Alert archive / Wyoming / Mesoscale Discussions in 2021
Mesoscale Discussion 629
The Storm Prediction Center issued this mesoscale discussion at May 15, 2021, 6:41 PM MDT for Banner County, Kimball County, Scotts Bluff County, Nebraska; 7 counties in Wyoming. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 15, 2021, 6:41 PM MDT (00:41 UTC)
- Expired
- May 15, 2021, 8:45 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Banner County, NE, Kimball County, NE, Scotts Bluff County, NE, Albany County, WY, Carbon County, WY, Converse County, WY, Goshen County, WY, Laramie County, WY, Natrona County, WY, Platte County, WY
The radar
The Cheyenne radar (KCYS), 121 km from the middle of the area, began a volume at 00:51 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
Riverton, WY (KRIW), launched 00:00Z, 0.7 hours before the alert went out and 246 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
- 100 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 1412 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -16 m²/s²
- 0-3 km storm-relative helicity
- 133 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted.
522
ACUS11 KWNS 160041
SWOMCD
SPC MCD 160041
NEZ000-WYZ000-160245-
Mesoscale Discussion 0629
NWS Storm Prediction Center Norman OK
0741 PM CDT Sat May 15 2021
Areas affected...Southeast Wyoming and far Western Nebraska
Concerning...Severe potential...Watch unlikely
Valid 160041Z - 160245Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated severe hail/damaging wind threat possible, watch
issuance unlikely.
DISCUSSION...Regional radar/satellite shows scattered convection
with fairly robust updrafts moving into south-central portions of
Wyoming. The ambient environment remains weakly unstable (MUCAPE
500-1000 J/kg) amid moderate deep-layer shear (35-40 kt effective
bulk shear). This activity may pose a risk for isolated severe hail
and damaging wind gusts for the next few hours.
As this activity traverses eastward off the high terrain it will
encounter richer low-level moisture, where 50 F dew point
temperatures are currently analyzed across portions of southeast
Wyoming. Should storms hold together, some intensification of the
activity can be expected. Given the ambient shear profile, storms
may congeal into more a linear mode (as suggested by recent HRRR
runs), perhaps maintaining a damaging wind threat later this
evening.
..Karstens/Grams.. 05/16/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CYS...RIW...
LAT...LON 41070470 41060670 41680803 41800876 42540901 42890840
43060629 42920461 42560408 42090349 41250329 41030370
41070470SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 6:12 PM MDT | Mesoscale Discussion | SPC | Arthur, Chase, Deuel, Garden, Hayes, Keith and 3 more | 63 min |
| May 16, 4:11 PM MDT | Mesoscale Discussion | SPC | Dundy | 94 min |
Nearby
Mesoscale Discussions in Wyoming, 2021Mesoscale Discussions in Nebraska, 2021Every mesoscale discussion in 2021
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.