ASSOCIATED COLD-FRONT ALOFT.
SURFACE TEMPERATURES HAVE COOLED TO BELOW FREEZING BELOW MOST OF THE
PRECIPITATION SHIELD...TO THE NORTH OF A LINE FROM DEWEY TO
MARTIN...THEN CUTTING SOUTHEASTWARD TO AINSWORTH AND O'NEILL NE. A
MESOSCALE WAVE IS DEVELOPING ALONG THE STRONG LOW-LEVEL BAROCLINIC
ZONE EVIDENT IN RECENT RADAR IMAGERY AND SURFACE ANALYSES...AND THE
LOCALIZED ENHANCEMENT IN WAA WILL AID THE DEVELOPMENT/TRANSLATION OF
THE NARROW HEAVY SNOW BANDS INTO THE MCD AREA. THE LIMITING FACTOR
FOR MORE WIDESPREAD HEAVY SNOW IS THE SUB SATURATED BOUNDARY LAYER
ON THE COOL SIDE OF THE FRONT...BUT THIS WILL BE MITIGATED SOMEWHAT
BY SUBLIMATION OF PRECIPITATION FOR A FEW HOURS AHEAD OF THE MAIN
SNOW BANDS. HOWEVER...LOW RELATIVE HUMIDITY BOUNDARY LAYER AIR WILL
CONTINUE TO ADVECT INTO SOUTHERN AND SOUTHEAST SOUTH DAKOTA. THIS IS
EXPECTED TO CONTRIBUTE TO SNOWFALL RATES MOSTLY DIMINISHING TO UNDER
1"/HR BY LATE AFTERNOON.
..CONIGLIO/GOSS.. 02/29/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FSD...ABR...LBF...UNR...
LAT...LON 44320274 44370133 44260015 43819924 43229882 42789906
42729963 43030061 43400182 43430212 43590270 43710299
44050300 44320274Nearby
Mesoscale Discussions in South Dakota, 2016Mesoscale Discussions in Nebraska, 2016Every mesoscale discussion in 2016
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.