Alert archive / South Dakota / Mesoscale Discussions in 2012
Mesoscale Discussion 1629
The Storm Prediction Center issued this mesoscale discussion at Jul 27, 2012, 6:52 PM MDT for 11 counties in South Dakota. It was in force for 83 min.
The area
The outline as issued.
The facts
- Issued
- Jul 27, 2012, 6:52 PM MDT (00:52 UTC)
- Expired
- Jul 27, 2012, 8:15 PM MDT
- In force
- 83 min
- Issued by
- the Storm Prediction Center
Counties Bennett County, SD, Haakon County, SD, Hughes County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Oglala Lakota County, SD, Stanley County, SD, Todd County, SD, Tripp County, SD
The radar
The Rapid City radar (KUDX), 97 km from the middle of the area, began a volume at 00:55 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 00:00Z, 0.9 hours before the alert went out and 100 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
- 3177 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- -50 m²/s²
- 0-3 km storm-relative helicity
- 175 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
427
ACUS11 KWNS 280052
SWOMCD
SPC MCD 280052
SDZ000-280215-
MESOSCALE DISCUSSION 1629
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT FRI JUL 27 2012
AREAS AFFECTED...WESTERN/CENTRAL SD
CONCERNING...SEVERE THUNDERSTORM WATCH 533...
VALID 280052Z - 280215Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 533
CONTINUES.
SUMMARY...SEVERE TSTM WATCH 533 CONTINUES UNTIL 06Z...WITH DAMAGING
WIND/SOME HAIL POTENTIAL LIKELY TO CONTINUE TO SPREAD EASTWARD
ESPECIALLY ACROSS SOUTHWEST/SOUTH-CENTRAL SD...INCLUDING THE I-90
CORRIDOR/PHILIP AREAS IN THE SHORT-TERM /THROUGH 01Z-02Z/. WILL
MONITOR CONVECTIVE TRENDS FOR THE POSSIBILITY OF AN ADDITIONAL WATCH
ACROSS SOUTH-CENTRAL SD.
DISCUSSION...A 50-MILE NORTH-SOUTH EXTENSIVE QUASI-LINEAR MCS/BOW
ECHO CONTINUES TO STEADILY ADVANCE EAST-NORTHEASTWARD AT AROUND
30-35 KT...CENTERED NEAR I-90 EAST OF THE RAPID CITY AREA AS OF
0030Z. A 54 KT WIND GUST WAS MEASURED AT RAPID CITY AS OF 2353Z.
LOW-LEVEL EASTERLY COMPONENT AHEAD OF THE MCS...COUPLED WITH
MODERATE WESTERLIES ALOFT AS SAMPLED BY THE RAPID CITY WSR-88D
VWP...WILL CONTINUE TO AID IN PERSISTENCE OF A
WELL-ORGANIZED/MODERATE-SPEED MCS OVER THE NEXT FEW HOURS. STEEP
LAPSE RATE ENVIRONMENT AND SHORT-TERM PERSISTENCE OF AMPLE LOW LEVEL
TEMPERATURE-DEWPOINT DIFFERENTIAL WILL REMAIN CONDUCIVE FOR
STRONG/SEVERE WIND DOWNDRAFTS. WHILE THE BOUNDARY LAYER WILL QUICKLY
DECOUPLE INTO MID-EVENING GIVEN ITS RELATIVE DRYNESS...AND
CORRESPONDING MCS INTENSITY MAY BEGIN TO DIMINISH AS INFLOW BECOMES
INCREASINGLY ELEVATED...MCS PERSISTENCE /AT LEAST TO SOME DEGREE/
INTO SOUTH-CENTRAL SD COULD BE AIDED BY INCREASING WARM ADVECTION IN
VICINITY OF ELEVATED WARM FRONTAL ZONE. SHORT-TERM MCS TRENDS WILL
CONTINUE TO BE MONITORED FOR THE POSSIBILITY /40 PERCENT/ OF AN
ADDITIONAL WATCH INTO SOUTH-CENTRAL SD.
..GUYER.. 07/28/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FSD...ABR...UNR...
LAT...LON 43150322 43700277 44200263 44700239 44990138 44469988
43559912 43000035 43150322Nearby
Mesoscale Discussions in South Dakota, 2012Every 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.