Alert archive / South Dakota / Mesoscale Discussions in 2018
Mesoscale Discussion 721
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2018, 10:14 AM MDT for Cherry County, Nebraska; 4 counties in South Dakota. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2018, 10:14 AM MDT (16:14 UTC)
- Expired
- Jun 13, 2018, 11:15 AM MDT
- In force
- 61 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
Counties Cherry County, NE, Bennett County, SD, Jackson County, SD, Mellette County, SD, Todd County, SD
The radar
The North Platte radar (KLNX), 116 km from the middle of the area, began a volume at 16:17 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
Rapid City, SD (KRAP), launched 12:00Z, 4.2 hours before the alert went out and 205 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
- 1512 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 127 m²/s²
- 0-3 km storm-relative helicity
- 200 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
218
ACUS11 KWNS 131615
SWOMCD
SPC MCD 131614
NEZ000-SDZ000-131715-
Mesoscale Discussion 0721
NWS Storm Prediction Center Norman OK
1114 AM CDT Wed Jun 13 2018
Areas affected...northern NE...southern SD
Concerning...Severe potential...Watch unlikely
Valid 131614Z - 131715Z
Probability of Watch Issuance...20 percent
SUMMARY...Large hail associated with elevated thunderstorms may
continue to persist for the next few hours. The limited spatial
extent of the expected threat will likely preclude a severe
thunderstorm watch issuance.
DISCUSSION...Mosaic radar data shows a cluster of thunderstorms
straddling the NE/SD vicinity to the west of the MO River. MRMS
data indicates hail size has ranged from 1-2.5 inches during the
past half hour. This activity is forming within a zone of warm air
advection and is implied by the strongly veering flow per KLNX VAD
data. The residual frontal zone is draped near and west of the area
from southwest NE northward into southwest SD. To the west of the
boundary, a pronounced moist axis is evident in surface
observational data with surface dewpoints in the lower 60s and
lowering into the middle 50s in north-central NE/south-central SD.
A weak mid-level vorticity lobe over eastern WY moving into
southwest SD/northern NE Panhandle may be partly responsible for the
ongoing thunderstorm uptick in coverage. As this feature slowly
moves eastward along the NE/SD border during the early afternoon, it
may continue to support additional elevated thunderstorms. Sporadic
occurrences of large hail may continue for the next few hours.
..Smith/Grams.. 06/13/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...LBF...UNR...
LAT...LON 42510138 43480204 43930122 43880023 42849972 42429995
42320062 42510138SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 5:31 PM MDT | Mesoscale Discussion | SPC | Chase, Dundy | 89 min |
Nearby
Mesoscale Discussions in South Dakota, 2018Mesoscale Discussions in Nebraska, 2018Every mesoscale discussion in 2018
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.