Alert archive / Colorado / Mesoscale Discussions in 2023
Mesoscale Discussion 1821
The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2023, 2:13 PM MDT for 11 counties in Colorado; 11 counties in Nebraska; Goshen County, Laramie County, Platte County, Wyoming. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 3, 2023, 2:13 PM MDT (20:13 UTC)
- Expired
- Aug 3, 2023, 4:15 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 25 counties
Adams County, CO, Arapahoe County, CO, Denver County, CO, El Paso County, CO, Elbert County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Goshen County, WY, Laramie County, WY, Platte County, WY
The radar
The Cheyenne radar (KCYS), 96 km from the middle of the area, began a volume at 20:14 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 8.2 hours before the alert went out and 276 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
- 156 J/kg
- Mixed-layer CIN
- -148 J/kg
- Mixed-layer LCL
- 944 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- 63 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
446
ACUS11 KWNS 032013
SWOMCD
SPC MCD 032013
NEZ000-COZ000-WYZ000-032215-
Mesoscale Discussion 1821
NWS Storm Prediction Center Norman OK
0313 PM CDT Thu Aug 03 2023
Areas affected...Southeast Wyoming...Nebraska Panhandle...Northeast
Colorado
Concerning...Severe potential...Watch possible
Valid 032013Z - 032215Z
Probability of Watch Issuance...60 percent
SUMMARY...Initial storm development is occurring from the Front
Range into southeast Wyoming. As storms intensify, large hail and
strong/severe wind gusts will be possible. A watch is possible this
afternoon as convective evolution becomes more clear.
DISCUSSION...The influence of a shortwave trough moving into the
northern Rockies is evident on visible satellite with storms
beginning to develop from the Laramie Range into the Front Range.
Convection from earlier this morning in eastern Colorado and parts
of western/central Nebraska has left some outflow that has been
slower to destabilize despite several hours of heating. Even so,
temperatures are starting to approach the low 80s F with dewpoints
remaining in the low 60s F away from the terrain. Additional storms
are expected to develop through the afternoon both along the terrain
and the Palmer Divide. While deep-layer shear is not overly strong,
particularly with northward extent, modest flow enhancement at mid
levels is contributing to 25-35 kts of shear. The most organized
storms will be capable of large hail. In general, a mixed mode of
marginal supercells and multicell clusters is expected with
potential for a linear segment or two to develop as storms interact.
Strong/severe wind gusts will become the primary threat over time as
this upscale growth occurs.
..Wendt/Thompson.. 08/03/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LBF...GLD...PUB...BOU...CYS...
LAT...LON 41720202 39820259 38560263 38350329 38450414 38680455
39110473 39370480 39900502 40370516 41090535 41630523
42620476 42690474 42980332 42920244 42600228 41720202SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 2, 8:36 PM MDT | Mesoscale Discussion | SPC | Adams, Arapahoe, Crowley, Denver, Douglas, Elbert and 3 more | 84 min |
| Aug 3, 2:57 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Arapahoe, Bent, Cheyenne, Crowley, Elbert and 12 more | 8 hr |
Nearby
Mesoscale Discussions in Colorado, 2023Mesoscale Discussions in Nebraska, 2023Mesoscale Discussions in Wyoming, 2023Every mesoscale discussion in 2023
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.