Alert archive / Kansas / Mesoscale Discussions in 2017

Mesoscale Discussion 1249

July 6, 2017Cheyenne County, Kit Carson County, Yuma County, Colorado; 9 counties in Kansas; Dundy County, Hitchcock County, Red Willow County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 6, 2017, 5:32 PM MDT for Cheyenne County, Kit Carson County, Yuma County, Colorado; 9 counties in Kansas; Dundy County, Hitchcock County, Red Willow County, Nebraska. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Jul 6, 2017, 5:32 PM MDT (23:32 UTC)
Expired
Jul 6, 2017, 7:30 PM MDT
In force
118 min
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Cheyenne County, CO, Kit Carson County, CO, Yuma County, CO, Cheyenne County, KS, Decatur County, KS, Gove County, KS, Logan County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Dundy County, NE, Hitchcock County, NE, Red Willow County, NE

The radar

The Goodland radar (KGLD), 24 km from the middle of the area, began a volume at 23:35 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 (KDEN), launched 12:00Z, 11.5 hours before the alert went out and 122 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 2017-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 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 2017-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 square meters per square second.1939Sfc1 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
3 J/kg
Mixed-layer CIN
-531 J/kg
Mixed-layer LCL
3285 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

882 
ACUS11 KWNS 062333
SWOMCD
SPC MCD 062332 
KSZ000-NEZ000-COZ000-070130-

Mesoscale Discussion 1249
NWS Storm Prediction Center Norman OK
0632 PM CDT Thu Jul 06 2017

Areas affected...Portions of eastern CO...northwestern KS...and far
southwestern NE

Concerning...Severe potential...Watch unlikely 

Valid 062332Z - 070130Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated damaging winds and perhaps some hail will remain
possible this evening with a cluster of thunderstorms moving slowly
southeastward. Watch issuance is not expected.

DISCUSSION...Thunderstorms that developed this afternoon across
western NE along a weak surface boundary/wind shift have congealed
into a loosely organized cluster across far southwestern NE into
northwestern KS over the past hour. Northwesterly mid-level flow
around 25-30 kt and a strongly veering wind profile are supporting
around 30-35 kt of effective bulk shear and some storm organization.
A very well-mixed boundary layer characterized by 40-50 F surface
temperature-dewpoint spreads will encourage efficient transfer of
convectively enhanced downdraft winds to the surface. Isolated
damaging winds should be the main threat with this multicell cluster
as it moves southeastward across northwestern KS through the
remainder of the evening within a weakly unstable airmass, although
some hail may also occur with the strongest cores. The marginal
thermodynamic and kinematic environment will likely limit a more
robust/widespread severe threat, and watch issuance is not expected.

..Gleason/Thompson.. 07/06/2017

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

ATTN...WFO...DDC...GLD...PUB...BOU...

LAT...LON   39100346 40090279 40300168 40270040 39530011 38780045
            38410228 38530322 39100346

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 5, 9:28 PM MDTMesoscale DiscussionSPCBoyd, Brown, Cedar, Holt, Keya Paha, Knox and 2 more2 hr

Nearby

Mesoscale Discussions in Kansas, 2017Mesoscale Discussions in Colorado, 2017Mesoscale Discussions in Nebraska, 2017Every mesoscale discussion in 2017

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.