Alert archive / Colorado / Mesoscale Discussions in 2020

Mesoscale Discussion 1007

June 26, 202028 counties in Colorado; Cheyenne County, Kimball County, Nebraska; Laramie County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 26, 2020, 12:07 PM MDT for 28 counties in Colorado; Cheyenne County, Kimball County, Nebraska; Laramie County, Wyoming. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Jun 26, 2020, 12:07 PM MDT (18:07 UTC)
Expired
Jun 26, 2020, 2:00 PM MDT
In force
113 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch likely
Chance of a watch
80%
All 31 counties

Adams County, CO, Arapahoe County, CO, Baca County, CO, Bent County, CO, Boulder County, CO, Broomfield County, CO, Cheyenne County, CO, Crowley County, CO, Denver County, CO, Douglas County, CO, El Paso County, CO, Elbert County, CO, Gilpin County, CO, Jefferson County, CO, Kiowa County, CO, Kit Carson County, CO, Larimer County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Otero County, CO, Phillips County, CO, Prowers County, CO, Pueblo County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO, Yuma County, CO, Cheyenne County, NE, Kimball County, NE, Laramie County, WY

The radar

The Denver radar (KFTG), 67 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 6.1 hours before the alert went out and 71 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-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2020-06-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 108 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2020-06-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
108 J/kg
Mixed-layer CIN
-365 J/kg
Mixed-layer LCL
1341 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

868 
ACUS11 KWNS 261807
SWOMCD
SPC MCD 261807 
KSZ000-COZ000-NEZ000-WYZ000-262000-

Mesoscale Discussion 1007
NWS Storm Prediction Center Norman OK
0107 PM CDT Fri Jun 26 2020

Areas affected...much of eastern Colorado...southeast
Wyoming...southwest Nebraska...far western Kansas

Concerning...Severe potential...Watch likely 

Valid 261807Z - 262000Z

Probability of Watch Issuance...80 percent

SUMMARY...Storms are expected to initiate along the Front Range
between 19 and 20Z, with primarily a damaging wind and hail threat
spreading east through evening.

DISCUSSION...Easterly surface winds behind the NE/KS boundary have
maintained 50s F dewpoints along and east of the Front Range, with
strong heating resulting in 1000-1500 J/kg MLCAPE. Light but deep
easterly low-level winds should prove favorable for
forward-propagating storm clusters producing damaging wind gusts
after about 20Z over much of eastern CO. Modest westerlies aloft
atop the surface easterlies will also elongate hodographs enough to
support a few long-lived cores producing large hail. A brief
supercell/weak tornado cannot be ruled out early in the event, prior
to large-scale outflow production.

..Jewell/Thompson.. 06/26/2020

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

ATTN...WFO...LBF...DDC...GLD...PUB...BOU...CYS...

LAT...LON   38870518 39580553 40140569 40510582 40570589 41370576
            41580544 41570458 41350299 41150256 40740218 40260205
            39720206 38290196 37580198 37240213 37050248 37090268
            37500441 37870485 38870518

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 26, 1:12 PM MDTSevere Thunderstorm WatchSPCAdams, Arapahoe, Baca, Bent, Boulder, Broomfield and 24 more10 hr
Jun 26, 3:51 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Crowley, Denver and 17 more84 min
Jun 25, 6:45 PM MDTMesoscale DiscussionSPCBlaine, Brown, Buffalo, Cherry, Custer, Dawson and 18 more60 min
Jun 26, 5:30 PM MDTMesoscale DiscussionSPCCass, Gage, Jefferson, Johnson, Nemaha, Otoe and 2 more90 min

Nearby

Mesoscale Discussions in Colorado, 2020Mesoscale Discussions in Nebraska, 2020Mesoscale Discussions in Wyoming, 2020Every mesoscale discussion in 2020

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.