Alert archive / Colorado / Mesoscale Discussions in 2021

Mesoscale Discussion 949

June 13, 202111 counties in Colorado

The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2021, 12:08 PM MDT for 11 counties in Colorado. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jun 13, 2021, 12:08 PM MDT (18:08 UTC)
Expired: Jun 13, 2021, 1:45 PM MDT
In force: 97 min
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, El Paso County, CO, Fremont County, CO, Gilpin County, CO, Huerfano County, CO, Jefferson County, CO, Teller County, CO

The radar

The Pueblo radar (KPUX), 91 km from the middle of the area, began a volume at 18:10 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, 6.1 hours before the alert went out and 200 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 827 J/kg
Mixed-layer CIN: -387 J/kg
Mixed-layer LCL: 1858 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

283 
ACUS11 KWNS 131809
SWOMCD
SPC MCD 131808 
COZ000-131945-

Mesoscale Discussion 0949
NWS Storm Prediction Center Norman OK
0108 PM CDT Sun Jun 13 2021

Areas affected...central and eastern Colorado

Concerning...Severe potential...Watch unlikely 

Valid 131808Z - 131945Z

Probability of Watch Issuance...5 percent

SUMMARY...A few severe storms may evolve off the higher terrain and
DCVZ early this afternoon. Weak shear should limit organization
potential into a few stronger multi-cell updrafts capable of hail or
isolated damaging wind gusts.

DISCUSSION...Midday visible satellite imagery showed towering
cumulus/incipient updrafts deepening along the Front Range and
Palmer Divide where strong solar heating is taking place.
Temperatures have warmed into the 70s and near 80F with dewpoints
ranging from the upper 40s to the west to near 60 F east of I-25.
While SPC mesoanalysis and RAP soundings indicate substantial MLCINH
(-100 to -300 J/kg) still exists with eastward extent, a narrow
corridor of destabilization (1000-2000 J/kg of MLCAPE) along the
immediate lee of the higher terrain may support a few strong/severe
storms early this afternoon. Aided in part by localized convergence
and orographic influences, MLCINH will gradually erode to the east
allowing storms, and the associated severe risk to expand onto the
high plains with time. Deep-layer shear will remain somewhat
marginal for organized convection at or about 25 kts. This should
favor a multicellular mode with the primary hazards being hail and
isolated damaging wind gusts. Given the expected sporadic nature of
any severe risk, a watch is not likely.

..Lyons/Grams.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PUB...BOU...

LAT...LON   37390512 37970524 38580552 39190572 40410589 40700568
            40590544 39510466 38980445 38540441 38170455 37310479
            37390512

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 12, 6:17 PM MDT	Mesoscale Discussion	SPC	Las Animas	118 min
Jun 13, 4:59 PM MDT	Mesoscale Discussion	SPC	Adams, Arapahoe, Bent, Broomfield, Crowley, Denver and 9 more	2 hr

Nearby

Mesoscale Discussions in Colorado, 2021 Every 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.