Alert archive / Colorado / Mesoscale Discussions in 2021
Mesoscale Discussion 1519
The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2021, 5:40 PM MDT for 14 counties in Colorado; Albany County, Laramie County, Platte County, Wyoming. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2021, 5:40 PM MDT (23:40 UTC)
- Expired
- Aug 13, 2021, 7:45 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Lake County, CO, Larimer County, CO, Park County, CO, Summit County, CO, Teller County, CO, Albany County, WY, Laramie County, WY, Platte County, WY
The radar
The Cheyenne radar (KCYS), 92 km from the middle of the area, began a volume at 23:40 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
Denver, CO (KDNR), launched 12:00Z, 11.7 hours before the alert went out and 228 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
- 18 J/kg
- Mixed-layer CIN
- -415 J/kg
- Mixed-layer LCL
- 1285 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- -31 m²/s²
- 0-3 km storm-relative helicity
- 13 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
096
ACUS11 KWNS 132340
SWOMCD
SPC MCD 132340
COZ000-WYZ000-140145-
Mesoscale Discussion 1519
NWS Storm Prediction Center Norman OK
0640 PM CDT Fri Aug 13 2021
Areas affected...southeast Wyoming and north-central Colorado
Concerning...Severe potential...Watch unlikely
Valid 132340Z - 140145Z
Probability of Watch Issuance...5 percent
SUMMARY...Thunderstorms will be possible this afternoon and evening,
primarily along the front range. Marginal hail and gusty winds will
be possible, but the overall coverage should preclude the need for a
watch.
DISCUSSION...Scattered thunderstorms may continue to develop this
afternoon and evening within a moist-upslope regime. Presently,
thunderstorms appear confined to the terrain and have shown little
propensity to move into the high Plains. Given the northerly flow on
the northeast side of the western anticyclone, this trend is likely
to continue.
Despite most-unstable CAPE up to 2000 J/kg, and effective-layer
shear of 30-40 knots, warm mid-level temperatures and neutral to
slightly rising mid-level heights will likely limit overall
convective intensity. Marginal hail and gusty thunderstorm outflows
will be possible with the strongest storms, but the overall lack of
organization and coverage should preclude any need for a watch.
..Marsh/Goss.. 08/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PUB...BOU...CYS...RIW...GJT...
LAT...LON 39770656 41470642 42290629 42710607 42830536 41840446
40110447 39170462 38720544 38750649 39770656Nearby
Mesoscale Discussions in Colorado, 2021Mesoscale Discussions in Wyoming, 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.